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National Wetland Plant List

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U. S. Army Corps of Engineers, Department of Defense.




The National Wetland Plant List (NWPL) is used to delineate wetlands for purposes of the Clean Water Act and the Wetland Conservation Provisions of the Food Security Act. Other applications of the list include wetland restoration, establishment, and enhancement projects. To update the NWPL, the U.S. Army Corps of Engineers (Corps), as part of an interagency effort with the U.S. Environmental Protection Agency (EPA), the U.S. Fish and Wildlife Service (FWS) and the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS), is announcing the availability of the draft National Wetland Plant List (NWPL) and its web address to solicit public comments. The public will now be provided the opportunity to comment and vote on the wetland indicator status ratings of the plants, species nomenclature changes and the revisions to the definition of indicator status ratings contained in the NWPL.


Written comments must be submitted on or before March 7, 2011.


You may submit comments on indicator status evaluations and general comments through the Web site identified below. Whenever possible, commenters should submit comments on-line at: http://wetland_​​. For instructions on how to submit comments online, please go to the supplementary section below.

For those without internet access, comments may be sent to Ms. Karen Mulligan, U.S. Army Corps of Engineers, Regulatory Community of Practice, 441 G St., NW., Washington, DC 20314-1000.

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Ms. Karen Mulligan, Headquarters, Regulatory Community of Practice, Washington, DC or Mr. Robert Lichvar, Director of the National Wetland Plant List, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory. Ms. Mulligan can be reached at (202) 761-4664 and Mr. Lichvar can be reached at (603) 646-4657.

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The effort to develop a comprehensive wetland plant list began with the FWS in 1976 and paralleled the development of their wetland classification system for the National Wetland Inventory (NWI), which culminated in Classification of Wetlands and Deepwater Habitats of the United States in 1979. A brief footnote in that publication mentions that the FWS intended to produce “a list of hydrophytes and other plants occurring in wetlands of the United States” for use in conjunction with the NWI. At about the same time the NRCS, then known as the Soil Conservation Service (SCS), initiated an effort to prepare a preliminary list of hydric soils, again for use with the NWI. Through a series of subsequent drafts, the FWS effort eventually led to the production of the National List of Plant Species That Occur in Wetlands: 1988 National Summary (List 88)—and associated regional lists.

The FWS initially derived the lists by searching some 300 national and regional floras and other scientific publications. This effort produced the Annotated National Wetland Plant Species Database, which documented the taxonomy, nomenclature, distribution, and ecology of wetland flora in the U.S. In 1987, the SCS (through a contract with the Biota of North America Program [BONAP]) updated the taxonomy and nomenclature that culminated in List 88. During the initial development of the database, a wetland rating system was created based on habitat Start Printed Page 778descriptions derived from the various regional floras, botanical manuals, and other scientific works.

In the early 1980s, the four primary Federal agencies involved in wetland delineation (Corps, EPA, FWS, and NRCS) realized the potential utility of the plant and soil lists for wetland delineation purposes in conjunction with wetland delineation manuals that were under development at that time. All wetland delineation manuals produced at the Federal level during the 1980s referenced these plant lists in defining hydrophytic vegetation.

The four agencies agreed to participate cooperatively on Regional Interagency Review Panels. A National Panel of wetland ecologists was assembled to review and further revise the various plant lists and the wetland rating system established by the FWS. This rating system, based on the frequency that a particular plant occurs within wetlands versus uplands, eventually led to the five indicator categories listed in List 88 (i.e., obligate wetland, facultative wetland, facultative, facultative upland, and obligate upland).

The FWS realized that subsequent editions of their List 88 would be inevitable and an appeal procedure was established for submitting proposed changes to the list (e.g. additions, deletions, and changes in indicator statuses). Since the original publication of List 88, many changes to the taxonomy and nomenclature of wetland plants have been proposed and accepted. Following the original publication of List 88, the FWS adopted a revised taxonomic standard, Synonymized Checklist of the Vascular Flora of the United States, Canada, and Greenland (Kartesz 1994), as a basis for the names included within the proposed list, National List of Vascular Plant Species that Occur in Wetlands (List 96).

The National Panel and the FWS considered it necessary to respond to requests for changes to List 88 and to the numerous revisions in both taxonomy and nomenclature by proposing List 96 and its derivative regional lists. The FWS published proposed changes to List 88 in the Federal Register (62 CFR 2680) on January 17, 1997, in compliance with a 1996 Memorandum of Agreement between the Corps, EPA, FWS, and NRCS. The National Panel received comments and, in conjunction with the Regional Panels, reviewed and considered all comments in developing the final draft of List 96. For a variety of reasons, List 96 was never finalized, and List 88 remains the only approved list of wetland plant indicator statuses.

In 2005, the FWS developed plans to update and adopt List 96 as List 05. This new List was to include all of the changes in scientific names and wetland indicator statuses that were needed because of taxonomic and nomenclatural changes; however, this update never occurred. In December 2006, the administration of the list was transferred from the FWS to the Corps through a Memorandum of Agreement, which renamed the list as the National Wetland Plant List. The list continues to be an interagency product maintained by the Corps, FWS, EPA, and NRCS. The National Panel consists of representatives from each of the four participating agencies who direct the continued development of the NWPL. They guide the work by updating the taxonomy and nomenclature along with wetland indicator statuses of wetland plants nationwide. The number of plants listed has changed since List 88; growing from 6,728 species to 7,662 in List 96, with the majority of the increase resulting from taxonomic and nomenclatural changes, including the addition of many infraspecific taxa (i.e., varieties and subspecies). By 2010, further advances in systematic science involving wetland plants resulted in an additional 1,600 infraspecific entries. Because of taxonomic and nomenclatural changes since 1988, the number of infraspecific taxa has increased to 2,200; substantially more than the original 12 in List 88 and 600 in List 96. Because this seemed to be an impractically high number of entries, the National Panel of the NWPL decided to revert back to the species-level taxonomy, and to not include any infraspecific taxa. Thus, the current review of the 8,558 species does not separately treat these infraspecific taxa with their own distinct wetland ratings and includes all the infraspecific taxa at the species-level.

Nomenclature Issues

Changes in nomenclature frequently affect the wetland indicator status. In the updated database, the currently accepted name is linked to the List 96 and List 88 scientific names and any former synonyms. This link allows a reviewer to consider all prior ratings, which may be critical information for species that have been merged or split. The National Panel established methods using List 96 draft ratings as the starting point to minimize effort and recognize prior updates from the 1990s. Many changes to nomenclature and scientific advances were considered during the updating of the NWPL, including the following outcomes:

1. Species names from List 96 that did not change and are currently accepted.

2. Species names from List 96 that were assigned a new species name (these include misapplication of genus, spelling, recognized author changed, etc.).

3. Two or more species names from List 96 that merged into one species name (these include all nomenclatural adjustments such as autonyms, homonyms, hybrids, isonyms, synonyms, tautonyms, etc.).

4. Species names from List 96 that were split into two or more species names.

5. New species of wetland taxa that were added since Kartesz's 1994 checklist.

Indicator Status Ratings

In List 88, there are five categories of indicator status, or ratings, used to describe a plant's likelihood for occurrence in a wetland versus an upland: Obligate Wetland (OBL), Facultative Wetland (FACW), Facultative (FAC), Facultative Upland (FACU), and Obligate Upland (UPL). These ratings represent the estimated probability of a species occurring in wetlands versus non-wetlands in a region. This method is problematic for two reasons: the ratings are not supported by numerical data, and the previous FWS definition of frequency, which was the basis for the division of groups that the wetland plant ratings were tied to, did not include a mathematical expression useful for testing the wetland ratings. These issues have led to misinterpretations of the frequency formula. To address some of these problems, the National Panel modified the definitions for the indicator status categories to increase clarity and to better describe species occurrences. The indicator status developed recently by the National Panel for updating the NWPL are; OBL—almost always is a hydrophyte, rarely in uplands; FACW—usually is a hydrophyte but occasionally found in uplands; FAC—commonly occurs as either a hydrophyte or non-hydrophyte; FACU—occasionally is a hydrophyte but usually occurs in uplands; UPL—rarely is a hydrophyte, almost always in uplands.

The original information supporting indicator status assignments, from List 88 through List 96, was qualitative and not quantitative. To better reflect this supporting information, the new category definitions are also based on qualitative descriptions, rather than numeric frequency ranges. The Start Printed Page 779percentage frequency categories used in the older definitions will only be used for testing problematic or contested species being recommended for indicator status changes.

The Update Process

Over the past year and a half, updates have occurred through a web-based application that allows many more users to access information, while also retaining a permanent and transparent update record. Using the secure Web site, the National and Regional Panels have been able work online in their efforts to generate a draft Federal update of the NWPL. Until this notice in the Federal Register, the public and other governmental entities have had access to the rest of the botanical data on the site, but not to the panel evaluations that were used to develop the draft NWPL.

Instructions for Providing Comments Online

When visiting the Web site the first time, the user will have to accept the Department of Defense (DoD) certificate associated with the secure Web site. Once on the Web site, the user needs to click on the link titled “PARTICIPATE IN THE NWPL UPDATE.” The commenter will be sent to a login page where they will enter their name, a user name (first initial and last name), password, e-mail address and select their institutional affiliation. The automatic login generator will, by e-mail, confirm the registration of the user name and password and the user can then login and proceed to the query page. The Corps wetland supplement regions map is shown in a color-coded format. Comments may be made on one or multiple wetland supplement regions. The entire wetland plant list for each wetland supplement region is shown on the results page after a region is chosen and accepted. All prior votes associated with the update can also be shown on the query results page by selecting the “Yes” “Show All Votes?” radio button at the top of the page. Each species has a red “vote” link in each row. Clicking on the red word “VOTE” for that species will send the commenter to the species page where a vote may be made. The species page includes scientific and common names, synonyms, voting history by the panels, 1988 and 1996 statuses and maps based on North American distributions and counties. This information can be considered when submitting comments on the wetland rating for the species. Comments including literature citations, experiential references, monitoring data and other relevant reports should be submitted through the “Questions or Comments? Contact us!” link on the homepage. All votes and comments will be compiled and sent to the Regional Panel for their consideration. In the Atlantic and Gulf Coastal Plains region, “more input needed” is marked in red for 75 species. The Corps is requesting assistance in the form of comments, literature references, data or experience for these species in the comment box to help clarify their status.

In all cases, the most useful comments are from specific knowledge or studies related to individual species. Reviewers should use their regional botanical and ecological expertise, field observations, reviews of the most recent indicator status information, appropriate botanical literature, floras, herbarium specimens with notation of habitat and associated species, habit data, relevant studies, and historic list information. Guessing is inappropriate, and for plants unknown to the reviewer, it is preferable that commenters select the “I do not know (DK)” option rather than simply guessing an indicator status.

If the commenter has other comments in general that are not species specific, there is an email contact link on the homepage. The link is titled “Questions or Comments? Contact us!”. By clicking on this link, the commenter can submit other comments in regard to the NWPL update in general.

For the purposes of determining a species frequency and abundance in wetlands, wetlands are defined as those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions (33 CFR 328.3 and 40 CFR 230.3). Such wetlands are identified using the Corps 1987 Wetland Delineation Manual or relevant regional supplements, whichever is more recent. Wetlands are identified using the three-factor approach. Because the species being evaluated is part of a vegetation assemblage, examining the other species present in relation to their assigned wetland fidelity may be useful in assessing hydrophytic vegetation.

Species newly proposed as wetland plants have been added to the Draft NWPL. Commenters who would like to propose a new wetland species to the list may do so on the home page. These species will be checked for current nomenclatural status, and their supportive data will be added to the Web site to assist with the assignment of a wetland rating. These newly proposed species and suggested ratings will be sent to the Regional Panels for review and will go through the same evaluation process as for species already on the list.

Recommendations for a different indicator status for select species in additional subregions may be submitted. The subregions are based on Land Resource Regions (LRRs) and Major Land Resource Areas (MLRAs) (​survey/​geography/​mlra/​) and are shown for each wetland supplement region on the NWPL Web site. If the commenter feels that a wetland supplement region needs a subregion that has not yet been developed, the commenter should identify the MLRAs involved and provide a list of species from within that region that need their own wetland ratings. These can be submitted on the home page by clicking on the link titled “PROPOSE NEW SPECIES.”

When assigning wetland indicator statuses, reviewers should consider the ecological information on the Web site, which includes prior information obtained by the FWS and others.

Commenters should use the status definitions described above and developed by the National Panel for updating the NWPL. The percentage frequency categories used in the older definitions can be used for testing problematic or contested species being recommended for indicator status changes.

A sampling and testing protocol is being developed for future recommended additions to the NWPL. Future requests for changes to wetland ratings will be evaluated using scientific approaches using limited but strategic field data. Submissions for future recommended changes in indicator status must follow the established protocols and must include submission of ecological data, literature review, testing description, and geographical data.

Wetland indicator designations such as No Indicator (NI), No Occurrence (NO), and No Agreement (NA) will not be used in the updated NWPL. Inclusion of Upland (UPL) plants was considered, but it was decided for this update of the NWPL they will not be included until after the update is complete. The addition of upland plants later is necessary to support wetland delineations that are typically done at the ecotone between wetland and upland landscapes. If a plant species has been identified as occurring in a wetland habitat, but is not listed in a regional or state list, the NWPL should be consulted to verify whether that species occurs in wetlands in adjacent areas before it is assumed to be UPL and Start Printed Page 780the NWPL is updated to label these species with this rating.

The plus and minus modifiers have been dropped, and only five indicator designations (i.e., OBL, FACW, FAC, FACU, UPL) will be used in the NWPL. All plants previously assigned these modifiers have been merged into their broader indicator category during the review and revision process, with the exception of those plants assigned FAC-. The National and Regional Panels, as well as the academics, reviewed all species from the 1996 National List of Plant Species that Occur in Wetlands (hereafter called the List, with specific versions noted by their year of establishment) that were assigned FAC- to appropriately categorize their wetland rating.

Future Actions

Public comments received through the web-based system will be compiled and tracked to provide an administrative record.

Regional Panels, in conjunction with the National Panel, will review comments from the Tribes, other federal agencies, states, and the public and will develop the final regional lists. The majority of final wetland ratings will be developed based on the analysis of all input and comments. For those species without general agreement, the National Panel will assign ratings using a specific protocol developed for this purpose.

After the National Panel assigns wetland ratings to non-consensus species and reviews all regional lists, it will develop the final NWPL.

Notice of the final NWPL will be published in the Federal Register along with the web address.

Maintenance and annual reviews and updates of the NWPL will be done using the web-based system.

Future for the NWPL Web Site

Protocols were developed to ensure that updates to the NWPL will occur biennially or as necessary and that they will follow scientifically acceptable procedures. The updating process will provide guidelines established by the National Panel for testing wetland indicator status ratings for future recommended changes and additions to the NWPL. The process will be supported by an interactive Web site where all procedures and supportive information will be posted. Information on this searchable Web site will include the names of all National and Regional Panel members, prior ecological information obtained by the FWS or Kartesz (BONAP) for each species, any comments previously made by others that was retained in the FWS database on the NWPL, and links to botanical literature and plant ecology information to support assignment of wetland indicator statuses of all species under consideration.

Once the NWPL is initially updated, this Web site will be expanded to include upland plants and facilitate regular updates as additional information is submitted and nomenclature changes. These changes will be generated through a modification of the web-based process outlined above. Regular updates based on nomenclature changes will be developed on a biennial basis. Anyone may petition for a change in indicator status for any taxon by submitting appropriate ecological data, literature review, testing description, and geographic data. This will include frequency and abundance data for the taxon in wetlands and uplands in a broad range of the wetland supplement region or subregion for which the change is proposed. Such data will be reviewed and evaluated by the appropriate Regional Panel, and any changes they recommend will go through a vetting process similar to the initial NWPL update. The Web site will contain the most recent, currently valid indicator statuses.


We utilize the NWPL to conduct wetland determinations under the authority of Section 404 of the Clean Water Act (33 U.S.C. 1344) and Section 10 of the Rivers and Harbors Act of 1899 (33 U.S.C. 401 et seq.).

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Dated: December 17, 2010.

Michael G. Ensch,

Chief, Operations and Regulatory, Directorate of Civil Works.

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[FR Doc. 2011-3 Filed 1-5-11; 8:45 am]