[Federal Register Volume 59, Number 180 (Monday, September 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-23156]


[[Page Unknown]]

[Federal Register: September 19, 1994]


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Part V





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17




Endangered and Threatened Wildlife and Plants; Determination of 
Endangered Status and Withdrawal of Proposal to Give Endangered Status; 
Final Rule and Proposed Rule
DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AB75

 
Endangered and Threatened Wildlife and Plants; Determination of 
Endangered Status for the Conservancy Fairy Shrimp, Longhorn Fairy 
Shrimp, and the Vernal Pool Tadpole Shrimp; and Threatened Status for 
the Vernal Pool Fairy Shrimp

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: The U.S. Fish and Wildlife Service (Service) determines 
endangered status pursuant to the Endangered Species Act of 1973, as 
amended (Act) for the Conservancy fairy shrimp (Branchinecta 
conservatio), longhorn fairy shrimp (Branchinecta longiantenna), and 
the vernal pool tadpole shrimp (Lepidurus packardi); and threatened 
status for the vernal pool fairy shrimp (Branchinecta lynchi). These 
four invertebrate species are restricted to vernal pools in the State 
of California and are in danger of extinction principally as the result 
of urban development, conversion of native habitats to agriculture, and 
stochastic (random) extinction by virtue of the small isolated nature 
of many of the remaining populations. This rule implements Federal 
protection and recovery provisions afforded by the Act for all of these 
animals.
    One species, the California linderiella (Linderiella occidentalis), 
which had been proposed for listing with the above species, has been 
withdrawn. Additional information that has become available to the 
Service since the publication of the proposed rule reveals that this 
species is more abundant than previously known. The Service has 
considered the additional information and has determined that the 
California linderiella is not likely to become either endangered or 
threatened throughout all or a significant portion of its range in the 
foreseeable future, and it does not qualify for listing under the Act. 
A notice withdrawing the proposal is published in the Federal Register 
concurrently with this final rule.

EFFECTIVE DATE: September 19, 1994.

ADDRESSES: The complete file for this final rule is available for 
public inspection, by appointment, during normal business hours at the 
Sacramento Field Office, U.S. Fish and Wildlife Service, 2800 Cottage 
Way Room E-1823, Sacramento, California 95825-1846.

FOR FURTHER INFORMATION CONTACT:
Chris Nagano or Jim Browning at the above address or by telephone (916/
978-4866).

SUPPLEMENTARY INFORMATION:

Background

    The Conservancy fairy shrimp, longhorn fairy shrimp, and the vernal 
pool fairy shrimp are members of the aquatic crustacean order 
Anostraca. The vernal pool tadpole shrimp is a member of the aquatic 
crustacean order Notostraca. They are endemic to vernal pools in the 
Central Valley, coast ranges, and a limited number of sites in the 
Transverse Range and Santa Rosa Plateau of California.
    The three fairy shrimp and the vernal pool tadpole shrimp live in 
vernal pools, an ephemeral freshwater habitat. None are known to occur 
in riverine waters, marine waters, or other permanent bodies of water. 
They are ecologically dependent on seasonal fluctuations in their 
habitat, such as absence or presence of water during specific times of 
the year, duration of inundation, and other environmental factors that 
include specific salinity, conductivity, dissolved solids, and pH 
levels. Water chemistry is one of the most important factors in 
determining the distribution of fairy shrimp and tadpole shrimp (Belk 
1977; Jamie King, University of California, in litt., 1992; Marie 
Simovich, University of San Diego, in litt., 1992). The four species 
included in this final rule are sporadic in their distribution, often 
inhabiting only one or a few pools in otherwise more widespread vernal 
pool complexes (Larry Eng, California Department of Fish and Game, 
pers. comm., 1990; Jamie King, in litt., 1992; Marie Simovich, in 
litt., 1992; Richard Brusca, San Diego Museum of Natural History, pers. 
comm., 1992).
    Fairy shrimp have delicate elongate bodies, large stalked compound 
eyes, no carapace, and 11 pairs of swimming legs. They swim or glide 
gracefully upside down by means of complex beating movements of the 
legs that pass in a wave-like anterior to posterior direction. Nearly 
all fairy shrimp feed on algae, bacteria, protozoa, rotifers, and bits 
of detritus (Pennak 1989). The second pair of antennae in the adult 
females are cylindrical and elongate, but in the males are greatly 
enlarged and specialized for clasping the females during copulation. 
The females carry the eggs in an oval or elongate ventral brood sac. 
The eggs are either dropped to the pool bottom or remain in the brood 
sac until the female dies and sinks. The ``resting'' or ``summer'' eggs 
are capable of withstanding heat, cold, and prolonged desiccation. When 
the pools refill in the same or subsequent seasons some, but not all, 
of the eggs may hatch. The egg bank in the soil may be comprised of the 
eggs from several years of breeding (Donald 1983). The eggs hatch when 
the vernal pools fill with rainwater. The early stages of the fairy 
shrimp develop rapidly into adults. These non-dormant populations often 
disappear early in the season long before the vernal pools dry up.
    Tadpole shrimp have dorsal compound eyes, a large shield-like 
carapace that covers most of the body, and a pair of long cercopods at 
the end of the last abdominal segment (Brusca and Brusca 1991; Pennak 
1989; Linder 1952; Longhurst 1955a; Lynch 1966, 1972). They are 
primarily benthic animals that swim with their legs down. Tadpole 
shrimp climb or scramble over objects, as well as plow along in bottom 
sediments. Their diet consists of organic detritus and living 
organisms, such as fairy shrimp and other invertebrates (Pennak 1989; 
Fryer 1987). Mating in tadpole shrimp is described by Longhurst 
(1955b). The females deposit their eggs on vegetation and other objects 
on the bottom. Vernal pool tadpole shrimp populations pass the dry 
summer months as diapaused eggs in pool sediments. Some of the eggs 
hatch as the vernal pools are filled with rainwater in the fall and 
winter of subsequent seasons.
    Vernal pools have a discontinuance occurrence in several regions of 
California. Generally vernal pool habitat is found west of the Sierra 
Nevada and extends from southern Oregon into northern Baja, California 
(Holland and Jain 1977, 1988). Vernal pools form in regions with 
Mediterranean climates where shallow depressions fill with water during 
fall and winter rains and then evaporate in the spring (Collie and 
Lathrop 1976; Holland 1976, 1978; Holland and Jain 1977, 1988; Norwick 
1992; Thorne 1984). Overbank flooding from intermittent streams may 
augment the amount of water in some vernal pools (Hanes et al. 1990). 
Downward percolation is prevented by the presence of an impervious 
subsurface layer, such as a claypan, hardpan, or volcanic stratum 
(Holland 1976, 1988). Due to local topography and geology, the pools 
are usually clustered into pool complexes (Holland and Jain 1988). 
Pools within a complex typically are separated by distances on the 
order of meters and may form dense, interconnected mosaics of small 
pools or a more sparse scattering of larger pools. Temporary inundation 
makes vernal pools too wet during the wetted period for adjacent upland 
plant species adapted to drier soil conditions, while rapid drying 
during late spring makes pool basins unsuitable for typical marsh or 
aquatic species that require a more permanent source of water. However, 
many indigenous plant and aquatic invertebrate species have evolved to 
occupy the extreme environmental conditions found in vernal pool 
habitats. Fairy shrimp and tadpole shrimp play an important role in the 
community ecology of many ephemeral water bodies (R. Brusca, pers. 
comm., 1992; Loring et al. 1988). They are fed upon by waterfowl (Ahl 
1991; Driver 1981; Krapu 1974; Swanson et al. 1974) and other 
vertebrates, such as western spadefoot toad (Scaphiopus hammondi) 
tadpoles (M. Simovich, pers. comm., 1991).
    The genetic characteristics of the three fairy shrimp and the 
vernal pool tadpole shrimp, as well as ecological conditions, such as 
watershed contiguity, indicate that populations of these animals are 
defined by pool complexes rather than by individual vernal pools 
(Fugate 1992; J. King, unpubl. data). Therefore, the most accurate 
indication of the distribution and abundance of the four vernal pool 
crustaceans is the number of inhabited vernal pool complexes. 
Individual vernal pools occupied by the four species listed herein are 
most appropriately referred to as subpopulations.
    Urban, water, flood control, highway, and utility projects, as well 
as conversion of wildlands to agricultural use, have eliminated vernal 
pools in southern California (Riverside and San Diego Counties), the 
Central Valley, and San Francisco Bay area (Jones and Stokes Associates 
1987). Changes in hydrologic pattern, overgrazing, and off-road vehicle 
use also imperil this aquatic habitat and the four species listed 
herein. Human activities that alter the watershed of vernal pools 
indirectly affect these animals. The flora and fauna in vernal pools or 
swales can change if the hydrologic regime is altered (Bauder 1986, 
1987). Anthropogenic activities that reduce the extent of the watershed 
or that alter runoff patterns (i.e., amounts and seasonal distribution) 
may eliminate the animals, reduce their population sizes or 
reproductive success, or shift the location of sites inhabited by these 
animals.
    According to Holland (1978), there were an estimated 1.7 million 
hectares (4.2 million acres) in the Central Valley that possibly 
supported vernal pools at the time Europeans arrived in California. 
Holland estimated that between 67 and 88 percent of this acreage was 
destroyed by 1973, largely by human activities (Holland 1978). However, 
both the acreage of historic vernal pool habitat and estimates of loss 
determined in this study have been disputed by others. Vernal pools in 
southern California have been highly impacted by human activities 
(Zedler 1987). The rate of loss of vernal pool habitat in parts of 
California has been estimated to occur at approximately 2 or 3 percent 
per year (Holland 1988).

Discussion of the Four Species

    The Conservancy fairy shrimp (Branchinecta conservatio), a member 
of the family Branchinetidae, was described from specimens collected at 
the Jepson Prairie Preserve, located in the Central Valley east of 
Travis Air Force Base in Solano County (Eng et al. 1990). The animal 
ranges in size from 14 to 27 millimeters (0.6 to 1.1 inches) long and 
is most similar in appearance to Lindahl's fairy shrimp (Branchinecta 
lindahli). However, the female brood pouch is fusiform and usually ends 
under abdominal segment 8 in the Conservancy fairy shrimp, whereas the 
pouch is cylindrical and usually ends under segment 4 in Lindahl's 
fairy shrimp. The large, oval pulvillus at the proximal end of the 
basal segment of the male antenna appears similar in both species, 
however, the terminal end of the distal antennal segments of the 
Conservancy fairy shrimp are distinctive (Eng et al. 1990).
    The Conservancy fairy shrimp inhabits vernal pools with highly 
turbid water. The species is known from six disjunct populations: Vina 
Plains, Tehama County; south of Chico, Tehama County; Jepson Prairie, 
Solano County; Sacramento National Wildlife Refuge, Glenn County (Joe 
Silviera, U.S. Fish and Wildlife Service, pers. comm., 1993), near 
Haystack Mountain northeast of Merced in Merced County; and the 
Lockewood Valley of northern Ventura County (Michael Fugate, University 
of California at Riverside, pers. comm., 1991). The pools inhabited by 
the Conservancy fairy shrimp are large, such as the 36 hectare (89 
acre) Olcott Lake at Jepson Prairie (Eng, pers. comm., 1990). The 
Conservancy fairy shrimp has been observed from November to early 
April. The pools at Jepson Prairie and Vina Plains inhabited by this 
animal have very low conductivity, total dissolved solids (TDS), and 
alkalinity (Barclay and Knight 1984; Eng et al. 1990). The Conservancy 
fairy shrimp is usually collected at cool temperatures and appears to 
be relatively long-lived (Simovich et al. 1992; Patton 1984).
    The longhorn fairy shrimp (Branchinecta longiantenna), a member of 
the family Branchinectidae, was described from specimens collected at 
Souza Ranch in the Kellogg Creek watershed, about 35 kilometers (22 
miles) southeast of the City of Concord, Contra Costa County (Eng et 
al. 1990). It ranges in size from 12.1 to 20.8 mm (0.5 to 0.8 inches). 
This species differs from other branchinectids in that a portion of the 
distal segment of its antennae is flattened in the antero-posterior 
plane rather than the latero-medial plane.
    The longhorn fairy shrimp inhabits clear to turbid grass-bottomed 
vernal pools in grasslands and clear-water pools in sandstone 
depressions. This species is known only from four disjunct populations 
along the eastern margin of the central coast range from Concord, 
Contra Costa County south to Soda Lake in San Luis Obispo County: the 
Kellogg Creek watershed, the Altamont Pass area, the western and 
northern boundaries of Soda Lake on the Carrizo Plain (Eng et al. 
1990), and Kesterson National Wildlife Refuge in the Central Valley 
(Dennis Woolington, U.S. Fish and Wildlife Service, in litt. 1993). All 
vernal pools inhabited by this species are filled by winter and spring 
rains and may remain inundated until June. The longhorn fairy shrimp 
has been observed from late December until late April. The water is 
grassland pools inhabited by this species has very low conductivity, 
TDS, and alkalinity (Eng et al. 1990).
    The vernal pool fairy shrimp (Branchinecta lynchi), a member of the 
family Branchinectidae, was described from specimens collected at Souza 
Ranch in the Kellogg Creek watershed, Contra Costa County, California 
(Eng et al. 1990). It ranges in size from 10.9 to 25.0 mm (0.4 to 1.0 
inches). This species most resembles the Colorado fairy shrimp 
(Branchinecta coloradensis). There are several differences in the 
antennae of the males of the two species, including the basal segment 
outgrowth below and posterior to the pulvillus, which is ridge-like in 
the vernal pool fairy shrimp but is cylindrical and often much larger 
in the Colorado fairy shrimp. The shorter brood pouch of the vernal 
pool fairy shrimp is pyriform, whereas the longer one in the Colorado 
fairy shrimp is fusiform (Eng et al. 1990).
    Although the vernal pool fairy shrimp has a relatively wide range, 
the majority of known populations inhabit vernal pools with clear to 
tea-colored water, most commonly in grass or mud bottomed swales, or 
basalt flow depression pools in unplowed grasslands, but one population 
occurs in sandstone rock outcrops and another population in alkaline 
vernal pools. The vernal pool fairy shrimp has been collected from 
early December to early May. The water in pools inhabited by this 
species has low TDS, conductivity, alkalinity, and chloride (Collie and 
Lathrop 1976). This species has a sporadic distribution within vernal 
pool complexes (Jones and Stokes, 1992, 1993; County of Sacramento 
1990; Patton 1984; Stromberg 1993; Sugnet and Associates 1993b) wherein 
the majority of pools in a given complex typically are not inhabited by 
the species. Simovich et al. (1992) reported that the vernal pool fairy 
shrimp typically is found at low population densities. Only rarely does 
the vernal pool fairy shrimp co-occur with other fairy shrimp species, 
but where it does, the vernal pool fairy shrimp is never the 
numerically dominant one (Eng et al. 1990). Although it can mature 
quickly, allowing populations to persist in short-lived shallow pools, 
it also persists later into the spring where pools are longer lasting 
(Simovich et al. 1992). Sugnet and Associates (1993b) listed 178 
records for the species out of 3092 ``discrete locations'' containing 
potential habitat in their report. These 178 records represent the 32 
known populations of the vernal pool fairy shrimp, which extend from 
Stillwater Plain in Shasta County through most of the length of the 
Central Valley to Pixley in Tulare County, and along the central coast 
range from northern Solano County to Pinnacles in San Benito County 
(Eng et al. 1990; M. Fugate, pers. comm., 1991; Sugnet & Associates 
1993b). Five of these populations are believed to be comprised of a 
single inhabited pool. Four additional, disjunct populations exist; one 
near Soda Lake in San Luis Obispo County, one in the mountain 
grasslands of northern Santa Barbara County, one near the Santa Rosa 
Plateau in Riverside County, and one near Rancho California in 
Riverside County. Three of these four isolated populations contain only 
a single known pool occupied by the vernal pool fairy shrimp.
    The vernal pool tadpole shrimp (Lepidurus packardi), a member of 
the family Triopsidae, was described by Eugene Simon in 1866 (Longhurst 
1955a). Longhurst (1955a) placed the name in synonymy with Lepidurus 
apus. Subsequently, Lynch (1972) examined the taxa and determined that 
Lepidurus packardi is a valid species. The Service accepts Lynch's 
taxonomic treatment of the genus Lepidurus, which maintains L. packardi 
as a species.
    Vernal pool tadpole shrimp adults reach a length of 50 millimeters 
(2 inches). They have about 35 pairs of legs and two long cercopods. 
This species superficially resembles the ricefield tadpole shrimp 
(Triops longicaudatus). However, Lepidurus possess a flat paddle-shaped 
supra-anal plate that is entirely lacking in members of the genus 
Triops (Pennak 1989; R. Brusca in litt., 1992; M. Simovich in litt., 
1992; J. King in litt., 1992). The vernal pool tadpole shrimp is known 
from 18 populations in the Central Valley, ranging from east of Redding 
in Shasta County south through the Central Valley to the San Luis 
National Wildlife Refuge in Merced County, and from a single vernal 
pool complex located on the San Francisco Bay National Wildlife Refuge 
in the City of Fremont, Alameda County.
    The vernal pool tadpole shrimp inhabits vernal pools containing 
clear to highly turbid water, ranging in size from 5 square meters (54 
square feet) in the Mather Air Force Base area of Sacramento County, to 
the 36 hectare (89 acre) Olcott Lake at Jepson Prairie. The pools at 
Jepson Prairie and Vina Plains have a very low conductivity, TDS, and 
alkalinity (Barclay and Knight 1984; Eng et al. 1990). These pools are 
located most commonly in grass bottomed swales of grasslands in old 
alluvial soils underlain by hardpan or in mud-bottomed pools containing 
highly turbid water.
    The life history of the vernal pool tadpole shrimp is linked to the 
phenology of the vernal pool habitat. After winter rainwater fills the 
pools, the populations are reestablished from diapaused eggs that lie 
dormant in the dry pool sediments (Ahl 1991; Lanway 1974). Ahl (1991) 
found that eggs in one pool hatched within three weeks of inundation 
and maturated to sexually reproductive adults in another three to four 
weeks. Simovich et al. (1992) reported sexually mature adults occurred 
in another pool three to four weeks after the pools had been filled. A 
female surviving to large size may lay up to six clutches of eggs, 
totaling about 861 eggs in her lifetime (Ahl 1991). The eggs are sticky 
and readily adhere to plant matter and sediment particles (Simovich et 
al. 1992). A portion of the eggs hatch immediately and the rest enter 
diapause and remain in the soil to hatch during later rainy seasons 
(Ahl 1991). The vernal pool tadpole shrimp matures slowly and is a 
long-lived species (Ahl 1991; Alexander 1976). Adults are often present 
and reproductive until the pools dry up in the spring (Ahl 1991; 
Simovich et al. 1992).

Previous Federal Actions

    Ms. Roxanne Bittman petitioned the Service to list the Conservancy 
fairy shrimp, longhorn fairy shrimp, vernal pool fairy shrimp, and 
California linderiella as endangered species in a letter dated November 
19, 1990, which was received by the Service on November 20, 1990. Ms. 
Bittman submitted additional information on these species in a letter 
dated November 20, 1990, which was received on November 26, 1990. On 
March 21, 1991, the Service made a 90-day finding that the petition 
contained substantial information indicating that the action requested 
may be warranted. A notice announcing this finding was published in the 
Federal Register on August 30, 1991 (56 FR 426968).
    Ms. Dee Warenycia petitioned the Service to list the vernal pool 
tadpole shrimp as an endangered species in a letter dated April 28, 
1991, which was received by the Service on April 30, 1991. On November 
21, 1991, the Service determined in the administrative 90-day finding 
that the petition contained substantial information that the action 
requested may be warranted. On May 8, 1992, the Service published a 
proposed rule in the Federal Register (57 FR 19856) to list the four 
fairy shrimp and vernal pool tadpole shrimp as endangered.

Summary of Comments and Recommendations

    In the May 8, 1992, proposed rule (57 FR 19856) and associated 
notifications, all interested parties were requested to submit factual 
reports or information that might assist the Service in determining 
whether these taxa warrant listing. Appropriate State agencies, county 
governments, including affected planning departments, Federal agencies, 
scientific organizations, and other interested parties were contacted 
and requested to comment. Notices of this proposal were published in 
the Santa Rosa Press Democrat, San Francisco Chronicle, Monterey 
Herald, Chico Enterprise Record, San Luis Obispo Telegram-Tribune, 
Santa Barbara News-Press, Modesto Bee, Sacramento Bee, and the Fresno 
Bee on June 5, 1992.
    On June 4, 1992, the Service received a written request for a 
public hearing from Mr. George Robson of the Tehama County Planning 
Department. Several other requests for a public hearing also were 
received. As a result, on August 13, 1992, the Service published a 
notice in the Federal Register (57 FR 36380) announcing the public 
hearing and reopening the comment period until September 18, 1992. The 
Service conducted a public hearing on August 31, 1992, at the Radisson 
Hotel in Sacramento, California. Testimony was taken from 6 p.m. to 8 
p.m. Twenty-one persons presented testimony.
    On September 18, 1992, the Service attended a public meeting held 
at the Red Bluff Community Center in Red Bluff, Tehama County, 
California. Six people presented oral and written comments to the 
Service.
    During the comment periods, the Service received 117 comments 
(letters and oral testimony). Several people submitted more than one 
comment to the Service. The Service received two petitions containing 
63 signatures of people supporting the listing and one petition 
containing 190 signatures of people opposed to the listing. The 
California Department of Parks and Recreation supported a listing of 
threatened for the four fairy shrimp but did not state a position on 
the vernal pool tadpole shrimp. The California Department of Fish and 
Game expressed concern for the fairy shrimp and also did not state a 
position on the vernal pool tadpole shrimp. Comments supporting the 
listing were received from 41 private parties, including the Riverside 
County Planning Department, and nine professional biologists from 
several institutions, including the Stanford University Center for 
Conservation Biology, University of California, University of San 
Diego, and San Diego Museum of Natural History. Comments opposing the 
listing were received from 34 private parties, organizations, and 
agencies including seven mosquito abatement districts. Opposition to 
the listing also was expressed by Congressman Wally Herger and 
Congressman Vic Fazio. Four commenters did not express an opinion.
    In addition, after the comment period closed, six parties, 
including the California Department of Fish and Game, requested that 
the Service extend the date of the final determination for the five 
species by six months pursuant to 16 U.S.C. 1533(b)(6). The Act 
provides for a six-month extension if the Secretary finds that ``* * * 
there is substantial disagreement regarding the sufficiency or accuracy 
of the available data relevant to the determination * * * for the 
purposes of soliciting additional data.'' One of these commenters 
submitted a report that summarized collection records and field work 
conducted in 1993 (Sugnet and Associates 1993b). The California 
Department of Fish and Game supported the extension but stated that 
they had no additional information. The California Native Plant Society 
opposed the six-month extension and urged the Service to immediately 
list the five species under the Act.
    The Service has reviewed all of the written and oral comments 
described above. Comments updating the data presented in the 
``Background'' or ``Summary of Factors Affecting the Species'' are 
incorporated in those sections of this final rule. Opposing comments 
and other comments concerning the rule have been organized into 
specific issues. These issues and the Service's response to each are 
summarized as follows:
    Issue 1: A number of commenters stated that a single public hearing 
was inadequate to obtain full public input on the proposal. They 
requested that public hearings be held in all of the towns and counties 
that contain vernal pools and swales inhabited by the five species.
    Service Response: The Service is obligated to hold one public 
hearing on a listing proposal if requested to do so within 45 days of 
publication of the proposal (16 U.S.C. 1533(b)(5)(E)). In addition to 
the public hearing held on August 31, 1992, the Service attended a 
public meeting organized by Congressman Vic Fazio in Red Bluff, on 
September 18, 1992. The public comment period was extended to September 
8, 1992, to allow all interested parties to provide written comments. 
In making a decision on a listing proposal, written comments are given 
the same weight as oral comments presented at hearings.
    Issue 2: Several respondents stated that the Service's notification 
of the public on this proposal was inadequate.
    Service Response: The Service went through an extensive 
notification process to make the public aware of this proposal; this 
process satisfied the requirements of the Act and is described at the 
beginning of this section.
    Issue 3: Many respondents concluded that listing the fairy shrimp 
and the vernal pool tadpole shrimp would result in adverse economic 
impacts to thousands of hectares of land and questioned the value of 
these animals to society. Two commenters requested that an analysis of 
the economic impact of listing these species be completed. Two 
commenters noted that these species are restricted to vernal pools but 
stated that listing would result in adverse economic impacts by 
eliminating future residential or commercial development in areas 
containing this habitat. Five commenters claimed the fairy shrimp and 
the vernal pool tadpole shrimp are ``insignificant'' species and that 
listing would interfere with the natural evolutionary process of 
extinction. On the other hand, a number of respondents asserted that 
opposition to the listing of the species was based solely on economic 
interests. They cited the ecological and educational value of vernal 
pool plants and animals. Four crustacean biologists noted the species 
can be considered ``living fossils'' and are of great scientific value 
to the study of biological evolution, systematics, and ecology.
    Service Response: Under section 4(b)(1)(A) of the Act, a listing 
determination must be based solely on the best scientific and 
commercial data available. The legislative history of this provision 
clearly states the intent of Congress to ``ensure'' that listing 
decisions are ``based solely on biological criteria and to prevent non-
biological criteria from effecting such decisions'' H.R. Rep. No. 97-
835, 97th Cong. 2d Sess. 19 (1982). As further stated in the 
legislative history, ``economic considerations have no relevance to 
determinations regarding the status of species.'' Because the Service 
is specifically precluded from considering economic impacts in a final 
decision on a proposed listing, the Service has not considered possible 
economic consequences of listing the three fairy shrimp and the vernal 
pool tadpole shrimp. There may be many opinions as to a particular 
species' contribution to society, including their aesthetic, 
scientific, or other significance, however, this contribution is not 
among the five factors upon which a listing determination is based.
    Issue 4: One commenter recommended that the Service prepare an 
Environmental Impact Statement (EIS), pursuant to the National 
Environmental Policy Act (NEPA), on this rule. He stated that a 
decision to list these five crustaceans is a major Federal action that 
significantly affects the quality of the human environment.
    Service Response: For the reasons set out in the NEPA section of 
this document, the Service takes the position that rules issued 
pursuant to section 4(a) of the Act do not require the preparation of 
an EIS. The courts held in Pacific Legal Foundation v. Andrus, 657 F2d. 
829 (6th Circuit 1981) that an EIS is not required for listing under 
the Act. The decision noted that preparing EIS's on listing actions 
does not further the goals of NEPA or the Act.
    Issue 5: One commenter requested that the Service conduct a Takings 
Implications Assessment under Executive Order 12630 for this listing 
action.
    Service Response: The Attorney General has issued guidelines to the 
Department of the Interior (Department) regarding implementation of 
Executive Order 12630.
    The Attorney General's guidelines state that Taking Implications 
Assessments (TIAs), which are used to analyze the potential for Fifth 
Amendment taking claims are to be prepared after, rather than before, 
an agency makes a decision upon which its discretion is restricted. In 
enacting the Endangered Species Act, Congress required the Department 
to list a species based solely upon scientific and commercial data 
indicating whether or not the species is in danger of extinction. No 
discretion is afforded and the Service may not withhold a listing based 
upon economic concerns. Therefore, even though a TIA is required, a TIA 
for a listing action is to be finalized only after the final decision 
whether to list a species is made.
    Issue 6: The California Department of parks and Recreation 
recommended that the four fairy shrimp should be listed as threatened 
species rather than endangered species.
    Service Response: The Service has determined that threatened status 
is appropriate for the vernal pool fairy shrimp. The proposal to list 
the California linderiella as an endangered species has been withdrawn. 
The rationale for these actions and endangered status for the two other 
fairy shrimp species and the vernal pool tadpole shrimp is described at 
the conclusion of the ``Summary of Factors Affecting the Species'' 
section.
    Issue 7: Several commenters expressed concern that it will be 
difficult or impossible to delist any or all of the crustaceans listed 
herein.
    Service Response: When the recovery goals for a species have been 
met, the Service may prepare a proposal to delist or reclassify it. The 
process for delisting or reclassifying a species, allowed for at 
section 4(b)(3)(A) of the Act, is the same process used for listing the 
species.
    Issue 8: Three respondents stated that compared to other federally 
listed crustaceans, the fairy shrimp and the vernal pool tadpole shrimp 
do not warrant listing under the Act.
    Service Response: The claim that the status of the fairy shrimp and 
the vernal pool tadpole shrimp do not warrant listing under the Act 
when compared with other listed crustaceans does not address the full 
range of issues and complexities bearing on listing decisions. The 
multiplicity of factors and relationships that must be considered and 
interpreted in assigning the appropriate status to listed taxa is 
sufficiently complex that patterns of consistency may not be 
necessarily agreed upon by all parties.
    Issue 9: Several respondents stated that critical habitat should be 
designated for the fairy shrimp and the vernal pool tadpole shrimp.
    Service Response: The Service believes that the danger posed by 
designating critical habitat at this time outweighs the potential 
benefits. As discussed in Factors ``A'' and ``E'' under the ``Summary 
of Factors Affecting the Species'' section below, all of the species 
included in this final rule could be adversely affected by acts of 
vandalism. The Service is aware of vernal pools that contained suitable 
habitat for these animals that apparently were destroyed to escape 
regulatory requirements. Designation of critical habitat at this time 
would increase the degree of threat facing these species.
    Issue 10: One commenter stated that there is not enough data on the 
species listed herein upon which to develop a recovery plan.
    Service Response: Section 4(f) of the Act directs the Secretary to 
develop and implement recovery plans for conservation and survival of 
listed endangered and threatened species. The Service intends to pursue 
the development of a recovery plan for the four species as soon as 
possible. Identification of needed research and acquisition of 
additional data are key components of most recovery plans.
    Issue 11: Several commenters stated that the California linderiella 
and the vernal pool fairy shrimp do not warrant listing because of 
their widespread distribution.
    Service Response: Species may be listed under the Act if one or 
more of the five listing criteria imperils the species with extinction 
or if the species is likely to become endangered in the foreseeable 
future, throughout all or a significant portion of its range. These 
criteria apply for narrowly, as well as widely distributed species. As 
described elsewhere in this final rule, the vernal pool fairy shrimp is 
imperiled by habitat loss from construction activities and degradation 
to the extent that 28 of the 32 known populations face one or more of 
the various threats described elsewhere in this rule. Thus, even though 
this species has a relatively wide range in California, it is imperiled 
by one or more of five factors throughout a significant portion of its 
range.
    At the time the proposed rule was published, the California 
linderiella was known from vernal pools in the Central Valley from 
central Tehama County to central Madera County and across the valley in 
the Sacramento area to the central and south coast mountains from Lake 
County south to Riverside County. Surveys conducted in 1993 and other 
information that has become available to the Service indicate that the 
range extends from Shasta County south to Fresno County and across the 
valley to the Coast and Transverse Ranges from Willits in Mendocino 
County south to near Sulfur Mountain in Ventura County. Within this 
area more vernal pools have been found to contain subpopulations of the 
California linderiella than was known at the time of the proposed rule. 
The populations in Riverside County have been determined to represent 
an undescribed species of Linderiella. The Service has carefully 
considered the additional information and has determined that the 
California linderiella fails to meet the definition of either an 
endangered or threatened species and has withdrawn it from 
consideration for endangered or threatened status.
    Issue 12: After the comment period closed, six parties requested 
that the Service extend the date of the final determination for these 
species pursuant to 16 U.S.C. 1533(b)(6). That section of the Act 
provides for a six-month extension to solicit additional data if the 
Secretary finds that ``there is substantial disagreement regarding the 
sufficiency or accuracy of the available data relevant to the 
determination.'' The parties asserted that additional information on 
the range and status of these animals could become available during 
this time period. One of these commenters submitted a report as the 
basis for their request that summarized museum, literature, and field 
records, the majority of which were collected in 1993, for the five 
species (Sugnet and Associates 1993b). A seventh party, the California 
Native Plant Society, stated that they were opposed to the six month 
extension and they urged the Service to immediately list the five 
species.
    Service Response: The report by Sugnet and Associates (1993b) 
provided a number of records for the California linderiella, vernal 
pool fairy shrimp, and the vernal pool tadpole shrimp that have been 
incorporated into this final rule. The report listed 3092 ``discrete 
locations'' that contained 703 records of the California linderiella, 
178 records of the vernal pool fairy shrimp, and 345 records of the 
vernal pool tadpole shrimp.
    The report by Sugnet and Associates (1993b) presented only township 
and range information on the locations of the California linderiella, 
vernal pool fairy shrimp, longhorn fairy shrimp, Conservancy fairy 
shrimp, and the vernal pool tadpole shrimp. A request by the California 
Department of Fish and Game to obtain the precise locations that served 
as the basis for the report was unsuccessful (letter from California 
Department of Fish and Game to Sugnet and Associates, dated December 
29, 1993; letter from Sugnet and Associates to California Department of 
Fish and Game, dated January 29, 1994). The report also treated the 
records of the individual vernal pools inhabited by the California 
linderiella, vernal pool fairy shrimp, and the vernal pool tadpole 
shrimp as ``discrete locations.'' However, as described in greater 
detail in the Background section, abundance of inhabited vernal pool 
complexes most appropriately describes the population status of the 
five vernal pool crustaceans; animals in individual pools most 
appropriately are referred to as subpopulations. Accordingly, the study 
by Sugnet and Associates (1993b) overestimated the number of 
populations of the California linderiella, vernal pool fairy shrimp, 
and the vernal pool tadpole shrimp. Statements in Sugnet and Associates 
(1993b), such as ``Results of this effort indicate that B. lynchi 
occurs at a total of 178 discrete locations * * *'', should be 
interpreted in light of the fact that a number of inhabited pools can 
occur within a single vernal pool complex, and that all of these could 
be threatened by a single project proposal. For example, the proposed 
Sunrise-Douglas development in Sacramento County contains over 500 
vernal pools (Sugnet and Associates 1993a). An unknown number of these 
pools contain the vernal pool fairy shrimp, and/or vernal pool tadpole 
shrimp.
    The data in Sugnet and Associates (1993b) and other information 
available to the Service increased the known ranges and number of 
populations from that described in the proposed rule for three of the 
five species and located additional populations for one species. The 
report identified a geographic range extension for the vernal pool 
tadpole shrimp and increased the number of populations from fourteen to 
seventeen; none were from unexpected areas or non-vernal pool habitat. 
Two additional populations of the Conservancy fairy shrimp were 
located, one at the Sacramento National Wildlife Refuge and one in 
northern Ventura County. The geographic distribution of the vernal pool 
fairy shrimp was not increased but additional pools containing this 
species were located within the known range and known populations of 
this animal.
    With the exception of the California linderiella, the Service 
concludes that the report by Sugnet and Associates (1993b) does not 
provide a basis for significant disagreement regarding the sufficiency 
or accuracy of the available data relevant to this listing action. 
Rather, the data presented in the report substantiates the rarity and 
fragmented distributions of the four species listed herein. Therefore, 
the Service has determined to issue a final regulation pursuant to 16 
U.S.C. 1533(b)(6)(i)(I).
    Issue 13: Many commenters, including the California Department of 
Transportation and Congressman Wally Herger, requested the Service 
delay or not list the five species because they believed additional 
distributional and ecological data are needed to determine the ``true'' 
status of these animals. Several people contended that the survey work 
and collection data upon which the proposed rule was based are 
inadequate. One commenter contended that this perceived lack of 
information would result in a procedurally inadequate listing. Eight 
commenters stated that the data utilized by the Service presents only 
collection places inhabited by the species. They asserted that the 
Service did not conduct a random field survey and failed to accurately 
delineate the distributions of the species. These parties contended 
that the absence of information on locations that are not inhabited by 
the animals suggests a general lack of extensive collection efforts or 
knowledge of them. To support the need for further field work, one 
commenter cited 18 records of the vernal pool fairy shrimp and 30 
records of the California linderiella that were not included in this 
proposed rule. This commenter did not provide any additional records of 
the Conservancy fairy shrimp, the longhorn fairy shrimp, or the vernal 
pool tadpole shrimp.
    Service Response: Scientifically credible data on the status of the 
five crustaceans was collected in a random 322 kilometer (200 mile) 
north-south transect in the Sacramento Valley from Fall River in Shasta 
County to Jepson Prairie in Solano County (Simovich et al. 1992). This 
study found that distinct segments totaling 35 kilometers (22 miles), 
or 11 percent of the transect, contain vernal pools and swales. Within 
the portions of the transect, the vernal pool tadpole shrimp and the 
vernal pool fairy shrimp were found on 16 kilometers (10 miles), the 
Conservancy fairy shrimp on 6 kilometers (4 miles), and the California 
linderiella on 10 kilometers (6 miles). The animals were not found in 
all pools and swales in suitable habitat areas in this study (J. King, 
in litt., 1992). King (in litt., 1992) reported that the vernal pool 
tadpole shrimp was found in only five pools on 8 kilometers (5 miles) 
of the 16 kilometers (10 miles) of vernal pools where the animal 
occurred, indicating a sparse distribution within much of the area 
where it occurs. The fairy shrimp species and the vernal pool tadpole 
shrimp largely were absent from extensive regions in the Sacramento 
Valley where degraded vernal pools still remain, such as the Red Bluff 
and Coyote Creek areas of Tehama County, and the Allendale area of 
Solano County (R. Brusca, in litt., 1992). The three crustacean 
biologists who conducted this research concluded that based on this 
random field survey, these fairy shrimp species and the vernal pool 
tadpole shrimp are rare throughout their ranges.
    A comparison of the maps in Sugnet and Associates (1993b) indicates 
that the number of occupied pools, and amount of suitable habitat for 
the 30 populations of the California linderiella are larger than for 
the 32 populations of the vernal pool fairy shrimp. In addition, the 
California linderiella is known from the north coast, San Francisco Bay 
area, western areas in the San Joaquin Valley, and the western 
foothills of the Sierra Nevada in San Joaquin and Stanislaus Counties 
where the vernal pool fairy shrimp is not known to be present (Sugnet 
and Associates 1993b).
    The Service concludes, as detailed in the ``Summary of Factors'' 
section, that there is sufficient biological evidence that the vernal 
pool fairy shrimp, Conservancy fairy shrimp, longhorn fairy shrimp, and 
the vernal pool tadpole shrimp warrant listing. Sampling conducted at 
various locations and intensities between 1981 and 1993 by biologists 
familiar with the four fairy shrimp and the vernal pool tadpole shrimp 
and their habitat provided adequate information on the distribution, 
habitat requirements, and most importantly, threats to the four species 
to warrant the present action. All additional data provided by 
respondents during the comment period, including the report by Sugnet & 
Associates (1993b) have been incorporated into this final rule; none of 
this data indicated that these taxa were not threatened or endangered. 
The Service's decision to propose the four fairy shrimp and the vernal 
pool tadpole shrimp was based on significant threats associated with 
habitat loss and fragmentation, rather than solely on the basis of 
population numbers.
    Issue 14: Several commenters, including Congressman Wally Herger, 
requested the precise locations of the populations of the species be 
widely disseminated or included in the final rule. One respondent 
requested that the Service notify all landowners whose property has 
been found to contain one or more of the species.
    Service Response: For the reasons discussed in the response dealing 
with critical habitat below, the Service concludes that providing the 
exact locations would increase the degree of threat facing these 
species.
    Issue 15: Some commenters were concerned that the Service did not 
give due consideration to the impacts of the six year drought in 
California. They contended that increased amounts of rainfall would 
result in greater numbers of the fairy shrimp and the vernal pool 
tadpole shrimp.
    Service Response: The average and above average rainfall levels 
that occurred in 1992/1993 did not reveal significant new populations 
of the five species in unexpected areas because most vernal pools held 
water, at least to some extent, during the drought that extended from 
1987 to 1992. Even very small, shallow vernal pools were observed to 
hold water, allowing reproduction of the four fairy shrimp and vernal 
pool tadpole shrimp during these drought years (J. King pers. comm. 
1992; M. Simovich pers. comm. 1992; Simovich et al. 1993). Also, 
natural vernal pool complexes are expected to have some pools that at 
least partially pond in drought years even though other pools may fill 
only during years of average or above average precipitation.
    Issue 16: Several commenters concluded that the data on the 
crustaceans does not demonstrate a historic and consistent decline in 
populations levels. One commenter stated that the data on the 
Conservancy fairy shrimp, longhorn fairy shrimp, and the vernal pool 
fairy shrimp is very limited because they were only recently described.
    Service Response: Relatively little information is available to 
reconstruct the distribution of the four species listed herein prior to 
the loss of vernal pool habitat that began in the late 1800's. However, 
the Service is required to evaluate species based on current and likely 
future threats to their status. As discussed in this final rule, 
numerous populations of the four species face severe, imminent threats 
that could result in substantial habitat losses and extirpations in the 
future. Since at least the mid-1980's, the human population has been 
growing rapidly throughout the Central Valley and other regions of 
California. Although three of the five crustaceans were described 
scientifically in 1990, their distribution and abundance are 
sufficiently documented relative to current and future threats to their 
continued existence. Field samples made from vernal pools have 
contained these three fairy shrimp prior to 1990. The earliest known 
collections of the Conservancy fairy shrimp were made in 1979, the 
vernal pool fairy shrimp in 1965, and the longhorn fairy shrimp in 
1937.
    Issue 17: The Contra Costa Water District reported that neither the 
Los Vaqueros Reservoir alternative nor the Kellogg Reservoir 
alternative would impact the single vernal pool complex inhabited by 
the vernal pool fairy shrimp within the watershed (John Gregg, Los 
Vaqueros Project, in litt., 1992).
    Service Response: The Los Vaqueros Reservoir project likely would 
result in adverse impacts to the California linderiella, vernal pool 
fairy shrimp, and the longhorn fairy shrimp based on an analysis of the 
environmental documents for this project (California Department of Fish 
and Game 1983; John Gregg, Los Vaqueros Project, in litt., 1992; Jones 
and Stokes 1986, 1989, 1990, 1991). On September 2, 1993, the Service 
issued a conference opinion to the Bureau of Reclamation for the 
effects of the Los Vaqueros Reservoir project on the three fairy shrimp 
species.
    Issue 18: One commenter stated that there are populations of the 
crustacean species located on nature preserves and for this reason the 
Service was urged to ``slow'' the listing process for these animals. 
Four people noted that portions of three preserves owned by the Nature 
Conservancy are inhabited by three of the fairy shrimp species and the 
vernal pool tadpole shrimp. One commenter concluded that this assured 
the long-term protection of these species. However, the other three 
commenters stated that the preserves were either not specifically 
managed for these animals or the sites are imperiled by activities on 
adjacent properties.
    Service Response: The Service recognizes that while some 
populations of the fairy shrimp and vernal pool tadpole shrimp are 
found on protected public and private lands, almost all are located in 
areas that are not secure against adverse impacts to these animals. 
Please refer to Factor D below, for an expanded discussion on 
landownership patterns and protection for these species.
    Issue 19: One commenter said the scientific articles containing 
data on the fairy shrimp that were used by the Service are ``primitive 
and unreliable'' and the taxonomy of these crustaceans is ``confused''. 
However, four recognized crustacean biologists noted that the taxonomy 
of fairy shrimp found in California had been reviewed recently in a 
peer-reviewed scientific journal and the taxonomic status of these 
species is widely accepted by current authorities.
    Service Response: Using the best and most recent systematic 
information from a number of reliable sources, including Eng et al. 
(1990), D. Belk (pers. comm., 192), and M. Fugate (pers. comm., 1992), 
the Service maintains that the Conservancy fairy shrimp, vernal pool 
fairy shrimp, and the longhorn fairy shrimp are valid species and no 
further taxonomic studies are needed.
    Issue 20: Several respondents, including Congressman Wally Herger 
contended that the vernal pool tadpole shrimp is a ``taxonomically 
unstable species''. One commenter stated that taxonomic confusion 
between Lemmon's tadpole shrimp (Lepidurus lemmoni) and the vernal pool 
tadpole shrimp should be resolved prior to any listing decision. 
Several commenters stated that the taxonomy of tadpole shrimps is 
unresolved and recommended that the Service not list the animal. 
Expressing a contrary position, three recognized authorities on 
crustaceans provided information showing the vernal pool tadpole shrimp 
is a biologically and taxonomically valid species. They reported that 
the vernal pool tadpole shrimp is distinct in both morphology and 
ecology from Lemmon's tadpole shrimp, which is restricted to alkaline 
lakes is western North America.
    Service Response: Using the best and most recent systematic 
information from a number of reliable sources, including Lynch (1972) 
and various crustacean biologists) (R. Brusca, in litt., 1992; M. 
Simovich, in litt., 1992; J. King, in litt,. 1992), the Service 
maintains that the vernal pool tadpole shrimp is a valid species and no 
further taxonomic studies are needed.
    Issue 21: Four respondents expressed concern that the Service was 
going to list the ricefield tadpole shrimp (Triops longicaudatus) a 
pest in rice fields in the Central Valley. They further stated that 
protection of this animal would be an ``economic disaster'' for rice 
growers of California. Alternatively, three recognized crustacean 
authorities provided information showing that the rice field tadpole 
shrimp is only distantly related to the vernal pool tadpool shrimp. 
They stated that T. longicaudatus is known to occur in the Central 
Valley only in rice fields while L. packardi is found only in vernal 
pools. One of the crustacean biologists stated that based on genetic 
studies, the two species are separated by genetic distances on the 
order of those normally found between crustacean orders (J. King, in 
litt., 1992). In addition, the four crustacean biologists noted that 
the two species are morphologically distinct and are easily 
distinguishable from each other.
    Service Response: The findings in this final rule reflect the 
published taxonomic literature and the expert opinion of recognized 
crustacean biologists.
    Issue 22: A number of commenters stated that Federal, State, and 
local regulatory processes provide adequate protection for the 
crustaceans. Two respondents said that listing would directly affect 
agriculture, industrial, and commercial development in areas that have 
been meticulously planned and subject to State laws such as the 
California Environmental Quality Act (CEQA) and California Subdivision 
Map Act. Some commenters noted the wetlands ``no-net-loss'' policies of 
several State and county agencies, while other cited section 404 of the 
Clean Water Act. On commenter analyzed data for a group of 29 
development projects in the Sacramento area and found that 56 percent 
of the vernal pools at these project sites had been preserved and 0.9 
hectare (2.2 acres) of vernal pools provided as mitigation for each 
acre impacted under Corps permit conditions pursuant to section 404 
requirements. The commenter stated that this group of projects is 
representative of the level of preservation afforded vernal pool 
habitat in the Sacramento area and further concluded that this level of 
protection may be equaled or exceeded for projects requiring section 
404 permits throughout the range of the five species. Another commenter 
noted that the Corps recently classified vernal pools at a proposed 
project site in Sacramento County as ``aquatic resources of national 
importance''. According to the commenter, this designation will cause 
the Corps to more closely evaluate impacts to vernal pools from 
proposed projects and thus provide significant protection to vernal 
pool habitat for the five crustacean species during a six-month time 
extension.
    Expressing a contrary position, several other commenters noted that 
Federal, State, and local laws have been ineffective in providing 
protection for these species. The Mount Lassen Chapter of the 
California Native Plant Society provided data on the destruction of two 
vernal pool complexes known to have been inhabited by the vernal pool 
tadpole shrimp in the City of Chico. They provided information on two 
other vernal pool complexes in Chico that are located on properties 
proposed for residential development. Another commenter stated that 
vernal pools in Santa Rosa have been eliminated despite the protective 
provisions of State law (CEQA). A number of respondents noted that 
destruction of vernal pools commonly is allowed if an attempt is made 
to create artificial habitat as compensation.
    Service Response: While vernal pool habitat has been preserved 
permanently under special conditions of section 404 permits for a 
number of projects, significant areas of vernal pool habitat continue 
to be lost in spite of the Corps jurisdictional authority to regulate 
these wetlands under the Clean Water Act. Since 1987, the Service has 
been tracking the Corps' implementation of Nationwide Permit 26 within 
the area of responsibility of the Service's Sacramento Field Office. A 
Service report produced in October 1992 showed that the Corps' 
Sacramento District authorized filling of 189 hectares (467 acres) of 
wetlands between 1987 and 1992 pursuant to Nationwide Permit 26 (U.S. 
Fish and Wildlife Service 1992). During this same time period, the 
Corps' San Francisco District authorized projects under Nationwide 
Permit 26 that filled a total of 104 hectares (257 acres) of wetlands 
of which 15.6 hectares (38.6 acres) were in the Santa Rosa Plain. The 
report notes that these figures are conservative estimates because 
notification of agencies for projects affecting less than 0.405 
hectares (1.0 acre) are not mandatory. The Service estimates that a 
majority of the wetland losses permitted in the Sacramento District 
constitute vernal pools. In addition, between December 1, 1992, and 
June 15, 1993, the Service identified 10 unauthorized projects in 
Sacramento and Butte Counties that destroyed or damaged between 8.5 and 
15 hectares (21 and 37 acres) of vernal pool habitat (D. Strait, pers. 
comm., 1993). The projects were not authorized because landowners 
either were not required or failed to comply with the regulatory 
requirements of the section 404 permitting process. In addition, gravel 
mines are proposed for significant areas in the Sacramento Valley, 
including an approximately 404 hectare (1,000 acres) site south of 
Mather Air Force Base that contains the California linderiella, vernal 
pool fairy shrimp, and the vernal pool tadpole shrimp. Under recent 
changes in the Corps of Engineers regulations, some gravel mining 
activities will be regulated. However, in the past, most of these 
activities were not subject to the provisions of the Clean Water Act.
    In December 1992, the Department of the Interior signed a revised 
Memorandum of Agreement with the Department of the Army that provides 
an administrative process for requesting higher level review of 
District Engineers' decisions on section 404 individual permit 
applications. One criterion necessary for higher level review under the 
Memorandum of Agreement is that the wetlands in question must 
constitute ``aquatic resources of national importance.'' The ultimate 
determination on whether the criterion is met will be made on a case-
by-case basis by the Assistant Secretary of the Army (Civil Works). 
Requests for higher level review only apply to projects subject to 
individual permits, not Nationwide permits. Projects determined by the 
Corp's Sacramento District to quality for authorization under 
Nationwide Permit 26 are not eligible for higher level review. 
Department of the Army concurrence with the designation of vernal pools 
at the project site at issue ``as aquatic resources of national 
importance'' does not ensure application of additional protection to 
vernal pools beyond that site (see discussion under Issue 29 and Factor 
D, ``Summary of Factors Affecting the Species'', for a complete 
discussion on the adequacy of existing regulatory mechanisms for the 
four species listed herein). Such a designation must be made on a site-
specific basis and, by itself, does not necessarily effect any 
protection of these resources. San Francisco District of the Corps 
considered possible revocation of Nationwide Permit 26 in the Santa 
Rosa Plain that would have ensured that all projects affecting wetlands 
in this area would require authorization on an individual permit basis 
and potential higher level review. However, the Corps decided instead 
to impose stricter conditions on the use of Nationwide Permit 26 in 
this area, including demonstration that no rare or endangered plant or 
animal species are supported on the wetlands within any proposed 
project site. The Corps also determined that individual permits would 
be required on wetlands that support federally proposed or listed 
threatened or endangered species. Regardless, of the four species 
listed herein, only the California linderiella is found at the Santa 
Rosa Plain and this area constitutes a small percentage of the overall 
geographical range of the species. Therefore, any additional protection 
afforded vernal pools in this area would not provide rangewide 
protection of these animals.
    Based on this and other information discussed under Factor D below, 
the Service concludes that proposed and on-going damage or destruction 
of vernal pools in California caused by urban and agricultural 
development is prevalent despite existing Federal, State, and local 
regulations and that existing levels of protection are not adequate to 
assure the survival of these species.
    Issue 23: One commenter completed a literature survey of three 
reports that addressed trends in overall wetland losses throughout 
California and the Central Valley, in particular. Essentially, this 
commenter concluded that the historic trend of wetland losses 
throughout California subsided in the mid-1980's and that current 
wetland acreages actually are increasing in the State, apparently as a 
result of the implementation of Federal wetland regulatory mechanisms.
    Service Response: Methodological flaws and ambiguities in the 
analysis conducted by this commenter invalidate the report's findings. 
The most serious flaw is the comparison of wetland acreages in various 
studies that focused on different geographic study areas. For example, 
the two Service reports reviewed by the commenter cannot be used 
together to draw conclusions on changes in wetland acreages because 
data from the Central Valley and the entire State are not comparable.
    Issue 24: Several commenters disputed the Service's statement in 
the proposed rule that 90 percent of the original vernal pool habitat 
throughout the Central Valley has been lost and that an estimated 2 to 
3 percent of vernal pool habitat continues to be lost annually. Several 
commenters contended that the study referenced by the Service actually 
showed a 67 to 88 percent historic loss of vernal pool acreage. One 
commenter further stated that additional interpretation and analysis of 
the data used in the study revealed that historic losses were 63 
percent. Based upon information contained in a separate document 
prepared by the Service, other commenters asserted that the actual loss 
more closely approximated 50 percent. After the comment period closed, 
one respondent commented that preliminary results from a newly-
initiated soils data analysis indicate that the original estimates of 
historic vernal pool losses in the Central Valley may be substantially 
less than was identified in the proposed rule. Another late commenter 
noted that U.S. Soil Conservation Service information supported recent 
conclusions drawn by other soil scientists that 404,700 hectares (1 
million acres) of soils suitable for vernal pool habitat remain from 
809,400 hectares (2 million acres) determined to have historically 
existed in the Central Valley, thus implying that historic losses were 
close to 50 percent.
    Service Response: After closer review of the referenced study 
(Holland 1978), the Service discovered apparent arithmetic errors in 
the estimates of historic vernal pool habitat (i.e., areas that could 
have supported pools) losses. Correction of these errors yields 
estimates of vernal pool habitat losses between 60 and 85 percent. 
Accordingly, the Service finds that the study's corrected estimates of 
historic vernal pool habitat loss in the Central Valley are reasonably 
close to the range of estimates determined by those commenters who 
criticized the study. Comments concerning a 50 percent habitat 
reduction based upon a Service publication appear to be derived from 
the Wetlands of the California Central Valley; Status and Trends 1939 
to mid-1980's (Frayer et al. 1989), which estimated losses of 
palustrine emergent wetlands. However, calculation of vernal pool 
losses cannot be deduced from the numerous wetland types categorized as 
``palustrine emergent wetlands.'' The results of the soils data 
analysis under preparation by the commenter were not available for 
review at the time of publication of this final rule.
    The purpose of addressing historic vernal pool losses in the 
proposed rule was to provide a historical context to the Central Valley 
ecosystem inhabited by the four crustacean species. It was not the 
intention, nor is it appropriate, to conduct an exhaustive analysis of 
information pertaining to the history of vernal pool habitat losses 
affecting the five crustacean species. Unverifiable and/or 
contradictory information on the extent of former and current vernal 
pool habitat will generate continued debate on this issue throughout 
the foreseeable future. In a legal context, the extent of historic 
habitat loss is of academic interest only, since the five factors at 50 
CFR 424.11(c) under which species may qualify for listing look 
prospectively to the future rather than retrospectively on the past. 
The relevant issues are whether the current extent of fairy and tadpole 
shrimp habitat is depleted and/or fragmented enough to render the 
species vulnerable to extinction, or whether foreseeable threats 
similarly threaten the species.
    Issue 25: Eight commenters, including four mosquito abatement 
districts, reported that vernal pools provided an important breeding 
source for mosquitoes. They stated that the listing of the fairy shrimp 
and the vernal pool tadpole shrimp, when coupled with the preservation 
and creation of vernal pools next to residential areas, will create a 
serious health risk to people. They were especially concerned about the 
western encephalitis mosquito (Culex tarsalis), a vector of western 
equine encephalitis and Saint Louis encephalitis. Some of the 
respondents also expressed concern about mosquito-borne malaria and 
yellow fever. A number of commenters stated that continued urban 
development would result in greater numbers of people being affected by 
mosquitoes and increase the need to control mosquitoes in vernal pools. 
The four mosquito abatement districts were concerned that listing of 
the crustaceans would increase the costs and restrictions on their 
control activities.
    Expressing a contrary position, four biologists stated that 
mosquitoes rarely are found in vernal pools and swales that have not 
been impacted by humans. They reported this is likely due to the 
presence of the high abundance of predatory crustaceans and aquatic 
insects that inhabit this ecosystem. A crustacean specialist noted that 
mosquitoes were absent or not present in significant numbers in pools 
inhabited by the fairy shrimp and the tadpole shrimp. Significant 
numbers of mosquito larvae were found in areas that contain created 
vernal pools or artificial bodies of water e.g., ditches and stock 
ponds where the crustaceans are sparse or absent. One biologist 
reported that no mosquito larvae were found in any of the 27 randomly 
sampled vernal pools at Beale Air Force Base (Mary Ann Griggs, private 
biologist, Colusa, California, in litt., 1992). However, mosquitos were 
found in areas that had augmented water supply from a pressure release 
valve on a well. The water supply produced a distinctively different 
flora and fauna than nearby vernal pools. Commenting biologists stated 
that the use of oil and mosquito fish (Gambusia affinis) will adversely 
affect vernal pool fauna, including the three fairy shrimp and the 
vernal pool tadpole shrimp, consequently allowing mosquitoes 
populations to sue vernal pools where they otherwise are controlled or 
eradicated by the nature pool fauna.
    Service Response: The best information available to the Service 
indicates that non-degraded vernal pools and swales do not provide a 
significant breeding source for mosquitoes. Mosquitoes do not appear in 
vernal pools until very late in the season, when they are unlikely to 
complete their development before the pools dry (Wright 1991; Stan 
Wright and Dave Brown, Sacramento-Yolo Mosquito Abatement District, 
pers. comm., 1993). This pattern likely is due to the ecology of vernal 
pool invertebrate communities rather than to oviposition timing of 
female mosquitoes or to water chemistry, since (1) duck ponds in the 
same area that fill at the same time as many vernal pools produce 
mosquitoes throughout the wet season while vernal pools do not, and (2) 
degraded pools and ruts without healthy vernal pool invertebrate 
communities support mosquito populations while undisturbed vernal pools 
in close proximity do not (S. Wright, pers. comm., 1993; J. King, pers. 
comm., 1993; Christopher Rogers, Redding Mosquito Abatement District, 
pers. comm., 1993).
    Female mosquitoes are attracted to gases produced by fermentation 
that indicate an abundance of decaying organic matter suitable for food 
for mosquito larvae (S. Wright, pers. comm., 1993). This likely is the 
cue used by females to select oviposition sites. Healthy vernal pools 
appear to have tight nutrient cycling and relatively low levels of 
decaying organic material, which makes them undesirable as oviposition 
sites for gravid mosquitoes. Only late in the season when the abundance 
of the invertebrates in vernal pools begins to decline are enough 
nutrients and organic material available to make the vernal pools 
attractive oviposition sites. By this time, however, it is often too 
late for the mosquito larvae to develop before the pools dry. 
Therefore, protecting vernal pools from disturbance and degradation can 
prevent vernal pools from becoming mosquito breeding grounds, thereby 
naturally preempting the need for artificial mosquito control in this 
habitat.
    Quantitative data collected from 64 vernal pools of widely varying 
types, depths, and locations on a random 322 kilometer (200 mile) 
north-south transect in the Central Valley from Fall River in Shasta 
County to Jepson Prairie in Solano County over an entire season 
indicate that mosquitoes are successful in breeding and developing only 
in pools that have been disturbed or degraded, or late in the season 
(J. King, pers. comm., 1993). Only about one third (34 percent) of the 
64 pools studied were occupied by mosquito larvae or pupae. Most of 
these pools had relatively low population densities of mosquitoes, and 
in all of these pools mosquitoes were only present later in the season. 
Of the 5 pools (8 percent) that did contain abundant mosquitoes, one 
was an artificially created pool and another appeared to be degraded by 
vehicular use and possibly discing.
    The Service recognizes that there could be potential conflicts with 
protection of the three fairy shrimp and the vernal pool tadpole shrimp 
in implementing mosquito control programs. The Service will be working 
with Federal, State, and local agencies, and examining additional 
alternatives, such as the use of Bacillus thuringiensis var. 
israelensis (Bti) and methoprene, to allow suppression programs to 
continue. In this way, the Service is confident that Federal listing 
will contribute to the survival of the four species and promote the 
understanding of their vernal pool environment without jeopardizing 
public health and safety.
    Issue 26: Several commenters expressed concern that listing of the 
crustaceans would curtail or eliminate cattle and livestock grazing in 
areas containing vernal pools. Two crustacean biologists reported that 
grazing by cattle and the crustacean species are compatible with each 
other. They stated that moderate to low levels of grazing likely have 
no adverse impacts on the fairy shrimp and the vernal pool tadpole 
shrimp.
    Service Response: The Service recognizes and acknowledges that low 
to moderate levels of livestock grazing likely have no impact or may be 
beneficial for these crustaceans. However, overgrazing in areas 
containing the shrimp and their habitat likely is detrimental to these 
species. High levels of pasture runoff may lead to increased siltation 
of vernal pool habitat, and high livestock densities may cause changes 
in pool water chemistry, water quality, and excessive physical 
disturbances, such as trampling.
    Issue 27: Several commenters reported the presence of the fairy 
shrimp in non-vernal pool habitats, such as irrigation return ditches, 
stock ponds, a backhoe pit, a gravel pit, and a depression left from 
scraping. One commenter stated that a historic vernal pool habitat site 
in southern Sacramento County that was disced, plowed, and farmed with 
winter wheat still contained inundated depressions inhabited by the 
vernal pool fairy shrimp and vernal pool tadpole shrimp. This example 
was used to support the contention that these species can survive and 
reproduce in degraded habitat. The commenter also noted that ``the site 
was not leveled unlike other properties in the area, and still retained 
some swale and hillock topography.'' (Bill Sugnet, Sugnet and 
Associates, in litt., 1992). Another respondent, based on anecdotal 
data, concluded that the habitat for the vernal pool fairy shrimp, and 
the vernal pool tadpole shrimp has been insufficiently described. He 
reported them from roadside ditches, scrapes, tire track depressions, 
or similar man-made ephemeral pools from 28 locations in Sacramento 
County (E.J. Koford, Ebasco Environmental, in litt., 1992). This 
commenter asserted that herbicides and/or mechanical weed control at 
sites located along some railroad tracks may have promoted the habitat 
for these species. One crustacean biologist, based on discussions, 
examination of photographs of these sites, and personal knowledge of 
the area concluded that they are remnant or disturbed vernal pools (J. 
King pers. comm., 1992).
    Service Response: The Service has reviewed carefully the assertion 
that the crustaceans are found in non-vernal pool habitat. A number of 
the sites that served as the basis for this belief have been examined 
by Service biologists and were found to represent degraded vernal pool 
habitat or, in one case, an ephemeral wetland located in a gravel pit 
that likely was colonized by fairy shrimp washed in from adjacent 
vernal pools during periods of high rainfall. Based on the best 
information available, the Service believes that a significant portion 
of these records most likely represent ``unusual'' vernal pools (e.g., 
rock depression pools) or vernal pool habitat that was incorrectly 
identified. Some of these records, such as roadside ditches, scraped 
areas, and airport runoff ditches almost certainly represent remnant 
vernal pool habitat or are part of the swale systems connected to 
vernal pools. Lack of experience or familiarity with vernal pool 
ecosystems likely has led some respondents to misinterpret these 
observations. Most of these disturbed habitats also are imperiled by 
urban development, gravel mining, and, in the cases of roadside 
ditches, grading and spraying of herbicides for highway maintenance. In 
addition, the accurate identification of fairy shrimp is extremely 
difficult because the morphological characters required to 
differentiate the various species are often extremely subtle and can be 
misinterpreted by biologists not specifically trained in fairy shrimp 
identification. Widespread, common species, such as Lindahl's fairy 
shrimp, can be mistaken for other fairy shrimp species. Some of the 
records of the California linderiella and vernal pool fairy shrimp in 
non-vernal pool habitats may result from such misidentifications.
    The potential for a fairy shrimp population to persist after 
habitat disturbance varies from case to case, depending upon specific 
circumstances, such as the nature and intensity of disturbance, how 
much of the original egg bank was destroyed, and other factors. With 
the exception of a few extremely rare cases, plowed fields that 
historically held vernal pool habitat do not support populations of 
these species. The example provided by the commenter is not typical of 
agricultural operations, as is pointed out in the commenter's statement 
that this site was ``unlike other properties in the
area . . .'' (B. Sugnet, in litt., 1992), with respect to the degree of 
disturbance (i.e., leveling) and adverse modification of the vernal 
pool habitat.
    Issue 28: Many respondents contended that the proposed rule did not 
reflect accurately the success of vernal pool ``creation'' efforts. For 
example, a number of commenters claimed that artificial vernal pools, 
primarily in Sacramento and Placer Counties, cited in Sugnet and 
Associates (1992), were successful and were adequate mitigation for 
adverse impacts to vernal pools resulting from urban development. Other 
commenters asserted that ongoing creation ratios of 2:1 or greater and 
the ability to transplant these animals makes it likely that the 
habitat for these species will increase over time.
    One commenter stated that the ability to successfully transplant 
the eggs of fairy shrimp and tadpole shrimp is well known. One 
submitted report (Sugnet and Associates 1992) asserted that the four 
fairy shrimp and vernal pool tadpole shrimp have been shown in the 
``literature and in field sampling to be extremely hardy and capable of 
surviving long-term in greatly disturbed conditions and artificial 
habitats''. The report also stated that there are technical papers that 
demonstrate the ability to rear shrimp in the laboratory. The party 
submitting this report stated that they have been creating vernal pools 
as mitigation for development projects and monitoring the fairy shrimp 
and tadpole shrimp for the past three years from 1989 to 1992. They 
stated that although the presence of adult fairy shrimp may be due to a 
certain number of eggs continuing to hatch from the initial inoculum in 
successive years due to differences in physiochemical parameters, the 
presence of mating individuals and gravid female fairy shrimp in 
artificial pools, as well as historically degraded habitat, leads them 
to conclude that natural reproductive mechanisms are still at work. The 
report stated that the California linderiella and the vernal pool fairy 
shrimp can be transplanted successfully from one vernal pool location 
to another. The supporting data and criteria by which success was 
determined were not specified in the report. Based partly on the above 
information, numerous commenters stated that the fairy shrimp and 
vernal pool tadpole shrimp were not imperiled.
    On the other hand, one crustacean biologist stated that the reports 
of successful vernal pool creation have been ``generally poorly 
controlled, completely lacking in long-term monitoring, and do not 
appear in the peer reviewed scientific
literature * * *'' (J. King, in litt., 1992). In addition, this 
commenter reported that ``contrary to common misconception these 
organisms [vernal pool tadpole shrimp] are not easily raised outside of 
their natural habitat.'' This crustacean specialist stated that their 
efforts to maintain viable reproductive vernal pool tadpole shrimp in 
the laboratory have been unsuccessful. Another biologist pointed out 
that long-term studies of the effect of mixing genotypes in created 
pools likely are adversely impacting the fairy shrimp and the vernal 
pool tadpole shrimp (M. Simovich, in litt., 1992).
    Eight biologists specializing in crustaceans or plants inhabiting 
vernal pools stated that these habitats are an intricate ecosystem and 
efforts to recreate them likely will not be successful until they are 
more fully understood. Furthermore, six fairy shrimp specialists 
concluded that protection of these animals is best assured via the 
preservation of extant habitat and its associated community.
    Service Response: In a review of 21 vernal pool creation projects 
dispersed throughout California, Ferren and Gervitz (1990) concluded 
that no conclusive data exist to substantiate the hypothesis ``that 
vernal pools can be restored or created to provide functional values 
within the range of variability of natural pools.'' Though some 
individuals (Sugnet and Associates et al. 1992) have claimed complete 
or some degree of success, these conclusions generally are based on 
anecdotal unscientific studies and the persistence of fairy shrimp 
after only a short period of time, e.g., three years or less. Moreover, 
the principal pool creation technique (i.e., relocation of soil from 
excavated pool bottoms versus inoculation of a known quantity of eggs) 
and lack of scientifically designed monitoring do not allow for 
collection of the necessary data to determine the long-term population 
viability of transplanted species.
    In a study on the preservation and management of vernal pools 
(Jones and Stokes Associates 1990), the researchers concluded that the 
``science of vernal pool creation is still in its infancy and is 
primarily an experimental mitigation technique.'' Environmental 
requirements, not dispersal, is likely the limiting factor in the 
distribution of the fairy shrimp and the vernal pool tadpole shrimp (D. 
Belk, pers. comm., 1992). The four species in this final rule require 
unknown, but more restrictive environmental conditions than more widely 
distributed taxa (J. King, in litt., 1992; M. Simovich, in litt., 1992; 
R. Brusca, pers. comm., 1992). There are no demonstrated proven long-
term populations of the fairy shrimp or the vernal pool tadpole shrimp 
in artificial habitats.
    Artifically created habitats also may increase the threat of 
hybridization between the four fairy shrimp and other more widespread 
species. For example, Lindahl's fairy shrimp is a widespread species 
found in western North America that inhabits a wide array of 
conditions, ranging from pools whose salinity is high enough to support 
brine shrimp (Artemia sp.) to snow melt pools. Poorly planned, careless 
construction, or haphazard placement of the substrate during vernal 
pool creation may enhance conditions for species like Lindahl's fairy 
shrimp. Laboratory studies have shown that Lindahl's fairy shrimp and 
the vernal pool fairy shrimp readily hybridize in the laboratory and 
produce viable first generation hybrids (Fugate, pers. comm., 1992). 
There is evidence that hybridization between other fairy shrimp has 
occurred in the field because of human actions. Belk (1977) reported 
that the westward dispersal from Texas and New Mexico of a desert fairy 
shrimp (Streptocephalus dorothae) across extensive expanses of arid 
land into Arizona may be due to the cattle ponds and livestock watering 
holes that were built after the 1800's in the region. Wiman (1979) 
reported that viable hybrid offspring are produced by this species and 
Mackin's desert fairy shrimp (Streptocephalus mackini), a resident 
species in Arizona.
    Given these uncertainties associated with vernal pool creation, the 
Service maintains that transplanting target species (e.g., listed, 
proposed, and candidate species) into artificial pools cannot be 
considered adequate replacement for the loss of occupied vernal pool 
habitat. Even if such transplantation of the fairy shrimp and the 
vernal pool tadpole shrimp and creation of their habitat were 
documented to be a proven procedure rather than an evolving problematic 
venture, artificial pool creation for the species listed herein would 
not fulfill the mandates of section 2 of the Act, which require the 
Service to develop programs that conserve the ecosystems upon which 
listed species depend. As discussed elsewhere herein, natural habitats 
throughout the ranges of the four species have been damaged or 
eliminated. As a result, the Service concludes that the continued 
survival and recovery of the three fairy shrimp and the vernal pool 
tadpole shrimp only can be assured, at this time, by the preservation 
of extant vernal pools and their associated watersheds.
    Issue 29: Several comments were received questioning the 
relationship between the Endangered Species Act and the Fifth Amendment 
to the U.S. Constitution (e.g., ``taking'' without just compensation).
    Service Response: The mere promulgation of a regulation, such as 
the enactment of a statute, is rarely sufficient to establish that 
private property has been taken unless the regulation on its face 
denies the property owner the economically viable use of his property. 
Listing pursuant to the Endangered Species Act does not automatically 
restrict all uses of one's land. A property owner cannot establish that 
his property has been taken as a result of a regulatory action such as 
the listing of a species until he has first submitted a proposal to 
develop the property and has received a determination as to the level 
of development that will be allowed. The property owner must apply for 
all available permits and waivers before a taking could potentially be 
established. With respect to listing, this means that no takings can be 
established until the property owner complies with section 10(a) of the 
Act and the Service concludes that no permit to take incidental to an 
otherwise lawful activity will be issued.
    Issue 30: The Service received a comment that requested an 
explanation of the applicability of Hoffman Homes Inc. v. EPA to vernal 
pools.
    Service Response: Hoffman Homes Inc. v. EPA, 916 F.2d 1310 (7th 
Cir. 1992) held that an isolated wetland, with no shown effect on 
interstate commerce, was not within EPA's nor the Corps of Engineers' 
jurisdiction to regulate. That decision was vacated in the same year 
(Hoffman Homes Inc. v. EPA, 975 F.2d 1554) and the issue reheard by the 
same court in 1993 (Hoffman Homes Inc. v. EPA, 999 F.2d 256). In its 
final interpretation of the issues presented in that case, the court 
held that waters whose use, degradation, or destruction could affect 
interstate commerce, were waters appropriately regulated by EPA and/or 
the Corps (emphasis added). Based upon the facts as presented in that 
case, however, the court could not find sufficient evidence to support 
a conclusion that the wetland in question could potentially affect 
interstate commerce. As such, the court determined this particular 
water body to be outside the realm of EPA or Corps jurisdiction.
    The Service is not aware how the EPA or Corps view this case 
relative to vernal pools. Regardless of the interpretation, however, it 
is the animal (as opposed to habitat) for which the Endangered Species 
Act will afford protection with this final regulation. Should it be 
determined that neither the Corps nor EPA have jurisdiction over these 
wetlands, and that section 7 is not therefore applicable, then the 
property owner may comply with the Endangered Species Act through 
section 10 of the Act.

Summary of Factors Affecting the Species

    After a thorough review and consideration of all information 
available, the Service has determined that the Conservancy fairy shrimp 
(Branchinecta conservatio Eng et al.), longhorn fairy shrimp 
(Branchinecta longiantenna Eng et al.), and the vernal pool tadpole 
shrimp (Lepidurus packardi Simon) should be classified as endangered 
species; and the vernal pool fairy shrimp (Branchinecta lynchi Eng et 
al.) should be classified as a threatened species. Procedures found at 
section 4(a)(1) of the Endangered Species Act (16 U.S.C. 1531 et seq.) 
and regulations (50 CFR part 424) promulgated to implement the listing 
provisions of the Act were followed. A species may be determined to be 
endangered or threatened due to one or more of the five factors 
described in section 4(a)(1). These factors and their application to 
the Conservancy fairy shrimp (Branchinecta conservatio), longhorn fairy 
shrimp (Branchinecta longiantenna), vernal pool fairy shrimp 
(Branchinecta lynchi), and the vernal pool tadpole shrimp (Lepidurus 
packardi) are as follows:
    A. The present or threatened destruction, modification, or 
curtailment of their habitat or range. All three fairy shrimp and the 
vernal pool tadpole shrimp are restricted to vernal pools in 
California. The habitat of these animals is imperiled by a variety of 
human-caused activities, primarily urban development, water supply/
flood control activities, and conversion of land to agricultural use. 
Habitat loss occurs from direct destruction and modification of pools 
due to filling, grading, discing, leveling, and other activities, as 
well as modification of surrounding uplands that alters vernal pool 
watersheds.
    Rapid urbanization of areas containing vernal pools poses a 
significant threat to the four species included in this final rule. In 
the Central Valley, at least five pool complexes that were known to 
contain suitable habitat for the vernal pool fairy shrimp and the 
vernal pool tadpole shrimp were eliminated by urban development in the 
late 1980's. Mitigation measures were either lacking or unsuccessful. 
In general, the growth rate of human populations and associated urban 
development throughout the Central Valley is equal to or exceeds that 
of any other region in California. Indicative of this growth rate are 
proposals to develop several new towns within the ranges of the vernal 
pool fairy shrimp and the vernal pool tadpole shrimp. As an example, 
two towns proposed in Placer and San Joaquin Counties would support 
80,000 and 44,000 people, respectively, and likely would impact 
significant amounts of vernal pool habitat for these species (Laver 
1991, Wiegand 1991).
    Vernal pools in the Redding area that likely provided habitat for 
the vernal pool fairy shrimp and the vernal pool tadpole shrimp have 
been impacted significantly by urban development and agricultural 
conversion. Aerial photographs of an approximately 61-hectare (150 
acre) area near the Redding Municipal Airport document that development 
occurring between 1952 and 1992 resulted in the loss of 62 percent and 
the degradation of 37 percent of the original vernal pools in this 
vernal pool complex (Jim Nelson, California Fish & Game, pers. com., 
1993). The remaining pools at this site are inhabited by the vernal 
pool fairy shrimp and the vernal pool tadpole shrimp. Vernal pool areas 
around the airport have been zoned for enterprise, and sewer lines have 
been installed in anticipation of development. Several proposed 
residential development projects in the Redding area (e.g., Argyle West 
and Eagle Crest projects) also would adversely affect the vernal pool 
fairy shrimp and the vernal pool tadpole shrimp. A proposed electrical 
transmission line also threatens several pools in the area. Eucalyptus 
farms have been established on many historic vernal pool sites around 
Redding and future groves are planted at the rate of approximately 810 
hectares (2,000 acres) per year (J. Nelson, California Department of 
Fish and Game, pers. comm. 1993).
    In the Chico area, certain areas inhabited by the vernal pool 
tadpole shrimp recently were ditched and drained (Patrick Kelly, Mount 
Lassen Chapter of the California Native Plant Society, in litt., 1992). 
In addition, at least four residential developments proposed in Chico, 
including the Simmons Ranch, Foothill Park, Sierra Technology, and 
Bidwell Ranch projects are proposed that would eliminate approximately 
810 hectares (2,000 acres) of habitat containing vernal pools inhabited 
by the vernal pool tadpole shrimp. No specific mitigation measures are 
included in these projects for this animal.
    Numerous residential and commercial development projects in the 
Sacramento area pose a severe threat to vernal pool complexes inhabited 
by populations of the vernal pool fairy shrimp and vernal pool tadpole 
shrimp. These proposed and ongoing projects, sponsored by Federal, 
State and local agencies, private interests, and local governments, 
include, but are not limited to the closure of Mather Air Force Base, 
modifications to Strawberry, Elk Grove, and Laguna Creeks, two proposed 
surface gravel mines, and numerous residential developments including 
the Elliot Ranch South, Churchill Downs, Elk Ridge Estates, and 
Sunrise-Douglas projects.
    Urban development and agricultural conversion imperil populations 
of the vernal pool fairy shrimp and vernal pool tadpole shrimp in the 
San Joaquin Valley. Castle Air Force Base is undergoing closure and the 
U.S. Bureau of Prisons has proposed to build a prison on vernal pools 
at this site known to contain the two fairy shrimp. The Corps has 
proposed the Merced County Streams project that would facilitate urban 
development in many areas that provide suitable habitat for the vernal 
pool fairy shrimp and the vernal pool tadpole shrimp. Numerous projects 
between Stockton and Bakersfield also would adversely impact the three 
species, including the Mueller Ranch gravel mine in Stanislaus County, 
a number of residential developments in San Joaquin County (e.g., the 
Liberty project would affect approximately 2,000 vernal pools), the 
Yosemite Lake project in Merced County, and the Ball Ranch project in 
Fresno County.
    Areas in the San Francisco Bay area that contain vernal pools also 
are undergoing substantial urban development. Vernal pools inhabited by 
the vernal pool fairy shrimp in the Livermore area of Alameda County 
have been adversely impacted by urban development, agriculture, and 
alteration of the hydrology of Altamont Creek (Alan Launer, Stanford 
University Center for Conservation Biology, in litt., 1992). The City 
of Livermore is evaluating land use options that could result in the 
conversion of 3,002 hectares (7,420 acres) of natural habitat, 
including vernal pools that provide suitable habitat for the vernal 
pool fairy shrimp, to urban use for up to 30,000 people (City of 
Livermore 1992; Susan Frost, Livermore Planning Department, pers. 
comm., 1993). The proposed expansion of the municipal airport at Byron 
Hot Springs in eastern Contra Costa County will eliminate a number of 
pools inhabited by the vernal pool fairy shrimp.
    Other vernal pools located in San Luis Obispo County, including 
most of the known populations of the longhorn fairy shrimp and at least 
one population of the vernal pool fairy shrimp, are located in 
subdivided areas with constructed roads and lots for sale and 
development (Eng et al. 1990; Dave Chipping, Amateur biologist, in 
litt., 1992). To date, some of the sites have been cleared and 
continued habitat loss is ongoing or impending. The Coastal Branch 
Phase II (Coastal Aqueduct) of the State Water Project, proposed by the 
California Department of Water Resources (Carol Nelson, California 
Department of Water Resources, in litt., 1993), annually would convey 
70,000 acre-feet of water from the Delta region of California to San 
Luis Obispo and Santa Barbara Counties. It is unclear if this source of 
water would allow urban development of the Soda Lake area, however, the 
longhorn fairy shrimp and the vernal pool fairy shrimp may be adversely 
affected by commercial development made possible by this project.
    A 36-hectare (14 acre) vernal pool located at Skunk Hollow in 
Riverside County containing a population of the vernal pool fairy 
shrimp likely will be adversely affected by urban development and 
possibly agricultural conversion (Art Davenport, Fish and Wildlife 
Service, pers. comm., 1994; Joseph Jolliffe, Riverside County Planning 
Department, in litt., 1992). The Rancho Bella Vista residential project 
would impact this vernal pool and, along with other major roadways, 
also impact the surrounding watershed (Joseph Jolliffe, in litt., 
1992). Skunk Hollow also contains a population of the Riverside fairy 
shrimp (Streptocephalus woottoni), an endangered species (58 FR 41384).
    Because of rapid urbanization, several highway projects are 
proposed that may affect the vernal pool fairy shrimp and the vernal 
pool tadpole shrimp. Vernal pools in the Sacramento area inhabited by 
the vernal pool fairy shrimp and the vernal pool tadpole shrimp would 
be affected adversely by the proposed widening of State Highway 16 in 
Sacramento County. The State of California has proposed to extend State 
Highway 505 from Vacaville to Collinsville in Solano County; this 
project directly and/or indirectly would impact vernal pools inhabited 
by the Conservancy fairy shrimp and the vernal pool tadpole shrimp (C. 
Goude, pers. comm., 1993). Vernal pools inhabited by the vernal pool 
tadpole shrimp may be affected by improvements to Highway 70 near 
Gridley in Butte County (Chris Collison, California Department of 
Transportation, pers. comm., 1993).
    Agricultural conversion poses a widespread threat to remaining 
vernal pools in the Central Valley. Sites containing fairy shrimp near 
Pixley in Tulare County and Haystack Mountain in Merced County are 
pockets of privately owned habitat remnants threatened by surrounding 
agricultural operations (Eng et al. 1990). A 148-hectare (365 acres) 
site with vernal pools adjacent to State Highway 41 north of Fresno in 
Fresno County that likely contained the vernal pool fairy shrimp was 
disced and graded in 1992 (Dames and Moore 1992). Two sites with vernal 
pools in the Sacramento Valley recently were plowed or disced and 
seeded with winter wheat, apparently in preparation for future urban 
development (C. Goude, pers. comm., 1993). Almond and fruit orchards in 
Stanislaus, Madera, and Fresno Counties continued to be planted in 
habitat suitable for the vernal pool fairy shrimp and the vernal pool 
tadpole shrimp (J. King pers. comm. 1993; K. Geer and J. Browning, 
U.S.F.W.S., pers. obs. 1994).
    Water supply/flood control activities also generally present a 
degree of disturbance to affected pools that would preclude survival of 
any substantial fraction of the populations. The timing, frequency, and 
length of inundation of the vernal pool habitat are critical to the 
three fairy shrimp and the vernal pool tadpole shrimp; any substantial 
hydrologic change in these factors adversely affect the four species. 
Diversion of watershed runoff feeding the pools can result in premature 
pool dry-down before the life cycle of these animals is completed. The 
three species of fairy shrimp and the vernal pool tadpole shrimp also 
are intolerant of flowing water that washes away the egg bank. 
Supplemental water from outside the natural watershed into vernal pools 
can change the habitat into a marsh-dominated or a permanent aquatic 
community that is unsuitable for the four species of vernal pool 
shrimps. The modification of vernal pool areas to create artificial 
reservoirs, such as the Modesto Reservoir and Turlock Lake in 
Stanislaus County, have led to the extirpation of the vernal pool 
tadpole shrimp population that was known to occur in the vernal pools 
where these reservoirs now lie (J. King, pers. comm., 1993). Vernal 
pool watershed areas have been reduced by conversion of uplands to 
paved or grass-turf surfaces, by damming of swales caused by road 
construction, or other construction activities. Physical barriers, such 
as roads and canals, unsuitably deepen a vernal pool upstream of a 
barrier, and can isolate a fairy shrimp or vernal pool tadpole shrimp 
population from a portion of its aquatic habitat. Surface runoff, 
including non-point runoff, is altered by disturbance from trenching, 
grading, scraping, off-road vehicles, intensive livestock grazing, or 
other activities that change amounts, patterns, and direction of 
surface runoff to ephemeral drainages. Presence of summer water also 
affects the hydrologic pattern. Introduction of water during the summer 
disrupts the life cycles of the fairy shrimp and the vernal pool 
tadpole shrimp by subjecting them to greater levels of predation by 
animals requiring more permanent sources of water. Increased water also 
converts vernal pools to unsuitable marsh habitat dominated by emergent 
vegetation (e.g., cattails).
    Direct and associated indirect impacts from the proposed Los 
Vaqueros Project, a water-storage project in the Kellogg Creek 
watershed of eastern Contra Costa County, would adversely impact two 
vernal pool complexes that support the highest diversity of fairy 
shrimp in the State (California Department of Fish and Game 1983). The 
rock pools in this area are inhabited by the vernal pool fairy shrimp 
and the longhorn fairy shrimp (John Gregg, Los Vaqueros Project, in 
litt., 1992). Proposed construction of a major roadway, high-pressure 
natural gas and petroleum pipelines, and 230,000 kV electrical 
transmission lines at the Los Vaqueros Reservoir site would adversely 
affect these species (Jones and Stokes Associates 1986, 1989, 1990, 
1991).
    Several proposed utility projects have the potential to affect all 
of the three fairy shrimp and the vernal pool tadpole shrimp. For 
example, the Pacific Gas Transmission Company--Pacific Gas and Electric 
natural gas pipeline project extending from the Canadian border along 
the west side of the Sacramento Valley to Fresno County has adversely 
impacted a number of vernal pools containing the vernal pool fairy 
shrimp, Conservancy fairy shrimp, and the vernal pool tadpool shrimp 
(Federal Regulatory Energy Commission 1991; Arnold 1990; C. Nagano, 
pers. obs., 1992 and 1993). The Service has issued a conference opinion 
to the Federal Energy Regulatory Commission on a portion of this 
project that will adversely impact the vernal pool fairy shrimp; 
however, the applicant has indicated the mitigation measures will not 
be implemented if the species is not listed (John Cassady, PGT-PG&E 
Pipeline Expansion Project, in litt., 1993).
    Off-road vehicle (ORV) use also imperils fairy shrimp and the 
vernal pool tadpole shrimp inhabiting vernal pools (Bauder 1986, 1987). 
ORVs cut deep ruts, compact soil, destroy native vegetation, and alter 
pool hydrology. Fire fighting, security patrols, military maneuvers, 
and recreational activities cumulatively have damaged vernal pool 
habitats in many areas (Bauder 1986, 1987). In Solano County, an off-
road vehicle park adjacent to the Jepson Prairie Reserve owned by the 
Nature Conservancy could adversely impact populations of the 
Conservancy fairy shrimp and the vernal pool tadpole shrimp.
    Other secondary impacts associated with urbanization include 
disposal of waste materials into habitat for the four species included 
in this final rule (Bauder 1986, 1987). Disposal of concrete, tires, 
refrigerators, sofas, and other trash adversely affects these animals 
by eliminating habitat, disrupting pool hydrology or, in some cases, 
through release of toxic substances. Dust and other forms of air or 
water pollution from commercial development or agriculture projects 
also may be deleterious to these animals.
    Filling of vernal pool wetlands without authorization from the 
Corps also poses a threat to these species (Tricia Richards, Sacramento 
County Planning and Community Development Department, in litt, 1991: D. 
Strait, pers. comm., 1993). In Stanislaus County, a site with 61 
hectares (150 acres) of vernal pool habitat that was potentially 
inhabited by the vernal pool fairy shrimp was converted to irrigated 
pasture in 1990 (Martha Naley, U.S. Fish and Wildlife Service, pers. 
comm., 1991). A 112 hectare (275 acre) site containing vernal pool and 
swale habitat for the vernal pool tadpole shrimp in the Jepson Prairie 
area in Solano County was destroyed by discing in October 1992 (C. 
Nagano and J. Knight, pers. obs., 1992).
    The Service is aware of 10 actions in the last 2 years in the 
Sacramento Valley, including agricultural conversion and urban 
development, that have resulted in the damage or destruction of as many 
as 17 hectares (43 acres) of vernal pools, exclusive of associated 
watersheds, that likely provided habitat for the vernal pool fairy 
shrimp and vernal pool tadpole shrimp (Dan Strait, U.S. Fish and 
Wildlife Service pers. comm., 1993). Some of these activities were 
undertaken without authority under the Clean Water Act. At least one of 
these parties likely intended to alter the elevations of the site to 
eliminate one or more of the parameters used by the Corps to define a 
wetland according to their 1987 jurisdictional manual. Other similar 
deliberate activities that are damaging or destroying vernal pools are 
likely occurring throughout the Central Valley (D. Strait, pers. comm., 
1993). The Service is concerned that unless a final rule for the four 
species is issued and effective immediately upon publication, this may 
result in landowners knowingly destroying the habitat of these animals. 
Previously, this has occurred with other endangered species that 
inhabit vernal pools in the Santa Rosa area of Sonoma County (C. D. 
Nagano and J. C. Knight, U.S. Fish and Wildlife Service, pers. obs., 
1992). Because of the immediate threat posed by these on-going 
activities, the Service finds that good cause exists for this rule to 
take effect immediately upon publication in accordance with 5 U.S.C. 
553(d)(3).
    B. Overutilization for commercial, recreational, scientific, or 
educational purposes. Not known to be applicable.
    C. Disease or predation. The three fairy shrimp and the vernal pool 
tadpole shrimp are a food item in the diet of migratory waterfowl and 
other native animals (Krapu 1974; Swanson et al. 1974; J. King, pers. 
comm., 1992). However, this naturally occurring predation is not 
considered a threat to the continued existence of these crustaceans.
    Introduction of the bullfrog (Rana catesbeiana) to areas inhabited 
by the vernal pool tadpole shrimp appears to increase the threat of 
predation facing this crustacean. These amphibians are voracious 
predators on many species of native and exotic animals. Large numbers 
of vernal pool tadpole shrimp were found in stomach content analysis of 
bullfrogs captured in vernal pools in the Chico area (Marc Hayes, 
Oregon State University, pers. comm., 1993; Robert Fisher, University 
of California, pers. comm., 1993). Although bullfrogs are unable to 
establish permanent breeding populations in vernal pools, dispersing 
immature males take up residence in these areas during the rainy season 
(Mark Jennings, U.S. National Biological Survey, pers. comm. to Peter 
Sorensen, 1994). A number of bullfrogs were observed at Jepson Prairie 
during the winter of 1992/1993 (C. Nagano, pers. obs. 1992/93).
    Vernal pool tadpole shrimp were found to have been parasitized by 
flukes (Trematoda) of an undetermined species at the Vina Plains, 
Tehama County (Ahl 1991). The gonads of both sexes were greatly reduced 
in size and their body cavities were filled with many young flukes 
(metacercariae). Ahl concluded that parasitic castration was the major 
limiting factor affecting reproduction of the vernal pool tadpole 
shrimp at the Vina Plains. The range and extent of this parasite is 
unknown.
    There are no known diseases affecting the three fairy shrimp and 
the vernal pool tadpole shrimp.
    D. The inadequacy of existing regulatory mechanisms. The primary 
cause for the decline of these species is loss of habitat from human 
activities. State and local laws and regulations have not been passed 
to protect the four species included in this final rule. Other 
regulatory mechanisms necessary for the conservation of vernal pools 
have proven inadequate and ineffective.
    The environmental review process under the California Environmental 
Quality Act for projects that result in loss of habitats that support 
these animals sometimes requires development and implementation of 
mitigation plans. However, the effectiveness of this statute in 
protecting vernal pool habitat has not been consistent. As documented 
above, fairy shrimp and vernal pool tadpole shrimp habitat typically 
has been eliminated without offsetting mitigation measures. Most 
mitigation plans that have been required were designed specifically for 
vernal pool plants. The artificial creation of vernal pools as 
compensatory mitigation has not been proven scientifically to be 
successful (Ferren and Gevirtz 1990; Zedler and Black 1988; J. King, in 
litt., 1992; M. Simovich, in litt., 1992; R. Brusca, in litt., 1992).
    Under section 404 of the Clean Water Act, the Corps regulates the 
discharge of fill material into waters of the United States, which 
include navigable waters, wetlands (e.g., vernal pools), and other 
waters. The Clean Eater Act requires project proponents to obtain a 
permit from the Corps prior to undertaking many activities (grading, 
discharge of soil or other fill material, etc.) that would result in 
fill of wetlands. The Corps promulgated Nationwide Permit 26 to address 
fill of isolated or headwater wetlands totalling less than 4 hectares 
(10 acres). Under Nationwide Permit 26, proposals that involve fill of 
wetlands less than one acre are considered authorized. Where fill would 
aversely modify between 0.4 and 4.0 hectares (one and 10 acres) of 
wetland, the Corps circulates for comment a predischarge notification 
to the Service and other interested parties to determine whether or not 
an individual permit should be required for fill activity and 
associated impacts.
    Individual Corps permits are required for discharge of fill 
material that would fill or adversely modify greater than 4 hectares 
(10 acres) of wetlands. The review process for individual permits is 
more rigorous than for nationwide permits. Unlike nationwide permits, 
an analysis of cumulative wetland impacts is required for individual 
permit applications. Resulting permits may include special conditions 
that require potential avoidance or mitigation for environmental 
impacts. On nationwide permits, the Corps has discretionary authority 
to require an individual permit if the Corps believes that resources 
are sufficiently important, regardless of the wetland's size. In 
practice, however, the Corps generally does not require an individual 
permit when a project qualifies for a nationwide permit, unless a 
threatened or endangered species or other significant resources would 
be adversely affected by the proposed activity. Most vernal pools and 
swales within the range of these three species of fairy shrimp and the 
vernal pool tadpole shrimp encompass less that 4 hectares (10 acres). 
The discontinuous distribution of these sites has allowed some 
landowners to divide large projects into several smaller projects. 
Wetland acreage on these smaller projects is usually under 4 hectares 
(10 acres), and therefore, most projects qualify for Nationwide Permit 
26. Discing and other farming or ranching practices, including 
overgrazing, can destroy vernal pool habitat without a permit from the 
Corps because many of these activities are exempt from regulation under 
the Clean Water Act. The discontinuous configuration of the pools and 
swales further obscures separation of these wetland losses.
    The Sacramento District of the Corps has several thousand vernal 
pools under its jurisdiction (Coe 1988), which includes most of the 
geographic range encompassing the four species listed herein. Areas 
occupied by these animals are undergoing rapid urbanization and current 
trends indicate 60 to 70 percent of these pools could be destroyed in 
the next 10 to 20 years (Coe 1988).
    The Conservancy fairy shrimp, vernal pool fairy shrimp, and the 
vernal pool tadpole shrimp are found in vernal pools within the Vina 
Plains in Tehama County. They likely are found in the vicinity of 
ephemeral swales and drainages that support Limnanthes floccosa ssp. 
calfornica (Butte County meadowfoam). This plant was listed as an 
endangered species on June 8, 1992 (57 FR 24192). These crustaceans 
could be protected indirectly by actions taken to conserve the Butte 
County meadowfoam. A ``conservation plan'' has been drafted for the 
City of Chico (Jokerst 1989) that details various actions designed to 
conserve the plant, such as creation of a preserve system. However, the 
draft plan does not address plant populations and vernal pool habitat 
outside city limits. Moreover, the City of Chico has yet to adopt the 
plan. Meanwhile, typical of other vernal pool areas, the Corps 
continues to use nationwide permits to authorize numerous residential 
developments in the Chico area.
    The Conservancy fairy shrimp and the longhorn fairy shrimp each 
have portions of one population on lands under public ownership. 
Portions of four populations of the vernal pool fairy shrimp are on 
lands under public ownership. Portions of eight populations of the 
vernal pool tadpole shrimp are on lands under public ownership. The 
Nature Conservancy owns or controls portions of vernal pool habitat, 
including Jepson Prairie in Solano County, Vina Plains in Tehama 
County, the Carrizo Plain in San Luis Obispo County, and Santa Rosa 
Plateau area in Riverside County. All three fairy shrimp species and 
the vernal pool tadpole shrimp occur on Conservancy property. 
Management plans for some Federal, State, local, and Conservancy 
properties include provisions to protect vernal pools but none 
specifically address these species. Surrounding privately owned vernal 
pool habitat and watershed are not protected.
    E. Other natural or man-made factors affecting their continued 
existence. The pools and, in some cases, pool complexes supporting the 
fairy shrimp species and the vernal pool tadpole shrimp are usually 
small and unforeseen natural and man-caused catastrophic events 
threaten the elimination of some sites. Many of the known populations 
of the four species are comprised of single or less than five pools 
(e.g., 3 of 6 Conservancy fairy shrimp populations, 1 of 3 longhorn 
fairy shrimp populations, 20 of 34 vernal pool fairy shrimp 
populations, 1 of the 18 vernal pool tadpole shrimp populations). In 
many cases, these populations are remnants of larger, multi-pool 
populations that originally existed in historic vernal pool complexes. 
Such populations are important for their genetic uniqueness, which has 
been documented for the Conservancy fairy shrimp and the vernal pool 
tadpole shrimp (Fugate 1993; J. King pers. comm. 1992). However, these 
important populations are those that have the most tenuous chances for 
long-term persistence due to population bottlenecks in conjunction with 
low gene flow between populations (J. King pers. comm. 1993). 
Additionally, some of the areas with the largest populations (i.e., 
greatest number of vernal pools remaining in pool complexes) are 
currently under threat of fragmentation by numerous proposed projects 
(e.g., Sacramento and Placer Counties).
    The four crustaceans in these small habitat patches are vulnerable 
to random fluctuations or variation (stochasticity) due to annual 
weather patterns and availability of food and other environmental 
factors superimposed on the cumulative threats described throughout 
this rule. The populations of the four species are isolated from other 
conspecific populations and are distributed in discontinuous vernal 
pool systems. Such populations are vulnerable to stochastic extinction. 
The breeding of closely related individuals may cause genetic problems 
in small populations of the four species, particularly in the 
expression of deleterious genes (known as inbreeding depression). 
Individuals and populations possessing deleterious genetic material are 
less able to cope with environmental conditions and adapt to 
environmental changes, even relatively minor ones. Further, small 
populations are subject to the effects of genetic drift (the random 
loss of genetic variability). The phenomenon also reduces the ability 
of individuals and populations to respond successfully to environmental 
stresses. Overall, these genetic factors could influence the 
survivability of isolated populations of each of the three fairy shrimp 
and the vernal pool tadpole shrimp.
    The Service has carefully assessed the best scientific and 
commercial information regarding past, present, and future threats 
faced by these species in determining to issue this final rule. Based 
on this evaluation, the preferred action is to list the Conservancy 
fairy shrimp, longhorn fairy shrimp, and the vernal pool tadpole shrimp 
as endangered; and the vernal pool fairy shrimp as threatened. The 
three fairy shrimp and the vernal pool tadpole shrimp are imperiled by 
rapid urbanization, conversion of land to agricultural use, off-road 
vehicle use, and changes in hydrologic patterns in areas they occupy. 
Only a small proportion of the pools are permanently protected from 
these threats. Numerous ongoing and proposed development projects pose 
an imminent threat to the three fairy shrimp and the vernal pool 
tadpole shrimp. Extraordinary increases in human populations and 
associated pressures from urban development have rendered existing 
regulatory mechanisms inadequate. Stochastic events, which commonly 
affect small isolated populations, also may result in extirpation of 
some populations of these species. Four of the six known populations of 
the Conservancy fairy shrimp are imperiled. There are threats to the 
four known populations of the longhorn fairy shrimp. Twenty-eight of 
the 32 known populations of the vernal pool fairy shrimp are under 
threat. Fourteen of the 18 known populations of the vernal pool tadpole 
shrimp are imperiled. Because the Conservancy fairy shrimp, longhorn 
fairy shrimp, and the vernal pool tadpole shrimp are in danger of 
extinction throughout all or a significant portion of their ranges, 
these species fit the definition of endangered as defined in the Act. 
Because the vernal pool fairy shrimp is likely to become an endangered 
species within the foreseeable future throughout all or a significant 
portion of its range, this species fits the definition of threatened as 
defined in the Act.
    The Service considers the change in the listing status from 
endangered to threatened of the vernal pool fairy shrimp to be 
warranted based on two factors. Since the proposed rule was published, 
data gathered by Sugnet and Associates (1993b) and information 
otherwise available to the Service indicate that the geographic extent 
and number of populations and subpopulations of this species are larger 
than was originally known. The distribution of the species is not so 
fragmented as to reduce the likelihood of recolonization. As mentioned 
previously in this final rule, recolonization following stochastic 
local extinctions is probably a determining factor for the long-term 
persistence of this species.
    Taking this information into consideration, as well as the actions 
discussed under factors A, C, D, and E in the ``Summary of Factors 
Affecting the Species'' section of this rule, the Service finds that 
the vernal pool fairy shrimp is not in imminent danger of extinction 
but is likely to become so in the foreseeable future throughout all or 
a significant portion of its range.
    Designation of critical habitat for the vernal pool fairy shrimp, 
longhorn fairy shrimp, Conservancy fairy shrimp, and the vernal pool 
tadpole shrimp is not prudent at this time for the reasons discussed 
below.

Critical Habitat

    Section 4(a)(3) of the Act, as amended, requires that to the 
maximum extent prudent and determinable, the Secretary designate 
critical habitat at the same time the taxa are listed. The Service 
finds that designation of critical habitat is not prudent for these 
species at this time. Because the three fairy shrimp and vernal pool 
tadpole shrimp face numerous anthropogenic threats (see Factor A in 
``Summary of Factors Affecting the Species''), the publication of 
precise maps and descriptions of critical habitat in the Federal 
Register would make these species more vulnerable to incidents of 
vandalism and, therefore, would contribute to the decline of these 
species. A number of sites inhabited by the four species occur on 
private land that is undergoing rapid urban and agricultural 
development. As documented above, some areas have been destroyed to 
eliminate vernal pool characteristics and escape regulatory 
jurisdiction by the Corps. The proper agencies have been notified 
concerning management requirements of these animals. Protection of the 
habitat of these species will be addressed through the recovery, 
section 7 consultation, and incidental take permitting processes. 
Federal involvement in areas where these animals occur can be 
identified without designation of critical habitat. Therefore, the 
Service finds that designation of critical habitat for these animals is 
not prudent at this time, because such designation likely would 
increase the degree of threat from vandalism or other human activities.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened under the endangered Species Act include recognition, 
recovery actions, requirements for Federal protection, and prohibitions 
against certain activities. Recognition through listing encourages and 
results in conservation actions by Federal, State, local, and private 
agencies, groups, and individuals. The Endangered Species Act provides 
for possible land acquisition and cooperation with the States and 
requires recovery actions be carried out for all listed species. Such 
actions are initiated following listing. The protection required of 
Federal agencies and the prohibitions against taking are discussed, in 
part, below.
    Section 7(a) of the Act, as amended, requires Federal agencies to 
evaluate their actions with respect to any species that is proposed or 
listed as endangered or threatened. Regulations implementing this 
interagency cooperation provision of the Act are codified at 50 CFR 
part 402. Section 7(a)(2) requires Federal agencies to insure that 
activities they authorize, fund, or carry out are not likely to 
jeopardize the continued existence of such a species or to destroy or 
adversely modify its critical habitat. If a Federal action may affect a 
listed species or its critical habitat, the responsible Federal agency 
must enter into formal consultation with the Service.
    As described above, the U.S. Army Corps of engineers exerts section 
404 jurisdiction over habitats supporting these animals. Nationwide 
permits are not valid where a federally listed endangered or threatened 
species would be affected by the proposed project. When listed species 
may be affected, formal consultation is required pursuant to section 7 
of the Act before nationwide permits become effective. In addition, the 
Department of Housing and Urban Development (HUD) may insure housing 
loans in areas that presently support these animals; HUD actions 
regarding these loans also would be subject to review by the Service 
under section 7 of the Act.
    Other Federal agencies that possibly could be affected if these 
animals are listed include the U.S. Air Force, U.S. Department of 
Agriculture (Farmers Home Administration), Veterans Administration, and 
the Department of Transportation (Federal Highways Administration). 
Populations of the longhorn fairy shrimp, vernal pool fairy shrimp, and 
the vernal pool tadpole shrimp occur on property owned by the Bureau of 
Land Management at the Carrizo Plain in San Luis Obispo County; and the 
U.S. Air Force at Castle Air Force Base, Mather Air Force Base, and 
Beale Air Force Base.
    The listing of these fairy shrimp and the vernal pool tadpole 
shrimp will also bring section 5 and 6 of the Endangered Species Act 
into effect. Section 5 authorizes acquisition of lands for the purposes 
of conserving endangered and threatened species. Pursuant to section 6, 
the Service would be able to grant funds to affected States for 
management actions aiding in protection and recovery of these animals.
    Listing these fairy shrimp and the vernal pool tadpole shrimp as 
endangered provides for the development of a recovery plan (or plans) 
for them. Such plan(s) will bring together State and Federal efforts 
for conservation of the animals. The plan(s) will establish a framework 
for agencies to coordinate activities and cooperate with each other in 
conservation efforts. The plan(s) will set recovery priorities and 
estimate costs of various tasks necessary to accomplish them. They also 
will describe site-specific management actions necessary to achieve 
conservation and survival of the fairy shrimp and the vernal pool 
tadpole shrimp.
    The Act and implementing regulations found at 50 CFR 17.21 for 
endangered species and 17.31 for threatened species set forth a series 
of prohibitions and exceptions that apply to all endangered wildlife 
and to threatened wildlife not covered by a special rule. These 
prohibitions, in part, make it illegal for any person subject to the 
jurisdiction of the United States to take, import or export, transport 
in interstate or foreign commerce in the course of commercial activity, 
or sell or offer for sale in interstate or foreign commerce any such 
species. It also is illegal to possess, sell, deliver, carry, 
transport, or ship any such wildlife that was illegally taken. Certain 
exceptions can apply to agents of Service and State conservation 
agencies.
    Permits may be issued to carry out otherwise prohibited activities 
involving endangered and threatened animal species under certain 
circumstances. Regulations governing permits are at 50 CFR 17.22, 
17.23, and 17.32. For endangered species, such permits are available 
for scientific purposes, to enhance the propagation or survival of the 
species, to alleviate economic hardship in certain circumstances, and/
or for incidental take in connection with otherwise lawful activities. 
For threatened species, there are also permits for zoological 
exhibition, educational purposes or other purposes consistent with the 
purposes of the Act. Further information regarding regulations and 
requirements for permits may be obtained from the U.S. Fish and 
Wildlife Service, Ecological Services, Endangered Species Permits, 911 
N.E. 11th Avenue, Portland, Oregon 97232-4181 (503/231-2063; FAX 503/
231-6243).

National Environmental Policy Act

    The Fish and Wildlife Service has determined that an Environmental 
Assessment, as defined under the authority of the National 
Environmental Policy Act of 1969, need not be prepared in connection 
with regulations adopted pursuant to section 4(a) of the Endangered 
Species Act of 1973, as amended. A notice outlining the Service's 
reasons for this determination was published in the Federal Register on 
October 25, 1983 (48 FR 49244).

References Cited

    A complete list of all references cited herein is available, 
upon request, from the Field Supervisor, Sacramento Field Office, 
(see ADDRESSES section).

Authors

    The primary authors of this final rule are Chris Nagano and Jim 
Browning, Sacramento Field Office, 2800 Cottage Way Room E-1823, 
Sacramento, California 95825 (916/978-4866).

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, and Transportation.

Regulations Promulgation

    Accordingly, part 17, subchapter B of chapter I, title 50 of the 
Code of Federal Regulations, is amended as set forth below:

PART 17--[AMENDED]

    1. The authority citation for Part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
4201-4245; Pub. L. 99-625, 100 Stat. 3500, unless otherwise noted.

    2. Section 17.11(h) is amended by adding in the table the following 
in alphabetical order under CRUSTACEANS to the List of Endangered and 
Threatened Wildlife to read as follows:


Sec. 17.11  Endangered and threatened wildlife.

* * * * *
    (h)* * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                      Species                                                  Vertebrate population                                                    
---------------------------------------------------      Historic range         where endangered or       Status     When listed    Critical    Special 
      Common name              Scientific name                                      threatened                                      habitat      rules  
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
                                                                      * * * * * * *                                                                     
       Crustaceans                                                                                                                                      
                                                                                                                                                        
                                                                      * * * * * * *                                                                     
Shrimp, Conservancy       Branchinecta conservatio  U.S.A. (CA).............  NA.....................  E                     549           NA         NA
 fairy.                                                                                                                                                 
                                                                                                                                                        
                                                                      * * * * * * *                                                                     
Shrimp, longhorn fairy..  Branchinecta              U.S.A. (CA).............  NA.....................  E                     549           NA         NA
                           longiantenna.                                                                                                                
                                                                                                                                                        
                                                                      * * * * * * *                                                                     
Shrimp, vernal pool       Branchinecta lynchi.....  U.S.A. (CA).............  NA.....................  T                     549           NA         NA
 fairy.                                                                                                                                                 
Shrimp, vernal pool       Lepidurus packardi......  U.S.A. (CA).............  NA.....................  E                     549           NA         NA
 tadpole.                                                                                                                                               
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Dated: August 31, 1994.
Mollie H. Beattie,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 94-23156 Filed 9-16-94; 8:45 am]
BILLING CODE 4310-55-P-M