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CFR Citation: 50 CFR Part 17

RIN ID: RIN 1018-AH76

NOTICE: RULES

ACTION: Endangered and threatened species:

DOCUMENT ACTION: Final rule.

SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; Endangered Status and Designation of Critical Habitat for Polygonum hickmanii (Scotts Valley polygonum)

DATES: This rule becomes effective on May 8, 2003.

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine endangered status pursuant to the Endangered Species Act of 1973, as amended (Act), for Polygonum hickmanii (Scotts Valley polygonum). Polygonum hickmanii is restricted to two sites in northern Scotts Valley, Santa Cruz County, California. We are also designating critical habitat pursuant to the Act for this species; 116 hectares (287 acres) of land are designated as critical habitat. This rule implements the protection and recovery provisions afforded by the Act for this species.

SUMMARY: Scotts Valley polygonum,

SUPPLEMENTAL INFORMATION

Polygonum hickmanii (Scotts Valley polygonum) is a recently described endemic plant species from Scotts Valley, Santa Cruz County, California (Hinds and Morgan 1995). Randy Morgan made the type collection in 1993 from a ``grassland [north] of Navarra Drive, [west] of Carbonero Creek'' (Hinds and Morgan 1995). The species was named after James C. Hickman, editor of the Jepson ManualHigher Plants of California (Hickman 1993) and author of the chapter on the genus Polygonum in the same reference. Hickman concurred with Morgan's assessment that the taxon was distinct (J.C. Hickman, in litt. 1991), but died before coauthoring the publication of a name. The plant is a small, erect, taprooted annual in the buckwheat family (Polygonaceae). It grows from 2 to 5 centimeters (cm) (1 to 2 inches (in)) tall and can be either single stemmed or profusely branching near the base in more mature plants. The linearshaped leaves are 0.5 to 3.5 cm (0.2 to 1.4 in) long, 1 to 1.5 mm (0.04 to 0.06 in) wide, and tipped with a sharp point. The single white flowers consist of two outer and three inner tepals (petallike structure) and are found in the axils of the bracteal leaves (modified leaves near the flower).

The nearest known location of a closely related species, Polygonum parryi, is at Mount Hamilton, about 48 kilometers (km) (30 miles (mi)) inland. Polygonum hickmanii differs from P. parryi in its larger white flowers, longer leaves, larger anthers and achenes, and longer, straight stem sheath (Hinds and Morgan 1995). According to the late Harold Hinds, who was reviewing the genus Polygonum in an upcoming volume of the Flora of North America (Flora of North America Editorial Committee, in prep.), he intended to continue to recognize the distinctness of P. hickmanii as a species in that volume (Harold Hinds, University of New Brunswick, pers. comm., 1998). His successor, Mihai Costea, indicates there is no reason to doubt the validity of the taxon (M. Costea, University of Guelph, Ontario, Canada, in litt. 2002).

As with many other annual species found within Mediterranean climates in California (Holland and Keil 1990), Polygonum hickmanii germinates in the fall or early winter in response to winter season rains. The plant grows slowly over the next few months and remains fairly inconspicuous until flowering begins in May. The panicles (floral branches) are indeterminate in their growth, meaning that the oldest flowers are found near the base of the stem and younger flowers found near the continually growing tip. The degree to which P. hickmanii depends on insect pollinators (rather than being self pollinated) has not been determined. However, Morgan observed a sphecid wasp (family Sphecidae) visitation to an individual P. hickmanii (R. Morgan, pers. comm., 1998).

With the type of floral development found in P. hickmanii, new flowers will continue to be produced until climate or microhabitat conditions are no longer favorable. Consequently, seed production ranges from a few dozen seeds in a typical individual to as many as two hundred in a particularly robust individual (Randy Morgan, biological consultant, pers. comm., 1998).

The seeds of many plant taxa within the buckwheat family (Polygonanceae) are known to be attractive forage to wildlife, who then inadvertently disperse some portion of the seed. Because the seed of Polygonum hickmanii are small, they most likely would be attractive to birds and small mammals including such species as blacktailed hares (Lepus californicus), pocket mice (Perognathus californicus), western gray squirrel (Sciurus griseus), ground squirrels (Otospermophilus beecheyi), striped skunks (Mephitis mephitis), opossums (Didelphis virginiana) and racoons (Procyon lotor).

Maintaining a seed bank (a reserve of dormant seeds, generally found in the soil) is important to the yeartoyear and longterm survival of annual plants (Baskin and Baskin 1978, Baskin and Baskin 1998). A seed bank includes all the mature seeds in a population and generally covers a larger area than the extent of observable plants seen in a given year (Given 1995). The number and location of standing plants (the observable plants) in a population varies annually due to a number of factors, including the amount and timing of rainfall, temperature, soil conditions, and the extent and nature of the seed bank. The extent of seed bank reserves is variable from population to population and large fluctuations in the number of standing plants at a given site may occur from one year to the next.

The distribution of Polygonum hickmanii has apparently been limited to the northern Scotts Valley area in Santa Cruz County, California. Two bodies of evidence support this theory. First, none of the herbarium collections of other Polygonum species that were checked in preparation for the publication of the name for P. hickmanii matched those collected from Scotts Valley. Herbaria that were searched included the Dudley Herbarium at Stanford University, the Jepson and University of California (UC) herbaria located at UC Berkeley, and the herbarium at the Missouri Botanic Garden (H. Hinds, in litt. 1998; R. Morgan, pers. comm., 1998). Secondly, predictive searches of other potentially suitable habitat in Santa Cruz County (based on soil type, local climate, and associated species) have failed to locate additional colonies of P. hickmanii (R. Morgan, pers. comm., 1998).

Polygonum hickmanii is found at two sites about 0.6 km (1 mi) apart at the northern end of Scotts Valley. The plant is found on gently sloping to nearly
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level shallow soils over outcrops of Santa Cruz mudstone and Purisima sandstone (Hinds and Morgan 1995). It frequently, though not always, occurs with the endangered Chorizanthe robusta var. hartwegii (Scotts Valley spineflower) (59 FR 5499) and other small annual herbs in patches within a more extensive annual grassland habitat. These small patches, scattered in a mosaic throughout the grassland plant community, 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 nonnative 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 waterholding capacity, and therefore more easily support the growth of nonnative grasses and herbs.

Although the patches of wildflower field habitat stand out in contrast to the surrounding grasslands, a closer look at the wildflower field patches reveals slight microhabitat differences within the patch itself. The outer edge, or ``ring'' of the patch supports the greatest diversity of the native herbs, which are found on the deepest soils within the patch. Moving toward the center of the patch, the soil layer is shallower, and another ring supporting primarily the endangered Chorizanthe robusta var. hartwegii occurs here. In the very center of the patch where the soils are shallowest, the greatest concentration of Polygonum hickmanii is found, and other species are sparse. The surface soil texture in the center of the wildflower fields tends to be consolidated and crusty rather than loose and sandy (Biotic Resources Group (BRG) 1998). Flowering in P. hickmanii lags behind that of the endangered Chorizanthe robusta var. hartwegii and the other herbs by 4 to 8 weeks, and the consolidated soil surface may play a role in supplying late spring moisture to the species (R. Morgan, pers. Comm. 2003).

Elevation of the sites is from 215 to 246 meters (m) (700 to 800 feet (ft)) (Hinds and Morgan 1995). In the Scotts Valley area, the grasslands tend to be located on the middle to lower slopes within the subwatersheds, while the slopes above the grasslands tend to support redwood and mixed forest plant communities. On the Polo parcel, the slopes become increasingly steep from west to east; slopes nearest to Carbonero Creek on the western edge of the parcel are less than 20 percent, the slopes in the middle of the parcel range from 20 to 40 percent, and the slopes along the eastern edge of the parcel up to the ridgeline reach over 40 percent. Geologic reports discuss several hazards that contribute to the geologic instability of the site. First, the site is within a seismically active region that experiences groundshaking. Second, the site has been subject to landslide activity, and evidences of past debris flows have been observed on the site. Third, due to the impermeable nature of the Purisima Formation bedrock, seasonal perched groundwater conditions are common in areas where the bedrock is overlain by alluvium (material deposited by flowing water) and colluvium (loose deposit of rock debris accumulated at the base of a cliff or slope), which contributes to slope instability (Impact Sciences 2000).

The geology of the Glenwood parcel has some similarities to the Polo parcel. Santa Cruz mudstone underlays the lower slopes and alluvial deposits, and the Purisima Formation underlays the upper slopes and ridges. The lowest elevations are along Carbonero Creek, which runs through the middle of the parcel from north to south. Similar to the Polo parcel, the mildest slopes are adjacent to the creek, while the slopes generally increase with increased distance from the creek, and slopes along the ridges to the east and west reach over 30 percent (Impact Sciences 1997, 1998). Geologic hazards on the site that contribute to slope instability include seismic hazards, landslide activity, high erosion, and sedimentation potential due to the presence of springs and drainages and the impermeable nature of the Purisima Formation on the upper slopes. Although soil erosion and sedimentation are natural processes, human activities can increase the rates above their natural levels (Global Change Research Information Office (GCRIC) 2002). Processes such as soil erosion on upper slopes, the accumulation of sedimentation on lower slopes, and soil compaction can alter the physical and chemical properties of those soils sufficiently to change their ability to store and supply nutrients and moisture needed by plants (GCRIC 2002). The persistence of plants with specific microhabitat requirements depends on maintaining the appropriate edaphic or soil conditions. Maintaining the stability of the higher slopes within a subwatershed are therefore important for maintaining the stability of the edaphic conditions directly downslope.

Polygonum hickmanii is associated with a number of native herbs including Chorizanthe robusta var. hartwegii, 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). Nonnative species present at the two sites include Filago gallica (filago) and Vulpia myuros (rattail) (California Natural Diversity Data Base (CNDDB) 1998; R. Morgan, pers. comm., 1998). In many cases, the habitat also supports a crust of mosses and lichens (BRG 1998).

For purposes of this rule, a concentration of individuals of Polygonum hickmanii will be referred to as a ``colony.'' Because of the close proximity of many of the colonies to each other (less than 0.4 km (0.2 mi) apart), it is unknown whether they function as genetically separate units or not. The approximate area occupied by any one colony ranges from the smallest at 1.5 m by 1.5 m (5 ft by 5 ft) to the largest at 15 m by 9 m (50 ft by 30 ft). Currently, there are approximately 11 colonies of P. hickmanii in total; the area covered by observable plants is less than 0.4 hectare (ha) (1 acre (ac)).

The Polygonum hickmanii colonies are split between two sitesthe Glenwood site and the Polo Ranch site. The Glenwood site is located north of Casa Way and west of Glenwood Drive in northern Scotts Valley; it contains five colonies on two parcels of land. One of these colonies is situated within a 3.6 ha (9 ac) preserve on a 19.4 ha (48 ac) parcel that is owned by the Scotts Valley Unified School District and is referred to as the ``School District'' colony (Denise Duffy and Associates 1998). The other four colonies at the Glenwood site are located approximately 0.21 km (0.13 mi) to the west of the School District colony, on a parcel of land owned by the Salvation Army (CNDDB 1998). These four colonies are referred to as the ``Salvation Army'' colonies. Additional suitable but unoccupied habitat is found on the east side of Glenwood Drive on a parcel owned by Glenwood/American Dream. This parcel was recently approved for a housing development; a large portion of the parcel will be designated as ``open space,'' and a management plan will be developed to take into consideration the conservation of sensitive resources (Wetlands Research Associates 2002). This open space area supports numerous colonies of Chorizanthe robusta var. hartwegii, which is frequently found in the same wildflower field patches as Polygonum hickmanii, as well as the endangered Ohlone tiger
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beetle (Cicindela ohlone) (Impact Sciences 2001).

The Polo Ranch site contains six colonies. This site is located just east of Highway 17 and north of Navarra Road in northern Scotts Valley, and is approximately 1.6 km (1 mi) east of the Salvation Army and School District colonies. These six colonies are situated within 0.2 km (0.1 mi) of one another, and all of these colonies occur on a parcel owned by Greystone Homes (Kathleen Lyons, BRG, in litt. 1997; Impact Sciences 2000).

Polygonum hickmanii is a shortlived annual species, and the total number of individuals can vary from year to year. In 2002, the total number of individual stems found at the Glenwood site was approximately 340 (140 on the School District parcel and approximately 200 on the Salvation Army parcel) (K. Lyons, in litt. 2002; Biotic Resources Group 2002); the Salvation Army parcel supported as many as 2,000 plants in 1998 (K. Lyons, pers. comm., 1998). In 1998, the total number of individuals on the Polo Ranch site was approximately 1,259 (K. Lyons, in litt. 1997).

Previous Federal Action

We first became aware of Polygonum hickmanii in 1992 during the development of the proposed listing rule for Chorizanthe robusta var. hartwegii (66 FR 10469). At that time, however, a name for the taxon had not formally been published, and so we did not consider it for listing under the Act. Once the name, P. hickmanii, was published by Hinds and Morgan (1995), we reviewed information in our existing files, in the California Natural Diversity Data Base, and new information on proposed projects being submitted to us for our review, and we determined that sufficient information existed to believe that listing may be warranted. Polygonum hickmanii was included in the list of candidate species published in the Federal Register on October 25, 1999 (64 FR 57534).

On November 9, 2000, we published a rule to propose (65 FR 67335) Polygonum hickmanii as an endangered species. At the time of the proposed listing, we determined that critical habitat for P. hickmanii was prudent, but deferred proposing critical habitat designation until a proposal to designate critical habitat could be developed for both P. hickmanii and Chorizanthe robusta var. hartwegii, a plant species already listed as endangered, because the two taxa share the same ecology and geographic location. We proposed critical habitat for both of these taxa on February 15, 2001 (66 FR 10469); the final critical habitat designation for Chorizanthe robusta var. hartwegii was published on May 29, 2002 (67 FR 37336). On May 22, 2002, the Center for Biological Diversity (CBD) filed a lawsuit alleging our failure to issue a final listing and critical habitat designation for P. hickmanii violated the time requirements specified in the Act. In settlement of this lawsuit, we agreed to complete the final listing and critical habitat designations by March 30, 2003.

Summary of Comments and Recommendations

In the November 9, 2000, proposed rule to list the species (65 FR 67335) and associated notifications, all interested parties were requested to submit factual reports or information that might contribute to the development of a final rule. A 60day comment period closed on January 8, 2001. Appropriate State agencies, county governments, Federal agencies, scientific organizations, and other interested parties were contacted and requested to comment. A notice announcing the publication of the listing proposal was published in the Santa Cruz Sentinel on November 16, 2000. Another comment period opened on February 15, 2001, when the proposed critical habitat designation for Chorizanthe robusta var. hartwegii and Polygonum hickmanii was published. This 60day comment period closed on April 16, 2001. A legal notice announcing the publication of the proposed critical habitat designation was published in the Santa Cruz Sentinel on February 24, 2001. Additionally, we published a notice on November 21, 2002, announcing the availability of the draft economic analysis on the proposed critical habitat designation. This notice subsequently opened the public comment period for 15 days, until December 6, 2002, on the proposed listing rule, the proposed critical habitat designation, and the draft economic analysis on the proposed critical habitat designation.

During the three comment periods, we received individually written comments from 17 parties. Twelve commenters expressed support for the listing proposal and the proposed critical habitat designation. One of the 17 commenters opposed the proposed critical habitat designation for Polygonum hickmanii. Four commenters were neutral, either on the proposed listing or the proposed critical habitat designation. Approximately 800 additional letters were submitted as part of a mailing campaign when critical habitat was proposed for the species. Of these, 23 were opposed, 1 was neutral, and the remaining were in support of the critical habitat designation.

We reviewed all comments received for substantive issues and new information regarding the proposed listing of Polygonum hickmanii; most of the comments received were minor technical comments, and corrections and additions were made to the final rule accordingly. We also reviewed comments regarding the proposed critical habitat designation for P. hickmanii. Similar comments were grouped into two general issues relating specifically to biological issues, and procedural and legal issues. These are addressed in the summary that follows.

Peer Review

In accordance with our peer review policy published on July 1, 1994 (59 FR 34270), we solicited the expert opinions of four peer reviewers regarding pertinent scientific or commercial data and assumptions relating to population status and biological and ecological information for the proposed listing of Polygonum hickmanii when it was published on November 9, 2000. Three of the four reviewers responded. These reviewers expressed support for the listing of the species and described the information included in the rule as factually correct to the best of their knowledge. Their comments are summarized in the following responses to comments and incorporated into the final rule.

We also solicited independent opinions from three additional knowledgeable individuals with expertise in one or several fields, including familiarity with the species, familiarity with the geographic region in which the species occurs, and familiarity with the principles of conservation biology, to review the proposed critical habitat designation when it was published on February 15, 2001. As recommended by the Service Directorate, we requested peer review from Sustainable Ecosystems Institute, as well as two other peer reviewers. All three of the peer reviewers supported the proposal, and provided us with comments that are summarized in the following responses to comments and incorporated into the final rule.

Issue 1: Biology and Methodology

Comment 1: The proposed critical habitat designation is not properly supported by the best scientific information available. In particular, the Service makes ``numerous and varied unsupported assertions regarding the biology and habitat requirements'' of the species, and did not use the data available to them.

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Response: As required by the Act and regulations (section 4(b)(2) and 50 CFR 424.12), we used the best scientific information available to determine areas that contain the physical and biological features that are essential for the conservation of Polygonum hickmanii. This information includes data from the California Natural Diversity Data Base (CNDDB 2000), geologic and soil survey maps (USGS 1989, SCS 1980), recent biological surveys and reports, our recovery plan for this species, additional information provided by interested parties, and discussions with botanical experts. We also conducted multiple site visits to the two locations that were proposed for designation.

Comment 2: One peer reviewer suggested expanding the list of primary constituent elements to include such factors as seed germination requirements, substrate salinity, microreliefs and microclimates within local habitats, seasonal and yearly groundwater levels, and bird populations that migrate within the range of Polygonum hickmanii.

Response: While we recognize that these factors may be important components of the habitats within which Polygonum hickmanii is found, we do not have sufficient information at this time that leads us to believe they are the primary factors essential to the conservation of P. hickmanii throughout its range.

Comment 3: One peer reviewer commented that, while the Service had reasonably performed the difficult task of identifying the primary constituent elements, that the importance of certain processes (e.g., habitat disturbance, pollination, seed dispersal) was not sufficiently supported in the proposal. Specifically, the reviewer asserts that pollination activity within colonies more likely has a major effect on seed set and population persistence than does pollination activity between colonies, and that the majority of pollination occurs across short distances. The concern is that general statements of opinion could be translated into major management actions without adequate scientific basis.

Response: The peer reviewer that supplied these comments was responding to a request to concurrently review critical habitat proposals for four plant taxa. While we were unable to confirm this with the peer reviewer, we believe that the concern was directed primarily to two other of the four species that have significantly larger distributions than Polygonum hickmanii, in which case the concern over discriminating between withincolony and betweencolony pollinator distances would be more germane.

With respect to P. hickmanii, the entire range of the species covers a distance of only 1.6 km (1 mi), with colonies clustered at the two proximal ends of this range. Although no information is available concerning the importance of pollinators to the longterm persistence of P. hickmanii, the distance between the colonies in each of the clusters is well within the 0.5 km (0.3 mi) distance that many native pollinators are thought to fly (Waser in litt. 2002).

Comment 4: One commenter submitted a map portraying a recommended revision to the proposed critical habitat covering the parcel owned by American Dream/Glenwood that would have reduced the extent of critical habitat on that parcel. The commenter suggested that the swath of low elevation grasslands that occur along Carbonera Creek in the middle of the Glenwood Unit could be eliminated from critical habitat, as well as a portion of the Carbonera Creek watershed above them. The commenter suggested that the lowlevel grasslands do not support the primary constituent elements. Further the commenter suggested that the presence of existing residential development and the Scotts Valley High School along Glenwood Drive would make this area less desirable as a movement corridor for wildlife functioning as dispersal agents for P. hickmanii.

Response: While this narrow area of lowelevation grasslands does not contain wildflower fields, it is a grassland plant community that supports pollinators and seed dispersal agents for the wildflower fields. In addition, the lowlevel grassland along Carbonero Creek provide an important corridor for dispersers between the colonies on the west side and suitable, but unoccupied wildflower field habitat on the east side of Glenwood Valley. Similarly, the lowlevel grasslands would also be an important corridor to potential pollinators between the two sides of Glenwood Valley once Polygonum hickmanii is reestablished on the east side of the valley. Therefore, the lowlevel grasslands that occur along Carbonero Creek do include primary constituent elements.

The recent development of the Scotts Valley High School has reduced the extent of the corridor between the east and west sides of Carbonero Creek, and has therefore increased the conservation value and importance of the remaining corridor for pollinators and seed dispersers. In the background section of this final rule, we have expanded the discussion of potential seed dispersers and pollinators, which are part of the primary constituent elements, to clarify the role that these elements may play in the longterm conservation of the species.

In the case of Polygonum hickmanii, we included conservation recommendations for this species in a multispecies recovery plan we published, which also addressed recovery actions for two listed insects and three listed plants (including the endangered Chorizanthe robusta var. hartwegii that occurs with P. hickmanii) in the Santa Cruz Mountains (Service 1998). Upon P. hickmanii being listed, we intend that the conservation recommendations included in this recovery plan will, in effect, become the recovery recommendation for this species. This plan identifies both State and Federal efforts for conservation of the plant and establishes a framework for agencies to coordinate activities and cooperate with each other in conservation efforts. The plan sets recovery priorities and describes sitespecific management actions necessary to achieve conservation and survival of the plant.

As part of the recovery recommendations for Polygonum hickmanii, the recovery plan states that all known sites would have to be in protected status, a habitat conservation plan would have to be in place with the City of Scotts Valley, and population numbers would have to be stable or increasing (Service 1998). The limited range of the species, the limited opportunities for conservation, and the existence of threats on all locations where it occurs makes conservation of the species very difficult. Further loss of habitat or compromising the ecological processes on which the species depends may eliminate the ability of the species to persist. Therefore, we believe it is necessary to include the lowelevation grasslands in the critical habitat designation.

Issue 2: Legal and Procedural Issues

Comment 5: The proposed designation fails to designate specific areas as critical habitat, but instead used a landscape approach.

Response: The critical habitat designation delineates areas that support locations of known individuals of Polygonum hickmanii and areas with the primary constituent elements we believe essential to the long term conservation of P. hickmanii. In fact, the distribution of P. hickmanii is so restricted that direct and indirect affects to its habitat will make recovery particularly challenging. However, [[Page 16974]]
given the limited distribution of the species, we were able to map critical habitat with a higher level of accuracy and therefore believe we have identified specific areas meeting the definition of critical habitat.

Comment 6: The proposed designation improperly includes areas not essential to the conservation of Polygonum hickmanii.

Response: As result of mapping limitations, not all parcels of land proposed as critical habitat contained habitat components essential to the conservation of Polygonum hickmanii. In developing the final designation, we reevaluated and modified the boundaries of the proposed designation as appropriate to exclude areas that did not contain the primary constituent elements. The use of recently acquired high resolution aerial photographs (April 2000) enabled us to more accurately map the designation. However, due to our mapping scale, some areas not essential to the conservation of P. hickmanii may be included within the boundaries of final critical habitat. Certain features, such as buildings, roads, other paved areas and urban landscaped areas do not contain the primary constituent elements for the species. Service staff at the contact numbers provided are available to assist landowners in discerning whether or not lands within the critical habitat boundaries actually possess the primary constituent elements for the species.

Comment 7: The commenter stated that the proposed designation should have delineated occupied and unoccupied habitat areas. Further, the commenter stated that there are a lack of data to demonstrate that colonies do in fact temporarily disappear or expand into areas surrounding the immediate vicinity of the current year's colony.

Response: In this final designation, both critical habitat units are occupied by either standing plants or support a Polygonum hickmanii seed bank, but each of the units probably contains areas that could be considered unoccupied by the species. ``Occupied'' is defined here as an area that may or may not have had aboveground standing plants of P. hickmanii during current surveys, but if no standing plants are apparent, the site likely contains a belowground seed bank of undeterminable boundary. All occupied sites contain some or all of the primary constituent elements and are essential to the conservation of the species, as described below. ``Unoccupied'' is defined here as an area that contains no aboveground standing plant of P. hickmanii and is unlikely to contain a viable seed bank (e.g., soils are currently deeper than what is optimal for the Polygonum hickmanii). The inclusion of unoccupied habitat in our critical habitat designation reflects the dynamic nature of the habitat and the life history characteristics of this taxon. Unoccupied habitat provides areas into which populations might expand, provides connectivity or linkage between colonies within a unit, and supports populations of pollinators and seed dispersal organisms.

Determining the specific areas that this taxon occupies is difficult for at least two reasons: (1) The way the current distribution of Polygonum hickmanii colonies is mapped can be variable, depending on the scale at which concentrations of individuals are recorded (e.g., many small concentrations versus one large concentration); and (2) depending on the climate and other annual variations in habitat conditions, the extent of the distributions of annual species such as P. hickmanii may either shrink and temporarily disappear or, if there is a residual seedbank present, enlarge and cover a more extensive area (Baskin and Baskin 1998). Because it is logistically difficult to determine how extensive the seed bank is at any particular site and because aboveground plants may or may not be present in all patches within a site every year, it would be difficult to quantify what proportion of each critical habitat unit may actually be occupied by P. hickmanii.

While the areas designated as critical habitat may include areas that do not currently support Polygonum hickmanii, we believe these areas are within the geographic area presently occupied by the species. However, even if they were considered to be outside this geographical area presently occupied, for the reasons discussed below we have determined that they are essential to the conservation of the P. hickmanii. Occupied areas, as well as the adjacent grassland areas provide the essential lifecycle needs of the species and provide some or all of the habitat components essential for the conservation of P. hickmanii. We are designating critical habitat for P. hickmanii in all areas that are known to currently be occupied by the species. In addition, we believe it is necessary to protect unoccupied habitat on the slopes above the known occurrences of P. hickmanii because its persistence depends on maintaining the stability of the slopes on which it occurs. As discussed in the Background section of this rule, the characteristics of the geology and soils in the area make these slopes naturally prone to soil erosion. Human activities on the slopes above occurrences of P. hickmanii can exacerbate the natural rates of erosion and increase the risk of extirpation to P. hickmanii on the slopes below. At this time, we are not aware of additional populations of P. hickmanii nor additional areas that can be occupied by the species in the future.

Comment 8: The commenter expressed concern about whether there was any new information to be found that would have bearing on the proposed endangered status of Polygonum hickmanii or on the identification of habitats essential to the species.

Response: We have reviewed new information from the CNDDB, biological surveys, and botanists in the field familiar with the species, and we have made numerous visits to field sites since the early 1990s. Based upon this information, we believe that the range of the species is limited to the Scotts Valley area. Since the early 1990s, habitat for the species has been destroyed due to several development projects, and additional habitat has been altered due to secondary impacts resulting from development. According to a review of the socioeconomic information available about the geographic area presented in the draft economic analysis, pressure on the remaining suitable habitat for the species from residential and commercial development and recreation has increased steadily since we first became aware of the species in the early 1990s. The increased pressure on the limited area currently available for this species reinforces its endangered status and the need to designate critical habitat.

Comment 9: The Service has failed to properly consider the economic and other impacts of designating particular areas as critical habitat.

Response: The draft economic analysis for P. hickmanii was first published concurrently with that for Chorizanthe robusta var. hartwegii. We accepted comments on the draft economic analysis during a 30day comment period for the latter species that started on September 19, 2001 (66 FR 48227). However, this comment was made prior to a subsequent reopening of the comment period for the draft economic analysis. On November 21, 2002 (66 FR 700199), we published another notice in the Federal Register announcing again the availability of the draft economic analysis for the critical habitat for Polygonum hickmanii. This notice opened a 15day public comment period on the draft economic analysis for the proposed designation of critical habitat for P. hickmanii. All comments received regarding the economic [[Page 16975]]
analysis for P. hickmanii are addressed in this Summary of Comments and Recommendations section. Additionally, an addendum to the economic analysis, incorporating the comments received on the economic analysis, has been completed and is available upon request (see ADDRESSES). We believe this economic analysis and its addendum along with this final rule do properly consider the economic and other impacts of designating particular areas as critical habitat.

Comment 10: The Service has improperly bifurcated or separated its consideration of the economic impacts and scientific analysis by not preparing the economic analysis at the time of the proposed critical habitat designation.

Response: Pursuant to section 4(b)(2) of the Act, we are to evaluate, among other relevant factors, the potential economic effects of the designation of critical habitat for Polygonum hickmanii. We published our proposed designation in the Federal Register on February 15, 2001 (66 FR 10469). At that time, our Division of Economics and their consultants, Industrial Economics, Inc., initiated the draft economic analysis. The draft economic analysis was made available for public comment and review beginning on November 21, 2002 (67 FR 70199), as well as in a previous 30day open comment period associated with Chorizanthe robusta var. hartwegii (September 19, 2001, 66 FR 48227). Following the 15day public comment period on the proposal and draft economic analysis opened on November 21, 2002, a final addendum to the economic analysis was developed. Both the draft economic analysis and final addendum were used in the development of this final designation of critical habitat for P. hickmanii. Please refer to the Economic Analysis section of this final rule for a more detailed discussion of these documents.

Comment 11: The Service has not provided a fair and meaningful opportunity for comment on its proposed critical habitat designation.

Response: In our proposed rule to list Polygonum hickmanii as endangered on November 9, 2000 (65 FR 67335), we found that designating critical habitat was prudent, but we stated that we would propose critical habitat concurrently with Chorizanthe robusta var. hartwegii in the future. An open comment period was held at that time to receive comments on the proposed listing, as well as the prudency
determination. We published a proposed rule to designate critical habitat for P. hickmanii on February 15, 2001 (66 FR 10469), and accepted comments from the public for 60 days, until April 16, 2001. The comment period was reopened from November 21, 2002, to December 6, 2002 (67 FR 70199), to allow for additional comments on the proposed designation and comments on the draft economic analysis of the proposed critical habitat.

We contacted all appropriate State and Federal agencies, county governments, elected officials, and other interested parties and invited them to comment. In addition, we invited public comment through the publication of a legal notice in the Santa Cruz Sentinel on November 16, 2000, after the proposed rule to list was published, and again on February 24, 2001, after the proposed critical habitat designation was published. We provided notification of the draft economic analysis through telephone calls, letters, and news releases faxed and/or mailed to affected elected officials, local jurisdictions, and interest groups. Additionally, the public had two opportunities to request a public hearing, but none was requested.

Comment 12: The Service should prepare and consider an environmental impact statement in keeping with the National Environmental Policy Act of 1969 (NEPA).

Response: We have determined that an Environmental Assessment and/ or an Environmental Impact Statement, as defined under the authority of NEPA, need not be prepared in connection with regulations adopted pursuant to section 4(a) of the Endangered Species Act, as amended. A notice outlining our reason for this determination was published in the Federal Register on October 25, 1983 (48 FR 49244). Also, the public involvement and notification requirements under both the Endangered Species Act and the Administrative Procedure Act provide ample opportunity for public involvement in the process, similar to the opportunities for public involvement and economic analysis of effects that would be provided in the NEPA process.

Summary of Factors Affecting the Species

Section 4(a)(1) of the Act (16 U.S.C. 1531 et seq.) and regulations (50 CFR part 424) promulgated to implement the Act set forth the procedures for adding species to the Federal lists. 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. These factors and their application to Polygonum hickmanii are as follows: A. The Present or Threatened Destruction, Modification, or Curtailment Of Its Habitat or Range

In addition to the colonies of Polygonum hickmanii at the Glenwood and Polo Ranch sites, other colonies of P. hickmanii may have occurred in Scotts Valley prior to publication of the species name in 1995. An existing housing development bordering the south side of the Glenwood site (Glen View) was built in the mid1980s, and one development bordering the south side of the Polo Ranch site (Navarra Drive) was built in the 1970s. However, the environmental analyses done at those times would not have recognized P. hickmanii as a distinct taxon.

None of the occupied habitat for Polygonum hickmanii is targeted for direct destruction. However, all occupied habitat will be subject to habitat alteration resulting from current and proposed projects. At the Glenwood site, construction of a high school was initiated in June 1998. The colony of P. hickmanii on this site is within an area designated as a grassland preserve intended to protect a number of sensitive plant species, including P. hickmanii, Minuartia californica (California sandwort), Plagiobothrys diffusus (San Francisco popcorn flower), and the endangered Chorizanthe robusta var. hartwegii. The preserve is 2 ha (4 ac) in size and is adjacent to a wetland preserve of slightly smaller size. The combined area of the two preserves form a 3.6 ha (9 ac) area, linear in shape, sandwiched between high school playing fields to the north and the existing Glen View development (also known as Casa Way) to the south. The colony of P. hickmanii is 18 m (60 ft) away from the edge of the preserve nearest to the playing field. A management plan for the grasslands preserve includes prescriptions for boundary protection, habitat enhancement, control of nonnative plant species, and a 10year monitoring program (BRG 1998). Although the effectiveness of this management plan has not yet been demonstrated, P. hickmanii will likely still be subject to habitat alteration due to the small size of the preserve and its proximity to other land uses. Problems with managing small preserves within urban areas have been documented previously (Jensen 1987, Clark et al. 1998, Howald 1993, Service 1995). See Factor E for additional discussion of inadequate preserve design on the longterm conservation of plants.

The kinds of habitat alteration that are anticipated to result from the high school project include changes in
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surface hydrologic conditions due to the increased watering of the ballfield upslope from the preserve; changes in surface water quality due to the application of fertilizers, herbicides, and pesticides on the ballfield and adjacent areas up slope from the preserve; an increase in the number of nonnative plant species that will likely invade from adjacent newly altered areas; and an increase in the amount of soil erosion, soil compaction, and disturbance to the soil crust caused by the increased numbers of students, pets, and bicycles coming into the preserve from adjacent areas. The nature of the thin soils and the crusts of mosses and lichens they support make them particularly vulnerable to any form of surface disturbance (Belknap 1990).

The Scotts Valley Water District constructed a series of pipelines, maintenance roads, and tanks to distribute recycled water in the northern Scotts Valley area (EMC Planning Group 1998; Scotts Valley Water District 1998). One pipeline and an allweather maintenance road pass through the southwestern corner of the preserve and continue to the north and west onto a parcel owned by the Salvation Army where a water tank would be installed. As originally proposed, this route was to come within 23 m (75 ft) of the colonies of Polygonum hickmanii on the Salvation Army parcel and within 18 m (60 ft) of the endangered Chorizanthe robusta var. hartwegii (K. Lyons, pers. comm., 1998). However, when road grading was initiated in July 1999, grading plans were not followed closely. Moreover, measures to minimize and mitigate impacts to sensitive resources included in the approved project were not implemented. As a result, road grading came to within 3 m (10 ft) of P. hickmanii and to within 6 m (20 ft) of C. r. var. hartwegii on the Salvation Army parcel; on the adjacent high school preserve, individuals of C. r. hartwegii were destroyed. (Vince Cheap, California Native Plant Society, in litt. 1999; V. Cheap, in litt. 2001).

The kinds of habitat alteration that are anticipated to impact Polygonum hickmanii from the Water District's project include changes in surface hydrology due to the placement of the road upslope from the colonies; changes in surface water quality due to the application of herbicides, pesticides, and tackifiers (dust reducing substances) on the road and roadsides upslope from the colonies; an increase in the amount of soil siltation from the upslope roadbank; soil erosion, soil compaction, and disturbance of the soil crust; and an increase in the number of nonnative plant species that will likely invade from the road.

A visit to the Glenwood site confirmed that the nonnative plant Genista monspessulana (French broom) has invaded to within a few feet of one of the colonies of Polygonum hickmanii in the last few years (Carole Kelley, Friends of Glenwood, pers. comm., 1998). If not controlled, this invasive plant could quickly eliminate habitat for the P. hickmanii. French broom is considered a pest species, which in some places forms impenetrable thickets that displace native vegetation and lower habitat value for wildlife (Habitat Restoration Group, no date; Bossard, et al. 2000).

A housing development proposed for the Polo Ranch site includes 30 to 40 housing units clustered on 7.3 of 47.0 ha (18 of 116 ac), with the remaining 38 ha (95 acres) kept as open space (City of Scotts Valley 1998). At the time the proposed rule to list Polygonum hickmanii was prepared, the proposed development placed houses and roadways within 18 m (60 ft) or closer to five out of six colonies of P. hickmanii and separated the colonies from each other, with three of the six colonies isolated on all sides either by existing or proposed dwellings and roadways. As of 2002, the planned layout of houses has been modified to include a 31m (100ft) setback from all but one of the colonies (M. Fodge, Planning Department, City of Scotts Valley, pers. comm., 2002; G. Deghi, consultant, pers. comm., 2002).

Alterations of habitat for Polygonum hickmanii that are likely to occur as a result of the Polo Ranch development are changes in surface hydrologic conditions due to the grading of roads and lots; soil erosion, soil compaction, and disturbance of the soil crust by humans, pets, and bicycle traffic; inadvertent (i.e., aerial drift) and intentional application of herbicides, pesticides, and fertilizers on roadsides and yards; inadvertent introduction of nonnative species (both weedy and ornamental); and dumping of yard wastes. Examples of alteration of habitat that have occurred on grasslands north of the backyards of existing housing along Navarra Drive (along the south edge of the Polo Ranch property) include gates and pathways leading from backyards onto the grassland, ivy creeping over fences and onto the grassland, oaks (Quercus sp.) planted within the grassland, and shade created by planted backyard trees (K. Lyons, pers. comm., 1998).

Although two of the projects (high school and recycled water distribution system) include plans for conservation of Polygonum hickmanii through developmentrelated mitigation, and the third project (Polo Ranch) would be expected to do so as well, the successful implementation of these mitigation plans has not been demonstrated. In particular, the size and characteristics of preserve areas and open spaces and the management actions prescribed through the environmental review process (see Factor D) are unlikely to be biologically adequate to ensure the longterm conservation of P. hickmanii and its habitat. In addition, since P. hickmanii colonies will be in preserves or open spaces that are small in area, support small numbers of individuals, and consist of degraded habitat, or that continue to receive secondary effects of adjacent human activities, they become more vulnerable to extirpation from naturally occurring events (see Factor E).

All habitat for Polygonum hickmanii is also threatened in general by the encroachment of nonnative grasses from the surrounding grasslands. Although several species of nonnative grass (e.g., Vulpia myuros) grow within the wildflower fields, these patches for the most part do not support the abundant growth of nonnative grasses (Bromus sp.) that occur on the adjacent, more mesic grassland habitat. These nonnative grasses on the mesic grasslands do not compete with P. hickmanii in the classic sense (competition for light, water, nutrients). However, the tall culms (stems) of nonnative grasses can physically drape over patches of wildflower field habitat, particularly the smaller patches, and deposit a mat of litter (thatch) that physically prohibits the species within the wildflower field from appearing. Because nonnative grasses and herbs produce more biomass than their native counterparts, they also produce more litter (Belknap et al. 2001). Although decomposition rates for nonnative species are likely no slower than those of native species, their faster rate of biomass production results in a greater accumulation of litter. Other cases of native species being overtaken by litter accumulation produced by nonnatives have been noted in desert ecosystems (Jayne Belknap, Biological Resources Division, pers. comm., 1998) and on the California Channel Islands (Rob Klinger, The Nature Conservancy, pers. comm., 1998).

In summary, habitat alteration and destruction, including urban development, road construction, and their attendant secondary impacts (including increased trampling from humans, pets, bicycles, and installation and maintenance of landscaped areas),
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are threats to the species. These activities cause soil erosion, soil compaction, disturbance of the soil crust, changes in soil hydrology, changes in water quality, encroachment of nonnative species, and accumulation of thatch.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

Overutilization or vandalism are not known to be threats to this species.

C. Disease or Predation

We found no evidence that disease is a factor affecting this species. Predation by cattle, livestock, or other wildlife species is not known to occur.

D. The Inadequacy of Existing Regulatory Mechanisms

Polygonum hickmanii currently receives no protection under Federal law, and it is not currently listed by the State of California.

Chorizanthe robusta var. hartwegiana, an endangered species, frequently occurs within the same wildflower field habitat as Polygonum hickmanii; however, in two locations P. hickmanii occurs without the former species. Even though C. r. var. hartwegiana was federally listed as endangered in 1994, and critical habitat was subsequently designated in 2002, these regulatory actions, and subsequent protections afforded the species and its habitat do not fully protect the frequently co occurring P. hickmanii under the Act for several reasons. First, in context of a consultation under section 7 of the Act, because of the restricted distribution of P. hickmanii within the wildflower field habitat, there may be circumstances in which an action proposed by a Federal action agency may jeopardize the continued existence of P. hickmanii or destroy or adversely modify its critical habitat, while the same action may not result in jeopardy or adverse modification for C. r. var. hartwegiana. In addition, because of differences in phenology between the two species (flowering period in P. hickmanii is beginning when that of C. r. var. hartwegiana is ending), it is also possible that the timing of an activity (e.g., grazing or spraying) could be a greater threat to one species than the other. Second, even though P. hickmanii shares the same wildflower field habitat with C. r. var. hartwegiana, it is possible that over time, the distribution of the two species among the wildflower field patches could shift, resulting in less overlap between the two species than is evident at this point in time. Thus, regulatory protections for C. r. var. hartwegiana may provide less protections for P. hickmanii. Third, because of the more restricted distribution of P. hickmanii and life history differences between the two plants, recovery actions implemented for C. r. var. hartwegiana may be inadequate to provide for the conservation of P. hickmanii.

The California Environmental Quality Act (CEQA) requires a full disclosure of the potential environmental impacts of proposed projects. The lead agency is the public agency with primary authority or jurisdiction over the project, and that agency is responsible for conducting a review of the project and consulting with other agencies concerned with the resources affected by the project. Section 15065 of the CEQA Guidelines requires a finding of significance if a project potentially ``reduce(s) the number or restrict(s) the range of a rare or endangered plant or animal.'' Species eligible for, but not yet listed by the State as threatened or endangered, are given the same protection as those species officially listed by State or Federal governments. The Rare Plant Scientific Advisory Committee for the California Native Plant Society has determined that Polygonum hickmanii meets the criteria for being included on CNPS' ``List 1B.'' The plants on List 1B meet the definitions of section 1901, chapter 10 of the California Department of Fish and Game Code, and are therefore eligible for State listing. It is mandatory that plants on List 1B be fully considered during preparation of environmental documents relating to CEQA. Once significant effects are identified, the lead agency may require mitigation for effects through changes in the project, or the lead agency may decide that overriding considerations make mitigation infeasible. In the latter case, projects may be approved that cause significant environmental damage, such as destruction of listed species. Therefore, the protection of listed species through CEQA depends upon the discretion of the lead agency involved; however, findings of ``overriding considerations'' are infrequent.

Inclusion of mitigation measures in a project approved through the CEQA process does not guarantee that such measures are implemented. The recycled water distribution project approved by the Scotts Valley Water District included measures to avoid and mitigate impacts to sensitive resources, including those for Polygonum hickmanii and Chorizanthe robusta var. hartwegii. However, grading for this project was initiated without implementing those measures, which resulted in a much narrower buffer zone left between the plant populations and the grading activity (Carl Wilcox, California Department of Fish and Game, in litt. 1999).

Certain local agencies are exempt from city and county regulations in accordance with chapter 1, paragraphs 53094 and 53096, of the State of California regulations on planning, zoning, and development laws (Governor's Office of Planning and Research 1996). The High School project for the Scotts Valley Unified School District is exempt from local permitting requirements; therefore, no permits or approvals were required from the City of Scotts Valley. Additionally, the recycled water distribution project for the Scotts Valley Water District is similarly exempted; therefore, no permits or approvals are required from either the City of Scotts Valley or the County of Santa Cruz. In July 1999, the Water District proceeded with road and tank pad grading for this project. This activity was initiated without fulfilling mitigation measures that called for sensitive areas to be flagged and fenced ahead of time, and resulted in grading that went beyond the scope of work for the project. Although the County of Santa Cruz notified the Water District that the additional grading was not exempted from applicable regulations, the only consequence is that the county has requested that the damaged areas be satisfactorily restored (Alvin James, County of Santa Cruz, in litt. 1999).

The establishment and implementation of a management plan for the preserve at the High School site does not provide for enforcement authority to maintain the physical integrity of the preserve. E. Other Natural or Manmade Factors Affecting Its Continued Existence

The design of preserves and open spaces related to project mitigation to date has been insufficient to provide for the longterm conservation of Polygonum hickmanii and other sensitive species that occur in the wildflower fields in Scotts Valley. Additionally, the threat of random extinction is increased in small populations of limited distribution (please see the ``Random Extinction'' section below for further discussion).

Inadequate Preserve Design

The need for adequate preserve design has been discussed by many biologists (Jensen 1987; Shafer 1995; Rathcke and Jules 1993; Kelly and Rotenberry 1993). To increase the certainty that a species will persist over a given interval of time,
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adequate habitat needs to be protected and land uses adjacent to the preserve need to be compatible with maintaining the integrity of the preserve. Habitat is not restricted solely to the area actually occupied by the species. It must include an area that is large enough to maintain the ecological functions upon which the species depends and have a ratio of edge to total area that minimizes fragmentation and edge effects.

Failure to protect sufficient habitat results in the eventual decline of the target species. Small preserves adjacent to urban areas have additional stress placed on them due to the need to manage a host of humancaused impacts. The increased stress urban wildland areas receive has been documented by many authors (Keeley 1993).

In the case of Polygonum hickmanii at the School District Preserve, the site remained unfenced and unsigned for several years, was subject to bicycle and heavy equipment traffic, and served as a repository for yard waste (C. Kelley, in litt. 1999). Local residents also have used the preserve for golf practice (Biotic Resources Group 2002). A management plan for the preserve was completed in 1998 (Wittwer, in litt. 2002). However, prescribed management actions are not always implemented according to schedule due to budget limitations.

Habitat fragmentation also affects plantpollinator interactions in a number of ways. The abundance of specific pollinators may decline due to the elimination of nesting sites, decreases in food source plants due to changes in composition of the plant community, increases in competition from nonnative pollinators, and increases in the exposure to pesticides (Rathcke and Jules 1993; Jennersten 1988; Kearns and Inouye 1997). In plant species that are obligate outcrossers (those that require pollinators to effect seed development), reduced pollinator availability can result in limited seed production. Even if a plant species is not an obligate outcrosser, genetic variability within the plant population can be reduced with potentially deleterious longterm consequences (see discussion below on random extinction). We believe the effects of habitat fragmentation discussed above are similar to those that could affect the longterm persistence of the Polygonum hickmanii.

Ecological processes that would be important to maintain within preserve areas for Polygonum hickmanii include, but are not limited to, the integrity of edaphic (soil) conditions, hydrologic processes (surface flows), the associated ``wildflower field'' plant community, plantpollinator interactions, and seed dispersal mechanisms. Maintaining such processes will be severely compromised by the small size of the areas being set aside as preserves or open spaces, the extent of edge subject to external influences, and the particular kinds of adjacent land use to which the preserves will be subject. Threats resulting from alteration of habitat due to adjacent changes in land use (discussed in Factor A) are exacerbated by the small size of the preserves and the proximity of nearly all of the colonies to the edges of the preserves or open spaces, or to roads. Distances of less than 24 m (80 ft) are not considered to be effective at buffering from chemical pollutants (e.g., herbicides, pesticides, and other contaminants) (Conservation Biology Institute (CBI) 2000). Depending on site configuration or circumstances, buffers of up to 91 m (300 ft) may not be adequate to provide sufficient buffering from invasive animals and increased fire frequency (CBI 2000) .

Random Extinction

This species is considered to have a high risk of extinction in the wild in the immediate future based on criteria put forth by the World Conservation Union, as modified for plants (Keith 1998). Species with few populations and individuals are vulnerable to the threat of naturally occurring events, causing extinction through mechanisms operating either at the genetic level, the population level, or the landscape level. Decrease in genetic variability will reduce the likelihood that individuals in a population will persist in a changing environment. Additionally, populations with lower levels of genetic diversity are more likely, on average, to experience reduced reproductive success due to inbreeding depression. Species with few populations or those that are low in number may be subject to forces at the population level that affect their ability to complete their life cycles successfully. For example, reduced numbers of individuals may lead to a reduction in number of pollinators and subsequently seed set. Additionally, if the host plants are partially selfincompatible, reduction in population size may lead to increased selfpollination and may reduce the level of genetic variability. At the landscape level, random natural events, such as storms, drought, or fire, could destroy a significant percentage of individuals or entire populations; a hot fire could destroy a seedbank as well. The restriction of colonies to small sites increases their risk of extinction from such naturally occurring events.

The genetic characteristics of Polygonum hickmanii have not been investigated; therefore, the degree to which these characteristics contribute to the likelihood of P. hickmanii being vulnerable to extinction for these reasons is unknown. However, random events operating at the population and landscape levels clearly have the potential for increasing the chance of extinction for P. hickmanii.

We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats faced by this taxon in determining the actions to take in this rule. Based on this evaluation, the appropriate action is to list Polygonum hickmanii as endangered. The species is threatened with extinction due to habitat alteration resulting primarily from urban development, inadequate preserve design, and vulnerability to naturally occurring events due to low numbers of individuals and occupied acreage of the entire taxon. All of the colonies are on private lands. Although conservation efforts have been prescribed as part of mitigation for two of the three projects (high school and recycled water distribution project), and are expected to be proposed for the third project (Polo Ranch development), the small extent of occupied habitat, small colony sizes, and imminent threats lessen the chance that such efforts will lead to secure, selfsustaining colonies at these sites.

Critical Habitat

Section 3 of the Act defines critical

FOR FURTHER INFORMATION CONTACT Connie Rutherford, Ventura Fish and Wildlife Office, at the above address or telephone number 805/6441766, facsimile 805/6443958 or email at connie_rutherford@fws.gov. Information regarding this rulemaking is available in alternate formats upon request.