Fish and Wildlife Service, Interior.
Final rule.
We, the U.S. Fish and Wildlife Service (Service), determine endangered species status for the Austin blind salamander (
This rule becomes effective September 19, 2013.
This final rule is available on the Internet at
Adam Zerrenner, Field Supervisor, U.S. Fish and Wildlife Service, Austin Ecological Services Field Office, 10711 Burnet Rd., Suite 200, Austin, TX 78758; by telephone 512–490–0057; or by facsimile 512–490–0974. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800–877–8339.
This rule lists the Austin blind salamander as an endangered species and the Jollyville Plateau salamander as a threatened species under the Act.
The Austin blind salamander was included in nine Candidate Notices of Review (67 FR 40657, June 13, 2002; 69 FR 24876, May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756, September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011). The listing priority number has remained at 2 throughout the reviews, indicating that threats to the species were both imminent and high in impact. In addition, on May 11, 2004, the Service received a petition from the Center for Biological Diversity to list 225 species we previously had identified as candidates for listing in accordance with section 4 of the Act, including the Austin blind salamander.
The Jollyville Plateau salamander was petitioned to be listed as an endangered species on June 13, 2005, by Save Our Springs Alliance. Action on this petition was precluded by court orders and settlement agreements for other listing actions until 2006. On February 13, 2007, we published a 90-day petition finding (72 FR 6699) in which we concluded that the petition presented substantial information indicating that listing may be warranted. On December 13, 2007, we published the 12-month finding (72 FR 71040) on the Jollyville Plateau salamander, which concluded that listing was warranted, but precluded by higher priority actions. The Jollyville Plateau salamander was subsequently included in all of our annual Candidate Notices of Review (73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011). Throughout the four reviews, the listing priority number has remained at 8, indicating that threats to the species were imminent, but moderate to low in impact. On September 30, 2010, the Jollyville Plateau salamander was petitioned to be emergency listed by Save Our Springs Alliance and Center for Biological Diversity. We issued a petition response letter to Save Our Springs Alliance and Center for Biological Diversity on December 1, 2011, which stated that emergency listing a species is not a petitionable action under the Administrative Procedure Act or the Act; therefore, we treat a petition requesting emergency listing solely as a petition to list a species under the Act.
On August 22, 2012, we published a proposed rule to list as endangered and designate critical habitat for the Austin blind salamander, Georgetown salamander (
Section 4(b)(6) of the Act and its implementing regulation, 50 CFR 424.17(a), requires that we take one of three actions within 1 year of a proposed listing: (1) Finalize the proposed listing; (2) withdraw the proposed listing; or (3) extend the final determination by not more than 6 months, if scientists knowledgeable about the species substantial disagreement regarding the sufficiency
The public comments we have received indicate substantial disagreement regarding the sufficiency or accuracy of the available data that is relevant to our determination of the proposed listing of the Georgetown and Salado salamanders. Therefore, in consideration of these disagreements, we are publishing a 6-month extension of final determination for the Georgetown and Salado salamanders elsewhere in today's
On the other hand, more research has been conducted, and, therefore, more is known about the life history, population trends, and threats to the Austin blind and Jollyville Plateau salamanders. Although there may be some disagreement among scientists knowledgeable about the Austin blind and Jollyville Plateau salamanders, the disagreement is not substantial enough to extend the final determination for these species. Therefore, this rule constitutes our final determination to list the Austin blind and Jollyville Plateau salamanders as an endangered and threatened species, respectively.
The Austin blind and Jollyville Plateau salamanders are neotenic (do not transform into a terrestrial form) members of the family Plethodontidae. Plethodontid salamanders comprise the largest family of salamanders within the Order Caudata, and are characterized by an absence of lungs (Petranka 1998, pp. 157–158). The Jollyville Plateau salamander has very similar external morphology. Because of this, the Jollyville Plateau salamander was previously believed to be the same species as the Georgetown and Salado salamanders; however, molecular evidence strongly supports that there is a high level of divergence between the three groups (Chippindale
As neotenic salamanders, they retain external feathery gills and inhabit aquatic habitats (springs, spring-runs, wet caves, and groundwater) throughout their lives (Chippindale
Each species inhabits water of high quality with a narrow range of conditions (for example, temperature, pH, and alkalinity) maintained by groundwater from various sources. Both the Austin blind and Jollyville Plateau salamanders depend on water in sufficient quantity and quality to meet their life-history requirements for survival, growth, and reproduction. Much of this water is sourced from the Edwards Aquifer, which is a karst aquifer characterized by open chambers such as caves, fractures, and other cavities that were formed either directly or indirectly by dissolution of subsurface rock formations. Water for the salamanders is provided by infiltration of surface water through the soil or recharge features (caves, faults, fractures, sinkholes, or other open cavities) into the Edwards Aquifer, which discharges from springs as groundwater (Schram 1995, p. 91). In addition, some Jollyville Plateau salamander populations rely on water from other sources. For instance, springs, such as Rieblin Spring, may discharge from the Walnut formation, and some, such as Pit Spring, may discharge from the Glen Rose formation (part of the Trinity Aquifer) (Johns 2012, COA, pers. comm.; Johnson
The Austin blind and Jollyville Plateau salamanders spend varying portions of their life within their surface habitats (the wetted top layer of substrate in or near spring openings and pools as well as spring runs) and subsurface habitats (within caves or other underground areas of the underlying groundwater source). Although surface and subsurface habitats are often discussed separately within this final rule, it is important to note the interconnectedness of these areas. Subsurface habitat does not necessarily refer to an expansive cave underground. Rather, it may be described as the rock matrix below the stream bed. As such, subsurface habitats are impacted by the same threats that impact surface habitat, as the two exist as a continuum (Bendik 2012, COA, pers. comm.).
Salamanders move an unknown depth into interstitial spaces (empty voids between rocks) within the spring or streambed substrate that provide foraging habitat and protection from predators and drought conditions (Cole 1995, p. 24; Pierce and Wall 2011, pp. 16–17). They may also use deeper passages of the aquifer that connect to the spring opening (Dries 2011, COA, pers. comm.). This behavior makes it difficult to accurately estimate population sizes, as only salamanders on the surface can be regularly monitored. However, techniques have been developed for marking individual salamanders, which allows for better estimating population numbers using “mark and recapture” data analysis techniques. These techniques have been used by the City of Austin (COA) on the Jollyville Plateau salamander (Bendik
The habitat of the Austin blind salamander occurs in the Barton Springs Segment of the Edwards Aquifer, while the habitats of the three other species occur in the Northern Segment of the Edwards Aquifer (although some reside in spring locations with different groundwater sources, as explained above). The recharge and contributing zones of these segments of the Edwards Aquifer are found in portions of Travis, Williamson, Blanco, Bell, Burnet, Lampasas, Mills, Hays, Coryell, and Hamilton Counties, Texas (Jones 2003, p. 3; Mahler
A stomach content analysis by the COA demonstrated that the Jollyville Plateau salamander preys on varying proportions of aquatic invertebrates, such as ostracods, copepods, mayfly larvae, fly larvae, snails, water mites, aquatic beetles, and stone fly larvae, depending on the location of the site (Bendik 2011b, pers. comm.). The feces of one wild-caught Austin blind salamander contained amphipods, ostracods, copepods, and plant material (Hillis
The Austin blind and Jollyville Plateau salamanders also share similar predators, which include centrarchid fish (carnivorous freshwater fish belonging to the sunfish family), crayfish (
The detection of juveniles in all seasons suggests that reproduction occur year-round (Bendik 2011a, p. 26; Hillis
More study is needed to determine the nature and extent of the dispersal capabilities of the Austin blind and Jollyville Plateau salamanders. It has been suggested that they may be able to travel some distance through subsurface aquifer conduits. For example, it has been thought that Austin blind salamander can occur underground throughout the entire Barton Springs complex (Dries 2011, COA, pers. comm.). The spring habitats used by salamanders of the Barton Springs complex are not connected on the surface, so the Austin blind salamander population could extend a horizontal distance of at least 984 feet (ft) (300 meters (m)) underground, as this is the approximate distance between the farthest two outlets within the Barton Springs complex known to be occupied by the species. However, a mark-and-recapture study failed to document the movement of endangered Barton Springs salamanders (
Due to the similar life history of the Austin blind salamander to the other three
A population's persistence (ability to survive and avoid extirpation) is influenced by a population's demographic factors (such as survival and reproductive rates) as well as its environment. The population needs of the central Texas salamander species are the factors that provide for a high probability of population persistence over the long term at a given site (for example, low degree of threats and high survival and reproduction rates). We are unaware of detailed studies that describe all of the demographic factors that could affect the population persistence of the Austin blind and Jollyville Plateau salamanders; however, we have assessed their probability of persistence by evaluating environmental factors (threats to their surface habitats) and what we know about the number of salamanders that occur at each site.
To estimate the probability of persistence of each population involves considering the predictable responses of the population to various environmental factors (such as the amount of food available or the presence of a toxic substance), as well as the stochasticity. Stochasticity refers to the random, chance, or probabilistic nature of the demographic and environmental processes (Van Dyke 2008, pp. 217–218). Generally, the larger the population, the more likely it is to survive stochastic events in both demographic and environmental factors (Van Dyke 2008, p. 217). Conversely, the smaller the population, the higher are its chances of extirpation when experiencing this demographic and environmental stochasticity.
We used the conservation principles of redundancy, representation, and resiliency (Shaffer and Stein 2000, pp. 307, 309–310) to better inform our view of what contributes to these species' probability of persistence and how best to conserve them. “Resiliency” is the ability of a species to persist through severe hardships or stochastic events (Tear
A variety of factors contribute to a species' resiliency. These can include how sensitive the species is to disturbances or stressors in its environment, how often they reproduce and how many young they have, how specific or narrow their habitat needs are. A species' resiliency can also be affected by the resiliency of individual populations and the number of populations and their distribution across the landscape. Protecting multiple populations and variation of a species across its range may contribute to its resiliency, especially if some populations or habitats are more susceptible or better adapted to certain threats than others (Service and NOAA 2011, p. 76994). The ability of individuals from populations to disperse and recolonize an area that has been extirpated may also influence their resiliency. As population size and habitat quality increase, the population's ability to persist through periodic hardships also increases.
A minimal level of redundancy is essential for long-term viability (Shaffer and Stein 2000, pp. 307, 309–310; Groves
Representation and the adaptive capabilities (Service and NOAA 2011, p. 76994) of each of the central Texas salamander species should also be conserved. Because a species' genetic makeup is shaped through natural selection by the environments it has experienced (Shaffer and Stein 2000, p. 308), populations should be protected in the array of different environments in which the salamanders occur (surface and subsurface) as a strategy to ensure genetic representation, adaptive capability, and conservation of the species.
To increase the probability of persistence of each species, populations of the Austin blind and Jollyville Plateau salamanders should be conserved in a manner that ensures their variation and representation. This result can be achieved by conserving salamander populations in a diversity of environments (throughout their ranges), including: (1) Both spring and cave locations, (2) habitats with groundwater sources from various aquifers and geologic formations, including the Edwards and Trinity Aquifers and the Edwards, Walnut, and Glen Rose formations, and (3) at sites with different hydrogeological characteristics, including sites where water flows come from artesian pressure, a perched aquifer, or resurgence through alluvial deposits (for example, artesian springs, Edwards and Edwards/Walnut headwater springs, and Bull Creek alluvial resurgence areas).
Information for Austin blind and Jollyville Plateau salamanders is discussed separately for each species in more detail below.
The Austin blind salamander has a pronounced extension of the snout, no external eyes, and weakly developed tail fins. In general appearance and coloration, the Austin blind salamander is more similar to the Texas blind salamander (
The Austin blind salamander occurs in Barton Springs in Austin, Texas. These springs are fed by the Barton Springs Segment of the Edwards Aquifer. This segment covers roughly 155 square miles (mi) (401 square kilometers (km)) from southern Travis County to northern Hays County, Texas (Smith and Hunt 2004, p. 7). It has a storage capacity of more than 300,000 acre-feet of water. The contributing zone for the Barton Springs Segment of the Edwards Aquifer that supplies water to the salamander's spring habitat extends into Travis, Blanco, and Hays Counties, Texas (Ross 2011, p. 3). Under drought conditions, Barton Springs (particularly Sunken Garden/Old Mill Springs) also receives some recharge from the Blanco River (Johnson
The Austin blind salamander is found in three of the four Barton Springs outlets in the COA's Zilker Park, Travis County, Texas: Parthenia (Main) Springs, Eliza Springs, and Sunken Garden (Old Mill or Zenobia) Springs where the Barton Springs salamander also occurs (Dries 2012, p. 4). Parthenia Springs provides water for the Barton Springs Pool, which is operated by the COA as a public swimming pool. These spring sites have been significantly modified for human use. The area around Parthenia Springs was impounded in the late 1920s to create Barton Springs Pool. Flows from Eliza and Sunken Garden Springs are also retained by concrete structures, forming small pools on either side of Barton Springs Pool (COA 1998, p. 6; Service 2005, pp. 1.6–25). The Austin blind salamander has not been observed at the fourth Barton Springs outlet, known as Upper Barton Springs (Hillis
From January 1998 to December 2000, there were only 17 documented observations of the Austin blind salamander. During this same timeframe, 1,518 Barton Springs salamander observations were made (Hillis
Surface-dwelling populations of Jollyville Plateau salamanders have large, well-developed eyes; wide, yellowish heads; blunt, rounded snouts; dark greenish-brown bodies; and bright yellowish-orange tails (Chippindale
The Jollyville Plateau salamander occurs in the Jollyville Plateau and Brushy Creek areas of the Edwards Plateau in northern Travis and southern Williamson Counties, Texas (Chippindale
The Jollyville Plateau salamander's spring-fed habitat is typically characterized by a depth of less than 1 ft (0.3 m) of cool, well oxygenated water (COA 2001, p. 128; Bowles
Some Jollyville Plateau salamander populations have likely experienced decreases in abundance in recent years. Survey data collected by COA staff indicate that four of the nine sites that were regularly monitored by the COA between December 1996 and January 2007 had statistically significant declines in salamander abundance over 10 years (O'Donnell
We requested comments from the public on the proposed designation of critical habitat for the Austin blind salamander and Jollyville Plateau salamanders during two comment periods. The first comment period associated with the publication of the proposed rule (77 FR 50768) opened on August 22, 2012, and closed on October 22, 2012, during which we held public meetings and hearings on September 5 and 6, 2012, in Round Rock and Austin, Texas, respectively. We reopened the comment period on the proposed listing rule from January 25, 2013, to March 11, 2013 (78 FR 5385). We also contacted appropriate Federal, State, and local agencies; scientific organizations; and other interested parties and invited them to comment on the proposed rule and draft economic analysis during these comment periods.
We received a total of approximately 416 comments during the open comment period for the proposed listing, proposed critical habitat, and associated documents. All substantive information provided during the comment periods has been incorporated directly into the final listing rule for the Austin blind and Jollyville Plateau salamanders and is addressed below. Comments from peer reviewers and State agencies are grouped separately below. Comments received are grouped into general issues specifically relating to the proposed listing for each salamander species. Beyond the comments addressed below, several commenters submitted additional reports and references for our consideration, which were reviewed and incorporated into this critical habitat final rule as appropriate.
In accordance with our peer review policy published on July 1, 1994 (59 FR 34270), we solicited expert opinions from 22 knowledgeable individuals with scientific expertise with the hydrology, taxonomy, and ecology that is important to these salamander species. The focus of the taxonomists was to review the proposed rule in light of an unpublished report by Forstner (2012) that questioned the taxonomic validity of the Austin blind, Georgetown, Jollyville Plateau, and Salado salamanders as separate species. We received responses from 13 of the peer reviewers.
During the first comment period we received public comments from SWCA Environmental Consultants (SWCA) and COA that contradicted each other. We also developed new information relative to the listing determination. For these reasons, we conducted a second peer review on: (1) Salamander demographics and (2) urban development and stream habitat. The peer reviewers were provided with the contradictory comments from SWCA and COA. During this second peer review, we solicited expert opinions from knowledgeable individuals with expertise in the two areas identified above, which included all of the peer reviewers from the first comment period except the taxonomists. We received responses from eight peer reviewers. The peer reviewers generally concurred with our methods and conclusions and provided additional information, clarifications, and suggestions to improve the final listing and critical habitat rule. Peer reviewer comments are addressed in the following summary and incorporated into the final rule as appropriate.
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Regarding comments from SWCA on the assessment of threats, peer reviewers made the following comments:
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Section 4(i) of the Act states, “the Secretary shall submit to the State agency a written justification for his failure to adopt regulations consistent with the agency's comments or petition.” Comments received from all State agencies and entities in Texas regarding the proposal to list the Austin blind and Jollyville Plateau salamanders are addressed below.
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With regard to the BCCP specifically, we recognize that the BCCP system offers some water quality benefits to the Jollyville Plateau salamander in portions of the Bull Creek, Brushy Creek, Cypress Creek, and Long Hollow Creek drainages through preservation of open space (Service 1996, pp. 2–28–2–29). Despite the significant conservation measures being achieved by the BCCP and their partners, the potential for groundwater degradation still exists from outside these preserves. For example, eight of the nine COA monitoring sites occupied by the Jollyville Plateau salamander within the BCCP have experienced water quality degradation where pollution sources likely originated upstream and outside of the preserved tracts (O'Donnell
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In regard to transparency, the OMB and Service's peer review guidelines mandate that we not conduct anonymous peer reviews. The guidelines state that we advise reviewers that their reviews, including their names and affiliations, and how we respond to their comments will be included in the official record for review, and, once all the reviews are completed, their reviews will be available to the public. We followed the policies and standards for conducting peer reviews as part of this rulemaking process.
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Further, the Service has relied on other data to support the conclusion that water quality is degrading in the Bull Creek watershed. For example, O'Donnell
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Exactly how much these species depend on surface water is unclear, but the best available information suggests that the productivity of surface habitat is important for individual growth. For example, a recent study showed that Jollyville Plateau salamanders had negative growth in body length and tail width while using subsurface habitat during a drought and that growth did
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Regarding the Hayes (2002) study, we acknowledge that an SAP of the EPA reviewed this information and concluded that atrazine concentrations less than 100 µg/L had no effects on clawed frogs in 2007. However, the 2012 SAP did reexamine the conclusions of the 2007 SAP using a meta-analysis of published studies along with additional studies on more species (EPA 2012, p. 35). The 2012 SAP expressed concern
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The second argument in Forstner (2012) is that the phylogenetic tree does not group all individuals of a given species into the same cluster or lineage. Forstner's (2012) conclusions are overly simplistic. The failure of all sequences of
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On August 22, 2012 (77 FR 50768), we published a proposed rule to list the Jollyville Plateau salamander as endangered. Based on additional information we received during the comment period on the proposed rule and after further analysis of the magnitude and imminence of threats to the species, we are listing the Jollyville Plateau salamander as a threatened species in this final rule. For more detailed information, please see
Section 4 of the Act and its implementing regulations (50 CFR 424) set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. A species may be determined to be an endangered or threatened species due to one or more of the five factors described in section 4(a)(1) of the Act: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these factors is discussed below.
Habitat modification, in the form of degraded water quality and quantity and disturbance of spring sites, is the primary threat to the Austin blind and Jollyville Plateau salamanders. Water quality degradation in salamander habitat has been cited as the top concern in several studies (Chippindale
Threats to the habitat of the Austin blind and Jollyville Plateau salamanders (including those that affect water quality, water quantity, or the physical habitat) may affect only the surface habitat, only the subsurface habitat, or both habitat types. For example, substrate modification degrades the surface springs and spring-runs, but does not impact the subsurface environment, while water quality degradation can impact both the surface and subsurface habitats, depending on whether the degrading elements are moving through groundwater or are running off the ground surface into a spring area (surface watershed). Our assessment of water quality threats from urbanization is largely focused on surface watersheds. Impacts to subsurface areas are also likely to occur from urbanization over recharge zones within the Edwards Aquifer region; however, these impacts are more difficult to assess given the limited information available on subsurface flows and drainage areas that feed into these subsurface flows to the springs and cave locations. These recharge areas are additional pathways for impacts to the Austin blind and Jollyville Plateau salamanders to occur that we are not able to precisely assess at each known salamander site. However, we can consider urbanization and various other sources of impacts to water quality and quantity over the larger recharge zone to the aquifer (as opposed to individual springs) to assess the potential for impacts at salamander sites.
The threats under Factor A will be presented in reference to stressors and sources. We consider a stressor to be a physical, chemical, or biological alteration that can induce an adverse response from an individual salamander. These alterations can act directly on an individual or act indirectly on an individual through impacts to resources the species requires for feeding, breeding, or sheltering. A source is the origin from which the stressor (or alteration) arises. The majority of the discussion below under Factor A focuses on evaluating the nature and extent of stressors and their sources related to urbanization, the primary source of water quality degradation, within the ranges of the Austin blind and Jollyville Plateau salamanders. Additionally, other stressors causing habitat destruction and modification, including water quantity degradation and physical disturbance to surface habitat, will be addressed.
Urbanization is the concentration of human populations into discrete areas, leading to transformation of land for residential, commercial, industrial, and transportation purposes. It is one of the most significant sources of water quality degradation that can affect the future survival of central Texas salamanders (Bowles
The ranges of the Austin blind and Jollyville Plateau salamanders reside within increasingly urbanized areas of Travis and Williamson Counties that are experiencing rapid human population growth. For example, the population of the COA grew from 251,808 people in 1970 to 656,562 people in 2000. By 2007, the population had grown to 735,088 people (COA 2007b, p. 1). This represents a 192 percent increase over the 37-year period. Population projections from the Texas State Data Center (2012, pp. 496–497) estimate that Travis County will increase in population from 1,024,266 in 2010, to 1,990,820 in 2050. This would be a 94 percent increase in the human population size over this 40-year period. The Texas State Data Center also estimates an increase in human population in Williamson County from 422,679 in 2010 to 2,015,294 in 2050, exceeding the size of Travis County. This would represent a 477 percent increase over a 40-year timeframe. All human population projections from the Texas State Data Center presented here are under a high growth scenario, which assumes that migration rates from 2000 to 2010 will continue through 2050 (Texas State Data Center and the Office of the State Demographer 2012, p. 9). By comparison, the national United States' population is expected to increase from 310,233,000 in 2010, to 439, 010,000 in 2050, which is about a 42 percent increase over the 40-year period (U.S. Census Bureau 2008, p. 1). Growing human populations increase demand for residential and commercial development, drinking water supply, wastewater disposal, flood control, and other municipal goods and services that alter the environment, often degrading salamander habitat by changing hydrologic regimes, and affecting the quantity and quality of water resources.
As development increases within the watersheds where the Austin blind and Jollyville Plateau salamanders occur, more opportunities exist for the detrimental effects of urbanization to impact salamander habitat. A comprehensive study by the USGS found that, across the United States, contaminants, habitat destruction, and increasing streamflow flashiness (rapid response of large increases of streamflow to storm events) resulting from urban development have been associated with the disruption of biological communities, particularly the loss of sensitive aquatic species (Coles
Several researchers have also examined the negative impact of urbanization on stream salamander habitat by making connections between salamander abundances and levels of development within the watershed. In 1972, Orser and Shure (p. 1,150) were among the first biologists to show a decrease in stream salamander density with increasing urban development. A similar relationship between salamanders and urbanization was found in North Carolina (Price
The impacts that result from urbanization can affect the physiology of individual salamanders. An unpublished study (Gabor 2012, Texas State University, pers. comm.) has demonstrated that Jollyville Plateau salamanders in disturbed habitats have greater stress levels than those in undisturbed habitats, as determined by measurements of water-borne stress hormones in disturbed (urbanized) and undisturbed streams (Gabor 2012, Texas State University, pers. comm.). Chronic stress can decrease survival of individuals and may lead to a decrease in reproduction. Both of these factors may partially account for the decrease in abundance of salamanders in streams within disturbed environments (Gabor 2012, Texas State University, pers. comm.).
Urbanization occurring within the watersheds of the Austin blind and Jollyville Plateau salamanders could cause irreversible declines or extirpation of salamander populations with continuous exposure over a relatively short time span. We consider this to be an ongoing threat of high impact for the Jollyville Plateau salamander that is expected to increase in the future as development within its range expands.
Impervious cover is another source of water quality degradation and is directly correlated with urbanization (Coles
Both nationally and locally, consistent relationships between impervious cover and water quality degradation through contaminant loading have been documented. In a study of contaminant input from various land use areas in Austin, stormwater runoff loads were found to increase with increasing impervious cover (COA 1990, pp. 12–14). This study also found that contaminant input rates of the more urbanized watersheds were higher than those of the small suburban watersheds. Soeur
Impervious cover has demonstrable impacts on biological communities within streams. Schueler (1994, p. 104) found that sites receiving runoff from high impervious cover drainage areas had sensitive aquatic macroinvertebrate species replaced by species more tolerant of pollution and hydrologic stress (high rate of changes in discharges over short periods of time). An analysis of nine regions across the United States found considerable losses of algal, invertebrate, and fish species in response to stressors brought about by urban development (Coles
We recognize that the long-term survey data of Jollyville Plateau salamanders using simple counts may not give conclusive evidence on the long-term trend of the population at each site. However, based on the threats and evidence from the literature, the declines in counts seen at urban Jollyville Plateau salamander sites are likely real declines in the population. We expect downward trends in salamander populations to continue into the future as human population growth and urbanization drive further declines in habitat quality and quantity.
For this final rule, we calculated impervious cover within the watersheds occupied by the Austin blind and Jollyville Plateau salamanders. In this analysis, we delineated the surface areas that drain into spring sites and which of these sites may be experiencing habitat quality degradation as a result of impervious cover in the surface drainage area. However, we only examined surface drainage areas for each spring site for the Jollyville Plateau salamander because we did not know the recharge area for specific spring or cave sites. This information was available for the Austin blind salamander and the Barton Springs system. Another limitation of this analysis is that we did not account for riparian (stream edge) buffers or stormwater runoff control measures, both of which have the potential to mitigate some of the effects of impervious cover on streams (Schueler
We examined studies that report ecological responses to watershed impervious- cover levels based on a variety of degradation measurements (Service 2013, Table 1, p. 4). Most studies examined biological responses to impervious cover (for example, aquatic invertebrate and fish diversity), but several studies measured chemical and physical responses as well (for example, water quality parameters and stream channel modification). The most commonly reported impervious cover level at which noticeable degradation to aquatic ecosystems begins to occur is approximately 10 percent, with more recent studies reporting levels of 10 percent and lower. Recent studies in the eastern United States have reported large declines in aquatic macroinvertebrates (the prey base of salamanders) at impervious-cover levels as low as 0.5 percent (King and Baker 2010, p. 1002; King
Various levels of impervious cover within watersheds have been cited as having detrimental effects to water quality and biological communities within streams (Schueler
• None: 0 percent impervious cover in the watershed
• Low: Greater than 0 percent to 10 percent impervious cover in the watershed
• Medium: Greater than 10 percent to 20 percent impervious cover in the watershed
• High: Greater than 20 percent impervious cover in the watershed
Sites in the Low category may still be experiencing impacts from urbanization, as cited in studies such as Coles
We estimated impervious cover percentages for each surface drainage area of a spring known to have at least one population of either an Austin blind or Jollyville Plateau salamander (cave locations were omitted). These estimates and maps of the surface drainage area of spring locations are provided in our refined impervious cover analysis (Service 2013, pp. 1–25). A total of 114 watersheds were analyzed, encompassing a total of 543,269 acres (ac) (219,854 hectares (ha)).
The Austin blind salamander had three watersheds delineated, one for each of the springs where the species is found. Eliza and Parthenia Springs had nearly identical large surface drainage areas, while the watershed of Sunken Garden (Old Mill) was found to be a much smaller area. Even though the level of impervious cover was Low in Eliza and Parthenia watersheds, most of the impervious cover occurs within 5 mi (8 km) of the springs.
We also calculated the impervious cover levels for the contributing and recharge zones of the Barton Springs Segment of the Edwards Aquifer. Unlike the known locations for the Jollyville Plateau salamander, the sources of subsurface water feeding the sites of Austin blind salamander (Barton Springs complex) are fairly well-delineated. Barton Springs is the principal discharge point for the Barton Springs Segment of the Edwards Aquifer, and recharge throughout most of the aquifer converges to this discharge point (Slade
For the Jollyville Plateau salamander, a total of 93 watersheds were delineated, representing 106 surface sites. The watersheds varied greatly in size, ranging from the 3-ac (1-ha) watershed of Cistern (Pipe) Spring to the 49,784-ac (20,147-ha) watershed of Brushy Creek Spring. Impervious cover also varied greatly among watersheds. Twelve watersheds had no impervious cover. Eighty-one of the 93 watersheds had some level of impervious cover, with 31 watersheds categorized as High, 26 as Medium, and 21 as Low. The highest level of impervious cover (48 percent) was found in the watershed of Troll Spring.
Based on our analysis of impervious-cover levels in land draining across the surface into salamander surface habitat (Service 2013, pp. 1–25), the Jollyville Plateau salamander had a high proportion of watersheds (47 of 93 analyzed) with medium and high levels of impervious cover. Conversely, the watersheds encompassing the Austin blind salamander were relatively low in impervious cover. No watersheds for the Austin blind salamander were classified as medium or high (that is, greater than 10 percent impervious cover). In addition, the recharge and contributing zones of the Barton Springs segment of the Edwards Aquifer were classified as low.
Although some watersheds in our analysis were classified as low, it is important to note that low levels of impervious cover (that is, less than 10 percent) may degrade salamander habitat. Recent studies in the eastern United States have reported large declines in aquatic macroinvertebrates (the prey base of salamanders) at impervious cover levels as low as 0.5 percent (King and Baker 2010, p. 1002; King
Although general percentages of impervious cover within a watershed are helpful in determining the general level of impervious cover within watersheds, it does not tell the complete story of how urbanization may be affecting salamanders or their habitat. Understanding how a salamander might be affected by water quality degradation within its habitat requires an examination of where the impervious cover occurs and what other threats to water quality (for example, non-point-source runoff, highways and other sources of hazardous materials, livestock and feral hogs, and gravel and limestone mining) are present within the watershed.
In addition, several studies have demonstrated that the spatial arrangement of impervious cover has impacts on aquatic ecosystems. An analysis of 42 watersheds in the State of Washington found that certain urban pattern variables, such as land use intensity, land cover composition, landscape configuration, and connectivity of the impervious area are important in predicting effects to aquatic ecosystems (Alberti
One major limitation of this analysis is that we only examined surface drainage areas (watersheds) for each spring site for the Jollyville Plateau salamander. In addition to the surface habitat, this salamander uses the subsurface habitat. Moreover, the base flow of water discharging from the springs on the surface comes from groundwater sources, which are in turn replenished by recharge features on the surface. As Shade
Impervious cover by itself within the watersheds of the Austin blind and Jollyville Plateau salamanders could cause irreversible declines or extirpation of populations with continuous exposure to water quality degradation stressors over a relatively short timespan. Given the current levels of impervious cover within the surface watersheds for the Jollyville Plateau salamander, we consider this to be a threat of high impact for this species that is expected to increase in the future as development within its range expands. Although the impervious cover level for the Austin blind salamander remains relatively low at the present time, impacts from this threat could increase in the future as urbanization expands.
The Edwards Aquifer is at risk from a variety of sources of contaminants and pollutants (Ross 2011, p. 4), including hazardous materials that have the potential to be spilled or leaked, resulting in contamination of both surface and groundwater resources (Service 2005, pp. 1.6–14–1.6–15). For example, a number of point-sources of pollutants exist within the Jollyville Plateau salamander's range. Utility structures such as storage tanks or pipelines (particularly gas and sewer lines) can accidentally discharge. Any activity that involves the extraction, storage, manufacture, or transport of potentially hazardous substances, such as fuels or chemicals, can contaminate water resources and cause harm to aquatic life. Spill events can involve a short release with immediate impacts, such as a collision that involves a tanker truck carrying gasoline. Alternatively, the release can be long term, involving the slow release of chemicals over time, such as a leaking underground storage tank.
A peer reviewer for the proposed rule provided information from the National Response Center's database of incidents of chemical and hazardous materials spills (
Hazardous material spills pose a significant threat to the Austin blind and Jollyville Plateau salamanders, and impacts from spills could increase substantially under drought conditions due to lower dilution and buffering capability of impacted water bodies. Spills under low flow conditions are predicted to have an impact at much smaller volumes (Turner and O'Donnell 2004, p. 26). For example, it is predicted that at low flows (10 cubic feet per second (cfs)) a spill of 360 gallons (1,362.7 liters) of gasoline 3 mi (4.8 km) from Barton Springs could be catastrophic for the Austin blind salamander population (Turner and O'Donnell 2004, p. 26).
A significant hazardous materials spill within stream drainages of the Austin blind salamander could have the potential to threaten its long-term survival and sustainability of multiple populations or possibly the entire species. Because the Austin blind salamander resides in only one spring system, a catastrophic spill in its surface and subsurface habitat could cause the extinction of this species in the wild. However, because the Jollyville Plateau salamander occurs in 106 surface and 16 cave populations over a broad range, the potential for a catastrophic hazardous materials spill to cause the extinction of this species in the wild is highly unlikely. Even so, a hazardous materials spill has the potential to cause localized Jollyville Plateau salamander populations to be extirpated. In combination with the other threats identified in this final rule, a catastrophic hazardous materials spill could contribute to the Jollyville Plateau salamanders' risk of extinction by reducing its overall probability of persistence. Furthermore, we consider hazardous material spills to be a potential significant threat to the Austin blind salamanders due to their limited distributions, the number of potential sources, and the amount of damage that could be done by a single event.
The risk of hazardous material spills from underground storage tanks is widespread in Texas and is expected to increase as urbanization continues to occur. As of 1996, more than 6,000 leaking underground storage tanks in Texas had resulted in contaminated groundwater (Mace
Leaking underground storage tanks have been documented as a problem within the Jollyville Plateau salamander's range (COA 2001, p. 16). The threat of water quality degradation from an underground storage tank could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with only one exposure event. This is considered to be an ongoing threat of high impact to the Jollyville Plateau salamander. Although we are unaware of any information that indicates underground storage tanks have resulted in spills within the vicinity of Austin blind salamander sites, they are likely present within the watersheds that recharge Barton Springs given its urbanized environment. We expect this to become a more significant
The transport of hazardous materials is common on many highways, which are major transportation routes (Thompson
Interstate Highway 35 crosses the watersheds that contribute groundwater to spring sites occupied by the Austin blind and Jollyville Plateau salamanders. A catastrophic spill could occur if a transport truck overturned and its contents entered the recharge zone of the Northern or Barton Springs Segments of the Edwards Aquifer. Transportation accidents involving hazardous materials spills at bridge crossings are of particular concern because recharge areas in creek beds can transport contaminants directly into the aquifer (Service 2005, pp. 1.6–14). The threat of water quality degradation from highways could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with only one exposure event. We consider this to be an ongoing threat to the Austin blind and Jollyville Plateau salamanders.
Energy pipelines are another source of potential hazardous material spills. They carry crude oil and refined products made from crude oil, such as gasoline, home heating oil, diesel fuel, and kerosene. Liquefied ethylene, propane, butane, and some petrochemicals are also transported through energy pipelines (U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 2013, p. 1). Austin blind salamander habitat is at risk from hazardous material spills that could contaminate groundwater. There is potential for a catastrophic spill in the Barton Springs Segment of the Edwards Aquifer, due to the presence of the Longhorn pipeline (Turner and O'Donnell 2004, pp. 2–3). Although a number of mitigation measures were employed to reduce the risk of a leak or spill from the Longhorn pipeline, such a spill could enter the aquifer and result in the contamination of salamander habitat at Barton Springs (EPA 2000, pp. 9–29–9–30).
A contaminant spill could travel quickly through the aquifer to Barton Springs, where it could impact Austin blind salamander populations. Depending on water levels in the aquifer, groundwater flow rates through the Barton Springs Segment of the Edwards Aquifer can range from 0.6 mi (1 km) per day to over 4 mi (6 km) per day. The relatively rapid movement of groundwater under any flow conditions provides little time for mitigation efforts to reduce potential damage from a hazardous spill anywhere within the Barton Springs Segment of the Edwards Aquifer (Turner and O'Donnell 2004, pp. 11–13).
The threat of water quality degradation from energy pipelines could by itself cause irreversible declines, extirpation, or significant declines in habitat quality of the Austin blind salamander with only one exposure event. Because the Austin blind salamander is found only at one location and can be extirpated by one catastrophic energy pipeline leak, we consider this to be an ongoing threat of high impact that will likely continue in the future. However, we are unaware of any information that indicates energy pipelines are located within the range of the Jollyville Plateau salamander and, therefore, do not consider this to be a threat for this species at this time.
Multiple municipality water lines also run through the surrounding areas of Barton Springs. A water line break could potentially flow directly into Barton Springs, exposing salamanders to chlorine concentrations that are potentially toxic (Herrington and Turner 2009, pp. 5, 6). Sewage spills are the most common type of spill within the Barton Springs watershed and represent a potential catastrophic threat (Turner and O'Donnell 2004, p. 27). Sewage spills often include contaminants such as nutrients, polycyclic aromatic hydrocarbons (PAHs), metals, pesticides, pharmaceuticals, and high levels of fecal coliform bacteria. Increased ammonia levels and reduced dissolved oxygen are the most likely impacts of a sewage spill that could cause rapid mortality of large numbers of salamanders (Turner and O'Donnell 2004, p. 27). Fecal coliform bacteria cause diseases in salamanders and their prey base (Turner and O'Donnell 2004, p. 27). Approximately 7,600 wastewater main pipelines totaling 349 mi (561.6 km) are present in the Barton Springs Segment of the Edwards Aquifer (Herrington
Sewage spills from pipelines also have been documented in watersheds supporting Jollyville Plateau salamander populations (COA 2001, pp. 16, 21, 74). For example, in 2007, a sewage line overflowed an estimated 50,000 gallons (190,000 liters) of raw sewage into the Stillhouse Hollow drainage area of Bull Creek (COA 2007c, pp. 1–3). Because the location of the spill was a short distance downstream of currently known salamander locations, no salamanders were thought to be affected.
The threat of water quality degradation from water and sewage lines could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with only one exposure event. We consider this to be an ongoing threat of high impact to the Austin blind and Jollyville Plateau salamanders that is likely to increase in the future as urbanization expands within the ranges of these species.
If water from swimming pools is drained into waterways or storm drains without dechlorination, impacts to
Water quality degradation from swimming pools in combination with other impacts could contribute to significant declines in habitat quality. Although swimming pools occur throughout the range of the Jollyville Plateau salamander, using 2012 Google Earth aerial images we identified only two sites for this species (Krienke Spring and Long Hog Hollow Tributary) with swimming pools located within 50 m (164 ft). We did not identify any other swimming pools within 50 m (164 ft) of any other salamander site. Therefore, we do not consider this to be an ongoing threat to the Austin blind or Jollyville Plateau salamanders at this time.
Short-term increases in pollutants, particularly sediments, can occur during construction in areas of new development. When vegetation is removed and rain falls on unprotected soils, large discharges of suspended sediments can erode from newly exposed areas resulting in increased sedimentation in downstream drainage channels (Schueler 1987, pp. 1–4; Turner 2003, p. 24; O'Donnell
Cave sites are also impacted by construction, as Testudo Tube Cave (Jollyville Plateau salamander habitat) showed an increase in nickel, calcium, nitrates, and nitrites after nearby road construction (Richter 2009, pp. 6–7). Barton Springs (Austin blind salamander habitat) is also under the threat of pollutant loading due to its proximity to construction activities and the spring's location at the downstream side of the watershed (COA 1997, p. 237). The COA (1995, pp. 3–11) estimated that construction-related sediment and in-channel erosion accounted for approximately 80 percent of the average annual sediment load in the Barton Springs watershed. In addition, the COA (1995, pp. 3–10) estimated that total suspended sediment loads have increased 270 percent over predevelopment loadings within the Barton Springs Segment of the Edwards Aquifer. Construction is intermittent and temporary, but it affects both surface and subsurface habitats. Therefore, we have determined that this threat is ongoing and will continue to affect the Austin blind and Jollyville Plateau salamanders and their habitats.
Also, the physical construction of pipelines, shafts, wells, and similar structures that penetrate the subsurface has the potential to negatively affect subsurface habitat for salamander species. It is known that these salamanders inhabit the subsurface environment and that water flows through the subsurface to the surface habitat. Tunneling for underground pipelines can destroy potential habitat by removing subsurface material, thereby destroying subsurface spaces/conduits in which salamanders can live, grow, forage, and reproduce. Additional material can become dislodged and result in increased sediment loading into the aquifer and associated spring systems. In addition, disruption of water flow to springs inhabited by salamanders can occur through the construction of tunnels and vertical shafts to access them. Because of the complexity of the aquifer and subsurface structure and because detailed maps of the underground conduits that feed springs in the Edwards Aquifer are not available, tunnels and shafts have the possibility of intercepting and severing those conduits (COA 2010b, p. 28). Affected springs could rapidly become dry and would not support salamander populations. The closer a shaft or tunnel location is to a spring, the more likely that the construction will impact a spring (COA 2010b, p. 28). Even small shafts pose a threat to nearby spring systems. We consider subsurface construction to be a threat to the surface and subsurface habitat of the Austin blind and Jollyville Plateau salamanders.
Examples of recent subsurface construction activities that had the potential to pose a threat to salamander surface and subsurface habitat are the Water Treatment Plant No. 4 pipeline and shaft construction and the Barton Springs Pool bypass tunnel repairs. In 2011, construction began on the Jollyville Transmission Main (JTM), a tunnel designed to transport treated drinking water from Water Treatment Plant No. 4 to the Jollyville Reservoir. The project also includes four working shafts along the tunnel route (COA 2010b, p. 1) that provide access points from the surface down to the tunnel. While this type of project has the potential to impact salamanders and their habitat, the COA took the salamanders into consideration and designed measures to avoid or minimize impacts. Because the tunnel is being constructed below the Edwards Aquifer and below the permeable portion of the Glen Rose formation (COA 2010b, p. 42; Toohey 2011, p. 1; COA 2011c, pp. 36, 46), the threat to the salamander from this particular tunnel is considered low.
Of the four Water Treatment Plant No. 4 shafts, only the one at the Four Points location appeared to be a potential threat to any Jollyville Plateau salamanders. However, construction on this shaft is now completed, and there have been no observed impacts to any springs or other downstream Jollyville Plateau habitat (COA 2012, pers. comm.). Within 1 mi (1.6 km) of the Four Points shaft location are 8 of 92 known Jollyville Plateau salamander sites. The closest locations (Spring 21 and Spring 24) are about 2,000 ft (610 m) or greater from the shaft. Best management practices designed to protect groundwater resources have been implemented into the design and construction of the Jollyville Transmission Main shafts. These practices include, but are not limited to: monitoring groundwater quality and spring flow, minimizing sediment discharges during construction, developing a groundwater impact contingency plan, locating working shafts in areas where the chance of encountering conduits to salamander springs is reduced, relocating the treatment plant from its original location near Jollyville Plateau salamander sites to within an area that has no known Jollyville Plateau salamander sites, dedicating 102 ac (41 ha) that was originally purchased for the Water Treatment Plant No. 4 project as conservation land in perpetuity as part of the Balcones Canyonlands Preserve system, creating contingency plans for unexpectedly high groundwater inflow to the shafts during their construction, and rerouting conduit flow paths around the shaft if encountered (COA 2010b, pp. 51–55).
In 2012, the COA began construction in Barton Springs Pool to repair and stabilize a bypass tunnel that allows both normal flow from Barton Creek and frequent small floods to bypass the swimming area to protect water quality within the pool. This project had the potential to affect both Barton Springs and Austin blind salamanders by directly injuring individuals found within the construction area, drying out areas of habitat during pool drawdowns, and subjecting them to potentially harmful chemicals and sediment (Service 2011, p. 27). However, the COA took the Barton Springs and Austin blind salamanders into careful consideration when planning this project and ultimately implemented a variety of protective measures to minimize threats to these species. Some
The threat of water quality degradation from construction activities could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with only one exposure event (if subsurface flows were interrupted or severed) or with repeated exposure over a relatively short timespan. From information available in our files and provided to us during the peer review and public comment period for the proposed rule, we found that all of the Austin blind salamander sites have been known to have had construction on their perimeters. Likewise, we are aware of physical habitat modification from construction activities at one of the known Jollyville Plateau surface sites. Therefore, we consider construction activities to be an ongoing threat of medium impact to the Austin blind salamander and low impact to Jollyville Plateau salamanders given their low exposure risk.
Construction activities within rock quarries can permanently alter the geology and groundwater hydrology of the immediate area and adversely affect springs that are hydrologically connected to impacted sites (Ekmekci 1990, p. 4; van Beynan and Townsend 2005, p. 104; Humphreys 2011, p. 295). Limestone rock is an important raw material that is mined in quarries all over the world due to its popularity as a building material and its use in the manufacture of cement (Vermeulen and Whitten 1999, p. 1). The potential environmental impacts of quarries include destruction of springs or collapse of karst caverns, as well as impacts to water quality through siltation and sedimentation, and impacts to water quantity through water diversion, dewatering, and reduced flows (Ekmekci 1990, p. 4; van Beynan and Townsend 2005, p. 104). The mobilization of fine materials from quarries can lead to the occlusion of voids and the smothering of surface habitats for aquatic species downstream (Humphreys 2011, p. 295). Quarry activities can also generate pollution in the aquatic ecosystem through leaks or spills of waste materials from mining operations (such as petroleum products) (Humphreys 2011, p. 295). For example, in 2000, a spill of almost 3,000 gallons (11,356 liters) of diesel from an above-ground storage tank occurred on a limestone quarry in New Braunfels, Texas (about 4.5-mi (7.2 km) from Comal Springs in the Southern Segment of the Edwards Aquifer) (Ross
Quarrying of limestone is another activity that has considerable potential to negatively affect the physical environments where salamanders are known to occur. Quarrying and mineral extractions are known to cause the downstream mobilization of sediment (Humphreys 2011, p. 295), which can occlude the interstitial spaces that salamanders use for protective cover. Quarrying can alter landforms, reduce spring discharge, cause drawdown of the water table, produce sinkholes, and destroy caves (van Beynen and Townsend 2005, p. 104). As quarries continue to expand, the risk of impacting salamander habitat increases. One quarry occurs in one of the surface watersheds (Brushy Creek Spring) where Jollyville Plateau salamanders are known to occur. This assessment was based on examining Google Earth 2012 aerial photos of each site from the surface drainage basins (surface watersheds) of each surface site. There may be additional avenues of potential impacts to the springs or cave sites through subsurface drainage basins that were not documented through this analysis.
The threat of physical modification of surface habitat from quarrying by itself could cause irreversible declines in population sizes or habitat quality at any of the Austin blind or Jollyville Plateau salamander sites. It could also work in combination with other threats to contribute to significant declines of salamander populations or habitat quality. Currently quarries are located in the surface watersheds of 1 of the 106 assessed Jollyville Plateau salamander surface sites. Therefore, we consider this an ongoing threat of low impact given the low exposure risk to the Jollyville Plateau salamander that could increase in the future. Physical modification of surface habitat from quarries is not considered an ongoing threat to the Austin blind salamander at this time. The Austin blind salamander's range is located in downtown Austin, and there are no active limestone quarries within the species' range or in its surface watershed.
Contaminants and pollutants are stressors that can affect individual salamanders or their habitats or their prey. These stressors find their way into aquatic habitat through a variety of ways, including stormwater runoff, point (a single identifiable source) and non-point (coming from many diffuse sources) discharges, and hazardous material spills (Coles
Amphibians, especially their eggs and larvae (which are usually restricted to a small area within an aquatic environment), are sensitive to many different aquatic pollutants (Harfenist
Polycyclic aromatic hydrocarbons (PAHs) are a common form of aquatic contaminants in urbanized areas that could affect salamanders, their habitat, or their prey. This form of pollution can originate from petroleum products, such as oil or grease, or from atmospheric deposition as a byproduct of combustion (for example, vehicular combustion). These pollutants accumulate over time on impervious cover, contaminating water supplies through urban and highway runoff (Van Metre
Petroleum and petroleum byproducts can adversely affect living organisms by causing direct toxic action, altering water chemistry, reducing light, and decreasing food availability (Albers 2003, p. 349). Exposure to PAHs at levels found within the Jollyville Plateau salamander's range can cause impaired reproduction, reduced growth and development, and tumors or cancer in species of amphibians, reptiles, and other organisms (Albers 2003, p. 354). Coal tar pavement sealant slowed hatching, growth, and development of a frog (
Limited sampling by the COA has detected PAHs at concentrations of concern at multiple sites within the range of the Jollyville Plateau salamander. Most notable were the levels of nine different PAH compounds at the Spicewood Springs site in the Shoal Creek drainage area, which were above concentrations known to adversely affect aquatic organisms (O'Donnell
The threat of water quality degradation from PAH exposure could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with continuous or repeated exposure. In some instances, exposure to PAH contamination could negatively impact a salamander population in combination with exposure to other sources of water quality degradation, resulting in significant habitat declines or other significant negative impacts (such as loss of invertebrate prey species). We consider this to be a threat of high impact to the Austin blind and Jollyville Plateau salamanders now and in the future as urbanization increases within these species' surface watersheds.
Pesticides (including herbicides and insecticides) are also associated with urban areas. Sources of pesticides include lawns, road rights-of-way, and managed turf areas, such as golf courses, parks, and ballfields. Pesticide application is also common in residential, recreational, and agricultural areas. Pesticides have the potential to leach into groundwater through the soil or be washed into streams by stormwater runoff.
Some of the most widely used pesticides in the United States—atrazine, carbaryl, diazinon, and simazine (Mahler and Van Metre 2000, p. 1)—were documented within the Austin blind salamander's habitat (Barton Springs Pool and Eliza Springs) in water samples taken at Barton Springs during and after a 2-day storm event (Mahler and Van Metre 2000, pp. 1, 6, 8). They were found at levels below criteria set in the aquatic life protection section of the Texas Surface Water Quality Standards (Mahler and Van Metre 2000, p. 4). In addition, elevated concentrations of organochlorine pesticides were found in Barton Springs sediments (Ingersoll
Another study by the USGS detected insecticides (diazinon and malathion) and herbicides (atrazine, prometone, and simazine) in several Austin-area streams, most often at sites with urban and partly urban watersheds (Veenhuis and Slade 1990, pp. 45–47). Twenty-two of the 42 selected synthetic organic compounds analyzed in this study were detected more often and in larger concentrations at sites with more urban watersheds compared to undeveloped watersheds (Veenhuis and Slade 1990, p. 61). Other pesticides (dichlorodiphenyltrichloroethane, chlordane, hexachlorobenzene, and dieldrin) have been detected at multiple Jollyville Plateau salamander sites (COA 2001, p. 130).
While pesticides have been detected at Austin blind salamander and Jollyville Plateau salamander sites, we do not know the extent to which pesticides and other waterborne contaminants have affected salamander survival, development, and reproduction, or their prey. However, pesticides are known to impact amphibian species in a number of ways. For example, Reylea (2009, p. 370) demonstrated that diazinon reduces growth and development in larval amphibians. Another pesticide, carbaryl, causes mortality and deformities in larval streamside salamanders (
We acknowledge that in 2007 a Scientific Advisory Panel (SAP) of the Environmental Protection Agency (EPA) reviewed the available information on atrazine effects on amphibians and concluded that atrazine concentrations less than 100 μg/L had no effects on clawed frogs. However, the 2012 SAP is currently reexamining the conclusions of the 2007 SAP using a meta-analysis of published studies along with additional studies on more species (EPA 2012, p. 35). The 2012 SAP expressed concern that some studies were discounted in the 2007 SAP analysis, including studies like Hayes (2002) that indicated that atrazine is linked to endocrine (hormone) disruption in amphibians (EPA 2012, p. 35). In addition, the 2007 SAP noted that their results on clawed frogs are insufficient to make global conclusions about the effects of atrazine on all amphibian species (EPA 2012, p. 33). Accordingly, the 2012 SAP has recommended further testing on at least three amphibian species before a conclusion can be reached that atrazine has no effect on amphibians at concentrations less than 100 μg/L (EPA 2012, p. 33). Due to potential differences in species sensitivity, exposure scenarios that may include dozens of chemical stressors simultaneously, and multigenerational effects that are not fully understood, we continue to view pesticides, including carbaryl, atrazine, and many others to which aquatic organisms may be exposed, as a potential threat to water quality, salamander health, and the health of aquatic organisms that comprise the diet of salamanders.
The threat of water quality degradation from pesticide exposure could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with continuous or repeated exposure. In some instances, exposure to pesticide contamination could negatively impact a salamander population in combination with exposure to other sources of water quality degradation, resulting in significant habitat declines or other significant negative impacts (such as loss of invertebrate prey species). We consider this an ongoing threat of high impact for the Austin blind salamander because this species occurs only in one location. For the Jollyville Plateau salamanders, this is currently a threat of low impact that is likely to increase in the future.
Nutrient input (such as phosphorus and nitrogen) to watershed drainages, which often results in abnormally high organic growth in aquatic ecosystems, can originate from multiple sources, such as human and animal wastes, industrial pollutants, and fertilizers (from lawns, golf courses, or croplands) (Garner and Mahler 2007, p. 29). As the human population grows and subsequent urbanization occurs within the ranges of the Austin blind and Jollyville Plateau salamanders, they likely become more susceptible to the effects of excessive nutrients within their habitats because their exposure increases. To illustrate, an estimated 102,262 domestic dogs and cats (pet waste is a potential source of excessive nutrients) were known to occur within the Barton Springs Segment of the Edwards Aquifer in 2010 (Herrington
Various residential properties and golf courses are known to use fertilizers to maintain turf grass within watersheds where Jollyville Plateau salamander populations are known to occur (COA 2003, pp. 1–7). Analysis of water quality attributes conducted by the COA (1997, pp. 8–9) showed significant differences in nitrate, ammonia, total dissolved solids, total suspended solids, and turbidity concentrations between watersheds dominated by golf courses, residential land, and rural land. Golf course tributaries were found to have higher concentrations of these constituents than residential tributaries, and both golf course and residential tributaries had substantially higher concentrations for these five water quality attributes than rural tributaries (COA 1997, pp. 8–9).
Residential irrigation of wastewater effluent is another source leading to excessive nutrient input into the recharge and contributing zones of the Barton Springs Segment of the Edwards Aquifer (Ross 2011, pp. 11–18; Mahler
Excessive nutrient input into aquatic systems can increase plant growth (including algae blooms), which pulls more oxygen out of the water when the dead plant matter decomposes, resulting in less oxygen being available in the water for salamanders to breathe (Schueler 1987, pp. 1.5–1.6; Ross 2011, p. 7). A reduction in dissolved oxygen concentrations could not only affect respiration in salamander species, but also lead to decreased metabolic functioning and growth in juveniles (Woods
Increased nitrate levels have been known to affect amphibians by altering feeding activity and causing disequilibrium and physical abnormalities (Marco
The threat of water quality degradation from excessive nutrient exposure could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with continuous or repeated exposure. At least five surface watersheds of the known Jollyville Plateau salamander's surface sites contain golf courses that could be contributing to excessive nutrient loads. In some instances, exposure to excessive nutrient exposure could negatively impact a salamander population in combination with exposure to other sources of water quality degradation, resulting in significant habitat declines or other significant negative impacts (such as loss of morphological deformities). We consider this an ongoing threat of medium impact for the Austin blind salamander and low impact for the Jollyville Plateau salamanders that will likely increase in the future.
Conductivity is a measure of the ability of water to carry an electrical current and can be used to approximate the concentration of dissolved inorganic solids in water that can alter the internal water balance in aquatic organisms, affecting the Austin blind and Jollyville Plateau salamanders' survival. Conductivity levels in the Edwards Aquifer are naturally low, ranging from approximately 550 to 700 micro Siemens per centimeter (μS cm
Conductivity can be influenced by weather. Rainfall serves to dilute ions and lower conductivity while drought has the opposite effect. The trends of increasing conductivity in urban watersheds were evident under baseflow conditions and during a period when precipitation was above average in all but 3 years, so drought was not a factor (NOAA 2013, pp. 1–7). The COA also monitored water quality as impervious cover increased in several subdivisions with known Jollyville Plateau salamander sites between 1996 and 2007. They found increasing ions (calcium, magnesium, and bicarbonate) and nitrates with increasing impervious cover at four Jollyville Plateau salamander sites and as a general trend during the course of the study from 1997 to 2006 (Herrington
High conductivity has been associated with declining salamander abundance. For example, three of the four sites with statistically significant declining Jollyville Plateau salamander counts from 1997 to 2006 are cited as having high conductivity readings (O'Donnell
The threat of water quality degradation from high conductivity could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with continuous or repeated exposure. In some instances, exposure to high conductivity could negatively impact a salamander population in combination with exposure to other sources of water quality degradation, resulting in significant habitat declines. We consider this an ongoing threat of high impact for the Jollyville Plateau salamander that is likely to increase in the future. Although we are unaware of any information that indicates increased conductivity is occurring within the ranges of the Austin blind salamander, we expect this to become a significant threat in the future for this species as urbanization continues to expand within its surface watersheds.
As groundwater levels decline, a decrease in hydrostatic pressure occurs and saline water is able to move into groundwater flow paths of the aquifer (Pavlicek
This saline water encroachment is detrimental to the freshwater biota in the springs and the aquifer, including the Austin blind and Jollyville Plateau salamanders and their prey. Most amphibian larvae cannot survive saline conditions (Duellman and Trueb 1986, p. 165). Ingersoll
The threat of water quality degradation from saline water encroachments could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with continuous or repeated exposure. In some instances, exposure to saline conditions could negatively impact a salamander population in combination with exposure to other sources of water quality degradation, resulting in significant habitat declines or another significant negative impact (such as loss of prey species). We consider this an ongoing threat of high impact for the Austin blind salamander that will continue in the future. At this time, we are unaware of any information that indicates low saline water encroachment is occurring within the range of the Jollyville Plateau salamander.
In an analysis performed by the COA (Turner 2005a, p. 6), significant changes over time were reported for several chemical constituents and physical parameters in Barton Springs Pool, which could be attributed to impacts from watershed urbanization. Conductivity, turbidity, sulfates, and total organic carbon increased over a 20- to 25-year time period while the concentration of dissolved oxygen decreased (Turner 2005a, pp. 8–17). A similar analysis by Herrington and Hiers (2010, p. 2) examined water quality at Barton Springs Pool and other Barton Springs outlets where Austin blind salamanders are found (Sunken Gardens and Eliza Springs) over a general period of the mid-1990s to the summer of 2009. Herrington and Hiers (2010, pp. 41–42) found that dissolved oxygen decreased over time in the Barton Springs Pool, while conductivity and nitrogen increased. However, this decline in water quality was not seen in Sunken Gardens Spring or Eliza Spring (Herrington 2010, p. 42).
Low dissolved oxygen can affect salamanders and other amphibians by reducing respiratory efficiency, metabolic energy, reproductive rate, and ultimately survival (Norris
The threat of water quality degradation from low dissolved oxygen could by itself cause irreversible declines or extirpation in local populations or significant declines in habitat quality of the Austin blind and Jollyville Plateau salamanders with continuous or repeated exposure. In some instances, exposure to low dissolved oxygen could negatively impact a salamander population in combination with exposure to other sources of water quality degradation, resulting in significant habitat declines. We consider this an ongoing threat of high impact for the Austin blind salamander due to their limited range. However, we consider this to be a threat of low impact to the Jollyville Plateau salamanders given the low risk of exposure.
Water quantity decreases and spring flow declines are considered threats to
Increased urbanization in the watershed has been cited as one factor, particularly in combination with drought that causes declines in spring flows (COA 2006, pp. 46–47; TPWD 2011, pp. 4–5). This is partly due to reductions in baseflow due to impervious cover. Urbanization removes the ability of a watershed to allow slow filtration of water through soils following rain events. Instead rainfall runs off impervious surfaces and into stream channels at higher rates, increasing downstream “flash” flows and decreasing groundwater recharge and subsequent baseflows from springs (Miller
Urbanization can also result in increased groundwater pumping, which has a direct impact on spring flows, particularly under drought conditions. Groundwater availability models demonstrate that 1 cfs of pumping will diminish Barton Springs flow by 1 cfs under drought-of-record (1950s drought) conditions (Smith and Hunt 2004, pp. 24, 36). Under the same conditions, these models suggest that present-day pumping rates will temporarily cease Barton Springs flow for at least a 4-month period under a repeat of drought-of-record conditions (Smith and Hunt 2004, pp. 24, 36).
From 1980 to 2000, groundwater pumping in the Northern Segment of the Edwards Aquifer nearly doubled (TWDB 2003, pp. 32–33). Total water use for Williamson County where the Jollyville Plateau salamander occurs was 82,382 acre feet (ac ft) in 2010, and is projected to increase to 109,368 ac ft by 2020, and to 234,936 ac ft by 2060, representing a 185 percent increase over the 50-year period (TWDB 2011, p. 78). Similarly, a 91 percent increase in total groundwater use over the same 50-year period is expected in Travis County (TWDB 2011, pp. 5, 72).
While the demand for water is expected to increase with human population growth, one prediction of future groundwater use in this area suggests a large drop in pumping as municipalities convert from groundwater to surface water supplies (TWDB 2003, p. 65). To meet the increasing water demand, the 2012 State Water Plan recommends more reliance on surface water, including existing and new reservoirs, rather than groundwater (TWDB 2012, p. 190). For example, one recommended project conveys water from Lake Travis to Williamson County (TWDB 2012, pp. 192–193). Another recommendation would augment the surface water of Lake Granger in Williamson County with groundwater from Burleson County and the Carrizo-Wilcox Aquifer (TWDB 2012, pp. 164, 192–193). However, it is unknown if this reduction in groundwater use will occur, and if it does, how that will affect spring flows for salamanders.
The COA found a negative correlation between urbanization and spring flows at Jollyville Plateau salamander sites (Turner 2003, p. 11). Field studies have also shown that a number of springs that support Jollyville Plateau salamanders have already gone dry periodically and that spring waters resurface following rain events (O'Donnell
Flow is a major determining factor of physical habitat in streams, which in turn, is a major determining factor of aquatic species composition within streams (Bunn and Arthington 2002, p. 492). Various land-use practices, such as urbanization, conversion of forested or prairie habitat to agricultural lands, excessive wetland draining, and overgrazing can reduce water retention within watersheds by routing rainfall quickly downstream, increasing the size and frequency of flood events and reducing baseflow levels during dry periods (Poff
Baseflow is defined as that portion of streamflow that originates from shallow, subsurface groundwater sources, which provide flow to streams in periods of little rainfall (Poff
Changes in flow regime can have a direct impact on salamander populations. For example, Barrett
The Service has determined that impervious cover due to urbanization in the salamanders' watersheds causes streamflow to shift from predominately baseflow to predominately stormwater runoff. For example, an examination of 24 stream sites in the Austin area revealed that increasing impervious cover in the watersheds resulted in decreased base flow, increased high-flow events of shorter duration, and more rapid rises and falls of the stream flow (Glick
The threat of water quantity degradation from urbanization could by itself cause irreversible declines in population sizes or habitat quality for the Austin blind and Jollyville Plateau salamanders. Also, it could by itself cause irreversible declines or the extirpation of a salamander population at a site with continuous exposure. We consider this to be an ongoing threat of high impact for the Austin blind and Jollyville Plateau salamanders that is likely to increase in the future.
Drought conditions cause lowered groundwater tables and reduced spring flows. The Northern Segment of the Edwards Aquifer, which supplies water to the Jollyville Plateau salamander's habitat, is vulnerable to drought (Chippindale
Low flow conditions during drought also have negative impacts to the Austin blind salamander and its ecosystem in the Edwards Aquifer and at Barton Springs. The long-term average flow at the Barton Springs outlets is approximately 53 cfs (1.5 cubic meters per second) (COA 1998, p. 13; Smith and Hunt 2004, p. 10; Hunt
The specific effects of low flow on central Texas salamanders can be inferred by examining studies on the Barton Springs salamander. Drought decreases spring flow and dissolved oxygen levels and increases temperature in Barton Springs (Turner 2004, p. 2; Turner 2009, p. 14). Low dissolved oxygen levels decrease reproduction in Barton Springs salamanders (Turner 2004, p. 6; 2009, p. 14). Turner (2009, p. 14) also found that Barton Springs salamander counts decline with decreasing discharge. The number of Barton Springs salamanders observed during surveys decreased during a prolonged drought from June 2008 through September 2009 (COA 2011d, pp. 19, 24, 27). The drought in 2011 also resulted in dissolved oxygen concentrations so low that COA used an aeration system to maintain oxygenated water in Eliza and Sunken Gardens Springs (Dries 2011, COA, pers. comm.). Drought also lowered water quality in Barton Springs due to saline water encroachments in the Barton Springs Segment of the Edwards Aquifer (Slade
The Austin blind and Jollyville Plateau salamanders may be able to persist through temporary surface habitat degradation because of their ability to retreat to subsurface habitat. Drought conditions are common to the region, and the ability to retreat underground may be an evolutionary adaptation to such natural conditions (Bendik 2011a, pp. 31–32). However, it is important to note that, although salamanders may survive a drought by retreating underground, this does not necessarily mean they are resilient to long-term drought conditions (particularly because sites may already be affected by other, significant stressors, such as water quality declines).
Drought may also affect surface habitats that are important for prey availability as well as individual and population growth. Therefore, sites with suitable surface flow and adequate prey availability are likely able to support larger population densities (Bendik 2012, COA, pers. comm.). Prey availability for carnivores, such as these salamanders, is low underground due to the lack of sunlight and primary production (Hobbs and Culver 2009, p. 392). Complete loss of surface habitat may lead to the extirpation of predominately subterranean populations that depend on surface flows for biomass input (Bendik 2012, COA, pers. comm.). In addition, length measurements taken during a COA mark-recapture study at Lanier Spring demonstrated that individual Jollyville Plateau salamanders exhibited negative growth (shrinkage) during a 10-month period of retreating to the subsurface from 2008 to 2009 (Bendik 2011b, COA, pers. comm.; Bendik and Gluesenkamp 2012, pp. 3–4). The authors of this study hypothesized that the negative growth could be the result of soft tissue contraction and/or bone loss, but more research is needed to determine the physical mechanism with which the shrinkage occurs (Bendik and Gluesenkamp 2012, p. 5). Although this shrinkage in body length was followed by positive growth when normal spring flow returned, the long-term consequences of catch-up growth are unknown for these salamanders (Bendik and Gluesenkamp 2012, pp. 4–5). Therefore, threats to surface habitat at a given site may not extirpate populations of these salamander species in the short term, but this type of habitat degradation may severely limit population growth and increase a population's overall risk of extirpation from other stressors occurring in the surface watershed.
The threat of water quantity degradation from drought by itself could cause irreversible declines in population sizes or habitat quality for the Austin blind and Jollyville Plateau salamanders. Also, it could negatively impact salamander populations in combination with other threats and contribute to significant declines in the size of the populations or habitat quality. For example, changes in water quantity will have direct impacts on the quality of that water, in terms of concentrations of contaminants and pollutants. Therefore, we consider this to be a threat of high impact for the Austin blind and Jollyville Plateau salamanders now and in the future.
The effects of climate change could potentially lead to detrimental impacts on aquifer-dependent species, especially coupled with other threats on water quality and quantity. Recharge, pumping, natural discharge, and saline intrusion of groundwater systems could all be affected by climate change (Mace
Climate change could compound the threat of decreased water quantity at salamander spring sites. An increased risk of drought could occur if evaporation exceeds precipitation levels in a particular region due to increased greenhouse gases in the atmosphere (CH2M HILL 2007, p. 18). The Edwards Aquifer is also predicted to experience additional stress from climate change that could lead to decreased recharge (Loáiciga
Furthermore, climate change could affect rainfall and ambient temperatures, which are factors that may limit salamander populations. Different ambient temperatures in the season that rainfall occurs can influence spring water temperature if aquifers have fast transmission of rainfall to springs (Martin and Dean 1999, p. 238). Gillespie (2011, p. 24) found that reproductive success and juvenile survivorship in the Barton Springs salamander, which occurs at the three spring sites where the Austin blind salamander is known to occur, may be significantly influenced by fluctuations in mean monthly water temperature. This study also found that groundwater temperature is influenced by the season in which rainfall events occur over the recharge zone of the aquifer. When recharging rainfall events occur in winter when ambient temperature is low, mean monthly water temperature at Barton Springs and Eliza Spring can drop as low as 65.5 °F (18.6 °C) and remain below the annual average temperature of 70.1 °F (21.2 °C) for several months (Gillespie 2011, p. 24).
The threat of water quantity degradation from climate change could negatively impact a population of any of the Austin blind and Jollyville Plateau salamanders in combination with other threats and contribute to significant declines in population sizes or habitat quality. We consider this to be a threat of moderate impact for the Austin blind and Jollyville Plateau salamanders now and in the future.
The Austin blind and Jollyville Plateau salamanders are sensitive to direct physical modification of surface habitat from sedimentation, impoundments, flooding, feral hogs, livestock, and human activities. Direct mortality to salamanders can also occur as a result of these threats, such as being crushed by feral hogs, livestock, or humans.
Elevated mobilization of sediment (mixture of silt, sand, clay, and organic debris) is a stressor that occurs as a result of increased velocity of water running off impervious surfaces (Schram 1995, p. 88; Arnold and Gibbons 1996, pp. 244–245). Increased rates of stormwater runoff also cause increased erosion through scouring in headwater areas and sediment deposition in downstream channels (Booth 1991, pp. 93, 102–105; Schram 1995, p. 88). Waterways are adversely affected in urban areas, where impervious cover levels are high, by sediment loads that are washed into streams or aquifers during storm events. Sediments are either deposited into layers or become suspended in the water column (Ford and Williams 1989, p. 537; Mahler and Lynch 1999, p. 177). Sediment derived from soil erosion has been cited as the greatest single source of pollution of surface waters by volume (Menzer and Nelson 1980, p. 632).
Excessive sediment from stormwater runoff is a threat to the physical habitat of salamanders because it can cover substrates (Geismar 2005, p. 2). Sediments suspended in water can clog gill structures in aquatic animals, which can impair breathing and reduce their ability to avoid predators or locate food sources due to decreased visibility (Schueler 1987, p. 1.5). Excessive deposition of sediment in streams can physically reduce the amount of available habitat and protective cover for aquatic organisms, by filling the interstitial spaces of gravel and rocks where they could otherwise hide. As an example, a California study found that densities of two salamander species were significantly lower in streams that experienced a large infusion of sediment from road construction after a storm event (Welsh and Ollivier 1998, pp. 1,118–1,132). The vulnerability of the salamander species in this California study was attributed to their reliance on interstitial spaces in the streambed habitats (Welsh and Ollivier 1998, p. 1,128).
Excessive sedimentation has contributed to declines in Jollyville Plateau salamander populations in the past. Monitoring by the COA found that, as sediment deposition increased at several sites, salamander abundances significantly decreased (COA 2001, pp. 101, 126). Additionally, the COA found that sediment deposition rates have increased significantly along one of the long-term monitoring sites (Bull Creek Tributary 5) as a result of construction activities upstream (O'Donnell
Effects of sedimentation on the Austin blind salamander is expected to be similar to the effects on the Jollyville Plateau salamander based on similarities in their ecology and life history needs. Analogies can also be drawn from data on the Barton Springs salamander. Barton Spring salamander population numbers are adversely affected by high turbidity and sedimentation (COA 1997, p. 13). Sediments discharge through Barton Springs, even during baseflow conditions (not related to a storm event) (Geismar 2005, p. 12). Storms can increase sedimentation rates substantially (Geismar 2005, p. 12). Areas in the immediate vicinity of the spring outflows lack sediment, but the remaining bedrock is sometimes covered with a layer of sediment several inches thick (Geismar 2005, p. 5). Sedimentation is a direct threat for the Austin blind salamander because its
The threat of physical modification of surface habitat from sedimentation by itself could cause irreversible declines in population sizes or habitat quality for any of the Austin blind and Jollyville Plateau salamanders' populations. It could also negatively impact the species in combination with other threats to contribute to significant declines. We consider this to be an ongoing threat of high impact for the Austin blind and Jollyville Plateau salamanders that is likely to increase in the future.
Impoundments can alter the salamanders' physical habitat in a variety of ways that are detrimental. They can alter the natural flow regime of streams, increase siltation, and support larger, predatory fish (Bendik 2011b, COA, pers. comm.), leading to a variety of impacts to the salamanders and their surface habitats. For example, a low-water crossing on a tributary of Bull Creek occupied by the Jollyville Plateau salamander resulted in sediment buildup above the impoundment and a scour hole below the impoundment that supported predaceous fish (Bendik 2011b, COA, pers. comm.). As a result, Jollyville Plateau salamanders were not found in this degraded habitat after the impoundment was constructed. When the crossing was removed in October 2008, the sediment buildup was removed, the scour hole was filled, and salamanders were later observed (Bendik 2011b, COA, pers. comm.). Many low-water crossings are present near other Jollyville Plateau salamander sites (Bendik 2011b, COA, pers. comm.).
All spring sites for the Austin blind salamander (Main, Eliza, and Sunken Garden Springs) have been impounded for recreational use. These sites were impounded in the early to mid-1900s. For example, a circular, stone amphitheater was built around Eliza Springs in the early 1900s. A concrete bottom was installed over the natural substrate at this site in the 1960s. It now discharges from 7 openings (each 1 ft (0.3 m) in diameter) in the concrete floor and 13 rectangular vents along the edges of the concrete, which were created by the COA to help restore flow. While the manmade structures help retain water in the spring pools during low flows, they have altered the salamander's natural environment. The impoundments have changed the Barton Springs ecosystem from a stream-like system to a more lentic (still water) environment, thereby reducing the water system's ability to flush sediments downstream and out of salamander habitat. Although a natural surface flow connection between Sunken Gardens Spring and Barton Creek has been restored recently (COA 2007a, p. 6), the Barton Springs system as a whole remains highly modified.
The threat of physical modification of surface habitat from impoundments by itself may not be likely to cause significant population declines, but it could negatively impact the species in combination with other threats and contribute to significant declines in the population size or habitat quality. We consider impoundments to be an ongoing threat of moderate impact to the Austin blind and Jollyville Plateau salamanders and their surface habitats that will likely continue in the future.
Flooding as a result of rainfall events can considerably alter the substrate and hydrology of salamander habitat. Extreme flood events have occurred in the Austin blind and Jollyville Plateau salamander's surface habitats (Pierce 2011a, p. 10; TPWD 2011, p. 6; Turner 2009, p. 11; O'Donnell
An increase in the frequency of flood events causes streambank and streambed erosion (Coles
Flooding can alter the surface salamander habitat by deepening stream channels, which may increase habitat for predaceous fish. Much of the Austin blind and Jollyville Plateau salamanders' surface habitat is characterized by shallow water depth (COA 2001, p. 128; Pierce 2011a, p. 3), with the exception of the Austin blind salamander at Main and Sunken Garden Springs. However, deep pools are sometimes formed within stream channels from the scouring of floods. Tumlison
The threat of physical modification of surface habitat from flooding by itself may not be likely to cause significant population declines, but it could negatively impact the species in combination with other threats and contribute to significant declines in the population size or habitat quality. We consider this to be a threat of moderate impact to the Austin blind and Jollyville Plateau salamanders that may increase in the future as urbanization and impervious cover increases within the surface watersheds of these species, causing more frequent and more intense streamflow flash flooding (see discussion in the “Urbanization” section under “Water Quality Degradation” above).
There are between 1.8 and 3.4 million feral hogs (
Feral hogs have become abundant in some areas where the Jollyville Plateau salamander occurs. O'Donnell
The threat of physical modification of surface habitat from feral hogs by itself may not be likely to cause significant population declines, but it could negatively impact the species in combination with other threats and contribute to significant declines in the population size or habitat quality. We consider this to be an ongoing threat of moderate impact to the Jollyville Plateau salamander that will likely continue in the future. We do not consider physical habitat modification from feral hogs to be a threat to the Austin blind salamander at this time or in the future.
Similar to feral hogs, livestock can negatively impact surface salamander habitat by disturbing the substrate and increasing sedimentation in the spring run where salamanders are often found. Poorly managed livestock grazing results in changes in vegetation (from grass-dominated to brush-dominated), which leads to increased erosion of the soil profile along stream banks (COA 1995, pp. 3–59) and sediment in salamander habitat. However, the Austin blind salamander's habitat is inside a COA park, and livestock are not allowed in the spring areas. Also, much of the Jollyville Plateau salamander habitat is in suburban areas, and we are not aware of livestock access to or damage in those areas. Therefore, we do not consider physical habitat modification from livestock to be a threat to the Austin blind or Jollyville Plateau salamanders at this time or in the future.
Some sites of the Austin blind and Jollyville Plateau salamanders have been directly modified by human-related activities. Frequent human visitation of sites occupied by the Austin blind and Jollyville Plateau salamanders may negatively affect the species and their habitat. Documentation from the COA of disturbed vegetation, vandalism, and the destruction of travertine deposits (fragile rock formations formed by deposit of calcium carbonate on stream bottoms) by foot traffic has been documented at one of their Jollyville Plateau salamander monitoring sites in the Bull Creek watershed (COA 2001, p. 21) and may have resulted in direct destruction of small amounts of the salamander's habitat. Other Jollyville Plateau salamander sites have also been impacted. Both Stillhouse Hollow Spring and Balcones District Park regularly receive visitors that modify the available cover habitat (by removing or arranging substrates). Balcones District Park is also regularly disturbed by off-leash dog traffic (Bendik 2012, COA, pers. comm.). Eliza Spring and Sunken Garden Spring, two of the three locations of the Austin blind salamander, also experience vandalism, despite the presence of fencing and signage (Dries 2011, COA, pers. comm.). The deep water of the third location (Parthenia Springs) likely protects the Austin blind salamander's surface habitat from damage from frequent human recreation. All of these activities can reduce the amount of cover available for salamander breeding, feeding, and sheltering.
The threat of physical modification of surface habitat from human visitation, recreation, and alteration by itself may not be likely to cause significant population declines, but it could negatively impact the species in combination with other threats and contribute to significant declines in the population size or habitat quality. We consider this to be an ongoing threat of moderate impact to the Austin blind and Jollyville Plateau salamanders that will likely continue in the future.
When considering the listing determination of species, it is important to consider conservation efforts that have been made to reduce or remove threats, such as the threats to the Austin blind and Jollyville Plateau Texas salamanders' habitat. A number of efforts have aimed at minimizing the habitat destruction, modification, or curtailment of the salamanders' ranges.
In a separate undertaking, and with the help of a grant funded through section 6 of the Act, the WCCF developed the Williamson County Regional HCP to obtain a section 10(a)(1)(B) permit for incidental take of federally listed endangered species in Williamson County, Texas. This HCP became final in October 2008. Although Jollyville Plateau salamanders present in southern Williamson County are likely influenced by the Edwards Aquifer Recharge Zone in northern Williamson County, the Williamson County Regional HCP does not include considerations for this species. However, in 2012, the WCCF began contracting to gather information on the Jollyville Plateau salamander in Williamson County.
Travis County and COA also have a regional HCP (the Balcones Canyonlands Conservation Plan) and section 10(a)(1)(B) permit that covers incidental take of federally listed species in Travis County. While the Jollyville Plateau salamander is not a covered species under that permit, the Balcones Canyonlands Preserve system offers some benefits to the Jollyville Plateau salamander in portions of the Bull Creek, Brushy Creek, Cypress Creek, and Long Hollow Creek drainages through preservation of open space (Service 1996, pp. 2–28, 2–29). Sixty-seven of 106 surface sites for the Jollyville Plateau salamander are within Balcones Canyonlands Preserves. However, eight of the nine COA monitoring sites occupied by the Jollyville Plateau salamander within the Balcones Canyonlands Preserve have experienced water quality degradation from disturbances occurring upstream and outside of the preserved tracts (O'Donnell
Additionally, the Buttercup Creek HCP was established to avoid, minimize, and mitigate for the potential negative effects of construction and operation of single and multifamily residences and a school near and adjacent to currently occupied habitat of the endangered Tooth Cave ground beetle (
In addition, several individual 10(a)(1)(B) permit holders in Travis County have established preserves and included provisions that are expected to benefit the Jollyville Plateau salamander. Twelve of the 16 known caves for the Jollyville Plateau salamander are located within preserves. Similar to the Williamson County Regional HCP and Balcones Canyonlands Conservation Plan, there is potential for adverse effects to salamander sites from land use activities outside the covered areas under the HCPs.
Furthermore, the COA is implementing the Barton Springs Pool HCP to avoid, minimize, and mitigate incidental take of the Barton Springs salamander resulting from the continued operation and maintenance of Barton Springs Pool and adjacent springs (COA 1998, pp. 1–53). Many of the provisions of the plan also benefit the Austin blind salamander. These provisions include: (1) Training lifeguard and maintenance staff to protect salamander habitat, (2) controlling erosion and preventing surface runoff from entering the springs, (3) ecological enhancement and restoration, (4) monthly monitoring of salamander numbers, (5) public outreach and education, and (6) establishment and maintenance of a captive-breeding program, which includes the Austin blind salamander. As part of this HCP, the COA completed habitat restoration of Eliza Spring and the main pool of Barton Springs in 2003 and 2004. A more natural flow regime was reconstructed in these habitats by removing large obstructions to flow. This HCP has recently been proposed for revision to include coverage for the Austin blind salamander and to extend the COA's permit for another 20 years (78 FR 23780, April 22, 2013).
Although these conservation efforts likely contribute water quality benefits to surface flow, surface habitats can be influenced by land use throughout the recharge zone of the aquifer that supplies its spring flow. Furthermore, the surface areas influencing subsurface water quality (that is draining the surface and flowing to the subsurface habitat) is not clearly delineated for many of the sites (springs or caves) for the Austin blind or Jollyville Plateau salamanders. Because we are not able to precisely assess additional pathways for negative impacts to these salamanders to occur, many of their sites may be affected by threats that cannot be mitigated through the conservation efforts that are currently ongoing.
Degradation of habitat, in the form of reduced water quality and quantity and disturbance of spring sites (physical modification of surface habitat), is the primary threat to the Austin blind and Jollyville Plateau salamanders. This threat may affect only the surface habitat, only the subsurface habitat, or both habitat types. In consideration of the stressors currently impacting the salamander species and their habitats along with their risk of exposure to potential sources of this threat, we have found the threat of habitat destruction and modification within the ranges of the Austin blind and Jollyville Plateau salamanders to have severe impacts on these species, and we expect this threat to continue into the future.
There is little available information regarding overutilization of the Austin blind and Jollyville Plateau salamanders for commercial, recreational, scientific, or educational purposes, although we are aware that some individuals of these species have been collected from their natural habitat for a variety of purposes. Collecting individuals from populations that are already small enough to experience reduced reproduction and survival due to inbreeding depression or become extirpated due to environmental or demographic stochasticity and other catastrophic events (see the discussion on small population sizes under
Currently, we do not consider overutilization from collecting salamanders in the wild to be a threat by itself, but it may contribute to significant population declines, and could negatively impact the species in combination with other threats.
Chytridiomycosis (chytrid fungus) is a fungal disease that is responsible for killing amphibians worldwide (Daszak
A condition affecting Barton Springs salamanders may also affect the Austin blind salamander. In 2002, 19 Barton Springs salamanders, which co-occur with the Austin blind salamander, were found at Barton Springs with bubbles of gas occurring throughout their bodies (Chamberlain and O'Donnell 2003, p.
The incidence of gas bubbles in salamanders at Barton Springs is consistent with a disorder known as gas bubble disease, or gas bubble trauma, as described by Weitkamp and Katz (1980, pp. 664–671). In animals with gas bubble trauma, bubbles below the surface of the body and inside the cardiovascular system produce lesions and dead tissue that can lead to secondary infections (Weitkamp and Katz 1980, p. 670). Death from gas bubble trauma is apparently related to an accumulation of internal bubbles in the cardiovascular system (Weitkamp and Katz 1980, p. 668). Pathology reports on affected animals at Barton Springs found that the symptoms were consistent with gas bubble trauma (Chamberlain and O'Donnell 2003, pp. 17–18). The cause of gas bubble trauma is unknown, but its incidence has been correlated with water temperature. Gas bubble trauma has been observed in wild Barton Springs salamanders only on rare occasions (Chamberlain, unpublished data) and has been observed in Austin blind salamanders in captivity only when exposed to water temperatures approaching 80 °F (26.7 °C) (Chamberlain 2011, COA, pers. comm.). Given these limited observations, we do not consider gas bubble trauma to be a threat to the Austin blind salamander now or in the future.
To our knowledge, gas bubble trauma has not been observed in Jollyville Plateau salamanders. However, if an increase in water temperature is a causative factor, this species may also be at risk during droughts or other environmental stressors that result in increases in water temperature.
Regarding predation, COA biologists found Jollyville Plateau salamander abundances were negatively correlated with the abundance of predatory centrarchid fish (carnivorous freshwater fish belonging to the sunfish family), such as black bass (
In summary, while disease and predation may be affecting individuals of these salamander species, these are not significant factors affecting the species' continued existence in healthy, natural ecosystems. Neither disease nor predation is occurring at a level that we consider to be a threat to the continued existence of the Austin blind and Jollyville Plateau salamanders now or in the future.
The primary threats to the Austin blind and Jollyville Plateau salamanders are habitat degradation related to a reduction of water quality and quantity and disturbance at spring sites (see discussion under Factor A above). Therefore, regulatory mechanisms that protect water from the Trinity and Edwards Aquifers are crucial to the future survival of these species. Federal, State, and local laws and regulations have been insufficient to prevent past and ongoing impacts to the Austin blind and Jollyville Plateau salamanders and their habitats from water quality degradation, reduction in water quantity, and surface disturbance of spring sites, and are unlikely to prevent further impacts to the species in the future.
Laws and regulations pertaining to endangered or threatened animal species in the State of Texas are contained in Chapters 67 and 68 of the Texas Parks and Wildlife Department (TPWD) Code and Sections 65.171–65.176 of Title 31 of the Texas Administrative Code (T.A.C.). TPWD regulations prohibit the taking, possession, transportation, or sale of any of the animal species designated by State law as endangered or threatened without the issuance of a permit. The Austin blind and Jollyville Plateau salamanders are not listed on the Texas State List of Endangered or Threatened Species (TPWD 2013, p. 3). Even if they were, State threatened and endangered species laws do not contain protective provisions for habitat. At this time, these species are receiving no direct protection from State of Texas regulations.
Under authority of the T.A.C. (Title 30, Chapter 213), the TCEQ regulates activities having the potential for polluting the Edwards Aquifer and hydrologically connected surface streams through the Edwards Aquifer Protection Program or “Edwards Rules.” The Edwards Rules require a number of water quality protection measures for new development occurring in the recharge, transition, and contributing zones of the Edwards Aquifer. The Edwards Rules were enacted to protect existing and potential uses of groundwater and maintain Texas Surface Water Quality Standards. Specifically, a water pollution abatement plan (WPAP) must be submitted to the TCEQ in order to conduct any construction-related or post-construction activities on the recharge zone. The WPAP must include a description of the site and location maps, a geologic assessment conducted by a geologist, and a technical report describing, among other things, temporary and permanent best management practices (BMPs).
However, the permanent BMPs and measures identified in the WPAP are designed, constructed, operated, and maintained to remove 80 percent of the incremental increase in annual mass loading of total suspended solids from the site caused by the regulated activity. This necessarily results in some level of water quality degradation since up to 20 percent of total suspended solids are ultimately discharged from the site into receiving waterways. Separate Edwards Aquifer protection plans are required for organized sewage collection systems, underground storage tank facilities, and aboveground storage tank facilities. Regulated activities exempt from the requirements of the Edwards Rules are: (1) The installation of natural gas lines; (2) the installation of telephone lines; (3) the installation of electric lines; (4) the installation of water lines; and (5) the installation of other utility lines that are not designed to carry and will not carry pollutants, storm water runoff, sewage effluent, or treated effluent from a wastewater treatment facility.
Temporary erosion and sedimentation controls are required to be installed and
The best available science indicates that measurable degradation of stream habitat and loss of biotic integrity occurs at levels of impervious cover within a watershed much less than this (see Factor A discussion above). The single known location of the Austin blind salamander and half of the known Jollyville Plateau salamander locations occur within those portions of the Edwards Aquifer regulated by the TCEQ. The TCEQ regulations do not address land use, impervious cover limitations, some nonpoint-source pollution, or application of fertilizers and pesticides over the recharge zone (30 TAC 213.3). In addition, these regulations were not intended or designed specifically to be protective of the salamanders. We are unaware of any water quality ordinances more restrictive than the TCEQ's Edwards Rules in Travis or Williamson Counties outside the COA.
Texas has an extensive program for the management and protection of water that operates under State statutes and the Federal Clean Water Act (CWA). It includes regulatory programs such as the following: Texas Pollutant Discharge Elimination System, Texas Surface Water Quality Standards, and Total Maximum Daily Load Program (under Section 303(d) of the CWA).
In 1998, the State of Texas assumed the authority from the Environmental Protection Agency (EPA) to administer the National Pollutant Discharge Elimination System. As a result, the TCEQ's TPDES program has regulatory authority over discharges of pollutants to Texas surface water, with the exception of discharges associated with oil, gas, and geothermal exploration and development activities, which are regulated by the Railroad Commission of Texas. In addition, stormwater discharges as a result of agricultural activities are not subject to TPDES permitting requirements. The TCEQ issues two general permits that authorize the discharge of stormwater and non-stormwater to surface waters in the State associated with: (1) small municipal separate storm sewer systems (MS4) (TPDES General Permit #TXR040000) and (2) construction sites (TPDES General Permit #TXR150000). The MS4 permit covers small municipal separate storm sewer systems that were fully or partially located within an urbanized area, as determined by the 2000 Decennial Census by the U.S. Census Bureau, and the construction general permit covers discharges of storm water runoff from small and large construction activities impacting greater than 1 acre of land. In addition, both of these permits require new discharges to meet the requirements of the Edwards Rules.
To be covered under the MS4 general permit, a municipality must submit a Notice of Intent (NOI) and a copy of their Storm Water Management Program (SWMP) to TCEQ. The SWMP must include a description of how that municipality is implementing the seven minimum control measures, which include the following: (1) Public education and outreach; (2) public involvement and participation; (3) detection and elimination of illicit discharges; (4) construction site stormwater runoff control (when greater than 1 ac (0.4 ha) is disturbed); (5) post-construction stormwater management; (6) pollution prevention and good housekeeping for municipal operations; and (7) authorization for municipal construction activities (optional). Municipalities located within the range of the Austin blind and Jollyville Plateau salamanders that are covered under the MS4 general permit include the Cities of Cedar Park, Round Rock, Austin, Leander, and Pflugerville, as well as Travis and Williamson Counties.
To be covered under the construction general permit, an applicant must prepare a stormwater pollution and prevention plan (SWP3) that describes the implementation of practices that will be used to minimize, to the extent practicable, the discharge of pollutants in stormwater associated with construction activity and non-stormwater discharges. For activities that disturb greater than 5 ac (2 ha), the applicant must submit an NOI to TCEQ as part of the approval process. As stated above, the two general permits issued by the TCEQ do not address discharge of pollutants to surface waters from oil, gas, and geothermal exploration and geothermal development activities, stormwater discharges associated with agricultural activities, and from activities disturbing less than 5 acres (2 ha) of land. Despite the significant value the TPDES program has in regulating point-source pollution discharged to surface waters in Texas, it does not adequately address all sources of water quality degradation, including nonpoint-source pollution and the exceptions mentioned above, that have the potential to negatively impact the Austin blind and Jollyville Plateau salamanders.
In reviewing the 2010 and 2012 Texas Water Quality Integrated Reports prepared by the TCEQ, the Service identified 14 of 28 (50 percent) stream segments located within surface watersheds occupied by the Austin blind and Jollyville Plateau salamanders where parameters within water samples exceeded screening level criteria (TCEQ 2010a, pp. 546–624; TCEQ 2010b, pp. 34–68; TCEQ 2012b, pp. 35–70; TCEQ 2012c, pp. 646–736). Four of these 28 (14 percent) stream segments have been identified as impaired waters as required under sections 303(d) and 304(a) of the Clean Water Act “. . .for which effluent limitations are not stringent enough to implement water quality standards” (TCEQ 2010c, pp. 77, 82–83; TCEQ 2012d, pp. 67, 73). The analysis of surface water quality monitoring data collected by TCEQ indicated “screening level concerns” for nitrate, dissolved oxygen, impaired benthic communities, sediment toxicity, and bacteria. The TCEQ screening level for nitrate (1.95 mg/L) is within the range of concentrations (1.0 to 3.6 mg/L) above which the scientific literature indicates may be toxic to aquatic organisms (Camargo
To discharge effluent onto the land, the TCEQ requires wastewater treatment systems within the Barton Springs Segment of the Edwards Aquifer recharge and contributing zones to obtain Texas Land Application Permits (TLAP) (Ross 2011, p. 7). Although these permits are designed to protect the surface waters and underground aquifer, studies have demonstrated reduced water quality downstream of TLAP sites (Mahler
The COA's water quality ordinances (COA Code, Title 25, Chapter 8) provide some water quality regulatory protection to the Austin blind and Jollyville Plateau salamander's habitat within Travis County. Some of the protections include buffers around critical environmental features and waterways (up to 400 ft (122 m)), permanent water quality control structures (sedimentation and filtration ponds), wastewater system restrictions, and impervious cover limitations (COA Code, title 25, Chapter 8; Turner 2007, pp. 1–2). The ordinances range from relatively strict controls in its Drinking Water Protection Zones to lesser controls in its Desired Development Zones. For example, a 15 percent impervious cover limit is in place for new developments within portions of the Barton Springs Zone, one of the Drinking Water Protection Zones, while up to 90 percent impervious cover is permitted within the Suburban City Limits Zone, one of the Desired Development Zones.
In the period after the COA passed water quality ordinances in 1986 and 1991, sedimentation and nutrients decreased in the five major Austin-area creeks (Turner 2007, p. 7). Peak storm flows were also lower after the enactment of the ordinances, which may explain the decrease in sedimentation (Turner 2007, p. 10). Likewise, a separate study on the water quality of Walnut Creek (Jollyville Plateau salamander habitat) from 1996 to 2008 found that water quality has either remained the same or improved (Scoggins 2010, p. 15). These trends in water quality occurred despite a drastic increase in construction and impervious cover during the same time period (Turner 2007, pp. 7–8; Scoggins 2010, p. 4), indicating that the ordinances are effective at mitigating some of the impacts of development on water quality. Another study in the Austin area compared 18 sites with stormwater controls (retention ponds) in their watersheds to 20 sites without stormwater controls (Maxted and Scoggins 2004, p. 8). In sites with more than 40 percent impervious cover, more contaminant-sensitive macroinvertebrate species were found at sites with stormwater controls than at sites without controls (Maxted and Scoggins 2004, p. 11).
Local ordinances have not been completely effective at protecting water quality to the extent that sedimentation, contaminants, pollution, and changes in water chemistry no longer impact salamander habitat (see “Stressors and Sources of Water Quality Degradation” discussion under Factor A above). A study conducted by the COA of four Jollyville Plateau salamander spring sites within two subdivisions found that stricter water quality controls (wet ponds instead of standard sedimentation/filtration ponds) did not necessarily translate into improved groundwater quality (Herrington
In addition, Title 7, Chapter 245 of the Texas Local Government Code permits “grandfathering” of certain local regulations. Grandfathering allows developments to be exempted from new requirements for water quality controls and impervious cover limits if the developments were planned prior to the implementation of such regulations. However, these developments are still obligated to comply with regulations that were applicable at the time when project applications for development were first filed (Title 7, Chapter 245 of the Texas Local Government Code, p. 1).
On January 1, 2006, the COA banned the use of coal tar sealant (Scoggins
The LCRA Highland Lakes Watershed Ordinance applies to lands located within the Lake Travis watershed in northwestern Travis County, as well as portions of Burnet and Llano Counties. This ordinance was implemented by LCRA beginning in 2006 to protect water quality in the Highland Lakes region. There are 14 Jollyville Plateau salamander sites located within the northwestern portion of Travis County covered by this ordinance. Development in this area is required to protect water quality by: (1) Providing water quality volume based on the 1-year storm runoff in approved best management practices (BMPs) (practices that effectively manage stormwater runoff quality and volume), (2) providing buffer zones around creeks that remain free of most construction activities, (3) installing temporary erosion and sediment control, (4) conducting water quality education, and (5) requiring water quality performance monitoring of certain BMPs. However, as with TPDES permitting discussed above, agricultural activities are exempt from the water quality requirements contained in the Highland Lakes Watershed Ordinance (LCRA 2005, pp. 8–21).
The Cities of Cedar Park and Round Rock, and Travis and Williamson Counties have some jurisdiction within watersheds occupied by either the Austin blind or Jollyville Plateau salamanders. The Service has reviewed ordinances administered by each of these municipalities to determine if they contain measures protective of salamanders above and beyond those already required through other regulatory mechanisms (Clean Water Act, T.A.C., etc.). Each of the cities has implemented their own ordinances that contain requirements for erosion control and the management of the volume of stormwater discharged from developments within their jurisdictions. However, as discussed above under Factor A, measurable degradation of stream habitat and loss of biotic integrity can occur at low levels of impervious cover within a watershed, and there are no impervious cover limit restrictions in Travis or Williamson Counties or for development within the municipalities of Cedar Park and Round Rock where the Jollyville Plateau salamander occurs.
The Barton Springs/Edwards Aquifer Conservation District permits and regulates most wells on the Barton Springs segment of the Edwards Aquifer, subject to the limits of the State of Texas law. They have established two desired future conditions for the Freshwater Edwards Aquifer within the Northern Subdivision of Groundwater
Surface water quality data collected by TCEQ and COA indicates that water quality degradation is occurring within many of the surface watersheds occupied by the Austin blind and Jollyville Plateau salamanders despite the existence of numerous State and local regulatory mechanisms to manage stormwater and protect water quality (Turner 2005a, pp. 8–17, O'Donnell
The Austin blind and Jollyville Plateau salamanders may be more susceptible to threats and impacts from stochastic events because of their small population sizes (Van Dyke 2008, p. 218). The risk of extinction for any species is known to be highly inversely correlated with population size (O'Grady
At small population levels, the effects of demographic stochasticity (the variability in population growth rates arising from random differences among individuals in survival and reproduction within a season) alone greatly increase the risk of local extinctions (Van Dyke 2008, p. 218). Although it remains a complex field of study, conservation genetics research has demonstrated that long-term inbreeding depression (a pattern of reduced reproduction and survival as a result of genetic relatedness) can occur within populations with effective sizes of 50 to 500 individuals and may also occur within larger populations as well (Frankham 1995, pp. 305–327; Latter
Current evidence from integrated work on population dynamics shows that setting conservation thresholds at only a few hundred individuals does not properly account for the synergistic impacts of multiple threats facing a population (Traill
Through a review of survey information available in our files and provided to us during the peer review and public comment period for the proposed rule, we noted the highest number of individuals counted during survey events that have occurred over the last 10 years. We used these survey counts as an index of salamander population health and relative abundance. We recognize these counts do not represent true population counts or estimates because they are reflective of only the number of salamanders observed in the surface habitat at a specific point in time. However, the data provide the best available information to consider relative population sizes of salamanders.
Through this assessment, we determined that surveys at many sites have never yielded as many as 50 individuals. In fact, 33 of the 106 (31 percent) Jollyville Plateau salamander surface sites have not yielded as many as 5 individuals at any one time in the last 10 years. Furthermore, surveys or salamander counts of only 8 of the 106 (8 percent) Jollyville Plateau salamander surface sites have resulted in more than 50 individuals at a time over the last 10 years. We also found that many of the salamander population counts have been low or unknown.
For the Austin blind salamander, the highest count observed at a single site over the last 10 years was 34 individuals; however, numbers this high are very rare for this species. Counts of three individuals or less have been reported most frequently since 1995. Because most of the sites occupied by the Austin blind and Jollyville Plateau salamanders are not known to have many individuals, any of the threats described in this final rule or even stochastic events that would not otherwise be considered a threat could extirpate populations. As populations are extirpated, the overall risk of extinction of the species is increased.
Small population sizes can also act synergistically with other traits (such as being a habitat specialist and having limited distribution, as is the case with the Austin blind and Jollyville Plateau salamanders) to greatly increase risk of extinction (Davies
In conclusion, we do not consider small population size to be a threat in and of itself to the Austin blind or Jollyville Plateau salamanders, but their small population sizes make them more vulnerable to extinction from other existing or potential threats, such as a major stochastic event. We consider the level of impacts from stochastic events to be moderate for the Jollyville Plateau salamander, because this species has more populations over a broader range. On the other hand, recolonization following a stochastic event is not likely for the Austin blind salamander due to its limited distribution and low numbers. Therefore, the impact from a stochastic event for the Austin blind salamander is a significant threat.
Increased levels of ultraviolet-B (UV–B) radiation, due to depletion of the stratospheric ozone layers, may lead to declines in amphibian populations
The effect of increased UV–B radiation on the Austin blind and Jollyville Plateau salamanders is unknown. It is unlikely the few cave populations of Jollyville Plateau salamanders that are restricted entirely to the subsurface are exposed to UV–B radiation. In addition, exposure of the Austin blind salamander may be limited because they largely reside underground. Surface populations of these species may receive some protection from UV–B radiation through shading from trees or from hiding under rocks at some spring sites. Substrate alteration may put these species at greater risk of UV–B exposure and impacts. Because eggs are likely deposited underground (Bendik 2011b, COA, pers. comm.), UV–B radiation may have no impact on the hatching success of these species.
In conclusion, the effect of increased UV–B radiation has the potential to cause deformities or developmental problems to individuals, but we do not consider this stressor to significantly contribute to the risk of extinction of the Austin blind and Jollyville Plateau salamanders at this time. However, UV–B radiation could negatively affect any of the Austin blind and Jollyville Plateau salamanders' surface populations in combination with other threats (such as water quality or water quantity degradation) and contribute to significant declines in population sizes.
Jollyville Plateau salamanders observed at the Stillhouse Hollow monitoring sites have shown high incidences of deformities, such as curved spines, missing eyes, missing limbs or digits, and eye injuries (O'Donnell
The highly restricted ranges of the salamanders and entirely aquatic environment make them extremely vulnerable to threats such as decreases in water quality and quantity. This is especially true for the Austin blind salamander, which is found in only one locality comprising three hydrologically connected springs of Barton Springs. Due to its limited distribution, the Austin blind salamander is sensitive to stochastic incidences, such as storm events (which can dramatically affect dissolved oxygen levels), catastrophic contaminant spills, and leaks of harmful substances. One catastrophic spill event in Barton Springs could potentially cause the extinction of the Austin blind salamander in the wild.
Although rare, catastrophic events pose a significant threat to small populations because they have the potential to eliminate all individuals in a small group (Van Dyke 2008, p. 218). In the proposed rule, we discussed that the presence of several locations of Jollyville Plateau salamanders close to each other provides some possibility for natural recolonization for populations of these species if any of these factors resulted in a local extirpation event (Fagan
In conclusion, restricted ranges could negatively affect any of the Austin blind and Jollyville Plateau salamanders' populations in combination with other threats (such as water quality or water quantity degradation) and lead to the species being at a higher risk of extinction. We consider the level of impacts from stochastic events to be moderate for the Jollyville Plateau salamander, because even though this species has more populations over a broader range, the range is still restricted and the species' continued existence could be compromised by a common event. On the other hand, recolonization following a stochastic event is less likely for the Austin blind salamander due to its limited distribution and low numbers. Therefore, the impact from a stochastic event for the Austin blind salamander is a significant threat.
The interactions among multiple stressors (contaminants, UV–B radiation, pathogens) may be contributing to amphibian population declines (Blaustein and Kiesecker 2002, p. 598). Multiple stressors may act additively or synergistically to have greater detrimental impacts on amphibians compared to a single stressor alone. Kiesecker and Blaustein (1995, p. 11,051) found a synergistic effect between UV–B radiation and a pathogen in Cascades frogs and western toads. Researchers demonstrated that reduced pH levels and increased levels of UV–B radiation independently had no effect on leopard frog (
Currently, the effect of synergistic stressors on the Austin blind and Jollyville Plateau salamanders is not fully known. Furthermore, different species of amphibians differ in their reactions to stressors and combinations of stressors (Kiesecker and Blaustein 1995, p. 11,051; Relyea
The effect of increased UV–B radiation is an unstudied stressor to the Austin blind and Jollyville Plateau salamanders that has the potential to cause deformities or development problems. The effect of this stressor is low at this time. Deformities have been documented in the Jollyville Plateau salamander, but at only one location (Stillhouse Hollow). We do not know what causes these deformities, and there is no evidence that the incidence rate is increasing or spreading. Therefore, the effect of UV–B radiation is low. Finally, small population sizes at most of the sites for the salamanders increases the risk of local extirpation events. We do not necessarily consider small population size to be a threat in and of itself to the Austin blind and Jollyville Plateau salamanders, but their small population sizes make them more vulnerable to extirpation from other existing or potential threats, such as stochastic events. Thus, we consider the level of impacts from stochastic events to be moderate for the Jollyville Plateau salamander and high for the Austin blind salamanders due to its more limited distribution and low numbers.
We have no information on any conservation efforts currently under way to reduce the effects of UV–B radiation, deformities, small population sizes, or limited ranges on the Austin blind and Jollyville Plateau salamanders.
Some of the threats discussed in this finding could work in concert with one another to cumulatively create situations that impact the Austin blind and Jollyville Plateau salamanders. Some threats to the species may seem to be of low significance by themselves, but when considered with other threats that are occurring at each site, such as small population sizes, the risk of extirpation is increased. Furthermore, we have no direct evidence that salamanders currently migrate from one population to another on a regular basis, and many of the populations are situated in a way (that is, they are isolated from one another) where recolonization of extirpated sites is very unlikely. Cumulatively, as threats to the species increase over time in tandem with increasing urbanization within the surface watersheds of these species, more and more populations will be lost, which will increase the species' risk of extinction.
The primary factor threatening the Austin blind and Jollyville Plateau salamanders is the present or threatened destruction, modification, or curtailment of its habitat or range (Factor A). Degradation of habitat, in the form of reduced water quality and quantity and disturbance of spring sites (surface habitat), is the primary threat to the Austin blind and Jollyville Plateau salamanders. Reductions in water quality occur primarily as a result of urbanization, which increases the amount of impervious cover in the watershed and exposes the salamanders to more hazardous material sources. Impervious cover increases storm flow, erosion, and sedimentation. Impervious cover also changes natural flow regimes within watersheds and increases the transport of contaminants common in urban environments, such as oils, metals, and pesticides. Expanding urbanization results in an increase of contaminants, such as fertilizers and pesticides, within the watershed, which degrades water quality at salamander spring sites. Additionally, urbanization increases nutrient loads at spring sites, which can lead to decreases in dissolved oxygen levels. Construction activities are a threat to both water quality and quantity because they can increase sedimentation and exposure to contaminants, as well as dewater springs by intercepting aquifer conduits.
Various other threats to habitat exist for the Austin blind and Jollyville Plateau salamanders as well. Drought, which may be compounded by the effects of global climate change, also degrades water quantity and reduces available habitat for the salamanders. Water quantity can also be reduced by groundwater pumping and decreases in baseflow due to increases in impervious cover. Flood events contribute to the salamanders' risks of extinction by degrading water quality through increased contaminants levels and sedimentation, which may damage or alter substrates, and by removing rocky substrates or washing salamanders out of suitable habitat. Impoundments are also a threat to the Austin blind and Jollyville Plateau salamanders. Feral hogs are a threat to Jollyville Plateau salamanders, because they can physically alter their surface habitat and increase nutrients. Additionally, catastrophic spills and leaks remain a threat for many salamander locations. All of these threats are projected to increase in the future as the human population and development increases within watersheds that provide habitat for these salamanders. Some of these threats are moderated, in part, by ongoing conservation efforts, such as HCPs, preserves, and other programs in place to protect land from the effects of urbanization and to gather water quality data that would be helpful in designing conservation strategies for the salamander species. Overall, we consider the combined threats of Factor A to be ongoing and with a high degree of impact to the Austin blind and Jollyville Plateau salamanders and their habitats.
Another factor affecting these salamander species is Factor D, the inadequacy of existing regulatory mechanisms. Surface water quality data collected by TCEQ indicates that water quality degradation is occurring within many of the surface watersheds occupied by the Austin blind and Jollyville Plateau salamanders despite the existence of numerous State and local regulatory mechanisms to manage stormwater and protect water quality. Human population growth and urbanization in Travis and Williamson Counties are projected to continue into the future as well as the associated impacts to water quality and quantity (see Factor A discussion above). Because existing regulations are not providing adequate protection for the salamanders or their habitats, we consider the existing regulatory mechanisms inadequate to protect the
Under Factor E we identified several stressors that could negatively impact the Austin blind and Jollyville Plateau salamanders, including the increased risk of local extirpation events due to small population sizes, UV–B radiation, and deformities. Although none of these stressors rose to the level of being considered a threat by itself, small population sizes and restricted ranges make the Austin blind and Jollyville Plateau salamanders more vulnerable to extirpation from other existing or potential threats, such as stochastic events. Thus, we consider the level of impacts from stochastic events to be high for the Austin blind and Jollyville Plateau salamanders due to their low numbers, and especially high for the Austin blind salamander due to its limited distributions.
Section 4 of the Act, and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(b)(1)(a), the Secretary is to make threatened or endangered determinations required by subsection 4(a)(1) solely on the basis of the best scientific and commercial data available to her after conducting a review of the status of the species and after taking into account conservation efforts by States or foreign nations. The standards for determining whether a species is threatened or endangered are provided in section 3 of the Act. An endangered species is any species that is “in danger of extinction throughout all or a significant portion of its range.” A threatened species is any species that is “likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” Per section 4(a)(1) of the Act, in reviewing the status of the species to determine if it meets the definitions of threatened or endangered, we determine whether any species is an endangered species or a threatened species because of any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued existence.
We evaluated whether the Austin blind and Jollyville Plateau salamanders are in danger of extinction now (that is, an endangered species) or are likely to become in danger of extinction in the foreseeable future (that is, a threatened species). The foreseeable future refers to the extent to which the Secretary can reasonably rely on predictions about the future in making determinations about the future conservation status of the species. A key statutory difference between a threatened species and an endangered species is the timing of when a species may be in danger of extinction, either now (endangered species) or in the foreseeable future (threatened species).
Based on our review of the best available scientific and commercial information, we conclude that the Austin blind salamander is in danger of extinction now throughout all of its range and, therefore, meets the definition of an endangered species. This finding, explained below, is based on our conclusions that this species has only one known population that occurs at three spring outlets in Barton Springs, the habitat of this population has experienced impacts from threats, and these threats are expected to increase in the future. We find the Austin blind salamander is at an elevated risk of extinction now, and no data indicate that the situation will improve without significant additional conservation intervention. We, therefore, find that the Austin blind salamander warrants an endangered species listing status determination.
Present and future degradation of habitat (Factor A) is the primary threat to the Austin blind salamander. This threat has primarily occurred in the form of reduced water quality from introduced and concentrated contaminants (for example, PAHs, pesticides, nutrients, and trace metals), increased sedimentation, and altered stream flow regimes. These stressors are primarily the result of human population growth and subsequent urbanization within the watershed and recharge and contributing zones of the Barton Springs Segment of the Edwards Aquifer. Urbanization is currently having impacts on Austin blind salamander habitat. For example, a study by the U.S. Geological Survey concluded that baseline water quality in the Barton Springs Segment of the Edwards Aquifer, in terms of nitrate, had shifted upward between 2001 and 2010 and was at least partially the result of an increase in the land application of treated wastewater (Mahler
Further degradation of water quality within the Austin blind salamander's habitat is expected to continue into the future, primarily as a result of an increase in urbanization. Substantial human population growth is ongoing within this species' range, indicating that the urbanization and its effects on Austin blind salamander habitat will increase in the future. The Texas State Data Center (2012, pp. 496–497) has reported a population increase of 94 percent for Travis County, Texas, from the year 2010 to 2050. Data indicate that water quality degradation at Barton Springs continues to occur despite the existence of current regulatory mechanisms in place to protect water quality; therefore, these mechanisms are not adequate to protect this species and its habitat now, nor do we anticipate them to sufficiently protect the species in the future (Factor D).
An additional threat to the Austin blind salamander is hazardous materials that could be spilled or leaked potentially resulting in the contamination of both surface and groundwater resources. For example, a number of point-sources of pollutants exist within the Austin blind salamander's range, including 7,600 wastewater mains and 9,470 known septic facilities in the Barton Springs Segment of the Edwards Aquifer as of 2010 (Herrington
In addition, construction activities resulting from urban development may negatively impact both water quality and quantity because they can increase sedimentation and dewater springs by intercepting aquifer conduits. It has been estimated that total suspended sediment loads have increased 270 percent over predevelopment loadings within the Barton Springs Segment of the Edwards Aquifer (COA 1995, pp. 3–10). The risk of a hazardous material spill and effects from construction activities will increase as urbanization
The habitat of Austin blind salamanders is sensitive to direct physical habitat modification, particularly due to human vandalism of the springs and the Barton Springs impoundments. Eliza Spring and Sunken Garden Spring, two of the three spring outlets of the Austin blind salamander, experience vandalism, despite the presence of fencing and signage (Dries 2011, COA, pers. comm.). Also, the impoundments have changed the Barton Springs ecosystem from a stream-like system to a more lentic (still-water) environment, thereby reducing the water system's ability to flush sediments downstream and out of salamander habitat. In combination with the increased threat from urbanization, these threats are likely driving the Austin blind salamander to the brink of extinction now.
Future climate change could also affect water quantity and spring flow for the Austin blind salamander. Climate change could compound the threat of decreased water quantity at salamander spring sites by decreasing precipitation, increasing evaporation, and increasing the likelihood of extreme drought events. The Edwards Aquifer is projected to experience additional stress from climate change that could lead to decreased recharge and low or ceased spring flows given increasing pumping demands (Loáiciga
Other natural or manmade factors (Factor E) affecting the Austin blind salamander population include UV–B radiation, small population sizes, stochastic events (such as floods or droughts), and synergistic and additive interactions among the stressors mentioned above. While these factors are not threats to the existence of the Austin blind salamander in and of themselves, in combination with the threats summarized above, these factors make the Austin blind salamander population less resilient and more vulnerable to extinction now.
Because of the fact-specific nature of listing determinations, there is no single metric for determining if a species is “in danger of extinction” now. In the case of the Austin blind salamander, the best available information indicates that habitat degradation has occurred throughout the only known Austin blind salamander population. The threat of urbanization indicates that this Austin blind salamander population is currently at an elevated risk of extinction now and will continue to be at an elevated risk in the future. These impacts are expected to increase in severity and scope as urbanization within the range of the species increases. Also, the combined result of increased impacts to habitat quality and inadequate regulatory mechanisms leads us to the conclusion that Austin blind salamanders are in danger of extinction now. This Austin blind salamander population has become degraded from urbanization, low resiliency and is subsequently at an elevated risk from climate change impacts and catastrophic events (for example, drought, floods, hazardous material spills). Therefore, because the only known Austin blind salamander population is at an elevated risk of extinction, the Austin blind salamander is in danger of extinction throughout all of its range now, and appropriately meets the definition of an endangered species (that is, in danger of extinction now).
Under the Act and our implementing regulations, a species may warrant listing if it is threatened or endangered throughout all or a significant portion of its range. The threats to the survival of this species occur throughout its range and are not restricted to any particular significant portion of its range. Accordingly, our assessments and determinations apply to this species throughout its entire range.
In conclusion, as described above, the Austin blind salamander is subject to significant threats now, and these threats will continue to become more severe in the future. After a review of the best available scientific information as it relates to the status of the species and the five listing factors, we find the Austin blind salamander is currently on the brink of extinction. Therefore, on the basis of the best available scientific and commercial information, we list the Austin blind salamander as an endangered species in accordance with section 3(6) of the Act. We find that a threatened species status is not appropriate for the Austin blind salamander because the overall risk of extinction is high at this time. The one existing population is not sufficiently resilient or redundant to withstand present and future threats, putting this species in danger of extinction now.
In the proposed rule (77 FR 50768, August 22, 2012), the Jollyville Plateau salamander species was proposed as endangered, rather than threatened, because at that time, we determined the threats to be imminent, and their potential impacts to the species would be catastrophic given the very limited range of the species. For this final determination, we took into account data that was made available after the proposed rule published, information provided by commenters on the proposed rule, and further discussions within the Service to determine whether the Jollyville Plateau salamander should be classified as endangered or threatened. Based on our review of the best available scientific and commercial information, we conclude that the Jollyville Plateau salamander is likely to become in danger of extinction in the foreseeable future throughout all of its range and, therefore, meets the definition of a threatened species, rather than endangered. This finding, explained below, is based on our conclusions that many populations of the species have begun to experience impacts from threats to its habitat, and these threats are expected to increase in the future. As the threats increase, we expect Jollyville Plateau salamander populations to be extirpated, reducing the overall representation and redundancy across the species' range and increasing the species' risk of extinction. We find the Jollyville Plateau salamander will be at an elevated risk of extinction in the future, and no data indicate that the situation will improve without significant additional conservation intervention. We, therefore, find that the Jollyville Plateau salamander warrants a threatened species listing status determination.
Present and future degradation of habitat (Factor A) is the primary threat to the Jollyville Plateau salamander. This threat has primarily occurred in the form of reduced water quality from introduced and concentrated contaminants (for example, PAHs, pesticides, nutrients, and trace metals), increased sedimentation, and altered stream flow regimes. These stressors are primarily the result of human population growth and subsequent urbanization within the watersheds and
Further degradation of water quality within the Jollyville Plateau salamander's habitat is expected to continue into the future, primarily as a result of an increase in urbanization. Substantial human population growth is ongoing within this species' range, indicating that the urbanization and its effects on Jollyville Plateau salamander habitat will increase in the future. The Texas State Data Center (2012, pp. 496–497, 509) has reported a population increase of 94 percent and 477 percent for Travis and Williamson Counties, Texas, respectively, from the year 2010 to 2050. Data indicate that water quality degradation in sites occupied by Jollyville Plateau salamanders continues to occur despite the existence of current regulatory mechanisms in place to protect water quality; therefore, these mechanisms are not adequate to protect this species and its habitat now, nor do we anticipate them to sufficiently protect the species in the future.
Adding to the likelihood of the Jollyville Plateau salamander becoming endangered in the future is the risk from hazardous materials that could be spilled or leaked, potentially resulting in the contamination of both surface and groundwater resources. For example, a number of point-sources of pollutants exist within the Jollyville Plateau salamander's range, including leaking underground storage tanks and sewage spills from pipelines (COA 2001, pp. 16, 21, 74). A significant hazardous materials spill within stream drainages of the Jollyville Plateau salamander has the potential to threaten the long-term survival and sustainability of multiple populations.
In addition, construction activities resulting from urban development may negatively impact both water quality and quantity because they can increase sedimentation and dewater springs by intercepting aquifer conduits. Increased sedimentation from construction activities has been linked to declines in Jollyville Plateau salamander counts at multiple sites (Turner 2003, p. 24; O'Donnell
The habitat of Jollyville Plateau salamanders is sensitive to direct physical habitat modification, such as those resulting from human recreational activities, impoundments, feral hogs, and livestock. Destruction of Jollyville Plateau salamander habitat has been attributed to vandalism (COA 2001, p. 21), human recreational use (COA 2001, p. 21), impoundments (O'Donnell
Future climate change could also affect water quantity and spring flow for the Jollyville Plateau salamander. Climate change could compound the threat of decreased water quantity at salamander spring sites by decreasing precipitation, increasing evaporation, and increasing the likelihood of extreme drought events. The Edwards Aquifer is predicted to experience additional stress from climate change that could lead to decreased recharge and low or ceased spring flows given increasing pumping demands (Loáiciga
Other natural or manmade factors (Factor E) affecting all Jollyville Plateau salamander populations include UV–B radiation, small population sizes, stochastic events (such as floods or droughts), and synergistic and additive interactions among the stressors mentioned above. While these factors are not threats to the existence of the Jollyville Plateau salamander in and of themselves in combination with the threats summarized above, these factors make Jollyville Plateau salamander populations less resilient and more vulnerable to population extirpations in the foreseeable future.
Because of the fact-specific nature of listing determinations, there is no single metric for determining if a species is “in danger of extinction” now. In the case of the Jollyville Plateau salamander, the best available information indicates that habitat degradation has resulted in measureable impacts on salamander counts. But, given that there are 106 surface and 16 cave populations, it is unlikely that any of the current threats are severe enough to impact all of the sites and result in overall species extirpation in the near future. The Jollyville Plateau salamander's risk of extinction now is not high (it is not in danger of extinction now). However, the threat of urbanization will cause the Jollyville Plateau salamander to be at an elevated risk of extirpation in the future. Also, the combined result of increased impacts to habitat quality and inadequate regulatory mechanisms leads us to the conclusion that Jollyville Plateau salamanders will likely be in danger of extinction within the foreseeable future. As Jollyville Plateau salamander populations become more degraded, isolated, or extirpated from urbanization, the species will lose resiliency and be at an elevated risk from climate change impacts and catastrophic events, such as drought, floods, and hazardous material spills. These events will affect all known extant populations, putting the Jollyville Plateau salamander at a high risk of extinction. Therefore, because the resiliency of populations is expected to decrease in the foreseeable future, the Jollyville Plateau salamander will be danger of extinction throughout all of its range in the foreseeable future, and appropriately meets the definition of a threatened species (that is, in danger of extinction in the foreseeable future).
After a review of the best available scientific information as it relates to the status of the species and the five listing factors, we find the Jollyville Plateau salamander is not currently in danger of extinction, but will be in danger of extinction in the future throughout all of
Under the Act and our implementing regulations, a species may warrant listing if it is threatened or endangered throughout all or a significant portion of its range. The threats to the survival of this species occur throughout its range and are not restricted to any particular significant portion of its range. Accordingly, our assessments and determinations apply to this species throughout its entire range.
Conservation measures provided to species listed as endangered or threatened species under the Act include recognition, recovery actions, requirements for Federal protection, and prohibitions against certain practices. Recognition through listing results in public awareness and conservation by Federal, State, tribal, and local agencies, private organizations, and individuals. The Act encourages cooperation with the States and requires that recovery actions be carried out for all listed species. The protection required by Federal agencies and the prohibitions against certain activities are discussed, in part, below.
The primary purpose of the Act is the conservation of endangered and threatened species and the ecosystems upon which they depend. The ultimate goal of such conservation efforts is the recovery of these listed species, so that they no longer need the protective measures of the Act. Subsection 4(f) of the Act requires the Service to develop and implement recovery plans for the conservation of endangered and threatened species. The recovery planning process involves the identification of actions that are necessary to halt or reverse the decline in the species' status by addressing the threats to its survival and recovery. The goal of this process is to restore listed species to a point where they are secure, self-sustaining, and functioning components of their ecosystems.
Recovery planning includes the development of a recovery outline shortly after a species is listed and preparation of a draft and final recovery plan. The recovery outline guides the immediate implementation of urgent recovery actions and describes the process to be used to develop a recovery plan. Revisions of the plan may be done to address continuing or new threats to the species, as new substantive information becomes available. The recovery plan identifies site-specific management actions that set a trigger for review of the five factors that control whether a species remains endangered or may be downlisted or delisted, and methods for monitoring recovery progress. Recovery plans also establish a framework for agencies to coordinate their recovery efforts and provide estimates of the cost of implementing recovery tasks. Recovery teams (comprising species experts, Federal and State agencies, nongovernmental organizations, and stakeholders) are often established to develop recovery plans. When completed, the recovery outline, draft recovery plan, and the final recovery plan will be available on our Web site (
Implementation of recovery actions generally requires the participation of a broad range of partners, including other Federal agencies, States, tribes, nongovernmental organizations, businesses, and private landowners. Examples of recovery actions include habitat restoration (for example, restoration of native vegetation), research, captive propagation and reintroduction, and outreach and education. The recovery of many listed species cannot be accomplished solely on Federal lands because their range may occur primarily or solely on non-Federal lands. To achieve recovery of these species requires cooperative conservation efforts on private, State, tribal, and other lands.
Once these species are listed, funding for recovery actions will be available from a variety of sources, including Federal budgets, State programs, and cost-share grants for non-Federal landowners, the academic community, and nongovernmental organizations. In addition, pursuant to section 6 of the Act, the State of Texas will be eligible for Federal funds to implement management actions that promote the protection or recovery of the Austin blind and Jollyville Plateau salamanders. Information on our grant programs that are available to aid species recovery can be found at:
Section 7(a) of the Act requires Federal agencies to evaluate their actions with respect to any species that is proposed or listed as endangered or threatened and with respect to its critical habitat, if any is designated. Regulations implementing this interagency cooperation provision of the Act are codified at 50 CFR Part 402. Section 7(a)(4) of the Act requires Federal agencies to confer with the Service on any action that is likely to jeopardize the continued existence of a species proposed for listing or result in destruction or adverse modification of proposed critical habitat. If a species is listed subsequently, section 7(a)(2) of the Act requires Federal agencies to ensure that activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of the species or destroy or adversely modify its critical habitat. If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency must enter into formal consultation with the Service.
Federal agency actions within the species habitat that may require conference or consultation or both as described in the preceding paragraph include management, construction, and any other activities with the possibility of altering aquatic habitats, groundwater flow paths, and natural flow regimes within the ranges of the Austin blind and Jollyville Plateau salamanders. Such consultations could be triggered through the issuance of section 404 Clean Water Act permits by the Army Corps of Engineers or other actions by the Service, U.S. Geological Survey, and Bureau of Reclamation; construction and maintenance of roads or highways by the Federal Highway Administration; landscape-altering activities on Federal lands administered by the Department of Defense; and construction and management of gas pipelines and power line rights-of-way by the Federal Energy Regulatory Commission.
The Act and its implementing regulations set forth a series of general prohibitions and exceptions that apply
We may issue permits to carry out otherwise prohibited activities involving endangered and threatened wildlife species under certain circumstances. Regulations governing permits are codified at 50 CFR 17.22 for endangered wildlife, and at 50 CFR 17.32 for threatened wildlife. With regard to endangered wildlife, a permit must be issued for the following purposes: for scientific purposes, to enhance the propagation or survival of the species, and for incidental take in connection with otherwise lawful activities.
Executive Order 12866 provides that the Office of Information and Regulatory Affairs in the Office of Management and Budget (OMB) will review all significant rules. The Office of Information and Regulatory Affairs has determined that this rule is not significant.
Executive Order 13563 reaffirms the principles of E.O. 12866 while calling for improvements in the nation's regulatory system to promote predictability, to reduce uncertainty, and to use the best, most innovative, and least burdensome tools for achieving regulatory ends. The executive order directs agencies to consider regulatory approaches that reduce burdens and maintain flexibility and freedom of choice for the public where these approaches are relevant, feasible, and consistent with regulatory objectives. E.O. 13563 emphasizes further that regulations must be based on the best available science and that the rulemaking process must allow for public participation and an open exchange of ideas. We have developed this rule in a manner consistent with these requirements.
This rule does not contain any new collections of information that require approval by OMB under the Paperwork Reduction Act. This rule will not impose recordkeeping or reporting requirements on State or local governments, individuals, businesses, or organizations. An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB control number.
We have determined that environmental assessments and environmental impact statements, as defined under the authority of the National Environmental Policy Act (NEPA; 42 U.S.C. 4321
In developing this rule, we did not conduct or use a study, experiment, or survey requiring peer review under the Data Quality Act (Pub. L. 106–554).
A complete list of all references cited in this rule is available on the Internet at
The primary author of this document is staff from the Austin Ecological Services Field Office (see
Endangered and threatened species, Exports, Imports, Reporting and recordkeeping requirements, Transportation.
Accordingly, we amend part 17, subchapter B of chapter I, title 50 of the Code of Federal Regulations, as follows:
16 U.S.C. 1361–1407; 1531–1544; 4201–4245; unless otherwise noted.
(h) * * *