# Endangered and Threatened Wildlife and Plants; Designation of Revised Critical Habitat for Allium munzii (Munz's onion) and Atriplex coronata var. notatior (San Jacinto Valley crownscale)

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URL: https://www.frixlaw.com/law-library/documents/fr%3A2012-8664

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** April 17, 2012
- **Citation:** 77 FR 23008

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R8-ES-2012-0008; 4500030114]
RIN 1018-AX42
Endangered and Threatened Wildlife and Plants; Designation of Revised Critical Habitat for Allium munzii (Munz's onion) and Atriplex coronata var. notatior (San Jacinto Valley crownscale)

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Proposed rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), propose to revise critical habitat for
Allium munzii
(Munz's onion) and for
Atriplex coronata
var.
notatior
(San Jacinto Valley crownscale) under the Endangered Species Act of 1973, as amended (Act). In total, approximately 889 acres (360 hectares) are being proposed for designation as critical habitat for
A. munzii
and approximately 8,020 acres (3,246 hectares) for
A. c.
var.
notatior.
All of the proposed revised critical habitat is located in Riverside County, California.

DATES:

We will accept comments received or postmarked on or before June 18, 2012. Comments submitted electronically using the Federal eRulemaking Portal (see
ADDRESSES
section, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in
FOR FURTHER INFORMATION CONTACT
by June 1, 2012.

ADDRESSES:

You may submit comments by one of the following methods:

(1)
Electronically:
Go to the Federal eRulemaking Portal:
http://www.regulations.gov.
In the Search box, enter Docket No. FWS-R8-2012-0008, which is the docket number for this rulemaking.

(2)
By hard copy:
Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R8-2012-0008; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.

We request that you send comments only by the methods described above. 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:

Executive Summary

Why we need to publish a rule.
This is a proposed rule to revise the designations of critical habitat for two endangered plant taxa, Munz's onion (
Allium munzii
) and San Jacinto Valley crownscale (
Atriplex coronata
var.
notatior
). Under the Endangered Species Act, any species that is determined to be threatened or endangered shall, to the maximum extent prudent and determinable, have habitat designated that is considered to be critical habitat. Designations and revisions of critical habitat can only be completed by issuing a rule.

Critical habitat was designated for Munz's onion and San Jacinto Valley crownscale in 2005. We agreed to reconsider the critical habitat designations in a settlement agreement in response to a complaint filed in court, and are submitting a proposed revised critical habitat designation for both plants.

We are proposing changes to the designation of critical habitat for Munz's onion and San Jacinto Valley crownscale.

• Our previous final critical habitat designation for Munz's onion in 2005 identified 176 acres (71 hectares) of U.S. Forest Service lands as critical habitat after excluding 1,068 acres (432 hectares) based upon Endangered Species Act exclusions. This proposed revised designation for Munz's onion includes five units in Riverside County, California, totaling 889 acres (360 hectares). We are considering excluding 790 acres (320 hectares) of lands from designation based on partnerships created with the establishment of permitted Habitat Conservation Plans or other Management Plans.

• No critical habitat was designated in the previous 2005 final designation for San Jacinto Valley crownscale after 15,232 acres (6,164 hectares) were excluded. This proposed revised designation for San Jacinto Valley crownscale includes three units in Riverside County, California, totaling 8,020 acres (3,246 hectares). We are considering excluding all 8,020 acres (3,246 hectares) of lands from critical habitat designation based on partnerships created with the establishment of a permitted Habitat Conservation Plan.

The basis for our action.
Under the Endangered Species Act, any species that is determined to be threatened or endangered shall, to the maximum extent prudent and determinable, have habitat designated that is considered to be critical habitat. Section 4(b)(2) of the Endangered Species Act states that the Secretary shall designate and make revisions to critical habitat on the basis of the best available scientific data after taking into consideration the economic impact, national security impact, and any other relevant impact of specifying any particular area as critical habitat. The Secretary may exclude an area from critical habitat if he determines that the benefits of such exclusion outweigh the benefits of specifying such area as part of the critical habitat, unless he determines, based on the best scientific data available, that the failure to designate such area as critical habitat will result in the extinction of the species.

We are preparing an economic analysis of the proposed revised designations of critical habitat.
In order to consider economic impacts, we are preparing a new analysis of the economic impacts of the proposed revised critical habitat designations and related factors. We will announce the availability of the draft economic analysis as soon as it is completed, at which time we will seek additional public review and comment.

We will seek peer review.
We are seeking the expert opinions of appropriate and independent specialists regarding this proposed rule to ensure that our critical habitat designations are based on scientifically sound data, assumptions, and analyses. We have invited these peer reviewers to comment during the proposed rule's public comment period on our specific assumptions and conclusions in this proposed rule to revise the designations of critical habitat. We will consider all comments and information received during the comment period in our preparation of the final determinations. Accordingly, the final decisions may differ from this proposal.

Public Comments

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned government agencies, the scientific community, industry, or any other

interested party concerning this proposed rule. We particularly seek comments concerning:

(1) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531
et seq.
), including whether there are threats to the taxon (a group of individuals recognized as a formal unit at any taxonomic rank (for example, a family, genus, species, subspecies, or variety;
Allium munzii
is a species,
Atriplex coronata
var.
notatior
is a variety) from human activity, which can be expected to increase due to the designation, and whether that increase in threat outweighs the benefit of designation such that the designation of critical habitat may not be prudent.

(2) Specific information on:

(a) The amount and distribution of
Allium munzii
and
Atriplex coronata
var.
notatior
habitat,

(b) Which areas within the geographical area occupied at the time of listing contain the physical or biological features essential to the conservation of the taxa and should be included in the designation and why,

(c) Special management considerations or protection of essential physical or biological features that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change, and

(d) Which areas outside the geographical area occupied at the time of listing are essential for the conservation of the taxa and why.

(3) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.

(4) Information on the projected and reasonably likely impacts of climate change on
Allium munzii
and
Atriplex coronata
var.
notatior
and proposed critical habitat.

(5) Comments or information that may assist us in identifying or clarifying the primary constituent elements (PCEs) for the two taxa.

(6) How the proposed revised critical habitat boundaries could be refined to more accurately circumscribe the areas meeting the definition of critical habitat.

(7) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation; in particular, any impacts on small entities, families, or tribes, and the benefits of including or excluding areas that exhibit these impacts.

(8) Which specific lands covered by the Western Riverside County Multiple Species Habitat Conservation Plan (Western Riverside County MSHCP) or other permitted HCPs and proposed for designation as critical habitat should be considered for exclusion under section 4(b)(2) of the Act and for those specific areas, how benefits of exclusion from the critical habitat designation would outweigh the benefits of inclusion in the designation. We are currently considering to exclude, under section 4(b)(2) of the Act, all lands covered by the Western Riverside County MSHCP or other permitted HCPs and Cooperative Agreements described in this proposed rule (see Exclusions Based on Other Relevant Impacts section below).

(9) 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.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in the
ADDRESSES
section. We request that you send comments only by the methods described in the
ADDRESSES
section.

We will post your entire comment—including your personal identifying information—on
http://www.regulations.gov.
You may request at the top of your document that we withhold personal information such as your street address, phone number, or email address from public review; however, we cannot guarantee that we will be able to do so.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on
http://www.regulations.gov,
or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office (see
FOR FURTHER INFORMATION CONTACT
).

Background

This is a proposed rule to revise the designations of critical habitat for two plant taxa,
Allium munzii
and
Atriplex coronata
var.
notatior.
The document is structured to address the taxa separately under each of the sectional headings that follow.

Allium munzii

It is our intent to discuss only those topics directly relevant to the proposed revised designation of critical habitat for
Allium munzii
in this section of this proposed rule. For more information on
A. munzii,
please refer to the proposed listing rule published in the
Federal Register
on December 15, 1994 (59 FR 64812), and the final listing rule published in the
Federal Register
on October 13, 1998 (63 FR 54975). Additional information on the biology of the species may be found in the first rule proposing critical habitat published in the
Federal Register
on June 4, 2004 (69 FR 31569), the subsequent final critical habitat rule published in the
Federal Register
on June 7, 2005 (70 FR 33015), and the 5-year review for
A. munzii
signed on June 17, 2009. These documents are available on our Web site at
http://www.fws.gov/carlsbad/
or
http://www.fws.gov/endangered/
under
Allium munzii
or Munz's onion.

When we listed
Allium munzii
as endangered in 1998, the genus
Allium
was included in the large broadly defined family Liliaceae (lily family). The genus
Allium
is now segregated in the family Alliaceae (onion family), and is recognized as such in the recent revision of the
Jepson Manual of Vascular Plants of California
(McNeal 2012, pp. 1289-1292). Upon review of available systematic and floristic literature and consultation with species experts, we are amending part 17, subchapter B of chapter I, title 50 of the Code of Federal Regulations to reflect the transfer of
Allium,
including
A. munzii,
from Liliaceae to Alliaceae. This transfer does not alter the description, distribution, or listing status of
A. munzii.

Description

Allium munzii
belongs to the
A. fimbriatum
complex, a group of seven species found primarily in California (McNeal 1992, p. 413).
Allium munzii
is a bulb-forming perennial herb that annually produces a single cylindrical leaf prior to flowering and, depending on rainfall and age of the plant, a scapose inflorescence (a leafless flower stalk that grows directly from the ground) 0.5 to 1.2 feet (ft) (15 to 35 centimeters (cm)) tall. The inflorescence is umbellate (each individual flower stalk radiates from the same point of attachment), and consists of 10 to 35 flowers. Each flower has six white or white with red midvein perianth segments (outer part of flower), 0.2 to 0.3 inch (in) (6 to 8 millimeters (mm)) long, which become red with age. The ovary is crested with fine, irregularly dentate processes and the fruit is a three-lobed capsule (McNeal 1992, p. 413).

Biology and Life History

Native
Allium
taxa typically require 3 to 5 years after seeds germinate for plants to reach maturity and produce flowers (Schmidt 1980, p. 164).
Allium
plants are adapted to survive

unfavorable seasons underground, as are all bulb-forming and corm-forming plants (geophytes) (Pütz 1992, p. 1433). Seedlings achieve the appropriate depth in the soil by the action of specialized roots that pull the young plants down through the soil (Pütz 1992, p. 1433).
Allium munzii
plants are dormant from mid-summer through autumn. The flowering period varies from year to year, but is generally between March and May (California Native Plant Society (CNPS) 2001, p. 67). After flowering and seed dispersal, the aboveground portions of
A. munzii
plants die back to the bulb. Following seed germination, at least 3 years are required for these bulb-forming plants to produce flowers (Wall 2012, pers. comm.).

Allium munzii
is adapted to seasonal (summer and fall) drought and variable annual rainfall. McNeal (1992, p. 413) observed that flowering in the
A. fimbriatum
complex appears to be correlated with rains in the late fall and early winter. As a result,
A. munzii
may occur in various states during a given growing season, including: (1) As dormant underground bulbs, (2) as seedlings and other pre-reproductive plants that only produce one leaf, (3) as adults with only one leaf that do not produce an inflorescence that year, (4) as adults that produce one leaf and an inflorescence, and (5) as seeds in a soil seedbank. When rainfall is heavier, most plants flower successfully (McNeal 1992, p. 413);
A. munzii
often does not flower in very dry years (Boyd 1988, p. 3), though most plants will sprout leaves and sometimes produce flower buds. In addition to sexual reproduction through seed production,
A. munzii
plants can reproduce asexually through vegetative division of the bulbs (Ellstrand 1993, p. 5; Ellstrand 1999, p. 1). We have no definitive information regarding pollinators of
A. munzii,
but it is likely that a number of insect species serve this function (Boyd 2007, pers. comm.). Small beetles of the family Anthicidae (ant-like flower beetles) were found on about one-third of the
A. munzii
inflorescences of a population in Temescal Canyon (The Environmental Trust 2002, p. 16); however, their role as pollinators was not confirmed.

Habitat and Soil Preferences

Allium munzii
is a narrow endemic plant discontinuously distributed along the southern edge of the greater Riverside-Perris area (Perris Basin) in western Riverside County, between the elevations of 1,200 to 2,700 ft (366 to 823 meters (m)) above mean sea level (AMSL), from Temescal Canyon southeast to the foothills of the San Jacinto Mountains (Boyd 1988, p. 2; Roberts
et al.
2004, pp. 10, 130). Climate in this area is characterized by cool, moist winters and hot, dry summers (Boyd 1988, p. 4).
Allium munzii
is found on level or slightly sloping areas or on terrace escarpments (California Natural Diversity Database (CNDDB) 2011a) and is strongly associated with mesic (wet) clay soils in western Riverside County (Boyd 1988, pp. 2, 4).
Allium munzii
occupy microhabitat sites created by the complex geology of the Perris Basin; these sites receive or retain more moisture than nearby or surrounding sites due to exposure, slope characteristics, hydrological characteristics, or topographic features (see, for example, the topography and geology discussion in Boyd (1983, pp. 10, 13-14, 18)).

Many of the clay soil types where
Allium munzii
occurs

typically support open native or nonnative grasslands. Specific designations include southern needlegrass grassland, mixed grassland, open coastal sage scrub or Riversidean sage scrub, or occasionally cismontane juniper woodlands (CNPS 2001, p. 67). The species is also considered a component of a “clay soil flora” that includes perennial herbs and a variety of annuals (Boyd 1988, p. 4). Plants are most frequently found in areas that are minimally disturbed and in areas where there is little competition and overcrowding from nonnative plants. In contrast, areas that consistently experience ground disturbance activities (such as disking for dryland farming) or are heavily infested with invasive, nonnative plants (particularly annual grasses) generally result in a decline in habitat quality and therefore declining
A. munzii
populations (Roberts 1998, pers. comm.; CNDDB 2011a).

Known soil associations with
Allium munzii
include, but are not limited to: Altamont, Auld, Bosanko, and Porterville clays of sedimentary origin. These clay soils are scattered in a band several miles wide and extend south of Corona, California, through Temescal Canyon and along the Elsinore Fault zone to the southwestern foothills of the San Jacinto Mountains (Boyd 1988, p. 2). Some of these soils are small pockets of clay soil (for example Gavilan Hills) and are not identified on coarse-scale soil maps (Boyd 2011a, pers. comm.). Wet clay soils facilitate the formation of soil channels for movement of young bulbs (Pütz 1992, p. 1433), which is necessary for establishment and persistence of
A. munzii
plants.
Allium munzii
is also found in rocky-sandy loam soil within rocky outcrops (such as North Domenigoni Hills) (CNDDB 2011a, Element Occurrence (EO) 10). These soils may be of sedimentary or igneous origin with a clay subsoil (such as Cajalco, Las Posas, or Vallecitos) (Knecht 1971, pp. 2-3, 21, 42, 62-64).

Spatial Distribution, Historical Range, and Population Size

As noted above,
Allium munzii
is a narrow endemic species with a naturally discontinuous distribution in western Riverside County (Boyd 1988, p. 2; Roberts
et al.
2004, pp. 10, 130). Its historical distribution may have been within clay soils scattered throughout the entire Perris basin in western Riverside County, which exhibits a complex physical geography characterized by several distinct geologic events and subsequent erosional processes that have produced numerous soil or sediment types on the remaining land forms (Dudley 1936, pp. 358-360, 376).
Allium munzii
shares its range and habitat with a portion of the range of the similar-appearing
A. haematochiton
(red-skinned onion). The two species can occur within several feet of each other, but they do not interbreed (CDFG 1989, p. 2).

In general, the distribution of plant taxa may be determined from a variety of sources including preserved herbarium specimens, survey reports, and various databases. Survey records typically contain information describing locations and numbers of plants, which can be called localities or groups of individual plants (up to several thousand in one location or only a few plants), or can be described as the actual number of individual plants. The precision of the location of survey sites varies from general area descriptions to road perimeters to more recent Global Positioning System (GPS) technology. The CNDDB, maintained by the California Department of Fish and Game (CDFG), is an ongoing effort to include herbarium records and survey reports for separate Element Occurrences (EOs) of all of the taxa tracked by the database. To constitute a separate EO, the site must be at least one-quarter mile from any other such site. Sequential surveys are accumulated in the EO report for the site. Because contribution to the database is not mandatory, some herbarium specimens and survey reports are not yet included in the database. In this proposed rule, our use of the term occurrence, often in relation to a critical habitat unit, may indicate an area that includes one or more point localities and EOs.

Although 6 of the 18 CNDDB-defined EOs have been detected since listing, the species' geographic range (greater Perris Basin) has remained essentially

the same since listing. We identified 13 populations of
Allium munzii
in our listing rule (63 FR 54975; October 13, 1998) that were primarily based on sites identified as CNDDB EOs and cited in the rule (EOs 2, 3, 5, 7-16). Since then, six new EOs have been included in the CNDDB database (CNDDB 2011a, EOs 17, 18, 20, 21, 22, and 23), and during our 2009 5-year review, we located another record (1994) that was unknown at the time of listing and that is not yet described in the CNDDB database (Service 2009, p. 38; proposed EO 24). At the time of our 2009 5-year review, we assessed the status of six EOs as follows: two CNDDB-defined EOs (EOs 1 and 8) are likely extirpated (locally extinct), three (EOs 20, 21, and 22) are vague locations or historical and of currently unknown condition, and one (EO 19) was likely based on a misidentified specimen and deleted by CNDDB (Service 2009, p. 9). In addition, the CNDDB has now combined EO 8 with EO 3 (CNDDB 2011a, EO3). We therefore concluded in our 5-year review that there were 18 extant (still in existence) EOs (EOs 2-7, 9-18, 23, and proposed EO 24) for
A. munzii,
all essentially within the same geographic range known at the time of listing. Because of the species' habitat requirements, we do not anticipate this geographic range will change significantly in the future, even if additional locations of plants are discovered.

The number of individual plants of
Allium munzii
detected in any one area differs from year to year and is not an accurate reflection of the actual number of individuals present. This is primarily due to the variety of life-history phases represented in a given area (see description in the Biology and Life History section above). Some surveyors may only sample flowering individuals while others may be able to sample plants with only the vegetative single leaf present. Because of the difficulties of obtaining reliable survey results and the fact that the number of standing individuals is dependent upon adequate rainfall, any estimation of individuals at a given location may vary by several orders of magnitude in any given year.

In the 1998 final listing rule we estimated that there were 20,000 to 70,000 individuals of
Allium munzii
(63 FR 54975; October 13, 1998). The largest recorded location of plants was at Harford Springs County Park and adjacent private lands (EO 2), with over 50,000 individuals observed in 1995 (Ellstrand 1996, p. 4). In our 5-year review, we found that, prior to listing, 10 CNDDB-defined EOs have supported 1,000 or more individuals in at least one year (Service 2009, Appendix 1, p. 33), while others support fewer individual plants (i.e., 500 or fewer plants).

Atriplex coronata var. notatior

It is our intent to discuss only those topics directly relevant to the proposed revised designation of critical habitat for
Atriplex coronata
var.
notatior
in this section of this proposed rule. For more information on
A. c.
var.
notatior,
please refer to the proposed listing rule published in the
Federal Register
on December 15, 1994 (59 FR 64812) and the final listing rule published in the
Federal Register
on October 13, 1998 (63 FR 54975). Additional information on the biology of this taxon may be found in the rule proposing critical habitat published in the
Federal Register
on October 6, 2004 (69 FR 59844), the subsequent final critical habitat designation published in the
Federal Register
on October 13, 2005 (70 FR 59952), and the 5-year review for
A. coronata
var.
notatior
signed on March 31, 2008. These documents are available on our Web site at
http://www.fws.gov/carlsbad/
or
http://www.fws.gov/endangered/
under
Atriplex coronata
var.
notatior
or San Jacinto Valley crownscale.

Description

Atriplex coronata
var.
notatior
is a bushy, erect, annual plant that has unisexual flowers on each plant. It is a member of the Chenopodiaceae (goosefoot family) (Munz 1974, p. 351). Plants are from 4 to 12 in (10 to 30.5 cm) high and generally appear gray and scaly during the growing season, becoming glabrous and straw-colored as they mature (Taylor and Wilken 1993, p. 501). The grayish leaves are sessile (stalkless and attached directly at the base), alternate, 0.3 to 0.8 in (8 to 20 mm) long, and elliptic to ovate-triangular in outline. The flowers occur in mixed clusters (Munz 1974, p. 353; Taylor and Wilken 1993, p. 501). The female flowers are obscure and develop spherical bracts in the fruiting phase. These bracts have dense tubercles (projections) that are roughly equal in number to the marginal teeth on the bracts (Munz 1974, p. 353; Taylor and Wilken 1993, p. 501).
Atriplex coronata
var.
notatior
can be distinguished from the more northern
A. c.
var.
coronata
by its erect stature, the spherical shape of the bracts together in fruiting stage, and the more numerous tubercles and marginal teeth on the bracts. The ranges of the two taxa do not overlap.
Atriplex coronata
var.
notatior
may co-occur with one or more of six native and one introduced
Atriplex
taxa within its range (Bramlet 1993b, p. 7-8) and can be distinguished from these taxa by a combination of characteristics, including life history, shape of the leaf, and size and form of the bract (Munz 1974, pp. 354-355; Taylor and Wilken 1993, p. 501).

Biology and Life History

The persistence of
Atriplex coronata
var.
notatior
depends

upon a hydrologic regime that includes seasonal and sporadic ponding or flooding in combination with slow drainage in alkaline soils and habitats. The duration and extent of ponding or flooding can be extremely variable from one year to the next depending on rainfall and local runoff conditions. Seasonal flooding is a necessary environmental process for
A. c.
var.
notatior
because it precludes invasion from upland plant species, restores disturbed alkali habitats, and helps to disperse seed. These elements form a dynamic physical and biological matrix that allows
A. c.
var.
notatior
to colonize favorable sites and retreat from less favorable sites in response to disturbance and variations in annual rainfall.

Atriplex coronata
var.
notatior
is reported to be a prolific seed producer (Ogden Environmental and Energy Services Corporation (OEESC) 1993, p. 27). Seed viability is believed to be at least 5 years (Bramlet 2004, pers. comm.). The number of viable seeds lost to seed predators or through dispersal to unsuitable habitats is unknown.
Atriplex coronata
var.
notatior
produces fruits capable of floating that may be dispersed during seasonal flooding (Sanders 2004, pers. comm.), specifically by slow-moving water flows during winter and spring rainfall events. Seeds generally germinate in the spring as flows recede, flower in April and May, and set fruit by May or June (Bramlet 1992, pers. comm.). The flowering period may extend to August in years when the water recedes late in the spring season (Munz 1974, p. 355; CNPS 2001, p. 93). The number of
A. c.
var.
notatior
plants in a population varies in response to rainfall, extent of winter flooding, and temperature (Roberts 1993, p. 3). These factors also influence the distribution of plants from one year to the next (Bramlet 1996, p. 3). Hydrology, flooding, and precipitation all play a role in the germination, flowering, fruiting, and seed dispersal of
A. c.
var.
notatior.

Habitat and Soil Preferences

Atriplex coronata var. notatior
is reliant on fixed landscape features that include: (1) Appropriate hydrology that allows for flooding and moist soil conditions during the winter and spring

months, and (2) alkali soils that drain slowly following the winter and spring rains. The ponding of water (but not prolonged inundation) that
A. c.
var.
notatior
needs for growth and reproduction requires these hydrologic conditions and underlying soils.

Atriplex coronata
var.
notatior
is found in alkali sink habitat, including alkali grassland and scrub (Bramlet 1996, p. 10). This includes the San Jacinto River and Mystic Lake floodplains, which represent dominant features of the dynamic San Jacinto River Watershed (Tetra Tech and WRIME 2007, p. 26), and smaller floodplains where the taxon resides such as Upper Salt Creek and Alberhill Creek. The San Jacinto River system is ephemeral, characterized by low flows except during and following rain events, whereas flow in the headwater tributaries of the watershed is perennial (Tetra Tech and WRIME 2007, p. 26). Mystic Lake is a natural sink in the San Jacinto Valley; runoff flows into the lake from the valley and, during large flow events, from the upper San Jacinto River (Tetra Tech and WRIME 2007, p. 28). The floodplain of the San Jacinto River occupied by
A. c.
var.
notatior
contains native vegetative communities including alkali sage scrub and Riversidean sage scrub.

The Upper Salt Creek locations of
Atriplex coronata
var.
notatior
are contained in a natural depression of the old Salt Creek tributary within the Salt Creek watershed. Habitats occupied by
A. c.
var.
notatior
in this floodplain include alkaline vernal pools, alkaline grassland, and alkali sink scrub habitats (Regional Environmental Consultants (RECON) 1995 pp. 15, 17; CNDDB 2011b). Major flood control channels, local roads and road ditches, and agricultural drainage ditches currently disrupt historical drainage patterns in Upper Salt Creek, reducing the degree and duration of ponding during the wet season (RECON 1995, p. 18).

Atriplex coronata
var.
notatior
has also been observed in the floodplain of Alberhill Creek, which is a part of the larger Temescal Wash region of western Riverside County. This area drains the Gavilan Hills region and the northeastern slope of the Santa Ana Mountains (Boyd 1983, p. 13). The floodplain floods periodically, including seasonal overflow from Lake Elsinore; this produces scouring and ponding in the alkali playa habitat occupied by
A. c.
var.
notatior.

Within these three floodplains,
Atriplex coronata
var.
notatior
is restricted to highly alkaline, silty-clay soils in association with the Willows soil series and to a lesser extent, the Domino, Traver, Waukena, and Chino soils series (Knecht 1971, p. 23, Bramlet 1993a, p. 4).
Atriplex coronata
var.
notatior
is adapted to grow in slow-draining alkaline-saline clay soils, which are usually found in floodplains or areas of seasonal ponding (Mitchell 1990, p. 1; Tierra Madre Consultants 1990, p. 2) with low permeability and low nutrient availability. In dry periods, these saline soils exhibit a white powdery surface (effloresce) of salts on their surface due to the evaporation of water (Mitchell 1990, p. 1). Within these soil types,
A. c.
var.
notatior
occupies seasonal and ephemeral wetlands, including floodplains and vernal pools that are seasonally inundated, and within areas dominated by alkali playas, alkali scrub, and alkali grassland (Bramlet 1992, pers. comm.); plants are generally found at the upper margin or on mounds within these wetlands (Bramlet 2004, pers. comm.). These habitats are dependent upon adjacent transitional wetlands, marginal wetlands, and upland areas within the watershed (59 FR 64821; December 15, 1994).

Spatial Distribution, Historical Range, and Population Size

At the time of listing,
Atriplex coronata
var.
notatior
was reported to be limited to the San Jacinto, Perris, Menifee, and Elsinore Valleys in western Riverside County. The listing rule identified 11 groupings of individual plants associated with the San Jacinto River and Old Salt Creek tributary drainages with one additional small population (185 plants) found to the southwest near Lake Elsinore (Alberhill Creek) (63 FR 54976; October 13, 1998). In our 5-year review, using data from range-wide surveys of the taxon completed from 1996 to 2001, we determined that
A. c.
var.
notatior
occupied the same general geographic range described at the time of its listing in 1998 (Service 2008, p. 5). Based on these survey data and the limited comprehensive surveys conducted since 2001, we currently believe that
A. c.
var.
notatior
continues to occupy the geographical areas described in our previous final critical habitat rule as occurrence complexes (70 FR 59952; October 13, 2005). These areas are defined by hydrologic processes (such as seasonal flooding) and alkali soil associations and include:

(1) The floodplain of the San Jacinto River at the San Jacinto Wildlife Area, including Mystic Lake;

(2) The floodplain of the San Jacinto River between the Ramona Expressway and Railroad Canyon Reservoir;

(3) The Upper Salt Creek Vernal Pool Complex in the western Hemet area; and

(4) The floodplain of Alberhill Creek north of Lake Elsinore (CNDDB 2011b).

The alkaline-saline soils associated with the taxon, primarily the Traver-Domino-Willows Association (Knecht 1971, p. 23), form a U-shaped band around the Lakeview Mountains within basins and valley floors of the greater Perris Valley basin (Tierra Madre Consultants 1990, p. 3) and encompass the San Jacinto River and Old Salt Creek drainages.

Atriplex coronata
var.
notatior
is subject to significant natural fluctuations in numbers of observed individuals in any given year, which varies in response to annual rainfall, extent and distribution of winter flooding, and temperature (Roberts 1993, p. 3; Bramlet and White 2004, Table 2). Differences in survey methodologies and proportion of range surveyed may also contribute to differences in annual counts of individuals. In addition, a viable seed bank may exist in the soil at a site for several years (Bramlet 2004, pers. comm.) even if plants are removed or fail to germinate for a season or if the site is disturbed (OEESC 1993, p. 27).

A status review and threat assessment for
Atriplex coronata
var.
notatior,
completed in October 1993 (prior to its listing in 1998), indicated that approximately 78,000 individuals were distributed throughout the “populations” defined by the CNDDB EOs (Roberts 1993, p. 3). At the time of listing, we estimated about 27,000
A. c.
var.
notatior
individuals occupied about 145 acres (ac) (59 hectares (ha)) of habitat (63 FR 54976; October 13, 1998). We used population and habitat acreage estimates from Bramlet and White (2004, Table 2) in our final critical habitat rule (70 FR 59955; October 13, 2005); however, these were combined data from the 1990s for the four geographical areas listed above. In our 2008 5-year review, we indicated a rangewide population estimate of 106,000 individuals of
Atriplex coronata
var.
notatior
based on estimates from surveys conducted in the spring of 2000 (Glenn Lukos Associates, Inc. 2000, p. 15). Approximately 84,000 of these individuals were found on 236.5 ac (95.7 ha) along the San Jacinto River between the Ramona Expressway and the mouth of Railroad Canyon for a total of 61 localities (Glenn Lukos Associates, Inc. 2000, p. 16). This study found that approximately 58,000 of the estimated 83,741 individual plants (or 69 percent) were located within farmed or otherwise altered areas impacted by regular disking and, in some areas, by

additional soil amendments. This report also noted that approximately 7,470 individuals were located within the San Jacinto Wildlife Area to the north (Glenn Lukos Associates Inc. 2000, p. 15).

Additional recent surveys of locations or localities (groups of individual plants) of
Atriplex coronata
var.
notatior
have been completed in portions of the middle and lower San Jacinto River floodplain as well as the Mystic Lake area in 2005, 2008, and 2009 (Rancho Santa Ana Botanic Garden 2006, 2010; White 2009, pers. comm.). Individual numbers of plants ranged from 21 to 220 per site. The Western Riverside Regional Conservation Agency (RCA) has also conducted limited surveys in a portion of the San Jacinto Wildlife Area since 2006 under the Western Riverside County MSHCP Rare Plant Survey program, finding fewer than 100 individuals for all 13 surveyed sites (Malisch, 2010, pers. comm.).

Surveys for sensitive plant species were also conducted within the Upper Salt Creek area in 2005 and 2006 for a proposed highway realignment project (CH2M Hill 2010). These surveys documented over 100,000 individual
Atriplex coronata
var.
notatior
plants within 555 localities in alkali grassland, alkali playa, and vernal pool habitats (CH2M Hill 2010, pp. 5-69, Appendix F (p. 5), and Figure 5.3-11). The largest number of locations of plants (90 percent) and the largest number of individual plants (over 100,000 plants) were all found in one general region of the Upper Salt Creek area (north of the San Jacinto Branch Line, south of Devonshire Avenue, east of California Avenue, and west of Warren Road) (CH2M Hill 2010, p. 5-69).

The results of these recent surveys (2005 through 2009), including some conducted during a wet year, indicate a more significant population of plants within the Upper Salt Creek area than was previously believed for the Upper Salt Creek location. These surveys do not represent a significant change in the distribution of
Atriplex coronata
var.
notatior
since the plant was listed. They do provide more precise locations for
A. c.
var.
notatior
within these two floodplains, and therefore an updated assessment of the distribution of the plant within the geographical area occupied at the time of listing.

Atriplex coronata
var.
notatior
is also found in the Alberhill Creek area. In 1997, 185 plants were observed on Willows soils in this floodplain within wetland habitat along Nichols Road, near the mouth of Walker Canyon (CNDDB 2011b, EO16). A survey in 2005 recorded 10 plants south of Nichols Road in nonnative grassland and alkali marsh habitat on Willows soil, within one-quarter mile (365 m) of the 1997 location (AMEC Earth and Environmental Inc., 2006b, p. 29).

Previous Federal Actions—
Allium munzii

Please see the final listing rule for
Allium munzii
for a description of previous Federal actions through October 13, 1998 (63 FR 54975). At the time of listing, we concluded that designation of critical habitat for
A. munzii
was not prudent because such designation would not benefit the species. On June 4, 2004, we published a proposed rule to designate 227 ac (92 ha) of critical habitat for
A. munzii
on Federal land (Cleveland National Forest) in western Riverside County, California (69 FR 31569). On June 7, 2005, we published a final rule designating 176 ac (71 ha) of the proposed land as critical habitat for
A. munzii
(70 FR 33015).

On March 22, 2006, we announced the initiation of the 5-year review for
Allium munzii
and opening of a 60-day public comment period to receive information (71 FR 14538). The
A. munzii
5-year review was signed on June 17, 2009, and found that no change was warranted to the endangered status of
A. munzii.

On October 2, 2008, a complaint was filed against the Department of the Interior (DOI) and the Service by the Center for Biological Diversity (
CBD
v.
Kempthorne,
No. 08-CV-01348 (S.D. Cal.)) challenging our final critical habitat designation for
Allium munzii.
In an order dated March 24, 2009, the U.S. District Court for the Central District of California, Eastern Division, adopted a Stipulated Settlement Agreement that was entered into by all parties. The agreement stipulates that the Service will reconsider critical habitat designations for both
A. munzii
and
Atriplex coronata
var.
notatior,
and shall submit to the
Federal Register
proposed revised critical habitat determinations for both plants by October 7, 2011. An extension for the completion of the new proposed determinations was granted on September 14, 2011; the new submission date to the
Federal Register
is April 6, 2012. Until the effective date of the final determinations (to be submitted to the
Federal Register
on or before April 6, 2013), the existing final critical habitat designations for
A. munzii
and
A. c.
var.
notatior
remain in place. We are proposing revised critical habitat designations for both
A. munzii
and
A. c.
var.
notatior
in this combined proposed rule.

Previous Federal Actions—Atriplex coronata var. notatior

Please see the final listing rule for
Atriplex coronata
var.
notatior
for a description of previous Federal actions through October 13, 1998 (63 FR 54975), including proposed critical habitat in 1994 (59 FR 64812; December 15, 1994). At the time of the final listing rule in 1998, the Service withdrew the proposed critical habitat designation based on the taxon's continued decline and determined that designation of critical habitat was not prudent, indicating that no benefit over that provided by listing would result from such designation (63 FR 54991; October 13, 1998).

On October 6, 2004, we published a proposed rule to designate critical habitat for
Atriplex coronata
var.
notatior
and identified 15,232 ac (6,164 ha) of habitat that met the definition of critical habitat (69 FR 59844). However, we concluded in the 2004 proposed rule under section 4(b)(2) of the Act that the benefits of excluding lands covered by the Western Riverside County MSHCP outweighed the benefits of including them as critical habitat and no lands were proposed for designation as critical habitat in the proposed rule. On October 13, 2005, we published a final critical habitat determination for
A. c.
var.
notatior
(70 FR 59952); there was no change from the proposed rule. We concluded that all 15,232 ac (6,136 ha) of habitat meeting the definition of critical habitat were located either within our estimate of the areas to be conserved and managed by the approved Western Riverside County MSHCP on existing Public/Quasi-Public Lands, or within areas where the MSHCP would ensure that future projects would not adversely alter essential hydrological processes and therefore all areas were excluded from critical habitat under section 4(b)(2) of the Act.

On March 22, 2006, we announced the initiation of the 5-year review for
Atriplex coronata
var.
notatior
and the opening of a 60-day public comment period to receive information (71 FR 14538). The 5-year review was signed on March 31, 2008, and found that no change was warranted to the endangered status of
A. c.
var.
notatior.

On October 2, 2008, a complaint was filed against the DOI and the Service by the Center for Biological Diversity (
CBD
v.
Kempthorne,
No. 08-CV-01348 (S.D. Cal.)) challenging our final critical habitat determinations for
Allium munzii
and
Atriplex coronata
var.
notatior
(see
Previous Federal Actions
—Allium Munzii section above for a

detailed account of this lawsuit and settlement agreement). We are proposing revised critical habitat designations for both
A. munzii
and
A. c.
var.
notatior
in this proposed rule.

Critical Habitat

Background

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

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

(a) Essential to the conservation of the species and

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

(2) Specific areas outside the geographical area occupied by the 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 to use and the use of all methods and procedures necessary to bring an endangered or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resource management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, and transplantation, and, in the extraordinary case where population pressures within a given ecosystem cannot be otherwise relieved, may include regulated taking.

Critical habitat receives protection under section 7 of the Act through the requirement that Federal agencies ensure, in consultation with the Service, that any action they authorize, fund, or carry out is not likely to result in the destruction or adverse modification of 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 non-Federal landowners. Where a landowner seeks or 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 obligation of the Federal action agency and the landowner is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid destruction or adverse modification of critical habitat.

Under section 3(5)(A)(i) of the Act, specific areas within the geographical area occupied by the species at the time it was listed are included in a critical habitat designation if they contain the physical or biological features (1) which are essential to the conservation of the species and (2) which may require special management considerations or protection. For these areas, critical habitat designations identify, to the extent known using the best scientific and commercial data available, those physical or biological features that are essential to the conservation of the species (such as space, food, cover, and protected habitat). In identifying those physical or biological features within an area, we focus on the principal biological or physical constituent elements (PCEs) (such as roost sites, nesting grounds, seasonal wetlands, water quality, tide, and soil type) that are essential to the conservation of the species.

Under section 3(5)(A)(ii) of the Act, specific areas outside the geographical area occupied by the species at the time it is listed are included in a critical habitat designation upon a determination that such areas are essential for the conservation of the species. For example, an area currently occupied by the species but that was not occupied at the time of listing may be essential for the conservation of the species and may be included in the critical habitat designation. We designate critical habitat in areas outside the geographical area occupied by a species only when a designation limited to its range would be inadequate to ensure the conservation of the species.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific 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, other unpublished materials, or experts' opinions or personal knowledge.

Habitat is dynamic, and species may move from one area to another over time. We recognize that critical habitat designated at a particular point in time may not include all of the habitat areas that we may later determine are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be needed for recovery of the species. Areas that are important to the conservation of the species, both inside and outside the critical habitat designation, will continue to be subject to: (1) Conservation actions implemented under section 7(a)(1) of the Act, (2) regulatory protections afforded by the requirement in section 7(a)(2) of the Act for Federal agencies to ensure their actions are not likely to jeopardize the continued existence of any endangered or threatened species, and (3) the prohibitions of section 9 of the Act if actions occurring in these areas may affect the species. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. These protections and conservation tools will continue to contribute to recovery of these taxa. 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, HCPs, or other species conservation planning efforts if new information available at the time of these planning efforts calls for a different outcome.

In particular, we recognize that climate change may cause changes in the arrangement of occupied habitat and will be a particular challenge for biodiversity because the interaction of additional stressors associated with

climate change and current stressors may push species beyond their ability to survive (Lovejoy 2005, pp. 325-326). The synergistic implications of climate change and habitat fragmentation are the most threatening facet of climate change for biodiversity (Hannah and Lovejoy 2005, p. 4). Climate models are being generated to examine what will happen in localized regions such as southern California, and many scientists believe warmer, wetter winters and warmer, drier summers will occur within the next century as well as an increase in extreme temperature events (e.g., Field
et al.
1999, pp. 2-3, 20; Christensen
et al.
2007, p. 891). Climate-related changes in California have been documented (Croke
et al.
1998, pp. 2128, 2130; Breashears
et al.
2005, p. 15144; McMullen and Jabbour 2009, p. 41; Dominguez
et al.
2010, p. 500), and predictions for California indicate prolonged drought and other climate-related changes into the future (Field
et al.
1999, pp. 8-10; Lenihan
et al.
2003, p. 1667; Hayhoe
et al.
2004, p. 12422; Breashears
et al.
2005, p. 15144; Seager
et al.
2007, p. 1181; IPCC 2007, p. 9).

Regional climate change models project that the southwestern California ecoregion occupied by
Allium munzii
and
Atriplex coronata
var.
notatior
could experience a mean annual temperature increase of 1.7 to 2.2 °Celsius (C) (3.06 to 3.96 °Fahrenheit (F)) by 2070 (Point Reyes Bird Observatory (PRBO) Conservation Science 2011, p. 40). These models also project vegetation changes for southwestern California. For example, the area of chaparral or coastal scrub is projected to decrease by 38 to 44 percent by 2070, while grassland, which currently occupies 3 percent of this region, is projected to increase by 345 to 390 percent (PRBO Conservation Science 2011, p. 42). A recent study on the effects of climate change to grassland assemblages in California, as measured by trait differences between native and nonnative plant taxa, predicted an increase in dominance of nonnative taxa in grass assemblages with an increase in temperature (Sandel and Dangremond 2011, p. 11).

The information currently available on the effects of global climate change and increasing temperatures does not adequately predict the location and magnitude of climate change effects to
Allium munzii
and
Atriplex coronata
var.
notatior;
therefore, we are unable to determine if any additional areas may be appropriate to include in this proposed revised critical habitat designation to address the effects of climate change. We specifically request information from the public on the currently predicted effects of climate change on
A. munzii
and
A. c.
var.
notatior
and their habitats (see Public Comments section above).

Physical or Biological Features

In accordance with sections 3(5)(A)(i) and 4(b)(1)(A) of the Act and regulations at 50 CFR 424.12, in determining which areas within the geographical area occupied at the time of listing to propose as revised critical habitat, we consider those physical or biological features that are essential to the conservation of the species and which may require special management considerations or protection. These 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, or 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.

Allium munzii

We derive the specific physical or biological features for
Allium munzii
from characteristics of the species' habitat, ecology, and life history as described in the Background section of this proposed rule, the previous critical habitat rule (70 FR 33015; June 7, 2005), the proposed listing rule (59 FR 64812: December 15, 1994), and the final listing rule (63 FR 54975; October 13, 1998). We have based our determination of the physical or biological features for
A. munzii
on the following:

Space for Individual and Population Growth and for Normal Behavior

Allium munzii
is a narrow endemic plant that is generally associated with mesic clay soils in western Riverside County, California, along the southern edge of the Perris Basin. Because of the physical geology in this part of the County, clay soils are scattered in a band, several miles wide, extending 40 miles (mi) (64 kilometers (km)) from Gavilan Hills to west of Temescal Canyon and Lake Elsinore at the eastern foothills of the Santa Ana Mountains, and along the Elsinore Fault Zone to the southwestern foothills of the San Jacinto Mountains near Lake Skinner and Diamond Valley Lake. These clay soils often exist as areas of smaller discrete pockets (clay lenses) that are often not identified on coarse-scale soil maps.
Allium munzii
is also found within other soil types. These include soil series of sedimentary or igneous origin within a clay subsoil, or rocky-sandy loam soils that fall between the finer-textured sandy clay loam and the coarser-textured loamy sands and have sufficient silt or clay components to provide coherence (stickiness) to the soil (Brown 2003, p. 3). Clay soils must be deep enough (at least 3 in (7.6 cm)) and remain wet long enough to expand during the rainy season in order to pull the seedling bulb down into the soil so the plant will survive until spring (Wallace 2011, pers. comm.).
Allium munzii
most frequently appears within intact habitats in which the soils and subsoils have been minimally altered or unaltered by ground-disturbing activities (such as disking, grading, excavating, or recontouring) and in more open areas where there is little competition and overcrowding from nonnative plants.

Allium munzii
is commonly restricted to locally wetter sites (Boyd 1988, p. 2) on level or slightly sloping (10-20 degrees) areas at elevations from 1,200 ft (366 m) AMSL (Skunk Hollow) to 2,700 ft (823 m) AMSL (Estelle Mountain) (Boyd 1988, p. 4). It is found on both south- and north-facing slopes (L&L Environmental Inc. 2003, p. 26; CNDDB 2011a). The native perennial and annual grassland communities, open coastal sage or Riversidean sage scrub, and occasionally cismontane juniper woodlands found on clay soils in Riverside County provide supporting habitat for
A. munzii.
Coupled with aspect and elevation, these plant communities in western Riverside County provide space for individual and population growth for
A. munzii
and are identified as a physical or biological feature for this species.

Food, Water, Air, Light, Minerals, or Other Nutritional or Physiological Requirements

Clay soil associations for
Allium munzii
include, but are not limited to: Altamont, Auld, Bosanko, and Porterville clays (70 FR 33022; June 7, 2005) or soil series of sedimentary or igneous origin (rocky-sandy loam) with a clay subsoil (such as Cajalco, Las Posas, and Vallecitos). Two populations of
A. munzii
are associated with these rocky or sandy loam soils on igneous rocky outcrops (Greene 1999, pers. comm.; CNDDB 2011a, EO 23). Most populations are associated with clay soils, which have a sticky adobe consistency when wet and large cracks when dry, and with rounded cobbles and boulders embedded within the soil (Boyd 1988, p. 4). Clay soils have

unique physical and chemical properties such as fine grain size, small pore space, and an expansive nature that often result in a hardpan layer that inhibits percolation and root penetration (Donahue
et al.
1977, p. 50). Clay soils are also rich in mineral nutrients such as calcium, magnesium, and potassium that are held tightly as positively charged ions (cations) and are absorbed by plant roots through cation exchange (Donahue
et al.
1977, pp. 10, 50, 106, 113, 121).

Allium munzii
is adapted to seasonal (summer and fall) drought and variable annual rainfall. Within areas of suitable clay soils or areas of smaller discrete pockets of clay within other soil types, microhabitats that receive or retain more moisture than surrounding areas (due to factors such as exposure, slope, and subsurface geology) are very important in determining where
A. munzii
is found (Boyd 2011b, pers. comm.) and are identified as physical or biological features for this species.

Sites for Reproduction

Sites for
Allium munzii
reproduction are coincident with those for individual and population growth.
Allium munzii
is generally restricted to clay soils but is also found on rocky loam soils (such as North Domenigoni Hills). The sites of these soils in western Riverside County are identified as a physical or biological feature for this species.

We have little information on pollinators or their habitat requirements for this taxon other than anecdotal observations of beetles on
Allium munzii
inflorescences in one population at Temescal Canyon (The Environmental Trust 2002, p. 16). Wind dispersal is the likely mechanism for seed distribution; however, no estimates of dispersal distances are available.

Habitats Protected From Disturbance or Representative of the Historical, Geographical, and Ecological Distributions of the Species

Allium munzii
is found in association with several plant communities, including southern needlegrass grassland, mixed grassland, open coastal sage scrub and Riversidean sage scrub, or occasionally cismontane juniper woodlands (CNPS 2001, p. 67). A characteristic clay soil flora, comprised of herbaceous annuals and perennials, is often associated with the small pockets of clay soils (see Habitat and Soil Preferences section above for
Allium munzii
) in southwestern Riverside County occupied by
A. munzii
(Boyd 1988, p. 4). In some instances, the observed differences in plant communities that occupy clay versus nonclay soils can be very different as is the case for the terraces in Temescal Canyon (Boyd 1988, p. 4). At other locations, such as Alberhill Mountain and the Gavilan Hills region, the grasslands form a mosaic with the surrounding scrub-type vegetation (Boyd 1988, p. 4);
A. munzii
is often found in open areas within these grassland communities.

Allium munzii
is also associated with nonnative plants, primarily invasive annuals (CDFG 1989, p. 2). However, nonnative plants have been identified as a threat to several populations of
A. munzii
(CNDDB 2011a, EOs 5, 6, 7, 10, 12, and 16). Activities that promote the spread of invasive weedy grasses, such as disking and grading, can suppress the inflorescence of
A. munzii
(Boyd 1988, p. 3). These activities can also kill plants and destroy hydrological characteristics of the site.

Native and, in some areas, nonnative plant communities found along the southern edge of the greater Riverside-Perris area are identified as a physical or biological feature for this taxon.

Atriplex coronata
var.
notatior

We derive the specific physical or biological features for
Atriplex coronata
var.
notatior
from studies of this taxon's habitat, ecology, and life history as described in the Background section of this proposed rule, the previous critical habitat rule (70 FR 59952; October 13, 2005), and the final listing rule (63 FR 54975; October 13, 1998). We have based our determination of the physical or biological features for
A. c.
var.
notatior
on the following:

Space for Individual and Population Growth and for Normal Behavior

Atriplex coronata
var.
notatior
occupies seasonal wetlands, including vernal pools and floodplains that receive seasonal inundation (Bramlet 1993a, p. 1). The taxon occurs within alkali playas, alkali scrub, alkali vernal pools, and alkali grasslands, where these habitats occur in association with slow-draining alkaline soils, particularly the Willows soil series, and to a lesser extent, the Domino, Traver, Waukena, and Chino soil series (Knecht 1971, p. 23 and accompanying map; Bramlet 1992 pers. comm.; Bramlet 1993a, p. 1;).
Atriplex coronata
var.
notatior
is therefore found adjacent to and dependent on floodplains, transitional wetlands, marginal wetlands, and scrub habitat within the watershed (59 FR 64812; December 15, 1994, p. 64821).

The four general geographical areas where
Atriplex coronata
var.
notatior
is known to occur are no longer pristine and have been particularly impacted by agricultural activities (Service 2008, p. 8). Dryland or irrigated farming activities in the San Jacinto River and Old Salt Creek floodplains have been occurring over the past 100 years. Most populations of plants within these locations are on privately owned undeveloped land that is disked frequently or has undergone intensive manure dumping (Roberts 1993, pp. 2-3; Roberts and McMillan 1997, pp. 1-5; Roberts 2004, pers. comm.; CNDDB 2011b). Habitats that support
A. c.
var.
notatior
can recover from disturbance from disking or dryland farming if left fallow and undisturbed (Roberts 1993, pp. 2-3). In the past, disking was intermittent, allowing for recovery periods for
A. c.
var.
notatior
(Roberts 1999, pers. comm.). Additionally,
Atriplex coronata
var.
notatior
can persist in the seed bank within lands that experience short-term disturbances and can germinate with the return of proper conditions (Roberts 1993, pp. 2-3). Thus, in those areas where elements of annual communities persist, disturbed annual grassland and alkali playa habitats can recover with the return of hydrological conditions to support
A. c.
var.
notatior
and therefore provide the physical or biological features for the taxon. However, once the seed bank is removed through activities such as laser leveling for agriculture development or significant alternation of soil chemistry, plants are unlikely to reestablish without extensive soil restoration (Bramlet 2010, pers. comm.). We have determined that alkali vernal pools and floodplains that receive seasonal inundation, including alkali playas, alkali scrub, alkali vernal pools, and alkali grasslands habitats, are a physical or biological feature for
A. c.
var.
notatior.

Food, Water, Air, Light, Minerals, or Other Nutritional or Physiological Requirements

Atriplex coronata
var.
notatior
requires a hydrologic regime that includes seasonal and large-scale flooding in combination with alkaline soils that exhibit low permeability and low nutrient availability. The plants occur along floodplains defined by seasonal ponding or flooding in the San Jacinto River and Upper Salt Creek drainages and within the Alberhill Creek floodplain in soils where mineral nutrients are tightly bound to silt and clay particles (Roberts 2004, pers. comm.). Depending on the amount of precipitation, the duration and extent of flooding or inundation can be extremely variable year to year. Seasonal flooding (typically over the winter and early spring) is an important process that

creates suitable alkali habitat for
A. c.
var.
notatior,
stimulates germination, prevents invasion from flood-intolerant plant species, restores disturbed areas, and helps disperse seed (Roberts 2004, pers. comm.). Additionally, large-scale flooding events, such as 10-, 50-, or 100-year floods, can restore or reset alkali habitat that has been colonized by upland species or disturbed by agricultural activities (Bramlet 1992, pers. comm.). The frequency, duration, and extent of seasonal ponding or flooding creates a dynamic matrix of habitat that allows
A. c.
var.
notatior
to colonize favorable sites and retreat from less favorable sites in response to disturbance and variations in annual rainfall. Irreversible actions (such as paving, redirection of sheet flow, or year-round flooding) that alter the hydrology of the seasonal wetlands and upland watersheds, or infringe upon the wetlands, may threaten the survival of
A. c.
var.
notatior.

The presence of
Atriplex coronata
var.
notatior
in floodplains depends on seasonal or large-scale flooding within valley drainages, as well as precipitation and runoff from the surrounding hillsides. The watershed and the upland areas that provide water to these floodplains are important for retaining the flooding regime. While some runoff originates from undeveloped hillsides, much of the watershed where
A. c.
var.
notatior
occurs has been developed, and the flows traveling to the ponded habitats can include urban runoff (RECON 1995, pp. 18, 21). Unless captured and routed to storm water detention (desilting) basins, this runoff can transport a variety of pollutants that can be detrimental to native plant communities, particularly the unique soil and vegetation characteristics of vernal pool and alkali playa habitats and the species that occupy them (Clark
et al.
1998, p. 251; Cahill
et al.
2001, p. 820; Battaglin
et al.
2009, p. 303). Therefore, a hydrologic regime that includes seasonal and large-scale flooding in combination with slow drainage in alkaline soils with low nutrient loads is identified as a physical or biological feature for this taxon.

Sites for Reproduction

Flooding or ponding of water during the rainy season, as indicated above, is important for the reproduction, germination, and seed dispersal of
Atriplex coronata
var.
notatior.
Two types of flood events are important for
A. c.
var.
notatior,
and they occur at two distinct scales: local, seasonal flooding and large-scale flooding (Roberts 2004, pers. comm.). Seasonal flooding determines the area of germination and affects local distribution of individual plants, while large-scale flooding (generally 20- to 50-year events) disrupts entire habitats with slow-moving water that can be present for weeks or months and rework the structure of the vegetative communities (Roberts 2004, pers. comm.). Together, these natural processes prevent invasion from upland vegetation, restore disturbed alkali habitats, and help distribute seed throughout the habitat. Natural alkali playa flood events therefore promote the colonization of
A. c.
var.
notatior
colonization within favorable sites, as well as the retreat from less favorable sites, in response to disturbance and variations in annual rainfall, thus creating conditions in which population abundance shifts annually through a mosaic of habitat and flooding (Bramlet 1996, p. 2-3). Relatedly,
A. c.
var.
notatior
is known to produce floating seeds that are likely dispersed during seasonal flooding by slow-moving flows within the floodplains and vernal pools where the plant occurs (Sanders 2004, pers. comm.). Therefore, flooding provides the conditions that stimulate the germination of
A. c.
var.
notatior
and controls the distribution of plants in the surrounding semi-arid environment both year-to-year and over decades. These natural floodplain processes are integral to the life history of
A. c.
var.
notatior
and are considered to be a physical or biological feature necessary to maintain a healthy population.

Primary Constituent Elements

Under the Act and its implementing regulations, we are required to identify the physical or biological features essential to the conservation of
Allium munzii
and
Atriplex coronata
var.
notatior
within the geographical area occupied at the time of listing, focusing on the features' primary constituent elements (PCEs). We consider PCEs to be the elements of physical or biological features that provide for a species' life-history processes and, under the appropriate conditions, are essential to the conservation of the species.

Allium munzii

Based on our current knowledge of the physical or biological features and habitat characteristics required to sustain the species' life-history processes, we determine that the PCEs specific to
Allium munzii
are:

(1) Clay soil series of sedimentary origin (for example, Altamont, Auld, Bosanko, Porterville), clay lenses (pockets of clay soils) of those series that may be found as unmapped inclusions in other soil series, or soil series of sedimentary or igneous origin with a clay subsoil (for example, Cajalco, Las Posas, Vallecitos):

(a) Found on level or slightly sloping landscapes or terrace escarpments;

(b) Generally between the elevations of 1,200 to 2,700 ft (366 to 823 m) above mean sea level;

(c) Within intact natural surface and subsurface structures that have been minimally altered or unaltered by ground-disturbing activities (for example, disked, graded, excavated, or recontoured);

(d) Within microhabitats that receive or retain more moisture than surrounding areas, due in part to factors such as exposure, slope, and subsurface geology; and

(e) Part of open native or nonnative grassland plant communities and clay soil flora, including southern needlegrass grassland, mixed grassland, and open coastal sage scrub or occasionally in cismontane juniper woodlands; or

(2) Outcrops of igneous rocks (pyroxenite) on rocky-sandy loam or clay soils within Riversidean sage scrub, generally between the elevations of 1,200 to 2,700 ft (366 to 823 m) above mean sea level.

With this proposed revised designation of critical habitat, we intend to identify the physical or biological features essential to the conservation of the species. All units and subunits proposed to be designated as critical habitat are currently occupied by
Allium munzii
and are within the geographical areas occupied at the time of listing.

Atriplex coronata
var.
notatior

Based on our current knowledge of the physical or biological features and habitat characteristics required to sustain the taxon's life-history processes, we determine that the PCEs specific to
Atriplex coronata
var.
notatior
are:

(1) Wetland habitat including floodplains and vernal pools:

(a) Associated with native vegetation communities, including alkali playa, alkali scrub, and alkali grasslands; and

(b) Characterized by seasonal inundation or localized flooding, including infrequent large-scale flood events with low nutrient loads; and

(2) Slow-draining alkali soils including the Willows, Domino, Traver, Waukena, and Chino soil series with:

(a) Low permeability;

(b) Low nutrient availability; and

(c) Seasonal ponding and evaporation.

With this proposed revised designation of critical habitat, we intend to identify the physical or biological

features essential to the conservation of the species. All units and subunits proposed to be designated as critical habitat are currently occupied by
Atriplex coronata
var.
notatior
and are within the geographical areas occupied at the time of listing.

Special Management Considerations or Protection

When designating critical habitat, we assess whether the specific areas within the geographical area occupied by the species at the time of listing contain physical or biological features which are essential to the conservation of the species and which may require special management considerations or protection. In all units or subunits, special management considerations or protection of the essential features may be required to provide for the growth, reproduction, and sustained function of the habitat on which
Allium munzii
and
Atriplex coronata
var.
notatior
depend.

Allium munzii

A detailed discussion of threats to
Allium munzii
and its habitat can be found in the final listing rule (63 FR 54975; October 13, 1998), the previous proposed and final critical habitat designations (69 FR 31569, June 4, 2004; 70 FR 33015, June 7, 2005), and the
A. munzii
5-year review signed on June 17, 2009 (Service 2009). Actions and development that alter habitat suitable for the species or affect the natural hydrologic processes upon which the species depends could threaten the species.

The physical or biological features essential to the conservation of
Allium munzii
all face ongoing threats that may require special management considerations or protection. Threats that may require special management considerations or protection of the physical or biological features include:

(1) Loss or degradation of native plant communities, such as grassland, open coastal sage scrub, and cismontane juniper woodlands, due to urban development, agricultural activities, and clay mining (PCEs 1 and 2);

(2) Disturbance of clay or other occupied soils by activities such as off-road vehicles (ORV) and fire management (PCEs 1 and 2);

(3) Invasion of nonnative plant species (PCEs 1 and 2); and

(4) Long-term threats including climatic variations such as extended periods of drought (PCE 1) (63 FR 54982-54986, October 13, 1998; 69 FR 31571, June 4, 2004; 70 FR 33023, October 13, 2005; Service 2009, pp. 10-22).

Further discussion of specific threats facing individual proposed revised critical habitat units or subunits for
Allium munzii
is provided in the unit descriptions under the Proposed Revised Critical Habitat Designation section below. In these proposed revised critical habitat units, special management considerations or protection may be needed to ensure the long-term existence of clay and alluvial soil integrity within habitats that support the physical or biological features essential to the conservation of
A. munzii.

Special management considerations or protection for areas occupied by
Allium munzii
include:

(1) Protection of habitat from urban development or destruction to maintain integrity of clay soils;

(2) Reduction of land conversion to agricultural uses and reduction of disking or dryland farming to maintain native habitats;

(3) Management and control of invasive nonnative plants to provide open areas for growth and reproduction; and

(4) Land acquisition or conservation easements for occurrences not already conserved to protect those populations within occupied habitats.

Atriplex coronata
var.
notatior

A detailed discussion of threats to
Atriplex coronata
var.
notatior
and its habitat can be found in the final listing rule (63 FR 54975; October 13, 1998), the previous proposed and final critical habitat designations (69 FR 59844, October 6, 2004; 70 FR 59952, October 13, 2005), and the
A. c.
var.
notatior
5-year review signed on March 31, 2008 (Service 2008). Actions and development that alter habitat suitable for
A. c.
var.
notatior
or affect the natural hydrologic processes upon which it depends could threaten the taxon. The physical or biological features essential to the conservation of
A. c.
var.
notatior
may require special management considerations or protection to reduce or eliminate the following threats:

(1) Loss of alkali vernal plain habitat (i.e., alkali playa, alkali scrub, alkali vernal pool, alkali annual grassland) and fragmentation as a result of activities such as urban development, manure dumping, animal grazing, agricultural activities, ORV activity, weed abatement, and channelization (PCEs 1 and 2);

(2) Indirect loss of habitat from the alteration of hydrology and floodplain dynamics (diversions, channelization, excessive flooding) (PCEs 1 and 2);

(3) Competition from nonnative plants (PCE 1); and

(4) Long-term threats including water pollution, climatic variations, and changes in soil chemistry and nutrient availability (PCE 1) (63 FR 54983, October 13, 1998; 69 FR 59847, October 6, 2004; 70 FR 59966, October 13, 2005; Service 2008, pp. 8-17).

Further discussion of specific threats facing individual units is provided in the unit descriptions under the Proposed Revised Critical Habitat Designation section below. Special management considerations or protection for
Atriplex coronata
var.
notatior
include:

(1) Protection of habitat, including underlying soils and chemistry, from development or destruction;

(2) Protection of floodplain processes to maintain natural, seasonal flooding regimes;

(3) Reduction of land conversion to agricultural uses and reduction of disking and dryland farming to maintain native habitats;

(4) Land acquisition or conservation easements for occurrences not already conserved to protect those populations within occupied habitats; and

(5) Implementation of manure and sludge dumping ordinances to maintain soil chemistry.

Criteria Used To Identify Critical Habitat

As required by section 4(b)(2) of the Act, we use the best scientific data available to designate critical habitat. We review available information pertaining to the habitat requirement of the species. In accordance with the Act and its implementing regulation at 50 CFR 424.12(e), we consider whether designating additional areas—outside those currently occupied as well as those occupied at the time of listing—are necessary to ensure the conservation of the species. We are not currently proposing to designate any areas outside the geographical areas currently occupied by
Allium munzii
or
Atriplex coronata
var.
notatior
because we consider those areas to be of sufficient quality, extent, and distribution to provide for the conservation of these taxa. We believe that the present quality habitat has, by survey, the demonstrated capacity to support self-sustaining occurrences of these taxa and that these areas containing the physical or biological features essential to the conservation of the species are dispersed in its range in a manner that provides for the survival and recovery of these taxa. We are proposing to designate as critical habitat some specific areas within the geographical

range currently occupied by
A. munzii,
but that were not known to be occupied at the time of listing. However, based on the best available scientific information, the life history of the plant (see Background section), and the limited survey efforts prior to listing, we believe that these specific areas are within the geographical area occupied by the species at the time of listing.

We reviewed the final critical habitat designations for
Allium munzii
and
Atriplex coronata
var.
notatior
(70 FR 33015, June 7, 2005; 70 FR 59952, October 13, 2005, respectively), information from State, Federal, and local government agencies, and from academia and private organizations that have collected scientific data on the species. We also used the information provided in the 5-year reviews for
A. munzii
and
A. c.
var.
notatior
(Service 2008; Service 2009). Other information we used for this proposed rule includes: CNDDB (CNDDB 2011a; CNDDB 2011b); reports submitted during consultations under section 7 of the Act; analyses for individual and regional HCPs where
A. munzii
and
A. c.
var.
notatior
are covered species; data collected from reports submitted by researchers holding recovery permits under section 10(a)(1)(A) of the Act; information received from local species experts; published and unpublished papers, reports, academic theses, or surveys; Geographic Information System (GIS) data (such as species population and location data, soil data, land use, topography, aerial imagery, and ownership maps); and correspondence with the Service from recognized experts
.
We analyzed this information to determine the specific areas within the geographical area occupied by the taxa at the time of listing that contain the physical or biological features essential to the conservation of
A. munzii
and
A. c.
var.
notatior.

Allium munzii

Allium munzii
occurs in relatively small population sizes, has a narrow geographic range (western Riverside County), and exhibits high habitat specificity, all of which make it vulnerable to land use changes. According to the Western Riverside County MSHCP,
A. munzii
is considered a narrow endemic plant species, a plant species that is highly restricted by its habitat affinities, edaphic requirements, or other ecological factors (Dudek and Associates 2003, pp. Def/Acr-ix and 6-28). Based on examination of soil maps for western Riverside County, Boyd (1988, p. 2) concluded that much of the scattered clay soil areas in the Perris Basin were heavily disturbed and estimated up to an 80 to 90 percent loss of potential
A. munzii
habitat in 1988.

We conducted a spatial analysis using a GIS-based approach to determine the percent of mapped clay soils (Altamont, Auld, Bosanko, Porterville) that were converted or lost to agricultural or urban land uses in the Perris Basin (based on 2007 land use GIS data). This is a conservative approach given that smaller pockets of clay soils are not shown on coarse-scale soil maps and may have been lost since the completion of the Riverside County soil map in 1971. We estimated that approximately 32 percent of these clay soils remain within suitable
Allium munzii
habitats (or a 67 percent loss) due to urban and agricultural development on plant communities associated with
A. munzii,
and includes both known and unknown locations of
A. munzii
populations. Based on the narrow endemism of this species, its reliance on clay soil types that are limited in geographic range in western Riverside County, and our estimated loss of 67 percent of these soils to urban or agricultural development, we believe that all of the units and subunits (as defined below and in the Summary of Changes from Previously Designated Critical Habitat section of this proposed rule) represent the present geographical area containing the physical or biological features essential to the conservation of this species which may require special management considerations or protection. This designation includes 17 of the CNDDB's EOs described in the Background section above.

We are proposing to designate as critical habitat specific areas within the geographical area occupied by
Allium munzii
at the time of listing in 1998. These specific areas include some areas within the present range of the species that had not yet been identified as occupied at the time of listing. We have determined that these areas are within the geographical area occupied by
A. munzii
at the time of listing based on the species life history and habitat requirements (see Background section above) and the following: (1) Locations of plants reported or detected since listing in 1998 are in close proximity (less than 1 mi (1.5 km)) to previously known locations and, (2) of the 10 new CNDDB-defined EOs reported since early 1980s surveys by Boyd (1988), 6 are within previous known occupied geographic regions of the greater Perris Basin (Temescal Canyon-Gavilan Hills/Plateau, Murrieta-Hot Springs areas) and the other 4 locations were found after surveys in the early 1990s within the Elsinore Peak (Santa Ana Mountains) and Domenigoni Hills regions. Additionally, we believe this currently occupied habitat was occupied at the time of listing given the species' naturally discontinuous distribution and occupation of microhabitats; the difficulty of accurately surveying for individual plants given the dormant (underground) phase of its life cycle prior to detection; and its restriction to small areas of clay soils in western Riverside County within the designated units and subunits.

For defining critical habitat units, we looked at elevation (1,200 to 2,700 ft (366 to 823 m) AMSL), soil types (primarily clay soils), spatial distribution of 17 CNDDB-defined EOs from CNDDB (CNDDB 2011a), 1 location identified by Ellstrand not included in the CNDDB database (Ellstrand 1993, 1994) (proposed EO 24, as mentioned in the Spatial Distribution, Historical Range, and Population Size section for
Allium munzii
), rare plant monitoring survey results from Western Riverside County Regional Conservation Authority (RCA) (Western Riverside County RCA 2006, 2007, 2008, 2009, 2010, and 2011), and other surveys.

To identify several unit and subunit boundaries for this proposed revised critical habitat, we consulted a species expert with considerable field experience in surveying for
Allium munzii.
Given the difficulty in observing individual plants due to the timing of inflorescence, stage of growth, and large areal extent (as discussed in the Background section), Boyd (2011b, pers. comm.) recommended expanding the area surrounding an observation of a location of plants (either a group or just a few individuals) to capture additional individual plants that might not have been observed. Based on extensive field experience (approximately 30 years) with
A. munzii,
Boyd (2011b, pers. comm.) recommended including a 100-m (328-ft) roughly circular area (or 50-m (164-ft) radius) to define the unit or subunit boundaries. Because
A. munzii
is strongly associated with clay soils (which are often found as pockets of small scattered (but discrete) clay lenses that are typically too small to be identified on coarse-soil soil maps (see the Habitat and Soil Preferences section for
A. munzii
above)), we used Boyd's recommendation of expanding the boundaries of observed plant locations to capture unobserved individuals in defining critical habitat units and subunits. Specifically, we used the Soil Conservation Service (now Natural Resources Conservation Service) soil mapping unit (2.47 ac or 1 ha) to refine Boyd's recommended radius of 164 to

183 ft (50 to 56 m). The 183-ft (56-m) radial distance translates into a 2.43-ac (0.98-ha) area, which is approximately equal to the soil mapping unit of 2.47 ac (1 ha). This methodology accounts for both potentially unobserved plants associated with CNDDB-defined EOs in areas of clay or rocky-sandy loam soils as well as encompassing the unmapped pockets of clay soil. In conjunction with the reported EOs, survey reports, and aerial photographs, this approach represents the best available information regarding areas currently occupied by
A. munzii
and that contain the physical or biological features essential to the conservation of the species and therefore accurately defines the unit and subunit polygons.

The following sources were used to define microhabitats (i.e., depressional areas that retain moisture) for
Allium munzii,
which included using underlying geology, slope, and aspect of hillsides within open areas of native and nonnative plant communities:

(1) For evaluating microtopography, including slope, aspect, and elevation, we used: (a) Digital elevation model (DEM) data from U.S. Geological Survey's (USGS) EROS Data Center, and (b) USGS 1:24,000 digital raster graphics (USGS topographic maps).

(2) For evaluating vegetative communities, spatial arrangement of these communities, and presence of disturbance or development, we used: (1) U.S. Department of Agriculture (USDA) National Agriculture Imagery Program (NAIP) aerial photography for 2010, and (b) ArcGIS online I3 Imagery Prime World 2D), validating conclusions made from examining these two satellite imagery data layers using high resolution Google Earth imagery.

(3) For subsurface geology, we used the USGS GIS layer of the Preliminary Digital Geologic Map of the Santa Ana, 1:100,000 quadrangle (USGS 2004).

We acknowledge that the extent of the geographic areas surveyed and the survey methodologies may differ within and among the recorded plant locations from year to year (see discussion regarding the detectability of this species in the Background section above). Based on our GIS analysis, the 5 units, further divided into 13 subunits, we propose as critical habitat are as follows: (1) Gavilan Hills (6 subunits), (2) Temescal Valley (4 subunits), (3) Elsinore Peak, (4) South Perris-Bachelor Mountain (3 subunits), and (5) North Domenigoni Hills. All units and subunits are within the present geographical range of the species and are currently occupied.

Atriplex coronata
var.
notatior

Atriplex coronata
var.
notatior
is endemic to the San Jacinto, Perris, Menifee, and Elsinore Valleys of western lowland Riverside County, and is restricted to highly alkaline, silty-clay soils (59 FR 64813; December 15, 1994). At the time of listing, 12 populations of
A. c.
var.
notatior
were known (corresponding to the CNDDB EOs at the time), 11 of which were associated with two general locations (the San Jacinto and Old Salt Creek floodplains). We have grouped the 12 CNDDB EOs and results from other surveys into four general locations (described below) and developed boundaries for three critical habitat units based on the geographic locations of observed plants.

All of the units (as defined below and in the Summary of Changes from Previously Designated Critical Habitat section) are within the geographical area occupied by
Atriplex coronata
var.
notatior
at the time of listing. These units contain the physical or biological features that are essential to the conservation of this taxon and may require special management considerations or protection.

Atriplex coronata
var.
notatior
is known from four general locations in western Riverside County, as previously identified in the 2004 proposed critical habitat rule (69 FR 59844; October 6, 2004). All three units proposed as critical habitat encompass these four areas and are within the geographical area occupied by the taxon at the time of listing. This range includes records of 15 EOs now recorded in the CNDDB database (CNDDB 2011b) and other survey data. To define critical habitat units, we examined the following information:

(1) Slow-draining alkali soils (Willows, Domino, Traver, Waukena, and Chino soil series) with low permeability.

(2) Seasonal and large-scale flood events (or ponded water) and subsequent scouring to create bare soils, as illustrated in historical aerial photographs.

(3) Spatial distribution of the EOs recorded in the CNDDB database (CNDDB 2011b), and

(4) Plant monitoring survey results from Western Riverside County RCA (2007, 2008, 2009, 2010, and 2011) and other surveys.

We recognize that the geographic extent surveyed and survey methodologies may differ within and among the locations of individual or groups of plants from year to year (see discussion regarding the detectability of this species in Background section above). Based on this analysis we defined the following three units: (1) Floodplain of the San Jacinto River from the San Jacinto Wildlife Area (including Mystic Lake) to Railroad Canyon Reservoir, (2) Upper Salt Creek, and (3) Alberhill Creek. All units are within the present geographical range of the taxon and are currently occupied.

Other Factors Involved With Delineating Critical Habitat

When determining proposed revised critical habitat boundaries, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because these lands lack physical or biological features necessary for
Allium munzii
and
Atriplex coronata
var.
notatior.
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 lands. Any such lands inadvertently left inside critical habitat boundaries shown on the maps of this proposed rule have been excluded by text in the proposed rule and are not proposed for designation as critical habitat. Therefore, if the critical habitat is finalized as proposed, a Federal action involving these lands would not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific action may affect the adjacent critical habitat.

We are proposing for designation of critical habitat lands that we have determined are within the geographical areas occupied by these taxa at the time of listing and contain sufficient elements of physical or biological features to support life-history processes essential for the conservation of the taxa. For
Allium munzii,
our proposed revision includes extant locations of plants not known at the time of listing, but that are within the geographical area occupied at the time of listing. All units contain the physical or biological features that are essential to the conservation of these taxa and may require special management considerations or protection.

Summary of Changes From Previously Designated Critical Habitat

Allium munzii

The areas identified in this proposed rule constitute a proposed revision to the critical habitat rule for
Allium munzii
published on June 7, 2005 (70 FR 33015) based on the following principles:

(1) We refined our method identifying the locations of
Allium munzii
and the

PCEs within those locations to more accurately reflect the physical or biological features that are essential to the conservation of
A. munzii.
We consolidated the PCEs to identify the primary element and then listed the related supporting components of that element. Specifically, we reviewed the CNDDB EO reports and other survey reports to define PCEs that reflect the physical and ecological characteristics found within the range of the CNDDB-defined EOs. This resulted in removing the previous PCE listed as alluvial soil series and reclassifying the locations of plants (with one exception) into their appropriate clay soil associations.

(2) We improved our mapping methodology to more accurately define the critical habitat boundaries and to better represent those areas that possess the physical or biological features essential to the conservation of
Allium munzii
using soils, elevation, and spatial configuration known from the most recent occurrence information. In this rule, we have grouped locations of
A. munzii
plants into critical habitat units and subunits and labeled each grouping as an occurrence; this is different than the term “Element Occurrence” used by CNDDB. As noted earlier, not all survey reports are included in the CNDDB database, particularly recent surveys, nor are the boundaries defined by CNDDB precise in location (some were recorded prior to Global Positioning System (GPS) technology or with older and less accurate GPS units); thus, for the purposes of defining units and subunits in this proposed rule, the polygons and point locations defined by CNDDB may not encompass all of the physical or biological features essential to the conservation of the species.

The areas identified in this proposed rule constitute a proposed revision to the critical habitat units designated for
Allium munzii
published on June 7, 2005 (70 FR 33015). The differences in these areas resulted from using the following methods:

(1) We combined the EO data recorded in the CNDDB database (CNDDB 2011a) with 2005 to 2011 survey results from the Western Riverside County Resource Conservation Agency (RCA) (Western Riverside County RCA 2005, 2008) and Rancho Santa Ana Botanical Garden (Boyd 2011c, pers. comm.). Using the 183-ft (56-m) radius discussed above, we delineated units and subunits.

(2) We combined one or both of the CNDDB EO spatial datasets with GIS-based maps of Porterville clay soils or other clay soil types to create the units and subunits using the 183-ft (56-m) boundary, and we incorporated recent survey data.

(3) For a few of the smaller subunits defined by point locations of small numbers of individual plants, we used CNDDB's previously defined 262-ft (80-m) radius polygon to determine the subunit boundary (CNDDB 2011a).

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

Atriplex coronata
var.
notatior

The areas identified in this proposed rule constitute a proposed revision to the critical habitat designated for
Atriplex coronata
var.
notatior
published on October 13, 2005 (70 FR 59952). The differences are as follows:

(1) We refined the PCEs to more accurately describe the physical or biological features essential to the conservation of
Atriplex coronata
var.
notatior
. We consolidated the PCEs to identify the primary element and relevant factors to that element based on review of the CNDDB database and recorded EOs.

(2) We improved our mapping methodology to more accurately define the critical habitat boundaries and to better represent those areas that possess the physical or biological features essential to the conservation of
Atriplex coronata
var.
notatior
using soils, elevation, and spatial configuration based on updated plant location information. We delineated boundaries using an intersection of seasonal ponding or flooding (and resulting bare soils), as observed in historical and recent aerial photographs (Riverside County Flood Control District photos from 1962, 1974, 1978, 1980, and 2010), with
A. coronata
var.
notatior
soil preferences (soil maps from Knecht 1971). In doing so, we also removed areas of urban or otherwise developed lands in all these areas. In addition, areas identified as “Right-of-Way” in the most current parcel database available from the Riverside County Assessor's Office were classified as either local land or State land depending on whether they were located adjacent to local roadways or Federal highways under State control.

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

(4) We revised the previous critical habitat units based on surveyed locations (or localities) of
Atriplex coronata
var.
notatior
as described above. As discussed above, we have grouped locations of
A. coronata
var.
notatior
plants into four general geographical areas and delineated these as our three critical habitat units. This delineation includes the EOs defined by CNDDB and locations of individual plants reported from other surveys.

Proposed Revised Critical Habitat Designation

Allium munzii

We are proposing approximately 889 ac (360 ha) in 5 units containing 13 subunits as critical habitat for
Allium munzii.
The areas we describe below constitute our current best assessment of areas that meet the definition of critical habitat for
A. munzii.
The units and subunits we propose as critical habitat are: (1) Gavilan Hills (Unit 1; 6 subunits), (2) Temescal Valley (Unit 2; 4 subunits), (3) Elsinore Peak (Unit 3), (4) South Perris and Bachelor Mountain (Unit 4; 3 subunits), and (5) North Domenigoni Hills (Unit 5). The approximate area of proposed revised critical habitat and land ownership within the units and subunits is shown in Table 1 below.

BILLING CODE 4310-55-P

EP17AP12.022

BILLING CODE 4310-55-C
Unit 1: Gavilan Hills

Unit 1 consists of 114.7 ac (46.4 ha). The Gavilan Hills Unit is located at the northwestern edge of the Perris Basin, northeast of the Santa Ana Mountains in western Riverside County. This unit

includes six occupied subunits within upland areas west of State Highway 74, south of Cajalco Road, and northeast of Interstate 15, all of which are within the geographical area occupied at the time of listing and which contain the physical or biological features essential to the conservation of the species. The Gavilan Hills region is geologically and topographically diverse with many soil types. Clay soil series occupied by
Allium munzii
in the Gavilan Hills Unit include Bosanko, Altamont, and Porterville; however, small pockets of clay (less than 2.47 ac (1 ha)) are often not indicated on soil maps (Boyd 1983, p. 19). The elevational range of the five subunits is 1,547 ft (472 m) to 2,632 ft (802 m) AMSL. Vegetation of the Gavilan Hills region is a complex association of scrub, woodland, and grass communities, including annual grasslands characterized by invasive nonnative plants in those areas where native communities have been heavily disturbed (Boyd 1983, pp. 32-33). Threats identified for the Gavilan Hills Unit include invasive nonnative plants, road construction and urban development, grazing, ORV activity, illegal dumping, and mowing for fire abatement. Therefore, the features essential to the conservation of the species in this unit may require special management considerations or protection to minimize impacts resulting from these threats (see Special Management Considerations or Protection section above).

Within the Gavilan Hills Unit, we are considering excluding all subunits within the planning area of the Western Riverside County MSHCP and the Lake Mathews MSHCP under section 4(b)(2) of the Act (see Exclusions section).

Subunit 1A: Estelle Mountain

The Estelle Mountain subunit (2.8 ac (1.1 ha)) is located within native and nonnative grassland habitat within the Lake Mathews/Estelle Mountain Reserve (2.3 ac (0.9 ha)) and on private land (0.48 ac (0.2 ha)). The Lake Mathews Multiple Species Habitat Conservation Plan/Natural Communities Conservation Plan (Lake Mathews MSHCP) assisted in establishing this multi-jurisdictional reserve encompassing over 12,000 ac (4,856 ha) and managed for multiple species use, including
Allium munzii,
in western Riverside County. The combined reserve is composed of a Multiple Species Reserve that consists of the existing State Ecological Reserve and the Lake Mathews HCP Mitigation Bank, Lake Mathews/Estelle Mountain Core Stephens' Kangaroo Rat Reserve, the Estelle Mountain Ecological Reserve owned by CDFG, and land owned by the Bureau of Land Management (BLM) located within the Riverside County Habitat Conservation Agency's Stephens' Kangaroo Rat Core Reserve. Collectively, these lands comprise the existing Lake Mathews/Estelle Mountain Existing Core “C” area of the Western Riverside County MSHCP (Service 2004, p. 65). Management of the reserve focuses largely on the Stephens' kangaroo rat (
Dipodomys stephensi
) and coastal California gnatcatcher (
Polioptila californica californica
). The reserve is not open to the public for recreational use, but is subject to grazing, illegal dumping, and ORVs.

This subunit contains clay soils (not illustrated on coarse-scale soils map) on cobble deposits in a small drainage, which creates the space and microhabitat (PCE 1) that meets the habitat needs for
Allium munzii
and comprises the physical or biological features essential to the conservation of the species.

Subunit 1B: Dawson Canyon

The Dawson Canyon subunit (4.8 ac (1.9 ha)) is located on private land to the east of Estelle Mountain. This occurrence, with a significant number of plants (more than 1,000) seen in 1986, has been described as scattered stands of
Allium munzii
within grassy flats and slopes containing clay soils on cobble deposits (CNDDB 2011a, EO 5). This subunit contains clay soils, sloping topography, and subsurface geology (PCE 1) that provide substrate and conditions suitable for the persistence of
A. munzii
and comprise the physical or biological features essential to the conservation of the species. This subunit is subject to threats related to road development and invasive, nonnative plants (CNDDB 2011a).

Subunit 1C: Gavilan Plateau

The Gavilan Plateau subunit (42.2 ac (17 ha)), bisected by a road, is located within Harford Springs County Park (north of Ida-Leona Road) and on private land (south of Ida-Leona Road) in grassy openings on clay soils. Populations of
Allium munzii
exceeded 5,000 plants at both locations in the early 1990s (CNDDB 2011a, EO 2). The private land portion of this subunit has been disked in the past and is threatened by urban development (CNDDB 2011a). Several locations of
A. munzii,
with small numbers of individual plants, were found on clay soils within the County Park in surveys conducted by Western Riverside County RCA in 2005 and 2008 (Drennen 2011, pers. comm.). The southern portion of this subunit has not been surveyed since 1998 (CNDDB 2011a). Mineral-rich clay soils within grassland and other native vegetative communities (PCE 1) in this subunit provide the physical or biological features that are essential to the conservation of this species.

Subunit 1D: Ida-Leona

The Ida-Leona subunit (4.5 acres (1.8 ha)) is located about 0.5 mi (0.8 km) east of the Ida-Leona mine on land occupied by a private residence. In 1999, one year after listing, a total of 12 plants were recorded from 2 locations at an elevation of 2,223 ft (677 m) within a coastal sage scrub-nonnative grass plant association (Greene 1999, pers. comm.). Although this subunit was not known to be occupied at the time of listing in 1998, we believe it was occupied in 1998 because, as discussed in Background section, it takes at least 3 years after seed germination for this bulb-forming plant to produce flowers (Wall 2012, pers. comm.). This location was surveyed specifically for
A. munzii
by a qualified botanist in April 1999, less than 1 year after listing; 12 flowering plants were found in 2 locations (Greene 1999, pers. comm.); thus, based on its biology (growth timeframe) as described above, plants would have been present in 1998. Additionally, as discussed in the Background section,
Allium munzii
is often difficult to observe in the field (e.g., plants are dormant from mid-summer through autumn) and is easily overlooked without site-specific surveys during ideal conditions for its life history.

The populations of
A. munzii
at this location are on the north-facing slope of a hillside, range in elevation between 1,200 to 2,700 ft (366 to 823 m) AMSL, and in a small drainage (mesic microhabitat) within native (sage scrub) and nonnative (grasses) habitat. The surveyed population was reported to be approximately 600 ft (183 m) from the nearest residence. Although the owners at the time of the survey indicated that they did not intend to develop the drainage where the species was located (Greene 1999, pers. comm.), potential threats for this subunit include nonnative grasses and mowing for fire abatement. The location is mapped as Lodo rocky loam, a weathered, medium-textured soil, at 8 to 25 percent slope, consisting of a relatively even mixture of sand, silt, and clay, with rock outcrops (PCE 2) (Knecht 1971, p. 43). This subunit contains the physical or biological features essential to the conservation of this species including substrate components and conditions suitable for growth.

Subunit 1E: Northeast Alberhill

The Northeast Alberhill subunit (58 ac (23.5 ha)) is found on open grassland, upslope of previously proposed developments and clay mining operations (CNDDB 2011a, EO 16). Several colonies were mapped in surveys in 1993 and 2003, with about 3,000 plants observed in 2003 (CNDDB 2011a EO 16). This occurrence was surveyed again in April 2011 and 25-100 plants were found; however, the population may have been larger than reported as the buds were difficult to detect due to the early timing of the survey (Drennen 2011, pers. comm.). Potential threats to this subunit include nonnative grasses and road construction (CNDDB 2011a EO 16). The physical components of this location (i.e., elevation range 1,706 ft to 2,325 ft (520 to 709 m) AMSL, sloping hillside) within spaces of open grassland (microhabitat) on clay soils (PCE 1) provide the physical or biological features essential to the conservation of
Allium munzii.

Subunit 1F: North Peak

The North Peak subunit (2.4 ac (1.0 ha)) is located at the southern end of the Gavilan Hills unit within the North Peak Conservation Bank. Several thousand
Allium munzii
plants were found in coastal sage scrub habitat in 1993 (CNDDB 2011a, EO 15). In 1995, an estimated 6,800 plants were located at the base of a north-facing slope above a drainage area (Michael Brandman Associates 1995, p. 3). A survey conducted in the spring of 2008 recorded an estimated 400 plants growing on a north-facing slope, just upslope (approximately 328 ft (100 m)) from the drainage area (Drennen 2011, pers. comm.). These physical or biological features, space and substrate for growth and local microhabitat (slope and location within a drainage area) (PCE 2), provide habitat features essential to the conservation of
A. munzii.
Nonnative grasses are considered a threat to
A. munzii
at this location; individual plants in this subunit were found to be more abundant in areas with less nonnative grasses (Drennen 2011, pers. comm.).

Unit 2: Temescal Valley

Unit 2 consists of 481 ac (195 ha) located within the geographical area occupied at the time of listing and all subunits contain the features essential to the conservation of the species. The Temescal Valley Unit is located along Interstate 15 at the base of the Gavilan Hills in western Riverside County. The Temescal Valley unit contains the Temescal Wash, which drains the Gavilan Hills region and the northeastern slope of the Santa Ana Mountains (Boyd 1983, p. 13). This unit contains unique physical geographic features, including escarpments (canyons), found along the Temescal Wash. These escarpments are formed through erosional processes and the progressive elevation of the Santa Ana Mountains; thus, they represent one of several distinct land forms within the Perris Basin, which has a complex geological history (reviewed by Dudley 1936). The so-called Alberhill clays where
Allium munzii
is found in the Temescal Valley Unit are considered one of the earliest sediments in the Perris Basin and are found on sloping surfaces of an ancient valley wall (Dudley 1936, p. 377). Threats identified for the Temescal Valley Unit include nonnative plants, urban development and related infrastructure, and grazing. Therefore, the features essential to the conservation of the species in this unit may require special management considerations or protection to minimize impacts resulting from these threats (see Special Management Considerations or Protection section above).

Within the Temescal Valley Unit, we are considering excluding all subunits contained within the Western Riverside County MSHCP planning area under section 4(b)(2) of the Act (see Exclusions section).

Subunit 2A: Sycamore Creek

The Sycamore Creek Subunit (also known as Indian Truck Trail, north and south) is 12.3 ac (5 ha) in area, and was historically associated with
Allium munzii
populations located on a terrace escarpment, within grassland habitat on clay soil overlying cobbles (Boyd 1988, p. 4; CNDDB 2011a, EO 3). This location is believed to have contained the type locality collected by Munz in 1922 (CNDDB 2011a).

This subunit previously contained CNDDB EO 8, which was extirpated when
Allium munzii
bulbs were removed from areas proposed for development of a residential complex (Sycamore Creek Project), and is now combined with EO 3 (CNDDB 2011a). A portion of the original population of
A. munzii
was preserved onsite and was placed within a conservation easement; additional clay soils were relocated to this easement area and another planning area for the purpose of restoring
A. munzii
habitat within Riversidean sage scrub habitat (Service 2001a, p. 10; Helix Environmental Planning 2010, p. 2).
Allium munzii
bulbs removed from areas proposed for development were later transplanted to three areas that are contained within this subunit. Transplantations were conducted in 2004, 2008, and 2009 with over 525 bulbs installed in the conservation areas (Helix Environmental Planning 2010, pp. 3-5). In November 2010, 310 additional bulbs were installed in four new plots bringing the transplant total to 820 bulbs for this site (Helix Environmental Planning 2010, pp. 5, 13). In the spring of 2011, 678 plants (83 percent) produced leaves, 533 (65 percent) produced flowers, and 205 (25 percent) produced seeds (Helix Environmental Planning 2011, p. 13).

The Army Corps of Engineers Clean Water Act section 404 permit conditions and conservation measures established in the Service's biological opinion for the Sycamore Creek Project (Service 2001a, p. 10) also require maintenance and monitoring of the transplant areas and restoration of Riversidean sage scrub habitat supporting
A. munzii;
these are included as part of the Habitat Mitigation and Monitoring Plan for the Sycamore Creek Specific Plan (The Planning Associates 2002). Nonnative plants represent a threat at this subunit. In 2011, invasive plant control (weeding, spot spraying) was conducted as part of required maintenance activities (Helix Environmental Planning 2011, p. 10). The subsurface geology, clay soils, and native habitat (PCE 1) within the onsite conservation areas comprise the physical or biological features essential to the conservation of
A. munzii.

Subunit 2B: De Palma Road

The De Palma Road subunit (12.8 ac (5.2 ha)) is located about 1 mi (1.6 km) southeast of the Sycamore Creek subunit along Temescal Wash. This occurrence of
Allium munzii
is found on Altamont clay soils with 15 to 25 percent slopes within nonnative grasses and sage scrub vegetation (Dudek 2011, p. 2). Grazing, displacement by nonnative invasive plants, and development pressures have been previously described (CNDDB 2011a, EO 7) as threats to this population given its close proximity to Interstate 15. As a result of proposed grading improvements to De Palma Road and a proposed Saddleback Estates residential development, a salvage and relocation operation was implemented in December 2007 for locations of
A. munzii
to be impacted by the grading footprint of the project (Dudek 2011, p. v). The proposed conservation area (containing three separate preserves) was designed to encompass most of the existing
A. munzii
plants, while individual plants outside the preserve areas were translocated onto a portion of

the preserve not known to support this taxon (Dudek 2011, p. 2). Subsequent to translocation, a maintenance and monitoring program was initiated. The 2010 survey found a total of 1,195 flowering individuals within the translocation area, and maintenance activities were conducted including weed and rodent control (Dudek 2011, pp. v-vi). A conservation easement was to be placed over the proposed preserve areas; however, the proposed development did not go forward and Riverside County is currently managing the area until the disposition of the parcel is finalized.

This subunit includes Altamont clay soils within the terrace escarpments on the west side of Temescal Wash. This physiographic setting containing the substrate components (Altamont clay soils) and suitable conditions (vegetation and microhabitat) (PCE 1) for the growth of
Allium munzii
provides the physical or biological features essential to the conservation of this species.

Subunit 2C: Alberhill Mountain

The Alberhill Mountain subunit is 300.5 ac (121.6 ha) of private land.
Allium munzii
occurs on clay soils in coastal sage scrub vegetation on the south slope directly adjacent to open pit clay mines (CNDDB 2011a, EO 6). Extensive mining of clay in the early 1980s resulted in the loss of two locations of plants (CNDDB 2011a), and Boyd (Boyd 1988, p. 2) speculated that the plant population in this area was once much larger. Surveys conducted by Western Riverside County RCA in 2008 recorded 9 localities ranging from 10 to 150 plants (Drennen 2011, pers. comm.). Threats to this subunit include a planned electrical subtransmission line and related infrastructure (power poles, equipment, construction impacts) (State of California Public Utilities Commission 2010). Potential impacts will vary depending on the exact route selected (AMEC Earth and Environmental Inc. 2006a, p. 2).

This subunit contains Altamont clay soils (PCE 1) necessary for the growth of
Allium munzii.
The minerals and unique properties of this clay soil provide the physical or biological features essential to the conservation of the species.

Although this subunit was not known to be occupied at the time of listing in 1998, we believe it was occupied in 1998 because, as discussed in Background section, it takes at least 3 years after seed germination for this bulb-forming plant to produce flowers (Wall 2012, pers. comm.). This location was surveyed specifically for
A. munzii
by a qualified botanist in April 1999, less than 1 year after listing; 12 flowering plants were found in 2 locations (Greene 1999, pers. comm.); thus, based on its biology (growth timeframe) as described above, plants would have been present in 1998. Additionally, as discussed in the Background section,
Allium munzii
is often difficult to observe in the field (e.g., plants are dormant from mid-summer through autumn) and is easily overlooked without site-specific surveys during ideal conditions for its life history.

Subunit 2D: Alberhill Creek

The Alberhill Creek (Alberhill Marsh) subunit (155.3 ac (62.8 ha)) is located on private land in a grassland (native and nonnative) community on a low hill adjacent to a channel of the Temescal Wash (CNDDB 2011a, EO 18). The CNDDB EO was discovered on clay soils in 2000; however, we believe it was occupied at the ti

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2012-8664. Public record. Not legal advice.