# Endangered and Threatened Wildlife and Plants; Proposed Revised Critical Habitat for Navarretia fossalis (Spreading Navarretia)

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URL: https://www.frixlaw.com/law-library/documents/fr%3AE9-13013

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** June 10, 2009
- **Citation:** 74 FR 27588

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R8-ES-2009-0038; 92210-1117-0000-B4]
RIN 1018-AW22
Endangered and Threatened Wildlife and Plants; Proposed Revised Critical Habitat for Navarretia fossalis (Spreading Navarretia)

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Proposed rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), propose to revise designated critical habitat for
Navarretia fossalis
(spreading navarretia). Approximately 6,872 acres (ac) (2,781 hectares (ha)) of habitat fall within the boundaries of the proposed revised critical habitat designation. This proposed revised designation of critical habitat is located in Los Angeles, Riverside, and San Diego Counties in southern California.

DATES:

We will accept comments from all interested parties until August 10, 2009. We must receive requests for public hearings, in writing, at the address shown in the
FOR FURTHER INFORMATION CONTACT
section by July 27, 2009.

ADDRESSES:

You may submit comments by one of the following methods:

•
Federal eRulemaking Portal:

http://www.regulations.gov.
Follow the instructions for submitting comments to Docket No. FWS-R8-ES-2009-0039.

•
U.S. mail or hand-delivery:
Public Comments Processing, Attn: FWS-R8-ES-2009-0038; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, Suite 222; Arlington, VA 22203. We will not accept e-mail or faxes. We will post all comments on
http://www.regulations.gov.
This generally means that we will post any personal information you provide us (see the Public Comments section below for more information).

FOR FURTHER INFORMATION CONTACT:

Jim Bartel, Field Supervisor, U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA 92011; telephone (760) 431-9440; facsimile (760) 431-5901. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at (800) 877-8339.

SUPPLEMENTARY INFORMATION:

Public Comments

We intend any final action resulting from this proposal to be as accurate and as effective as possible. Therefore, we request comments or suggestions on this proposed rule. We particularly seek comments concerning:

(1) The reasons we should or should not revise the designation of habitat as “critical habitat” under section 4 of the Endangered Species Act of 1973, as amended (Act; 16 U.S.C. 1531
et seq.
), including whether the benefit of designation would outweigh any threats to the species caused by the designation, such that the designation of critical habitat is prudent.

(2) Specific information on:

• Areas that provide habitat for
Navarretia fossalis
that we did not discuss in this proposed critical habitat rule,

• Areas containing the features essential to the conservation of
N. fossalis
that we should include in the designation and why,

• Areas not containing features essential for the conservation of the species and why, and

• Areas not occupied at the time of listing that are essential to the conservation of the species and why.

(3) Land-use designations and current or planned activities in the areas proposed as critical habitat, as well as their possible effects on proposed critical habitat.

(4) Comments or information that may assist us in identifying or clarifying the primary constituent elements.

(5) How the proposed revised critical habitat boundaries could be refined to more closely circumscribe the landscapes identified as containing the features essential to the species' conservation.

(6) Any probable economic, national-security, or other impacts of designating particular areas as critical habitat, and, in particular, any impacts on small entities (e.g., small businesses or small governments), and the benefits of including or excluding areas that exhibit these impacts.

(7) Whether any specific subunits being proposed as critical habitat should be excluded under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any particular area outweigh the benefits of including that area under section 4(b)(2) of the Act.

(8) The potential exclusion of the portion of the subunit (Unit 2) being proposed as critical habitat within the jurisdiction of the City of Carlsbad Habitat Management Plan, a subarea plan under the San Diego Multiple Habitat Conservation Plan under section 4(b)(2) of the Act, and whether the benefits of exclusion of this area outweigh the benefits of including this area as critical habitat, and why.

(9) Specific reasons whether we should exclude, under section 4(b)(2) of the Act, the subunit proposed as critical habitat within the unincorporated community of Ramona in San Diego County (Subunit 4E), an area where the County of San Diego is working on a Habitat Conservation Plan (HCP) called the “North County Plan” with the Service that is currently available for public review (The North County Plan is available on the Internet at:
http://www.sdcounty.ca.gov/dplu/mscp/nc.html
), and whether the benefits of exclusion of this area outweigh the benefits of including this area as critical habitat, and why.

(10) The potential exclusion of the subunits being proposed as critical habitat within the jurisdiction of the County of San Diego Subarea Plan (Subunit 3A and portions of Subunits 5B, 5F, and 5I) under the San Diego Multiple Species Conservation Plan under section 4(b)(2) of the Act, and whether the benefits of exclusion of this area outweigh the benefits of including this area as critical habitat, and why.

(11) The potential exclusion of the subunits being proposed as critical habitat within the jurisdiction of the Western Riverside County Multiple Species Habitat Conservation Plan (Subunits 6A, 6B, 6C, 6D, and 6E) under section 4(b)(2) of the Act, and whether the benefits of exclusion of this area would outweigh the benefits of including this area as critical habitat, and why.

(12) Information on any quantifiable economic costs or benefits of the proposed revised designation of critical habitat.

(13) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.

Our final determination concerning critical habitat for
Navarretia fossalis
will take into consideration all written comments and any additional information we receive during the comment period. These comments are included in the public record for this rulemaking and we will fully consider them in the preparation of our final determination. On the basis of public comments, we may, during the development of our final determination, find that areas within the proposed designation do not meet the definition

of critical habitat, that some modifications to the described boundaries are appropriate, or that areas may or may not be appropriate for exclusion under section 4(b)(2) of the Act.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in the
ADDRESSES
section. We will not consider comments sent by e-mail or fax or to an address not listed in the
ADDRESSES
section.

If you submit a comment via
http://www.regulations.gov,
your entire comment—including any personal identifying information—will be posted on the Web site. If you submit a hardcopy comment that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy comments on
http://www.regulations.gov.

Background

It is our intent to discuss only those topics directly relevant to the proposed revised designation of critical habitat in this proposed rule. No new information pertaining to the species description, life history, ecology, or habitat of
Navarretia fossalis
was received following the 2005 final critical habitat designation for this species; summary information relevant to this species' critical habitat is provided below. This rule incorporates new information on the distribution of
N. fossalis
that was not available when we completed our 2005 final critical habitat designation for this species. For more information on
N. fossalis,
refer to the final listing rule published in the
Federal Register
on October 13, 1998 (63 FR 54975), and the designation of critical habitat for
N. fossalis
published in the
Federal Register
on October 18, 2005 (70 FR 60658). Additionally, more information on this species can be found in the Recovery Plan for the Vernal Pools of Southern California (Recovery Plan) finalized on September 3, 1998 (Service 1998a).

Species Description

Navarretia fossalis
is a low, mostly spreading or ascending, annual herb, 4 to 6 inches (in.) (10 to 15 centimeters (cm)) tall. The lower portions of the stems are mostly glabrous (bare). The leaves are soft and finely divided, 0.4 to 2 in. (1 to 5 cm) long, and spine-tipped when dry. The corolla (i.e., flower tube and petals) are white to lavender-white with linear petals and are arranged in flat-topped, compact, leafy heads. The fruit is an ovoid, 2-chambered capsule (Moran 1977, pp. 155-156; Day 1993, p. 847). The fruit of this species consists of indehiscent (i.e., not opening spontaneously at maturity to release seeds) capsules 0.08 to 0.12 in. (2 to 3 millimeters (mm)) long containing 5 to 25 seeds (Moran 1977, p. 156; Day 1993, p. 847). The seeds develop a sticky, slimy coating when wet, which may retain moisture and aid in germination (Moran 1977, p. 156).

Habitat

Navarretia fossalis
grows in natural vernal pool habitat, seasonally flooded alkali vernal plain habitat (a habitat that includes alkali playa, alkali scrub, alkali vernal pool, and alkali annual grassland), and man-made irrigation ditches and detention basins (Bramlet 1993a, pp. 10, 14, 21-23; Ferren and Fiedler 1993, pp. 126-127; Spencer 1997, pp. 8, 13). A common feature of the
N. fossalis
habitat is its ephemerally wet, flooded, or ponded nature (i.e., habitat is wet for a portion the year and dry the remainder of the year), and in this rule, we use the term “ephemerally wet habitats” to refer to
N. fossalis
habitat. These habitats are periodically wet or ponded from October to May, and dry from June to September. The period of time during which these habitats pond is referred to as the “period of inundation.” This time period varies from year to year depending on the timing and amount of precipitation. Despite the ephemeral nature of the wetland habitat where
N. fossalis
occurs its habitat occurs and relies on “fixed landscape features” that include (1) mounds of soil that are interspersed with depressed areas (basins) that harbor appropriate clay soils that provide ponding opportunities during winter and spring months; or (2) flood plain areas with alkali soils that drain slowly following winter and spring rains. The ponding that
N. fossalis
requires for its growth and reproduction would not be present without this underlying topography, which is a fixed and permanent feature of the landscape. So even though the wetland habitat is ephemeral, the habitat where
N. fossalis
occurs is geographically fixed and there are only a limited number of locations that can support this species.

Life History

The life cycle of
Navarretia fossalis
begins with the germination of seeds when the habitat is in the wetland phase (i.e., flooded or ponded) during winter and spring months. In contrast to most species of Navarretia, which are unable to grow in vernal pool habitat,
N. fossalis
and other vernal pool Navarretias have indehiscent fruit/capsules. This means that the capsules that hold the seeds do not break apart when the seeds mature, and instead the seeds are held on the plant until the capsules absorb water and expand to break open the fruit after a substantial rain (Crampton 1954, pp. 233-234; Spencer and Rieseberg 1998, p. 82). After the seeds are released from the capsules, they come in contact with the wet soil and are able to germinate. This enables the seeds to germinate under favorable conditions when the habitat is inundated with the winter and spring rains. After germination, plants grow and flower in May and June as the habitat dries (Glenn Lukos Associates, Inc. 2000, p. 17). Subsequently, the plant produces fruit and senesces in the hot, dry summer months. The cycle begins again each year when the fall and spring rains begin.

In addition to the general life history for
Navarretia fossalis,
there are two important evolutionary traits that contribute to this species survival: (1) Its relatively limited seed dispersal capability; and (2) the presence of a persistent seed bank.

Navarretia fossalis
has “limited dispersal capabilities,” which is one cause of this species' narrow distribution, and also demonstrates this species' ability to persist in occupied habitat. The seeds of
N. fossalis
are not dispersed far from the parent plant, because the seed capsules are indehiscent and do not shatter when the plants dry in the summer heat (Crampton 1954, pp. 233-234; Spencer 1997, p. 17). Instead, the seeds remain on the dried plant until heavy winter rains break up the dry plants and cause the seed capsules to open (Spencer 1997, p. 17). In a local context, the limited dispersal for
N. fossalis
is advantageous because the seeds stay in suitable habitat rather than being transported into areas that do not provide suitable habitat (Zedler 1990, pp. 130-134). As a result, the bulk of the seeds produced by
N. fossalis
stay close to the parent plants and contribute to the persistence of the species within the local area. Conversely, the limited dispersal of this species results in a decreased ability for this species to colonize new habitats. In relation to the conservation of this species, conserving occupied localities will help to conserve this species because
N. fossalis
has traits that allow it to be successful in the same habitat year after year. Additionally, putting resources towards the conservation will help prevent local extinctions, which in the case of a species with limited dispersal

capabilities, could be detrimental to the species (Spencer 1997, p. 17).

Navarretia fossalis
has a persistent seed bank that makes occupied sites more valuable for conservation than potential, but unoccupied, habitat. Elam (1998, p. 182) indicates that many plants restricted to vernal pool habitat are thought to have a persistent seed bank. At one site where
N. fossalis
was salvaged, both standing plants and soil that contained plants encased in silt were collected. In germination tests, both the current crop of seeds (standing plants) and the seeds encased in silt (presumably from previous years) were viable (Wall 2004, pp. 2-3). Additional studies should be conducted to better quantify the seed bank that exists for
N. fossalis,
but we believe the currently available information demonstrates that
N. fossalis
has a persistent seed bank in occupied areas. Therefore, the preservation of the seed bank is important to the conservation of this species, primarily with native occurrences where the seed bank has built up over several years. Native occurrences contrast with translocated occurrences (where seed or plants are moved from one location to another) because in most translocations, only seed from a single year is moved and used to establish a new occurrence. In a native occurrence, seed has been deposited in the local area year after year. Therefore, native occurrences have a more varied seed bank and will more likely persist into the future.

Geographic Range and Status

Navarretia fossalis
is distributed from northwestern Los Angeles County and western Riverside County, south through coastal San Diego County, California, to northwestern Baja California, Mexico (Moran 1977, p. 156; Oberbauer 1992, p. 7). It is found at elevations between sea level and 4,250 feet (ft) (1,300 meters (m)) in vernal pool and seasonally flooded alkali vernal plain habitats (Day 1993, pp. 847-848; Tibor 2001, p. 229; California Natural Diversity Database (CNDDB) 2008, pp. 1-44).

In the United States,
Navarretia fossalis
is limited to Los Angeles, Riverside, and San Diego Counties in southern California. At the time of listing (1998),
N. fossalis
was known from approximately 30 occurrences, with 60 percent of the known plants concentrated in three areas: Otay Mesa in southern San Diego County, along the San Jacinto River in western Riverside County, and near Hemet in Riverside County (referred to as the Salt Creek Seasonally Flooded Alkali Plain in the current proposed revised critical habitat rule) (October 13, 1998, 63 FR 54975). In the final listing rule (October 13, 1998, 63 FR 54975), we estimated that less than 300 ac (121 ha) of habitat in the United States was occupied by this species in approximately 30 occurrences. This habitat estimate only quantified the areas where
N. fossalis
was physically found (i.e., ponded areas of ephemeral wetlands) and did not include the intermixed upland areas and local watersheds necessary to support the conservation of this species. For this reason, we have identified a much larger area as proposed critical habitat for
N. fossalis
in this rule than the 300 ac (121 ha) of occupied habitat discussed in the final listing rule for this species. Each area that we propose as critical habitat contains a current occurrence of
N. fossalis;
however,
N. fossalis
does not physically occur throughout the entirety of each area. The 6,872 ac (2,781 ha) proposed as critical habitat contains occurrences of
N. fossalis
and surrounding upland areas that contain the primary constituent elements essential to support
N. fossalis
where it physically occurs within the proposed critical habitat. For information about how this proposed critical habitat rule compares to the final critical habitat designated for this species in 2005, see the “Summary of Changes From Previously Designated Critical Habitat” section below.

In Mexico,
Navarretia fossalis
is limited to northwestern Baja California. At the time of listing (1998),
N. fossalis
was known from approximately nine occurrences concentrated in three areas: Along the international border, on the plateaus south of the Rio Guadalupe and north of Ensenada, and on the San Quintin coastal plain (Moran 1977, p. 156).

In this proposed rule, we use the word “occurrence” to refer to a specific area where
Navarretia fossalis
has been positively identified. An occurrence of
N. fossalis
is not necessarily synonymous with a population of
N. fossalis.
One occurrence may refer to several localized areas where
N. fossalis
has been found in habitat that is continuous and connected, such as the several mile stretch along the San Jacinto River in Riverside, California, where
N. fossalis
occurs intermittently (although the habitat is essentially continuous). One occurrence may also refer to only one localized area where
N. fossalis
has been found, in habitat that is isolated, such as the vernal pools at the Poinsettia Lane Commuter Station in Carlsbad, California, where the next closest occurrence is several miles (kilometers) away. The occurrences that we defined in this rule are not the same as the element occurrences described by the California Natural Diversity Database (CNDDB).

As part of this proposed revised critical habitat, we reviewed the available data on
Navarretia fossalis.
We determined that a total of 51 documented occurrences exist from the United States and that 49 of these occurrences are extant (i.e., currently supporting an occurrence of
N. fossalis
). Since this species was listed in 1998, 17 additional occurrences have been documented from survey reports and herbarium collections. We believe that the recently documented occurrences were extant at the time of listing because this species has limited dispersal capabilities, and the species can only occur in specific habitat types with fixed landscape features. (Limited dispersal is defined and discussed in detail in paragraph 3 of the “Life History” section. “Fixed landscape features” we further defined the first time we used this terminology (paragraph 1 of the “Habitat” section.) It is unlikely that any new occurrences were established during the relatively short, ten-year time period following the listing of this species. Instead, we believe the areas discovered to contain
N. fossalis
in the years since the listing were occupied for many years prior to listing of the species and were only recently documented due to increased number of surveys for this species. Additionally, all recently documented occurrences of
N. fossalis
are within the historical geographical range of the species. Therefore, throughout this rule we refer to all occurrences as “occupied at the time of listing” whether the areas were documented before or after the species was listed.

As part of our review of data on this species, we were able to get a more complete list of the past herbarium collections for
Navarretia fossalis
in Baja California, Mexico; all of which were made prior to the listing of this species. Our current list of collections from Mexico indicates that there are 12 specific locations where
N. fossalis
has been found in Baja California (Sanborn 2009, pp. 2-3). Other than the original collection information, we have no specific data on these occurrences; however, development, clay mining, and agricultural activities have been ongoing in the areas where
N. fossalis
has been found in the past (Moran 1984, pp. 175-178). We cannot make any specific conclusions about how many of these occurrences are extant, but we do think that this species is as rare in Mexico as it is in the United States and that its existence is threatened by

development, clay mining, and agricultural activities in Mexico.

Areas Needed for Conservation: Core and Satellite Habitat Areas

Details about the distribution and status of this species provide important background information for understanding the areas that we are proposing for revised critical habitat. The areas that contain the features essential for the conservation of
Navarretia fossalis
and that we are proposing as revised critical habitat in this rule are represented by core habitat areas and satellite habitat areas. Core habitat represents the most critical areas in conserving this species, including areas that contain the highest concentrations of
N. fossalis
and the largest contiguous blocks of habitat for this species. We identified four core habitat areas; three core habitat areas were identified in the listing rule (along the San Jacinto River, in the Upper Salt Creek drainage, and on Otay Mesa), and in the current revised proposed critical habitat rule, we added one additional area that we believe represents a core habitat area (Mesa de Burro on the Santa Rosa Plateau). In addition to the four core areas,
N. fossalis
occurs at several other sites that make up the range of this species; many of these sites also contain the features essential to the conservation of this species.

In this rule, we use the term “satellite habitat areas” to mean habitat areas that support occurrences that are smaller than those supported by the “core habitat areas,” but provide the means to significantly contribute to the recovery of
N. fossalis.
Satellite habitat areas provide connectivity between the core habitat areas by shortening the distances that pollen and seeds would need to be transferred, fill in gaps that would exist in the species range, if only the core habitat areas were conserved, support stable occurrences (e.g., occurrences that continue to persist in an area), and likely support genetically unique occurrences. The satellite habitat areas are generally smaller than the core habitats. However, the satellite habitat areas contain the features essential to the conservation of
N. fossalis.

Together, the core habitat areas and satellite habitat areas represent a matrix of viable occurrences that provide the stability, resilience, and flexibility that this species requires to survive current threats and adapt to future threats that may be caused by environmental changes. Special management considerations or protection of the core habitat areas and satellite habitat areas will help with the recovery of
N. fossalis
and bring the species to the point where the protections of the Act are no longer needed.

The four core habitat areas where this species occurs are large, both in number of occupied areas and in terms of the occurrence size (greater than 3,000 plants). The core habitat areas support self-sufficient occurrences that have been resilient to human impacts at the landscape scale. These core habitat areas contain the largest occurrences of
N. fossalis,
and, therefore, the conservation of these areas and the essential features contained therein will make a substantial contribution to the recovery of this species.

We have determined, however, that the conservation of the core habitat areas alone will not be sufficient to provide for recovery of
Navarretia fossalis
. As a result, we believe that the conservation of satellite habitat areas is essential for the recovery of this species. Satellite habitats include: (1) Important peripheral occurrences of this species that are on the geographic edge of this species' distribution; (2) occurrences that are isolated from other occurrences by geographic features; and (3) areas that are nested within the distribution of this species and provide connections between the core habitat areas and other satellite habitat areas. The satellite habitat areas are dispersed throughout the range of this species. Therefore, we believe the protection and management of both core and satellite habitat areas will result in a matrix of viable occurrences and supportive habitat areas that will provide for the long-term conservation of
N. fossalis.

Previous Federal Actions

On October 18, 2005 (70 FR 60658), we published our final designation of critical habitat for
Navarretia fossalis.
On December 19, 2007, the Center for Biological Diversity filed a complaint in the U.S. District Court for the Southern District of California challenging our designation of critical habitat for
N. fossalis
and
Brodiaea filifolia
(
Center for Biological Diversity
v.
United States Fish and Wildlife Service et al.
, Case No. 07-CV-02379-W-NLS). This lawsuit challenged the validity of the information and reasoning we used to exclude areas from the 2005 critical habitat designation for
N. fossalis.
On July 25, 2008, we reached a settlement agreement, in which we agreed to reconsider critical habitat designation for
N. fossalis.
The settlement stipulated that we submit a proposed revised critical habitat designation for
N. fossalis
to the
Federal Register
for publication on or before May 29, 2009, and submit a final revised critical habitat designation to the
Federal Register
for publication on or before May 28, 2010.

Critical Habitat

Critical habitat is defined in section 3 of the Act as:

(1) The specific areas within the geographical area occupied by a species, at the time it is listed in accordance with the Act, on which are found those physical or biological features

(a) Essential to the conservation of the species and

(b) That may require special management considerations or protection; and

(2) Specific areas outside the geographical area occupied by a species at the time it is listed, upon a determination that such areas are essential for the conservation of the species.

Conservation, as defined under section 3 of the Act, means the use of all methods and procedures that are necessary to bring any endangered or threatened species to the point at which the measures provided under the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resources management, such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, transplantation, and—in the extraordinary case where population pressures within a given ecosystem cannot otherwise be relieved—regulated taking.

Critical habitat receives protection under section 7(a)(2) of the Act through the prohibition against Federal agencies carrying out, funding, or authorizing the destruction or adverse modification of critical habitat. Section 7(a)(2) of the Act requires consultation on Federal actions that may affect critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation does not allow the government or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by private landowners. Where a landowner requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the consultation requirements of section 7(a)(2) would apply, but even in the event of a destruction or adverse modification finding, the landowner's obligation is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid

destruction or adverse modification of critical habitat.

For inclusion in a critical habitat designation, the habitat within the geographical area occupied by the species at the time of listing must contain physical and biological features that are essential to the conservation of the species, and be included only if those features may require special management considerations or protection. Critical habitat designations identify, to the extent known using the best scientific data available, habitat areas that provide essential life cycle needs of the species (i.e., areas on which are found the Primary Constituent Elements (PCEs) laid out in the appropriate quantity and spatial arrangement essential to the conservation of the species). Under the Act, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed as critical habitat only when we determine that those areas are essential for the conservation of the species.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific and commercial data available. Further, our Policy on Information Standards Under the Endangered Species Act (published in the
Federal Register
on July 1, 1994 (59 FR 34271)), the Information Quality Act (section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated Information Quality Guidelines provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.

When we are determining which areas should be designated as critical habitat, our primary source of information is generally the information developed during the listing process for the species. Additional information sources may include the recovery plan for the species, articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, or other unpublished materials and expert opinion or personal knowledge.

Habitat is often dynamic, and species may move from one area to another over time. Furthermore, we recognize that designation of critical habitat may not include all habitat areas that we may eventually determine are necessary for the recovery of the species, based on scientific data not now available to the Service. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not promote the recovery of the species.

Areas that support occurrences, but are outside the critical habitat designation, will continue to be subject to conservation actions we implement under section 7(a)(1) of the Act. They are also subject to the regulatory protections afforded by the section 7(a)(2) jeopardy standard, as determined on the basis of the best available scientific information at the time of the agency action. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. Similarly, critical habitat designations made on the basis of the best available information at the time of designation will not control the direction and substance of future recovery plans, habitat conservation plans (HCPs), or other species conservation planning efforts if new information available to these planning efforts calls for a different outcome.

Methods

As required by section 4(b) of the Act, we used the best scientific and commercial data available in determining areas occupied at the time of listing that contain the features essential to the conservation of
Navarretia fossalis.
We reviewed the approach to the conservation of
N. fossalis
provided in its recovery plan (Service 1998a, pp. 1-113, appendices), the 2005 final designation of critical habitat for
N. fossalis
(October 18, 2005, 70 FR 60658), information from State, Federal, and Local government agencies, and information from academia and private organizations that collected scientific data on the species. Other information we used for this proposed revised critical habitat includes: The CNDDB (CNDDB 2008, pp. 1-44); published and unpublished papers, reports, academic theses, surveys; Geographic Information System (GIS) data (such as species occurrence data, soil data, land use, topography, aerial imagery, and ownership maps); correspondence to the Service from recognized experts; and other information as available.

Primary Constituent Elements

In accordance with section 3(5)(A)(i) of the Act and regulations at 50 CFR 424.12(b), in determining which areas occupied by the species at the time of listing to propose as critical habitat, we consider those physical and biological features that are essential to the conservation of the species that may require special management considerations or protection. We consider the physical and biological features to be the primary constituent elements (PCEs) laid out in the appropriate quantity and spatial arrangement for the conservation of the species. The PCEs include, but are not limited to:

(1) Space for individual and population growth and for normal behavior;

(2) Food, water, air, light, minerals, or other nutritional or physiological requirements;

(3) Cover or shelter;

(4) Sites for breeding, reproduction, and rearing (or development) of offspring; and

(5) Habitats that are protected from disturbance or are representative of the historical, geographical, and ecological distributions of a species.

We derived the PCEs required for
Navarretia fossalis
from its biological needs. The area proposed for designation as revised critical habitat consists of ephemeral wetland habitat for the reproduction and growth of
N. fossalis,
intermixed wetland and upland habitats that act as the local watershed to support the ephemeral wetland habitat, and the topography and soils that support ponding during winter and spring months. The methods of dispersal and pollination for
N. fossalis
are not well understood and may not be captured by this proposed revised critical habitat. Likewise, the larger watershed areas that support the ephemeral wetland habitat are difficult to define and may require hydrological data and modeling that are not available; therefore, areas beyond the local watershed are not included in this proposed critical habitat rule. The PCEs and the resulting physical and biological features essential for the conservation of
N. fossalis
are derived from studies of this species' habitat, ecology, and life history as described below, in the “Background” section in this proposed rule, as well as in the previous critical habitat rule (October 18, 2005, 70 FR 60658), and in the final listing rule published in the
Federal Register
on October 13, 1998 (63 FR 54975).

Habitats That Are Representative of the Historic Geographical and Ecological Distribution of the Species

Navarretia fossalis
is restricted to temporary wetlands in southern California and northwestern Baja

California (Moran 1977, pp. 155-156; Oberbauer 1992, p. 7; Day 1993, p. 847; CNDDB 2008, pp. 1-44), and primarily associated with vernal pools and seasonally flooded alkali vernal plain habitats (Moran 1977, pp. 155-156; Bramlet 1993a, p. 10; Day 1993, p. 847; Ferren and Fiedler 1993, pp. 126-127). In Los Angeles County,
N. fossalis
is known to occur in vernal pools on Cruzan Mesa and the associated drainage of Plum Canyon. In Riverside County,
N. fossalis
is known to occur in large vernal pools with basins that range in size from 0.5 ac (0.2 ha) to 10.0 ac (4.0 ha) (e.g., CNDDB 2008, EO 43, 44), and in temporary wetlands that are described as seasonally flooded alkali vernal plain habitat along the San Jacinto River and near Salt Creek in Hemet (e.g., CNDDB 2008, EO 22, 23, 24). In San Diego County,
N. fossalis
is found in vernal pools that are smaller than those in Riverside County, ranging in size from 0.01 ac (0.005 ha) to 0.2 ac (0.09 ha) and are often found in clusters of several vernal pools referred to as vernal pool complexes (e.g., CNDDB 2008, EO 4, 14, 19). In Mexico,
N. fossalis
is known from fewer than 12 occurrences, of which the main occurrences are clustered in three areas: along the international border, on the plateaus south of the Rio Guadalupe, and on the San Quintin coastal plain (Moran 1977, p. 156).

Ephemeral Wetland Habitat

Despite the variation in the types of habitat where
Navarretia fossalis
is found (i.e., vernal pool habitat and seasonally flooded alkali vernal plain habitat), these ephemeral wetlands all share the same temporary nature (i.e., areas fill with water during winter or spring months and dry completely during summer and fall months).
Navarretia fossalis
depends on both the inundation and the drying of its habitat for survival. This type of ephemerally wet habitat does not support upland plants that live in a dry environment year round or wetland plants that require year round moisture to become established (Keeler-Wolf
et al.
1998). Rather, these habitats support specialized plants, such as
N. fossalis
that are able to grow in the open niche created by the exclusion of strictly upland and wetland plants.

Navarretia fossalis
primarily occurs in ephemeral wetland habitat, more specifically, vernal pool and seasonally flooded alkali vernal plain habitat (Moran 1977, pp.156-157; Bramlet 1993a, p. 10; Bramlet 1993b, p. 14; Day 1993, p. 847). Vernal pools form during the winter rains in depressions that are part of a gently sloping, undulating landscape, where soil mounds are interspersed with basins. This landscape is called “mima-mound” topography (Cox 1984, pp. 1397-1398), which is situated above an impervious soil layer called a “hard pan” or “clay pan.” Additionally, the final listing rule states that
N. fossalis
can occur in ditches and other artificial depressions associated with degraded vernal pool habitat (63 FR 54975, October 13, 1998; Moran 1977, p. 155).

Seasonally flooded alkali vernal plain habitat includes alkali playa, alkali scrub, alkali vernal pool, and alkali annual grassland components. The hydrologic regime for this habitat involves sporadic flooding (as described above) in combination with slow drainage on the alkaline soils. The habitat floods locally on a seasonal basis. Mid-range floods occur less frequently, approximately every 20 to 50 years, but are necessary to maintain the habitat by removing scrub vegetation (Roberts 2004, p. 4). During a typical, seasonal flooding period, alkali scrub vegetation expands its distribution into the deeper areas of the seasonally flooded alkali vernal plain habitat and crowds out the more ephemeral wetland species. During a large scale flooding period, standing and slow draining water remains for weeks or months and results in the death of alkali scrub vegetation. As a result, conditions become favorable for annual species (e.g.,
Navarretia fossalis
) to regain and locally expand their range (Bramlet 2004, p. 8; Roberts 2004, p. 4).

Intermixed Wetland and Upland Habitats That Act as the Local Watershed

Vernal pools within a vernal pool complex are hydrologically connected to one another within the local geographical context. Seasonally flooded alkali vernal plain habitats are also hydrologically connected by flowing water. Water flows over the surface from one vernal pool to another or throughout the seasonally flooded alkali vernal plain. Due to an impervious clay layer or hard pan, water also flows and collects below ground such that the soil becomes saturated with water. The result of the movement of the water through vernal pool and seasonally flooded alkali vernal plain systems is that pools fill and hold water continuously for a number of days following the initial rainfall (Hanes
et al.
1990, p. 51). For this reason, these hydrologic systems are best described from a watershed perspective. The local watershed associated with a vernal pool complex or seasonally flooded alkali vernal plain includes all surfaces in the surrounding area that flow into the vernal pool complex or seasonally flooded alkali vernal plain. Some hydrologic systems (e.g., the San Jacinto River, the Salt Creek Seasonally Flooded Alkali Plain) have watersheds that cover a large area and that contribute to filling and the hydrological dynamics of the system, while other hydrologic systems have very small watersheds (e.g., Carroll Canyon, Nobel Drive) and fill almost entirely from direct rainfall (Hanes
et al.
1990, p. 53; Hanes and Stromberg 1998, p. 38). It is also possible that subsurface inflows from surrounding soils within a watershed contribute to filling some vernal pools and seasonally flooded alkali vernal plains (Hanes
et al.
1990, p. 53; Hanes and Stromberg 1998, p. 48).

Topography and Soils That Support Ponding During Winter and Spring

Impervious subsurface layers of clay soils or hardpan geology, combined with flat to gently sloping topography, serve to inhibit rapid infiltration of rainwater, resulting in ponded water in vernal pools and seasonally flooded alkali vernal plains (Bramlet 1993a, p. 1; Bauder and McMillian 1998, pp. 57-59). These soils also act as a buffer to moderate the water chemistry and rate of water loss to evaporation (Zedler 1987, pp. 17-30). In Los Angeles County, the vernal pools that support
Navarretia fossalis
are found on Cieneba-Pismo-Caperton soils (Service GIS analysis). In western Riverside County, the seasonally flooded alkali vernal plain habitat that supports
N. fossalis
is found on Domino, Traver, Waukena, and Chino soils (Bramlet 1993a, p. 1, 10; December 15, 1994, 59 FR 64812). In San Diego County, the vernal pool habitat that supports
N. fossalis
is found on Huerhuero, Placentia, Olivenhain, Stockpen, and Redding soils (Service GIS analysis).

Primary Constituent Elements for Navarretia fossalis

Under the Act and its implementing regulations, we are required to identify the physical and biological features within the geographical area occupied by
Navarretia fossalis
at the time of listing that are essential to the conservation of the species and which may require special management considerations or protection. The physical and biological features are those PCEs laid out in a specific special arrangement and quantity determined to be essential to the conservation of the species. All areas proposed as critical habitat for
N. fossalis
were occupied at the time of listing (see the “Geographic Range and Status” section for a more detailed explanation) and are currently

occupied, are within the species' geographic range, and contain sufficient essential features to support at least one life history function.

Based on our current knowledge of the life history, biology, and ecology of
Navarretia fossalis,
and the requirements of the habitat to sustain the essential life history functions of the species, we determined that the PCEs specific to
N. fossalis
are:

(1) PCE 1—Ephemeral wetland habitat. Vernal pools (up to 10 ac (4 ha)) and seasonally flooded alkali vernal plains that become inundated by the winter rains and hold water or have saturated soils for 2 weeks to 6 months during a year with average rainfall. This period of inundation is long enough to promote germination, flowering, and seed production for
N. fossalis
and other native species typical of vernal pool and seasonally flooded alkali vernal plain habitat, but not so long that true wetland species inhabit the areas.

(2) PCE 2—
Intermixed wetland and upland habitats that act as the local watershed.
Areas characterized by mounds, swales, and depressions within a matrix of upland habitat that results in intermittently flowing surface and subsurface water in swales, drainages, and pools that support the habitat described in PCE 1, and provide the water that allows for the inundation described in PCE 1.

(3) PCE 3—
Soils that support ponding during winter and spring.
Soils found in areas characterized in PCE 2 that allow for ponding of water because they have a clay component or other property that creates an impermeable surface or subsurface layer. The properties of these soils contribute to reduced percolation and minimal run-off of water, all of which lead to supporting the habitat and period of inundation described in PCE 1. These soil types are known to include, but are not limited to: Cieneba-Pismo-Caperton soils in Los Angeles County; Domino, Traver, and Willows soils in Riverside County; and Huerhuero, Placentia, Olivenhain, Stockpen, and Redding soils in San Diego County.

With this proposed designation of critical habitat, we intend to conserve the physical and biological features essential to the conservation of the species, through the identification of the appropriate quantity and spatial arrangement of the PCEs sufficient to support the life history functions of the species. For
Navarretia fossalis,
the size of the ephemeral wetland habitat can vary a great deal, but the important factor (i.e., the appropriate quantity and spatial arrangement of the PCEs) in any of the subunits proposed as critical habitat is that the vernal pool or alkali playa habitat has intact and functioning hydrology and intact adjacent upland areas that ensure a functioning ecosystem. All units and subunits proposed as critical habitat contain the PCEs in the appropriate quantity and spatial arrangement essential to the conservation of this species and support multiple life processes for
N. fossalis.

Special Management Considerations or Protection

When designating critical habitat, we assess whether the occupied areas contain the physical and biological features that are essential to the conservation of the species, and whether these features may require special management considerations or protection.

The area proposed for designation as revised critical habitat will require some level of management to address the current and future threats to the physical and biological features essential to the conservation of the species. In all units, special management considerations or protection of the essential features may be required to provide for the sustained function of the ephemeral wetland ecosystems on which
N. fossalis
depends. The designation of critical habitat does not imply that lands outside of critical habitat do not play an important role in the conservation of
N. fossalis.
Activities with a Federal nexus that may affect areas outside of critical habitat, such as development, agricultural activities, and road construction, are still subject to review under section 7 of the Act if they may affect
N. fossalis,
because Federal agencies must consider both effects to the plant and effects to critical habitat independently. The prohibitions of section 9 of the Act applicable to
N. fossalis
under 50 CFR 17.71 (e.g., reduce to possession or maliciously damage or destroy on Federal lands) also continue to apply both inside and outside of designated critical habitat.

Researchers estimate that greater than 90 percent of the vernal pool habitat in southern California has been converted as a result of past human activities (Bauder and McMillian 1998, pp. 56-67; Keeler-Wolf
et al.
1998, pp. 10, 60-61, 63-64). A detailed discussion of threats to
Navarretia fossalis
and its habitat can be found in the final listing rule (October 13, 1998, 63 FR 54975), the previous critical habitat designation (October 18, 2005, 70 FR 60658), and the Recovery Plan for Vernal Pools of Southern California (Service 1998a, pp.1-113, appendices). The features essential to the conservation of
N. fossalis
require special management considerations or protection to reduce the following threats, among others: habitat destruction and fragmentation from urban and agricultural development; pipeline construction; alteration of hydrology and floodplain dynamics; excessive flooding; channelization; water diversions; off-road vehicle activity; trampling by cattle and sheep; weed abatement; fire suppression practices (including discing and plowing to remove weeds and create fire breaks); competition from nonnative plant species; and direct and indirect impacts from some human recreational activities (October 13, 1998, 63 FR 54975; Service 1998a, p. 7).

Criteria Used To Identify Critical Habitat

We are proposing to designate critical habitat in areas that were occupied by the species at the time of listing and continue to be occupied today, and that contain the PCEs in the quantity and spatial arrangement to support life history functions essential for the conservation of the species (see the “Geographic Range and Status” section for more information). We are not proposing to designate any areas outside the geographical area occupied at the time of listing. All units and subunits proposed contain the PCEs in the appropriate quantity and spatial arrangement essential to the conservation of this species and support multiple life processes for
N. fossalis.

As required by section 4(b)(1)(A) of the Act, we use the best scientific and commercial data available in determining areas that contain the features that are essential to the conservation of
Navarretia fossalis.
The “Methods” section summarizes the data used for this proposed revised critical habitat. This proposed revised rule is an effort to update our 2005 final designation of critical habitat for
N. fossalis
with the best available data. In some areas that were analyzed in 2005, we have new information that led us to either add or remove areas from this proposal to revise critical habitat.

This section provides details of the process and criteria we used to delineate proposed revised critical habitat. This proposed revised rule is the result of a progression of conservation efforts for
Navarretia fossalis.
This progression is based largely on the past analysis of the areas that are required for the conservation of
N. fossalis
as presented in the Recovery Plan for Vernal Pools of Southern California (Service 1998a, pp.1-113, appendices), the 2005 final critical habitat designation, and new

information we obtained on the species and its distribution since listing. Table 1 shows the changes in identified essential habitat between the 1998 Recovery Plan, the 2005 final critical habitat designation, and this proposed revised critical habitat designation. The unit names used in this proposed revised critical habitat are based on the names used for management areas used in the 1998 Recovery Plan. The specific changes made to the 2005 final designation of critical habitat are summarized in the “Summary of Changes From Previously Designated Critical Habitat” section of this rule.

Table 1—Areas Identified as Essential to Navarretia Fossalis Conservation

Location*
Recovery plan appendix
Final critical habitat (2005)
Proposed revised critical habitat (2009)

Unit 1: Los Angeles Basin-Orange Management Area

Cruzan Mesa
F
1A
1A.

Plum Canyon
N/A
1B
1B.

Unit 2: San Diego: Northern Coastal Mesa Management Area

Stuart Mesa, Marine Corps Base (MCB) Camp Pendleton, Recovery plan (RP)** name: Stuart Mesa
F
4(a)(3) exemption
4(a)(3) exemption.

Wire Mountain, MCB Camp Pendleton, RP name: Wire Mountain
F

4(a)(3) exemption.

Poinsettia Lane Commuter Station, RP name: JJ 2 Poinsettia Lane
F
2 (partially excluded under section 4(b)(2))
2.

Unit 3: San Diego: Central Coastal Mesa Management Area

Santa Fe Valley (Crosby Estates)
N/A

3A.

Carroll Canyon (D 5-8)

3B.

Nobel Drive (X 5)

3C.

Large Pool southwest of runway, MCAS Miramar
N/A

4(a)(3) exemption.

EE1-2, MCAS Miramar, RP name: EE1-2, Miramar Interior
F
4(a)(3) exemption

Kearny Mesa (U 19)
N/A
4(a)(3) exemption

New Century (BB 2), RP name: BB 2 New Century
G

Montgomery Field, RP name: N1-4, 6 Montgomery Field
F
Excluded under section 4(b)(2)
3D.

Unit 4: San Diego: Inland Management Area

San Marcos (North L 15), RP name: L 7, 8, 14-20
G

San Marcos (Northwest L 14), RP name: L 7, 8, 14-20
G

San Marcos (L 1-6), RP name: L 1-6, 9-13 San Marcos
F
4C1
4C1.

San Marcos (L 9-10), RP name: L 1-6, 9-13 San Marcos
F
4C2
4C2.

San Marcos (L 11-13), RP name: L 1-6, 9-13 San Marcos
F
4D
4D.

San Marcos (North L 15), RP name: L 7, 8, 14-20
G

Ramona, RP name: Ramona
F

Ramona, RP name: Ramona T
G
4E
4E.

Unit 5: San Diego: Southern Coastal Mesa Management Area

Sweetwater Vernal Pools (S1-3), RP name: Sweetwater Lake
F
5A ( partially excluded under section 4(b)(2))
5A.

Otay River Valley (M2)

5B
5B.

Otay Mesa (J26), RP name: J 26 Otay Mesa
F
5C

Proctor Valley (R1), RP name: R Proctor Valley
F

5F.

Otay Reservoir (K3-5), RP name: K3-5 Otay River
F

5G.

K1, 2, RP name: K 1, 2, 6, 7 Otay River
G
Excluded under section 4(b)(2)

K 6, 7, RP name: K 1, 2, 6, 7 Otay River
G

Western Otay Mesa vernal pool complexes, RP name: J 2, 5, 7, 11-21, 23-30 Otay Mesa/J 3 Otay Mesa
F/G
Excluded under section 4(b)(2)
5H/5I.

Western Otay Mesa vernal pool complexes (J 32 (West Otay A + B), J 33 (Sweetwater High School))
N/A

5H.

Eastern Otay Mesa vernal pool complexes, RP name: 23-30 Otay Mesa/J 22 Otay Mesa
F/G
Excluded under section 4(b)(2)
5H/5I.

Eastern Otay Mesa vernal pool complexes, RP name: J 19, 27, 28E, 28W Otay Mesa

Excluded under section 4(b)(2)

RP name: J (undescribed)
G

Unit 6: Riverside Management Area

San Jacinto River, RP name: San Jacinto
F
Excluded under section 4(b)(2)
6A.

Salt Creek Seasonally Flooded Alkali Plain, RP name: Hemet/Salt Creek
F
Excluded under section 4(b)(2)
6B.

Wickerd Road and Scott Road Pools
N/A

6C.

Skunk Hollow, RP name: Skunk Hollow

Excluded under section 4(b)(2)
6D.

RP name: Temecula
F

Mesa de Burro, RP name: Santa Rosa Plateau
F
Excluded under section 4(b)(2)
6E.

Total Areas (out of 39 areas listed in this table)
27
22
27.

*This table does not include all locations that are occupied by
Navarretia fossalis.
It includes only those locations that were included in Appendix F or G of the Recovery Plan; designated, excluded, or exempt in 2005; or proposed as critical habitat in the current rule. Note: The alpha-numeric labels were applied in the recovery plan.

**RP name = Name in recovery plan, if different from the current rule.

Appendices F and G of the Recovery Plan provide information on the areas that are needed to stabilize (or prevent extinction of)
Navarretia fossalis
(Appendix F) and the areas that are needed to reclassify (or recover)
N. fossalis
(Appendix G). In Table 1, we summarized the data from the recovery plan. According to this summary, 27 locations were highlighted as areas that needed to be conserved and managed to recover
N. fossalis.
Our 2005 final rule to designate critical habitat used the Recovery Plan as the basis for designating areas as critical habitat; however, the rule included some additions and subtractions of those areas determined as essential to the conservation of
N. fossalis
in the Recovery Plan. Nine areas that the Recovery Plan identified as important were not identified in the 2005 final rule as essential to the conservation of
N. fossalis,
and four areas were added that were not highlighted in the Recovery Plan. The nine areas that were in the Recovery Plan but not included in the 2005 final rule were sites for which we did not have specific occurrence data or areas where recent surveys had not found
N. fossalis.
For these reasons, we do not believe these areas are essential to the conservation of
N. fossalis
and we did not include them in the 2005 critical habitat designation. The four areas that were added to the 2005 final rule were locations where the occurrence data indicated that these areas contained the features essential to the conservation of
N. fossalis.

A total of 22 areas were identified in the 2005 final rule as essential to the conservation of
N. fossalis
(see Table 1). There are eight occurrences of
N. fossalis
that were highlighted in the Recovery Plan that we did not include in this proposed revised critical habitat. We do not have detailed information on these occurrences, and during recent surveys at some of these sites,
N. fossalis
has not been observed. Additionally, we included areas in this proposed revised critical habitat (based on new data) that were not highlighted in the Recovery Plan. While some of the areas are different, we believe that the non-inclusion of some areas in the Recovery Plan and the inclusion of other areas for which we have better data will achieve the overall goal of the Recovery Plan for
N. fossalis
and provide for the conservation of this species.

In this proposed revised designation of critical habitat for
Navarretia fossalis,
we selected areas based on the best scientific data available that possess those physical and biological features essential to the conservation of the species, and that may require special management considerations or protection. We took into account the past conservation planning that occurred for
N. fossalis
in the Recovery Plan and in the 2005 critical habitat designation. For this proposed revised rule, we completed the following steps to delineate critical habitat: (1) Compiled all available data on
N. fossalis
into a GIS database; (2) reviewed data to ensure accuracy; (3) determined which occurrences existed at the time of listing; (4) determined which areas are currently occupied; (5) defined the areas containing the features essential to the conservation of
N. fossalis
in terms of core habitat areas and satellite habitat areas; (6) determined if each occupied area represents core habitat or satellite habitat and, therefore, should be proposed as critical habitat; and (7) for both core and satellite habitat areas, mapped the specific locations that contain the essential physical and biological features (PCEs in the quantity and spatial arrangement needed to support life history functions essential for
N. fossalis
). These steps are described in detail below.

(1) We compiled all available data on
Navarretia fossalis
into a GIS database. Data on locations where
N. fossalis
occurs was based on collections and observations made by botanists (both amateur and professional), biological consultants, and academic researchers. We compiled data from the following sources to create our GIS database for
N. fossalis:
(1) Data used in the Recovery Plan and in the 2005 final critical habitat rule for
N. fossalis;
(2) the CNDDB data report for
N. fossalis
and accompanying GIS records (CNDDB 2008, pp. 1-44); (3) data presented in the City of San Diego's Vernal Pool Inventory for 2002-2003 (City of San Diego 2004, pp. 1-125, appendices); (4) the data report for
N. fossalis
from the California Consortium of Herbaria and accompanying Berkeley Mapper GIS records (Consortium of California Herbaria 2008, pp. 1-17); (5) the Western Riverside County Multiple Species Habitat Conservation Plan (Western Riverside County MSHCP) species GIS database; and (6) the Carlsbad Fish and Wildlife Office's internal species GIS database, which includes the species data used for the San Diego Multiple Species Conservation Plan (MSCP) and the San Diego Multiple Habitat Conservation Plan (MHCP), reports from section 7 consultations, and FWS observations of

N. fossalis
(CFWO internal species GIS database).

(2) We reviewed the data that we compiled to ensure its accuracy. We checked each data point in our database to ensure that it represented an original collection or observation of
Navarretia fossalis.
Data that did not represent an original collection or observation was removed from our database. Secondly, we checked each data point to ensure that it was mapped in the correct location. Data points that did not match the description for the original collection or observation were remapped in the correct location or removed from our database.

(3) We determined which occurrences existed at the time of listing. We concluded that all known occurrences, except for a single occurrence translocated after this species was listed, were extant at the time of listing. We drew this conclusion because
Navarretia fossalis
has limited dispersal capabilities. We believe that the documentation of additional occurrences after the species was listed was due to an increased effort to survey for this species. Therefore, except on the single occasion where this species was translocated to a new location, all of the areas that we know of for this species were occupied prior to the time this species was listed. In other words, we do not believe that this species has naturally colonized any new areas since it was listed.

(4) We determined which areas are currently occupied. For areas where we had past occupancy data for
Navarretia fossalis,
we assumed the area is currently occupied unless: (a) Two or more rare plant surveys conducted during the past 10 years did not find
N. fossalis
(providing the surveys were conducted in years with average rainfall and during the appropriate months to find this species (March, April, and May); or (b) the site was significantly disturbed since the last observation of the species at that location.

(5) We defined the areas necessary for conservation of
N. fossalis
in terms of “core habitat areas” and “satellite habitat areas.” See the “Areas Needed for Conservation: Core and Satellite Habitat Areas” section in this rule for definitions of these areas.

(6) We determined if each occupied area represents core habitat or satellite habitat, and, therefore, should be proposed as critical habitat. In the final listing rule (63 FR 54975, October 13, 1998), we stated that 60 percent of the known occurrences of
Navarretia fossalis
are concentrated in three locations: Otay Mesa in southern San Diego County, along the San Jacinto River in western Riverside County, and near Hemet in Riverside County (referred to as the Salt Creek Seasonally Flooded Alkali Plain in this proposed rule). These three areas represent core habitat for
N. fossalis.
In addition to these three core habitat areas, Mesa de Burro in Riverside County represents core habitat for this species due to the large size of the occurrence observed there in 2008 and because of the large amount of intact vernal pool habitat on this mesa. In total, we identified four core habitat areas for
N. fossalis.
These four areas represent large, interconnected ephemeral wetlands. Large occurrences of
N. fossalis
are currently present in these four areas, but there have been significant impacts to these areas in the form of habitat fragmentation, nonnative plant invasion, agricultural activities, and recreational use. These four core habitat areas are essential to the conservation of
N. fossalis
because the conservation of these areas will anchor the overall conservation effort for this species. Additionally, the conservation of these four areas will sustain the largest occurrences of
N. fossalis
and allow for
N. fossalis
to persist where it will be less constrained by the threats that negatively impact its essential habitat features (PCEs).

Habitat areas outside the four core habitat areas also support stable, intact occurrences of
Navarretia fossalis.
These satellite areas represent unique habitat within this species' range that also contain the PCEs laid out in the appropriate quantity and spatial arrangement essential for the conservation of the species. The conservation of multiple areas that support occurrences dispersed throughout the range of
N. fossalis
will allow occurrences to persist and expand, ensuring that this species will not go extinct. The satellite habitat areas occur over a wide range of soils and at various elevations that include several occurrences over a range of environmental variables, the preservation of which will help maintain the genetic diversity of
N. fossalis.
The satellite habitat areas allow for connections between existing occurrences of
N. fossalis,
and together with the core habitat areas, will create a sustainable matrix of habitat for this species that will enable it to evolve and respond to future environmental changes.

Areas were selected as satellite habitat areas if they are: (1) Important peripheral occurrences of this species that are on the geographic edge of this species' distribution; (2) occurrences that are isolated from other occurrences by geographic features; or (3) areas that are nested within the distribution of this species and provide connections between the core habitat areas and other satellite habitat areas.

(7) For the core and satellite habitat areas, we mapped the specific areas that contain the physical and biological features (the PCEs) in the quantity and spatial arrangement needed to support life history functions essential for
Navarretia fossalis.
We first mapped the ephemeral wetland habitat in the occupied area using occurrence data, aerial imagery, and 1:24,000 topographic maps. We then mapped the intermixed wetland and upland habitats that make up the local watersheds and the topography and soils that support the occupied ephemeral wetland habitat. We mapped this area using USGS topographic 1:24,000 scale maps, aerial imagery, and soil maps to identify the gently sloping area associated with ephemeral wetland habitat and any adjacent areas that slope directly into the ephemeral wetland habitat which likely contribute to the hydrology of the ephemeral wetland habitat. In most cases, we delineated the border of the proposed revised critical habitat around the occupied ephemeral wetlands and associated local watershed areas to follow natural breaks in the terrain such as ridgelines, mesa edges, and steep canyon slopes.

When determining the proposed revised critical habitat boundaries, we made every effort to map precisely only the areas that contain the PCEs and provide for the conservation of
Navarretia fossalis.
However, we cannot guarantee that every fraction of proposed revised critical habitat contains the PCEs due to the mapping scale that we use to draft critical habitat boundaries. Additionally, we made every attempt to avoid including developed areas such as lands underlying buildings, paved areas, and other structures that lack PCEs for
N. fossalis.
The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed areas. Any developed structures and the land under them inadvertently left inside critical habitat boundaries shown on the maps of this proposed revised critical habitat are excluded by text in this rule and are not proposed for critical habitat designation. Therefore, Federal actions involving these lands would not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific actions may affect the species or PCEs in adjacent critical habitat.

Summary of Changes From Previously Designated Critical Habitat

The areas identified in this rule constitute a proposed revision from the areas we designated as critical habitat for
Navarretia fossalis
on October 18, 2005 (70 FR 60658). The differences include the following:

(1) We refined the PCEs to more accurately define the physical and biological features that are essential to the conservation of
Navarretia fossalis.
The PCEs were written in both the 2005 final critical habitat and this proposed rule to describe the ephemeral wetland habitat where
N. fossalis
occurs, the associated watersheds that support the ephemeral wetland habitat, and the soils and topography that allow water to pond during winter and spring months. In the PCE related to the vernal pools and flooded alkali vernal plains where
N. fossalis
occurs, we added information relating to the necessary timing and duration of ponding in the ephemeral wetlands where
N. fossalis
occurs (PCE 1). In the PCE related to the local watershed and filling of the ephemeral wetland habitat, we discussed the landforms that contribute to the local hydrology and local watershed (PCE 2). In the PCE related to soils types associated with habitat for
N. fossalis,
we state that these soil types facilitate the slow percolation and minimal run-off of water necessary for the ephemeral wetland habitat where
N. fossalis
occurs (PCE 3).

(2) We revised the criteria used to identify critical habitat. Similar to the 2005 critical habitat, we used the Recovery Plan as the basis for our criteria. However, in this proposed revised critical habitat we conducted an additional analysis of all the
Navarretia fossalis
data currently available. The result of the additional analysis was that some areas identified as essential in the 2005 designation were removed and other areas were included in this proposed rule that were not identified as essential in the 2005 designation. We described the steps that we used to identify and delineate the areas that we are proposing as critical habitat in more detail compared to the 2005 critical habitat designation to ensure that the public better understands why the areas are being proposed as critical habitat.

(3) We improved our mapping methodology to more accurately define the critical habitat boundaries and to better represent those areas that possess the physical and biological features essential to the conservation of the species. This proposed revised rule identifies 12,313 fewer acres (4,983 ha) considered essential to the conservation of
Navarretia fossalis
than we identified in the 2005 rule. However, this reduction is primarily due to our attempt to better represent the areas that contain the essential features for
N. fossalis.
For example, in the 2005 final rule, we delineated large areas of watershed habitat as essential, which resulted in large, poorly defined critical habitat areas. The major reductions to the 2005 critical habitat are discussed in detail below (see #6). Finally, in the 2005 final rule, we used a 100-meter grid to delineate critical habitat. In this proposed revised rule, we mapped the areas that contain the PCEs as accurately as possible by more directly approximating the delineation of essential areas rather than using a 100-meter grid to map essential areas. However, we acknowledge the possibility that, due to mapping, data, and resource constraints, there may be some undeveloped areas mapped as critical habitat that do not contain the PCEs.

(4) We identified several areas we are considering for exclusion from this proposed revised critical habitat designation under section 4(b)(2) of the Act. Any exclusions in our upcoming final revised critical habitat designation could differ from the exclusions we made in the 2005 final critical habitat designation.

(5) We added and subtracted some subunits and revised the area of proposed revised critical habitat. The 2005 final critical habitat designation (70 FR 60658, October 18, 2005) included 4 units and 10 subunits, comprising a total of 652 ac (264 ha), which were grouped to match the management areas described in the 1998 Recovery Plan. This proposed revision includes 6 units with 24 subunits (two of which are exempt from designation under section 4(a)(3)(B) of the Act), comprising a total of 7,086 ac (2,868 ha) of land considered essential to the conservation of
N. fossalis.
These 6 units and 24 subunits match the units and subunits in the 2005 critical habitat to the extent that the subunits overlap and match the management areas described in the 1998 Recovery Plan. In 2005 we identified 18,747 ac (7,587 ha) of land containing features essential to the conservation of
N. fossalis
that we did not designate as critical habitat. The lands were either exempt from critical habitat under section 4(a)(3)(B) of the Act or we excluded them under section 4(b)(2) of the Act. In this proposed revised rule, 2 subunits on MCB Camp Pendleton (145 ac (59 ha)) and MCAS Miramar (69 ac (28 ha)) are exempt under section 4(a)(3)(B) of the Act. We are also considering excluding certain areas under section 4(b)(2) of the Act from the final designation. Specifically, we are requesting public comment on the potential exclusion of 5,675 ac (2,296 ha) covered by the Western Riverside County Multiple Species Habitat Conservation Plan (MSHCP), 3 ac (1 ha) covered by the Carlsbad Habitat Management Plan (HMP) under the San Diego Multiple Habitat Conservation Plan (MHCP), and 86 ac (35 ha) covered by the County of San Diego under the San Diego Multiple Species Conservation Plan (MSCP).

In Table 2 below, we provide a comparison between the 2005 final critical habitat designation and this proposed revised critical habitat rule. The table identifies the change in area for each subunit in the 2005 critical habitat designation and our new areas for units and subunits in this proposed revised critical habitat designation. Some areas designated in the 2005 rule are not proposed as critical habitat because they do not meet the criteria we are using to designate critical habitat (See Table 2). Additionally, there are areas being proposed as critical habitat that were not considered in the 2005 final critical habitat because we have determined that these areas contain features essential for the conservation of
Navarretia fossalis.

Table 2—A Comparison of the Areas Identified as Containing Features Essential to the Conservation of
Navarretia fossalis
in the 2005 Final Critical Habitat Designation and This Proposed Revised Critical Habitat Designation

Location*
2005 Final critical habitat
Subunit
Area containing essential features
2009 Proposed revised critical habitat
Subunit
Area containing essential features
Difference (2009 minus 2005)
Area

Unit 1: Los Angeles Basin-Orange Management Area

Cruzan Mesa
1A
294 ac (119 ha)
1A
129 ac (52 ha)
−165 ac (−67 ha).

Plum Canyon
1B
32 ac (13 ha)
1B
32 ac (13 ha)
0 ac (0 ha).

Unit 2: San Diego: Northern Coastal Mesa Management Area

MCB Camp Pendleton
4(a)(3) exemption
67 ac (27 ha)
4(a)(3) exemption
145 ac (59 ha)
78 ac (32 ha).

Poinsettia Lane Commuter Station
2; partially excluded under section 4(b)(2)
22 ac (9 ha)
2
9 ac (4 ha)
−13 ac (−5 ha).

Unit 3: San Diego: Central Coastal Mesa Management Area

Santa Fe Valley
Proposed as Unit 3, but determined not essential

Not proposed

Santa Fe Valley (Crosby Estates)

3A
5 ac (2 ha)
5 ac (2 ha).

Carroll Canyon

3B
20 ac (8 ha)
20 ac (8 ha).

Nobel Drive

3C
37 ac (15 ha)
37 ac (15 ha).

MCAS Miramar
4(a)(3) exemption
61 ac (25 ha)
4(a)(3) exemption
69 ac (28 ha)
8 ac (3 ha).

Montgomery Field
Excluded under section 4(b)(2)
38 ac (16 ha)
3D
48 ac (20 ha)
10 ac (4 ha).

Unit 4: San Diego: Inland Management Area

San Marcos (Upham)
4C1
34 ac (14 ha)
4C1
34 ac (14 ha)
0.

San Marcos (Universal Boot)
4C2
32 ac (13 ha)
4C2
32 ac (13 ha)
0.

San Marcos (Bent Avenue)
4D
7 ac (3 ha)
4D
5 ac (2 ha)
−2 ac (−1 ha).

Ramona
4E
86 ac (35 ha)
4E
135 ac (55 ha)
49 ac (20 ha).

Unit 5: San Diego: Southern Coastal Mesa Management Area

Sweetwater Vernal Pools (S1-3)
5A; partially excluded under section 4(b)(2)
163 ac (66 ha)
5A
95 ac (38 ha)
−68 ac (−27 ha).

Otay River Valley (K1 and K2)
Excluded under section 4(b)(2)
57 ac (23 ha)
Not proposed, determined not essential

−57 ac (−23 ha).

Otay River Valley (M2)
5B and excluded under section 4(b)(2)
109 ac (44 ha)
5B
24 ac (10 ha)
−85 ac (−34 ha).

Otay Mesa (J26)
5C and excluded under section 4(b)(2)
19 ac (8 ha)
Not proposed, determined not essential

−19 ac (−8 ha).

Arnie's Point
Proposed as Subunit 5D, but determined not essential

Not proposed

Proctor Valley (R1-2)

5F
88 ac (36 ha)
88 ac (36 ha).

Otay Lakes (K3-5)

5G
140 ac (57 ha)
140 ac (57 ha).

Western Otay Mesa vernal pool complexes
Excluded under section 4(b)(2)
117 ac (47 ha)
5H
143 ac (58ha)
26 ac (11 ha).

Eastern Otay Mesa vernal pool complexes
Excluded under section 4(b)(2)
277 ac (112 ha)
5I
221 ac (89 ha)
−56 ac (−23 ha).

Unit 6: Riverside Management Area

San Jacinto River
Excluded under section 4(b)(2)
10,774 ac (4,360 ha)
6A
3,550 ac (1,437 ha)
−7,224 ac (−2,924 ha).

Salt Creek Seasonally Flooded Alkali Plain
Excluded under section 4(b)(2)
2,233 ac (904 ha)
6B
1,054 ac (427 ha)
−1,179 ac (−477 ha).

Wickerd Road and Scott Road Pools
Excluded under section 4(b)(2)
275 ac (111 ha)
6C
205 ac (83 ha)
−70 ac (−28 ha).

Skunk Hollow
Excluded under section 4(b)(2)
306 ac (124 ha)
6D
158 ac (64 ha)
−148 ac (−60 ha).

Mesa de Burro
Excluded under section 4(b)(2)
4,396 ac (1,779 ha)
6E
708 ac (287 ha)
−3,688 ac (−1,493 ha).

Total Area Essential for the Conservation of
Navarretia fossalis

19,399 ac (7,851 ha)

7,086 ac (2,868 ha)
−12,313 ac (−4,983 ha).**

*This table does not include all locations that are occupied by
Navarretia fossalis.
It includes only those locations that were designated as critical habitat in 2005 or proposed as critical habitat in this rule.

**Values in this table may not sum due to rounding.

(6) Following is a list of the areas reduced or enlarged in this proposed revision to critical habitat designation, or eliminated from the 2005 final critical habitat designation, and an explanation of why these areas are no longer considered to contain the PCEs in the appropriate spatial arrangement and quantity essential to the conservation of
Navarretia fossalis.

(a) Cruzan Mesa—The habitat identified as essential to the conservation of
N. fossalis
on Cruzan Mesa in 2005 included the areas on top of this mesa where occurrences of
N. fossalis
had been found. The slopes of the mesa were also included due to the gridding technique that was used to describe critical habitat in the 2005 final rule. Because the mesa slopes do not contribute to the watershed of the vernal pools on Cruzan Mesa occupied by
N. fossalis,
they were removed. This area was reduced by 165 ac (67 ha).

(b) Poinsettia Lane Commuter Station—The habitat identified as essential to the conservation of
N. fossalis
at the Poinsettia Lane Commuter Station in 2005 included several vernal pools where occurrences of
N. fossalis
had been found. Due to the base map layer and the coarseness of the gridding techniques used in the 2005 final rule, some of the area designated as critical habitat consisted of developed residential lots and some of the area was on the west side of the railroad tracks where
N. fossalis
has not been found. These areas do not contribute to the watershed of the vernal pools at the Poinsettia Lane Commuter Station and were removed. In some places the boundary of this proposed subunit includes lands that were not mapped in 2005 due to our change in mapping methodology to better capture the watershed for these vernal pools. This area was reduced by 13 ac (5 ha).

(c) San Marcos (Bent Avenue)—The habitat identified as essential to the conservation of
N. fossalis
in San Marcos in 2005 included several vernal pools where occurrences of
N. fossalis
had been found. In the 2005 final rule, we were unaware that the designated critical habitat included developed areas. These areas do not contribute to the watershed of the vernal pools in San Marcos and were removed. This area was reduced by 2 ac (1 ha).

(d) Ramona—The habitat identified as essential to the conservation of
N. fossalis
in Ramona in the 2005 final rule captured the vernal pools where
N. fossalis
had been found, but did not capture the associated watershed area. In some places, the boundary of this proposed subunit includes lands that were not mapped in 2005 due to our change in mapping methodology to better capture the watershed for the vernal pools in this area. This area was enlarged by 49 ac (20 ha).

(e) Montgomery Field—The habitat identified as essential to the conservation of
N. fossalis
at Montgomery Field in the 2005 final rule did not capture all of the vernal pool and associated watershed area essential for the conservation of
N. fossalis.
In some places, the boundary of this proposed subunit includes lands that were not mapped in 2005 due to our change in mapping methodology to better capture the vernal pools and watershed area in this subunit. This area was enlarged by 10 ac (4 ha).

(f) Sweetwater Vernal Pools—The habitat identified as essential to the conservation of
N. fossalis
at the Sweetwater Vernal Pools in the 2005 final rule included several vernal pools where occurrences of
N. fossalis
had been found. Due to the coarseness of the gridding technique used in the 2005 final rule, the lands designated included areas that actually slope away from the vernal pools. These areas do not contribute to the watershed of the Sweetwater vernal pools and were removed. This area was reduced by 68 ac (27 ha).

(g) Otay River Valley (K1 and EO 10)—The habitat identified as essential to the conservation of
N. fossalis
in the Otay River Valley at the K1 and K2 vernal pool complexes are not known to support
N. fossalis
at this time. We have no data that indicates
N. fossalis
occurred in the K1 vernal pool complex.
Navarretia fossalis
was last reported in the Otay River Valley at CNDDB EO 10 in 1981. At this time, we do not believe that the unoccupied habitat in the Otay River Valley is essential for the conservation of
N. fossalis.
More occupied habitat exists for
N. fossalis
than we were aware of when the 1998 Recovery Plan was written and we believe that the species can be recovered with the management and protection of habitat that is currently occupied. We removed 57 ac (23 ha) in the Otay River Valley.

(h) Otay River Valley (M2)—The habitat identified as essential to the conservation of
N. fossalis
in the Otay River Valley in 2005 included several vernal pools where occurrences of
N. fossalis
had been found. Due to the coarseness of the gridding technique in the 2005 final rule, the lands designated included areas that actually slope away from the vernal pools. These areas do not contribute to the watershed of the vernal pools in the Otay River Valley and were removed. This area was reduced by 85 ac (34 ha).

(i) Otay Mesa (J26)—The habitat identified as essential to the conservation of
N. fossalis
on Otay Mesa at the J26 vernal pool complex is not known to support an occurrence of
N. fossalis
at this time, and we have no data that indicates
N. fossalis
ever occurred in the J26 vernal pool

complex. Surveys of the area conducted by the City of San Diego in 2003 did not locate
N. fossalis
in the J26 vernal pool complex. The 1998 Recovery Plan indicated the J26 vernal pool complex is important for the stabilization of
N. fossalis
as a species. However, at this time, we do not believe that the unoccupied habitat at the J26 vernal pool complex in Otay Mesa is essential for the conservation of
N. fossalis.
More occupied habitat for this species exists than we were aware of when the 1998 Recovery Plan was written and we believe that
N. fossalis
can be recovered with the management and protection of habitat that is currently occupied. We removed 19 ac (8 ha) at the J26 vernal pool complex.

(j) Western Otay Mesa vernal pool complexes—The habitat identified as essential to the conservation of
N. fossalis
within the Western Otay Mesa vernal pool complexes in 2005 included several vernal pools where occurrences of
N. fossalis
had been found. Due to the coarseness of the gridding technique used in the 2005 final rule, the lands designated included areas that actually slope away from the vernal pools. These areas do not contribute to the watershed of the vernal pools within the Western Otay Mesa vernal pool complexes and were removed. There are also additional areas that provide habitat for
N. fossalis
that were not included in the 2005 final rule. These areas meet our criteria for critical habitat as described in this proposed revised critical habitat and have been included. In some places, the boundary of this proposed subunit includes essential habitat that was not mapped in 2005. When our mapping methods changed, we used more detailed maps to ensure that all vernal pool complexes occupied by
N. fossalis
were accurately mapped. Overall, this area was enlarged by 26 ac (11 ha).

(k) Eastern Otay Mesa vernal pool complexes—The habitat identified as essential to the conservation of
N. fossalis
within the Eastern Otay Mesa vernal pool complexes in 2005 included several vernal pools where occurrences of
N. fossalis
had been found. Due to the coarseness of the gridding technique used to describe critical habitat in the 2005 final rule, the lands designated included areas that actually slope away from the vernal pools. These areas do not contribute to the conservation of
N. fossalis
within the Eastern Otay Mesa vernal pool complexes and were removed. There are also additional areas that provide habitat for
N. fossalis
that were not included in the 2005 final rule. These areas meet our criteria for critical habitat as described in this proposed revised critical habitat and have been included. In some places, the boundary of this proposed subunit includes lands that were not mapped in 2005. When our mapping methods changed, we used more detailed maps to ensure that all vernal pool complexes occupied by
N. fossalis
were accurately mapped. Overall, this area was reduced by 57 ac (23 ha).

(l) San Jacinto River—The habitat identified as essential to the conservation of
N. fossalis
along the San Jacinto River in 2005 included a large area north of the habitat known to support occurrences of
N. fossalis.
This area is referred to as Mystic Lake. It is an ephemeral lake bed that only fills during years of high rainfall. Mystic Lake may help create conditions that result in the appropriate habitat for
N. fossalis
to the south (downstream). However, based on the best available data, we do not believe that this area provides an essential contribution to the viability of the occurrences of
N. fossalis
along the San Jacinto River. In this proposed revised rule we have identified the ephemeral wetland habitat that supports occurrences of
N. fossalis
and local associated watershed areas as PCEs. The Mystic Lake area included in the 2005 critical habitat rule does not constitute part of the local associated watershed area for the San Jacinto River occurrences as defined in this proposed revised rule. Although the Mystic Lake area may contribute to conservation of
N. fossalis
in a general sense, it is not occupied by the species and we do not consider it to be essential to the conservation of the species. In addition to the removal of the Mystic Lake area, some habitat on the outer edges of the San Jacinto River flood plain were removed from critical habitat because they do not contain the physical and biological features that are essential to the conservation of this species. This area was reduced by 7,224 ac (2,924 ha).

(m) Salt Creek Seasonally Flooded Alkali Plain—The habitat identified as essential to the conservation of
N. fossalis
at the Salt Creek Seasonally Flooded Alkali Plain in 2005 included a large area to the west that is outside of the local watershed for this vernal pool complex. Upon closer examination of USGS 1:24,000 scale topographic maps, we determined that some areas identified in the 2005 rule as essential to the conservation of
N. fossalis
do not fall within the local watershed of this vernal pool complex. Impacts originating from these more distant watershed areas could affect the vernal pool complex, but we do not believe that these areas contain essential physical and biological features or are otherwise essential to the conservation of this species in the Salt Creek Seasonally Flooded Alkali Plain. This area was reduced by 1,179 ac (477 ha).

(n) Wickerd Road and Scott Road Pools—The habitat identified as essential to the conservation of
N. fossalis
at the Wickerd Road and Scott Road Pools in 2005 included two vernal pools where occurrences of
N. fossalis
had been found. Due to the coarseness of the gridding technique that was used to describe critical habitat in the 2005 final rule, some of the areas consisted of developed residential lots. These areas do not contribute to the watershed of the vernal pools at Wickerd Road and Scott Road Pools and were removed. In some places the boundary of this proposed subunit includes lands that were not mapped in 2005 due to our change in mapping methodology to better capture the watershed for these two pools. This area was reduced by 70 ac (28 ha).

(o) Skunk Hollow—The habitat identified as essential to the conservation of
N. fossalis
at Skunk Hollow in 2005 included two vernal pools where occurrences of
N. fossalis
had been found. Due to the coarseness of the gridding technique that was used to describe critical habitat in the 2005 final rule, some of the areas designated consisted of developed residential lots. There were also some areas included that slope away from the vernal pools. These areas do not contribute to the watershed of the vernal pools at Skunk Hollow and were removed. In some places, the boundary of this proposed subunit includes lands that were not mapped in 2005 due to our change in mapping methodology to better capture the watershed for these two pools. This area was reduced by 148 ac (60 ha).

(p) Santa Rosa Plateau (Renamed “Mesa de Burro” in this revised proposed critical habitat rule)—The habitat identified as essential to the conservation of
N. fossalis
on the Santa Rosa Plateau in the 2005 rule included the entire plateau area (i.e., flat table-like geological formations), which contains three distinct plateaus. Upon further review, we found that
N. fossalis
only occurs on one of the plateaus: Mesa de Burro. We determined that only the Mesa de Burro plateau contains the physical and biological features essential to the conservation of this species. The other areas on the Santa Rosa Plateau are not known to support
N. fossalis
and are not hydrologically connected to Mesa de Burro, and therefore are not essential to the conservation of
N. fossalis.
This area was reduced by 3,688 ac (1,493 ha).

(7) The following areas we consider to contain features essential to the conservation of the species have been added to this proposed revised critical habitat, but were not considered essential to the conservation of
Navarretia fossalis
in the 2005 final critical habitat designation: Santa Fe Valley (Crosby Estates); Carroll Canyon; Nobel Drive; Proctor Valley; and Otay Lakes. We have added a total of 290 ac (117 ha) of proposed critical habitat in these five new subunits. An explanation of how the added areas contribute to the conservation of
N. fossalis
is provided below in the “Proposed Revised Critical Habitat Designation” section.

Proposed Revised Critical Habitat Designation

We are proposing 6 units that include 22 subunits as critical habitat for
Navarretia fossalis.
The critical habitat areas we describe below, which include the 22 subunits we are proposing as critical habitat but not the 2 subunits that are exempt from critical habitat, constitute our best assessment at this time of areas that meet the definition of critical habitat for
N. fossalis.
Table 3 identifies the approximate area of each proposed critical habitat subunit by landownership. These subunits, which generally correspond to the geographic area of the subunits delineated in the 2005 designation (see Table 2 for a detailed comparison of this proposed rule and the 2005 designation), if finalized, will replace the current critical habitat designation for
N. fossalis
in 50 CFR 17.96(a). The critical habitat areas we describe below constitute our best assessment of areas determined to be occupied at the time of listing that contain the primary constituent elements with the appropriate spatial arrangement and quantity (i.e., essential features) that may require special management considerations or protection. We are not proposing any unoccupied areas or areas outside of the species' historical range because we determined that occupied lands within the species' historical range are sufficient for the conservation of
N. fossalis,
providing that these lands are protected and receive special management considerations for
N. fossalis.

Table 3—Area Estimates (Acres (ac) Hectares (ha)) and Land Ownership for
Navarretia fossalis
Proposed Revised Critical Habitat

Location
Federal
State government
Local government
Private
Total

Unit 1: Los Angeles Basin-Orange Management Area

1A. Cruzan Mesa

129 ac (52 ha)
129 ac (52 ha).

1B. Plum Canyon

32 ac (13 ha)
32 ac (13 ha).

Unit 2: San Diego: Northern Coastal Mesa Management Area

MCB Camp Pendleton
4(a)3 exemption*

4(a)3 exemption.*

2. Poinsettia Lane Commuter Station

6 ac (2 ha)
3 ac (1 ha)
9 ac (4 ha).

Unit 3: San Diego: Central Coastal Mesa Management Area

3A. Santa Fe Valley (Crosby Estates)

5 ac (2 ha)
5 ac (2 ha).

3B. Carroll Canyon

16 ac (7 ha)
3 ac (1 ha)
20 ac (8 ha).

3C. Nobel Drive

37 ac (15 ha)

37 ac (15 ha).

MCAS Miramar
4(a)3 exemption*

4(a)3 exemption.*

3D. Montgomery Field

48 ac (20 ha)

48 ac (20 ha).

Unit 4: San Diego: Inland Management Area

4C1. San Marcos (Upham)

34 ac (14 ha)
34 ac (14 ha).

4C2. San Marcos (Universal Boot)

15 ac (6 ha)
17 ac (7 ha)
32 ac (13 ha).

4D. San Marcos (Bent Avenue)

5 ac (2 ha)
5 ac (2 ha).

4E. Ramona

3 ac (1 ha)
132 ac (53 ha)
135 ac (55 ha).

Unit 5: San Diego: Southern Coastal Mesa Management Area

5A. Sweetwater Vernal Pools (S1-3)
23 ac (9 ha)
1 ac (<1 ha)
71 ac (29 ha)

95 ac (38 ha).

5B. Otay River Valley (M2)

24 ac (10 ha)
24 ac (10 ha).

5F. Proctor Valley (R1-2)

51 ac (21 ha)
37 ac (15 ha)
88 ac (36 ha).

5G. Otay Lakes (K3-5)

140 ac (57 ha)

140 ac (57 ha).

5H. Western Otay Mesa vernal pool complexes

45 ac (18 ha)
98 ac (40 ha)
143 ac (58 ha).

5I. Eastern Otay Mesa vernal pool complexes

221 ac (89 ha)
221 ac (89 ha).

Unit 6: Riverside Management Area

6A. San Jacinto River

1,504 ac (608 ha)

2,046 ac (828 ha)
3,550 ac (1,437 ha).

6B. Salt Creek Seasonally Flooded Alkali Plain

1,054 ac (427 ha)
1,054 ac (427 ha).

6C. Wickerd Road and Scott Road Pools

205 ac (83 ha)
205 ac (83 ha).

6D. Skunk Hollow

158 ac (64 ha)
158 ac (64 ha).

6E. Mesa de Burro

675 ac (273 ha)

32 ac (13 ha)
708 ac (287 ha).

Total
23 ac (9 ha)
2,180 ac (882 ha)
434 ac (176 ha)
4,235 ac (1,714 ha)
6,872 ac (2,781 ha).**

* 145 ac (59 ha) of federally owned land on MCB Camp Pendleton and 69 ac (28 ha) of federally owned land MCAS Miramar are exempt from this critical habitat (see “Exemptions under Section 4(a)(3) of the Act” section).
** Values in this table may not sum due to rounding.

Critical Habitat Units

Presented below are brief descriptions of all subunits and reasons why they meet the definition of critical habitat for
Navarretia fossalis.
The units in this proposed revised critical habitat correspond to the management areas described in the 1998 Recovery Plan for Vernal Pools of Southern California. Each subunit contains either (1) a core habitat area; or (2) a satellite habitat area that provide connectivity between core habitat areas or other satellite habitat areas that are captured in other subunits. Areas identified as subunits that harbor satellite habitat areas were identified as containing features essential to the conservation of the species (compared to other areas not identified as essential habitat) due to a combination of their geographic proximity to core habitat areas, their status as an area that supports a stable occurrence (representing occurrences that continue to persist within a given geographic area), and the likelihood that these particular habitat areas support genetically unique occurrences. Other areas not chosen as satellite areas/subunits include occurrences that are represented by one or more of the following characteristics: small population size, no detailed information on occurrence, lack of observations during recent surveys, locations not identified in the Recovery Plan, or areas that have low likelihood of persistence due to fragmentation or enclosure by developed areas, resulting in unstable occurrences.

Unit 1: Los Angeles Basin—Orange Management Area

Unit 1 is located in northwestern Los Angeles County and consists of two subunits totaling 161 ac (65 ha) of private land.

Subunit 1A: Cruzan Mesa

Subunit 1A is located near the City of Santa Clarita in Los Angeles County, California. This subunit is on Cruzan Mesa, northwest of Forest Park and the Sierra Highway and southwest of Vasquez Canyon Road. Subunit 1A consists of 129 ac (52 ha) of private land and meets our selection criteria as satellite habitat. Cruzan Mesa is one of the only areas in Los Angeles County that supports mesa-top vernal pools. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis,
provides potential connectivity with Subunit 1B, and likely supports a genetically distinct occurrence because of the separation of these two northern occurrences from other occurrences of
N. fossalis.
This subunit and subunit 1B (described below) represent the most northern occurrences of this species. Subunit 1A contains physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., mowing, grading) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Subunit 1B: Plum Canyon

Subunit 1B is located near the City of Santa Clarita in Los Angeles County, California. This subunit is in Plum Canyon, west of Forest Park and the Sierra Highway and north of Plum Canyon Road. Subunit 1B consists of 32 ac (13 ha) of private land and meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis,
provides potential connectivity with Subunit 1A, and likely supports a genetically distinct occurrence because of the separation of these two northern occurrences from other occurrences of
N. fossalis.
The Plum Canyon vernal pool habitat occurs on a flat area down-slope from the vernal pools on Cruzan Mesa. The vernal pools on Cruzan Mesa (Subunit 1A) and Plum Canyon represent the only habitat for
N. fossalis
in Los Angeles County and the most northern occurrences of this species. Subunit 1B contains physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species within this subunit. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Unit 2: San Diego—Northern Coastal Mesa Management Area

Unit 2 is located in Northern Coastal San Diego County and consists of one subunit totaling 9 ac (4 ha), as well as, the exempt areas on MCB Camp Pendleton. This unit contains 6 ac (3 ha) owned by the North County Transit District, and 3 ac (1 ha) of private land. MCB Camp Pendleton is exempt in this revised critical habitat designation for
Navarretia fossalis
under section 4(a)(3)(B) of the Act because the 2007 Integrated Natural Resources Management Plan (INRMP) for MCB Camp Pendleton provides a benefit to
N. fossalis
(see the “Exemptions under Section 4(a)(3) of the Act” section of this proposed rule for a detailed discussion).

Unit 2: Poinsettia Lane Commuter Station

Unit 2 is located adjacent to the City of Carlsbad in San Diego County, California. This subunit is loosely

bounded by Avenida Encinas on the north, a housing development on the east, Poinsettia Lane on the south, and train tracks on the west. Unit 2 consists of approximately 9 ac (4 ha) that includes 6 ac (2 ha) of land owned by State or local governments and 3 ac (1 ha) of private land. Unit 2 meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
on MCB Camp Pendleton and in Subunits 4C1, 4C2, and 4D. The Poinsettia Lane vernal pool complex consists of a series of vernal pools that run parallel to the berm created by the train tracks. Unit 2 contains the physical and biological features that are essential to the conservation of
N. fossalis
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., unauthorized recreational use) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations. We are considering this subunit for exclusion under 4(b)(2) of the Act; please see the “Proposed Exclusions under Section 4(b)(2) of the Act” section of this proposed rule for more information.

Unit 3: San Diego: Central Coastal Mesa Management Area

Unit 3 is located in Central Coastal San Diego County and consists of four subunits totaling 110 ac (45 ha), as well as the exempt lands on MCAS Miramar. This unit contains 102 ac (42 ha) owned by State and local governments, and 8 ac (3 ha) of private land. MCAS Miramar is exempt in this proposed revised critical habitat designation for
Navarretia fossalis
under section 4(a)(3)(B) of the Act, because the 2006 INRMP for MCAS Miramar provides a benefit to
N. fossalis
(see the “Exemptions under Section 4(a)(3) of the Act” section of this proposed rule for a detailed discussion).

Subunit 3A: Santa Fe Valley: Crosby Estates

Subunit 3A is located southwest of Lake Hodges and east of the unincorporated community of Rancho Santa Fe. This subunit is loosely bounded by a driving range to the north and northwest, High Society Way on the east and southeast, and Country Girl Lane on the southwest. Subunit 3A consists of 5 ac (2 ha) of private land and meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
in San Marcos and in Subunit 3B. The Crosby Estates vernal pool complex consists of a series of vernal pools on a flat area 150 ft (46 m) above the San Dieguito River. This vernal pool complex occurred naturally, but it had been degraded by past agricultural activities. It was restored as to its current condition when the adjacent area was developed. Subunit 3A contains physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations. We are considering this subunit for exclusion under 4(b)(2) of the Act; please see the “Proposed Exclusions under Section 4(b)(2) of the Act” section of this proposed rule for more information.

Subunit 3B: Carroll Canyon

Subunit 3B is located in the City of San Diego in San Diego County, California. This subunit is located to the southwest of the intersection of Parkdale Avenue and Osgood Way, and is loosely bounded by residential development on the north, open space to the east, and a quarry to the south and west. Subunit 3B consists of approximately 20 ac (8 ha) that includes 17 ac (7 ha) of land owned by State or local governments and 3 ac (1 ha) of private land. Subunit 3B meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
in Subunits 3A and 3C. The Carroll Canyon vernal pool complex consists of a group of vernal pools on the edge of a mesa north of Carroll Canyon. Historically, there may have been more habitat for this species in this area; however, the majority of vernal pool habitat in the vicinity of this subunit has been developed. Subunit 3B contains the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., trespass, illegal trash dumping) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Subunit 3C: Nobel Drive

Subunit 3C is located in the City of San Diego in San Diego County, California. This subunit is loosely bounded by the 805 interstate on the northeast, the train tracks on the south, and Nobel Drive on the northwest. Subunit 3C consists of 37 ac (15 ha) of land owned by State or local governments and meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
in Subunits 3B and 3D. The Nobel Drive vernal pool complex consists of a group of vernal pools on a mesa-top north of Rose Canyon. Subunit 3C contains the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities

(e.g., unauthorized recreational use) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Subunit 3D: Montgomery Field

Subunit 3D is located in the City of San Diego in San Diego County, California. This subunit is located at Montgomery Field (airport) to the northeast of the runway area. Subunit 3D consists of 48 ac (20 ha) of land owned by the City of San Diego and meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity with the occurrence of
N. fossalis
in Subunit 3C. The Montgomery Field vernal pool complex consists of a large group of vernal pools east of the runway area at Montgomery Field, although only the northeastern portion of this vernal pool complex is being proposed as critical habitat.
Navarretia fossalis
has not been documented in the southeastern portion of this vernal pool complex. The northeastern portion and southeastern portion of this vernal pool complex are hydrologically disconnected by past development of the area. Subunit 3D contains the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Unit 4: San Diego: Inland Management Area

Unit 4 is located in Inland San Diego County and consists of four subunits totaling 206 ac (83 ha). This unit contains 15 ac (6 ha) owned by State and local governments, and 191 ac (77 ha) of private land.

Subunits 4C1, 4C2, and 4D: San Marcos

Subunits 4C1, 4C2, and 4D are located in the City of San Marcos in San Diego County, California. These three subunits consist of three separate vernal pool complexes. The first (Subunit 4C1) is loosely bounded by La Mirada Drive on the northeast, Las Posas Road on the southeast, Linda Vista Drive on the southwest, and South Pacific Street on the northwest. The second (Subunit 4C2) is loosely bounded by Linda Vista Drive on the northeast, Las Posas Road on the east, West San Marcos Boulevard on the south, and South Pacific Street on the west. The third (Subunit 4D) is loosely bounded by South Bent Avenue on the northeast, commercial development on the southeast and southwest, and Linda Vista Drive on the northwest. Subunit 4C1 consists of 34 ac (14 ha) of private land, Subunit 4C2 consists of 15 ac (6 ha) of land owned by local government and 17 ac (7 ha) of private land, and Subunit 4D consists of 5 ac (2 ha) of private land. These three subunits meet our selection criteria as satellite habitat areas because they support stable occurrences of
Navarretia fossalis
and provide potential connectivity between occurrences of
N. fossalis
in Unit 2 and Subunit 4E. We grouped these vernal pool complexes because of the clustered nature of these occurrences. These subunits have separate subunit numbers to be consistent with the numbering identified in the previous critical habitat designation. Subunits 4C1, 4C2, and 4D contain the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in these subunits may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., commercial development, trespass, off-road vehicle use) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Subunit 4E: Ramona

Subunit 4E is located in the unincorporated community of Ramona. This subunit is loosely bounded by the Ramona Airport and Ramona Airport Road on the north, Sawday Road on the east, Santa Maria Creek on the south, and a series of rock outcrops on the west. Subunit 4E consists of approximately 135 ac (55 ha) that includes 3 ac (1 ha) of land owned by State or local governments and 132 ac (53 ha) of private land. Subunit 4E meets our selection criteria as satellite habitat. As satellite habitat, this subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity with occurrences of
N. fossalis
in Subunits 4C1, 4C2, and 4D. The vernal pools in this subunit occur in gently sloping grassland habitat and are at the highest elevation where
N. fossalis
is known to occur. Subunit 4E contains the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., agricultural activities, recreational use) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Unit 5: San Diego: Southern Coastal Mesa Management Area

Unit 5 is located in Southern San Diego County and consists of six subunits totaling 711 ac (288 ha). This unit contains 23 ac (9 ha) of federally owned land, 308 ac (124 ha) of land owned by State and local governments, and 380 ac (154 ha) of private land.

Subunit 5A: Sweetwater Vernal Pools

Subunit 5A is located southwest of the Sweetwater Reservoir. This subunit is loosely bounded by the Sweetwater Reservoir on the north, steeply sloping topography on the east, State Route 125 on the south, and an unnamed drainage on the west. Subunit 5A consists of approximately 95 ac (38 ha) and includes 23 ac (9 ha) of Federal land that is part of the San Diego National Wildlife Refuge Complex and 72 ac (29 ha) of land owned by State or local governments and meets our selection criteria as satellite habitat. This satellite habitat subunit supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
in Subunits 5B and 5F. Some of the area occupied by
N. fossalis
was lost during the construction of State Route 125. The soil

from that area was salvaged and is being used to restore other vernal pools in this subunit. Subunit 5A contains the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., unauthorized recreational use) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations.

Subunit 5B: Otay River Valley

Subunit 5B is located adjacent to the City of Chula Vista in San Diego County, California. This subunit is loosely bounded by Olympic Parkway on the north, a housing development on the east, and a landfill to the southwest. Subunit 5B consists of 24 ac (10 ha) of private land and meets our selection criteria as satellite habitat, which supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
in Subunits 5A and 5H. Subunit 5B contains the physical and biological features that are essential to the conservation of
N. fossalis,
including ephemeral wetland habitat (PCE 1), intermixed wetland and upland habitats that act as the local watershed (PCE 2), and the topography and soils that support ponding during winter and spring months (PCE 3). The physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from nonnative plant species and activities (e.g., unauthorized recreational use) that occur in the vernal pool basins. Please see the “Special Management Considerations or Protection” section of this proposed rule for a discussion of the threats to
N. fossalis
habitat and potential management considerations. We are considering the portion of this subunit covered by the County of San Diego Subarea Plan under the MSCP for exclusion under 4(b)(2) of the Act; please see the “Proposed Exclusions under Section 4(b)(2) of the Act” section of this proposed rule for more information.

Subunit 5F: Proctor Valley

Subunit 5F is located between the unincorporated communities of Eastlake and Jamul in San Diego County, California. This subunit is located along Proctor Valley Road in Proctor Valley. Subunit 5F consists of approximately 88 ac (36 ha) and includes 51 ac (21 ha) of land owned by the City of San Diego and 37 ac (15 ha) of private land. Subunit 5F meets our selection criteria as satellite habitat, which supports a stable occurrence of
Navarretia fossalis
and provides potential connectivity between occurrences of
N. fossalis
in Subunits 5A and 5G. The vernal pools in this subunit occur in Proctor Valley on a flat area that is slightly elevated from the stream channel that runs through this valley. The vernal pools in this subunit to the west of Proctor Valley Road have been severely impa

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3AE9-13013. Public record. Not legal advice.