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Proposed Rule

Endangered and Threatened Wildlife and Plants; Reopening of Public Comment Period and Notice of Availability of Draft Economic Analysis for Proposed Critical Habitat Determination for the Chorizanthe robusta

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Fish and Wildlife Service, Interior.


Proposed rule; reopening of public comment period and notice of availability of draft economic analysis.


We, the U.S. Fish and Wildlife Service (Service) announce the availability of a draft economic analysis for the proposed designation of critical habitat for Chorizanthe robusta var. hartwegii (Scotts Valley spineflower). We are also providing notice of the reopening of the public comment period for the proposal to designate critical habitat for this plant to allow all interested parties to comment simultaneously on the proposed rule and the associated draft economic analysis. Comments previously submitted need not be resubmitted as they already have been incorporated into the public record and will be fully considered in the final rule. Comments submitted during this comment period will also be incorporated into the public record and will be fully considered in the final rule.


The comment period is opened and we will accept comments until October 19, 2001. Comments must be received by 5 p.m. on the closing date. Any comments that are received after the closing date may not be considered in the final decision on this proposal.


Copies of the draft economic analysis are available on the Internet at “ or by writing to the Field Supervisor, U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, California 93003.

All written comments should be sent to the Field Supervisor at the above address. You may also send comments by electronic mail (e-mail) to “”. Please submit electronic comments in ASCII file format and avoid the use of special characters and encryption. Please include “Attn: RIN 1018-AH82” and your name and return address in your e-mail message. If you do not receive a confirmation from the system that we have received your e-mail message, contact us directly by calling our Ventura Fish and Wildlife Office at phone number 805-644-1766. Comments and materials received will be available for public inspection, by appointment, during normal business hours at the above Service address.

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Catrina Martin, Assistant Field Supervisor, Ventura Fish and Wildlife Office, at the above address (telephone 805-644-1766; facsimile 805-644-3958).

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Chorizanthe robusta var. hartwegii is a low-growing herb with rose-pink involucral margins confined to the basal portion of the teeth and an erect habit. The aggregate flowers (heads) are medium in size (1 to 1.5 cm (0.4 to 0.6 in.) in diameter) and distinctly aggregate. The plant germinates during the winter months and flowers from April through June. Although pollination ecology has not been studied for this taxon, it is likely visited by a wide array of pollinators; observations of pollinators on other species of Chorizanthe that occur in Santa Cruz County have included leaf cutter bees (megachilids), at least 6 species of butterflies, flies, and sphecid wasps. Each flower produces one seed; depending on the vigor of individual plants, dozens, if not hundreds, of seeds could be produced. The importance of pollinator activity in seed set has been demonstrated in another species of Chorizanthe by the production of seed with low viability where pollinator access was limited (Harding Lawson Associates 2000). Seed dispersal is facilitated by the involucral spines, which attach the seed to passing animals. Chorizanthe robusta var. hartwegii is one of two varieties of the species C. robusta. The other variety (C. robusta var. robusta), known as the robust spineflower, is known from the coast of southern Santa Cruz and northern Monterey counties and also is listed as endangered.

Chorizanthe robusta var. hartwegii is known from two sites about one mile apart at the northern end of Scotts Valley in Santa Cruz County, California. One site is located north of Casa Way and west of Glenwood Drive in northern Scotts Valley, referred to as the “Glenwood” site. The second site, located just east of Highway 17 and north of Navarra Road in northern Scotts Valley, is referred to as the “Polo Start Printed Page 48228Ranch” site. The plant is found on gently sloping to nearly level, fine-textured, shallow soils over outcrops of Santa Cruz mudstone and Purisima sandstone (Hinds and Morgan 1995). Chorizanthe robusta var. hartwegii occurs with Polygonum hickmanii and other small annual herbs in patches within a more extensive annual grassland habitat. These small patches have been referred to as “wildflower fields” because they support a large number of native herbs, in contrast to the adjacent annual grasslands that support a greater number of non-native grasses and herbs. While the wildflower fields are underlain by shallow, well-draining soils, the surrounding annual grasslands are underlain by deeper soils with a greater water-holding capacity, and therefore more easily support the growth of non-native grasses and herbs. The surface soil texture in the wildflower fields tends to be consolidated and crusty rather than loose and sandy (Biotic Resources Group (BRG) 1998). Elevation of the sites is from 215 to 245 meters (m) (700 to 800 feet (ft)) (Hinds and Morgan 1995). The climate in the city of Santa Cruz, 13 km (8 mi) to the south, is characterized by an average of 76.7 cm (30 in.) of rain per year, and an average temperature of 14 degrees Celsius (57 degrees Fahrenheit) per year, while the city of Los Gatos, 16 km (10 mi) to the north, averages 129.9 cm (51 in.) of rain per year, and an average temperature of 15 degrees Celsius (58 degrees Fahrenheit) per year (Worldclimate 1998).

Chorizanthe robusta var. hartwegii is associated with a number of native herbs including Polygonum hickmanii (Scotts Valley polygonum), Lasthenia californica (goldfields), Minuartia douglasii (sandwort), Minuartia californica (California sandwort), Gilia clivorum (gilia), Castilleja densiflora (owl's clover), Lupinus nanus (sky lupine), Brodiaea terrestris (brodiaea), Stylocline amphibola (Mount Diablo cottonweed), Trifolium grayii (Gray's clover), and Hemizonia corymbosa (coast tarplant). Non-native species present include Filago gallica (filago) and Vulpia myuros (rattail) (California Natural Diversity Data Base (CNDDB) 1998; Randy Morgan, biological consultant, pers. comm. 1998). In many cases, the habitat also supports a crust of mosses and lichens (Biotic Resources Group 1998).

Pursuant to the Endangered Species Act of 1973, as amended (Act), Chorizanthe robusta var. hartwegii, was listed as endangered on February 4, 1994 (59 FR 5499). On February 15, 2001, we published in the Federal Register (66 FR 10469) a rule proposing critical habitat for the Chorizanthe robusta var. hartwegii. Approximately 125 hectares (310 acres) of land fall within the boundaries of the proposed critical habitat designation. Proposed critical habitat is located in Santa Cruz County, California, as described in the proposed rule.

Section 4(b)(2) of the Act requires that the Secretary shall designate or revise critical habitat based upon the best scientific and commercial data available and after taking into consideration the economic impact of specifying any particular area as critical habitat. Based upon the previously published proposal to designate critical habitat for Chorizanthe robusta var. hartwegii and comments received during the previous comment period, we have prepared a draft economic analysis of the proposed critical habitat designation. The draft economic analysis is available at the above Internet and mailing address.

Public Comments Solicited

We have reopened the comment period at this time in order to accept the best and most current scientific and commercial data available regarding the proposed critical habitat determination for the Scotts Valley spineflower and the draft economic analysis of proposed critical habitat determination. Previously submitted written comments on this critical habitat proposal need not be resubmitted. We will accept written comments during this reopened comment period. The current comment period on this proposal closes on October 4, 2001. Written comments may be submitted to the Ventura Fish and Wildlife Office in the ADDRESSES section.

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Authority: The authority for this action is the Endangered Species Act of 1973 (16 U.S.C. 1531 et seq.).

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Dated: September 7, 2001.

Daniel S. Walsworth,

Acting Manager, California/Nevada Operations Office.

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[FR Doc. 01-23247 Filed 9-18-01; 8:45 am]