DESCRIPTION OF SPECIAL STATUS SPECIES
Yuma Clapper (Rallus longirostris yumanensis)
The Yuma clapper rail inhabits marshes along the lower Colorado River. from near the Nevada-California border, south to the Colorado Delta region of Mexico (Anderson, 1983). Much of this marsh habitat has developed on the silt deposits behind Bureau of Reclamation (Reclamation) dams (Eddleman et al, 1988). Clapper rails also occur m marshes around the Salton Sea and elsewhere in the Imperial Valley where suitable marsh habitat exist (Bennett and Ohmart, 1978). Historic occurrence of the Yuma dapper rail in the Imperial Valley is not well documented, but the species apparently occurred around the Salton Sea at least as early as 1940 (Abbot, 1940; referenced in Anderson, 1983).
Principal clapper rail population concentrations occur at the Imperial Wildlife Area-Wister Unit and the Salton Sea National Wildlife Refuge. Rails are also known to occur between Drops 3 and 4 along the All-American Canal (AAC) and in outer seep areas associated with the Coachella and East Highline Canals (Gould, 1975; Jurek, 1975; Bennett and Ohmart, 1973; Kasprzyk et al, 1987).
Preferred Yuma clapper rail habitat generally consists of freshwater marshes with stands of mature emergent vegetation such as cattail or bulrush, shallow water, and accessible high ground for nesting areas (Smith, 1974). The highest densities of clapper rails occur in stands of cattails dissected by narrow channels of flowing water (Anderson, 1983). Food primarily consists of crayfish (Procambrus sp. and Orcopectes sp.). although dapper rails tend to be opportunistic arid will feed on other items such as small fish, dams. and aquatic insects when available (Ohmart and Tomlinson. 1977).
Until recently it was thought that most Yuma dapper rails migrated in the fall as the crayfish resource became dormant (Anderson and Ohmart, 1985). Recent studies indicate that along the lower Colorado River, at least 70 percent of the population does not migrate, and crayfish are active all year (Eddleman, 1989). The year-long residency of this population clapper rails along the lower Colorado River as well as in the Salt Creek marsh area may be at least partly due to resource.
Yuma Clapper Rail Survey Results
Along the Coachella Canal, past dapper rail surveys were conducted by Jurek (1975), Could (1975), and Bennett and Ohmart (1978). Jurek's (1975) studies were limited to an area outside the project area between the Coachella Canal and the East Highline Canal from the AU-American Canal to Beat Road. Gould's (1975) report included a census in the Salt Creek area in 1974 when Yuma clapper rails were not detected. The area surveyed is described as the "river section of.. . Sait Creek.. which indicates that the upstream end where the majority of the marsh vegetation is located was not surveyed. Bennett and Ohmart's work in 1977 was more extensive and included marshes with the Salt Creek area, as well as the other sources of inflow to the Salton Sea and associated marshes of the Salton Sea area. They documented the presence of 14 Yuma dapper rails on Salt Creek, at least 12 of which were paired.
Yuma clapper rail surveys were conducted during the periods March 29-30, and April 19-21, 1988, as part of studies associated with the proposed Coachella Canal project (Reclamation, 198k). Transects were walked along the perimeter of each marsh area. At approximately every 100 yards, tape recorded calls of Yuma dapper rails and California black rails were broadcast through a loudspeaker. To survey Yuma dapper rails, two types of calls were broadcast, the "kek" call of the unpaired male, and the "clatter" calls typical of paired Yuma clapper rails (Reynard, 1974). Each tape recorded call was played, then repeated after a silence of 20 seconds duration. Responses were noted and categorized.
Yuma clapper rails were found in the Salt Creek marsh area in the vicinity at Dos Palmas Ranch during both the March and April surveys. In March, Yuma clapper rails were solely eliciting the 'kek calls typical of unpaired male birds. By mid-April, birds seemed to have paired, as evidenced by the "clatter" calls of dueting birds. All clapper rail vocalizations emanated from dense stands of cattail with standing water. The surveys indicated that at least eight Yuma clapper rails were present in March and six birds were present in April. This number does not necessarily indicate the total number of rails present in the area at that time.
Desert Pupfish (Cyprinodon macularius)
Desert pupfish are endemic to the Gila River drainage in Arizona, the Sonoyta River drainage in northern Sonora.Mexico. and the lower Colorado River drainage, including the Salton Sea and several of its tributaries in California and Baja California (Miller, 1943; in Environmental Science and Engineering, 1983). In recent years, the distribution of the desert pupfish has become very limited in California and it is now only found in the Salton Sea and several of its tributaries (Black. 1979). Abundance of the desert pupfish has declined in the Salton Sea area. A major factor leading to this decline has been the establishment of exotic, tropical species that may prey on or compete with desert pup fish for available food and space (Black. 1980).
Habitat requirement of the desert pupfish include a sand-silt substrate, an abundance of rooted aquatic plants and filamentous algae, water depths of not more than 12 inches, surface flows of not more than 1 cubic foot per second, and water temperatures above freezing in winter (Black. 1980). These conditions prevail in major portions of Salt Creek but not in the Coachella Canal.
The upper portion of Salt Creek appears to be the best habitat for pupfish in Salt Creek. A waterfall provides a downstream barrier. There are shallow backwater areas with abundant food and cover (Bureau of Land Management (ELM), 1982).
Desert pupfish have not been found during fish inventories in the Coachella Canal (Minckley et al., 1983; Mueller et al., 1984. Thiery and Mizumoto, 1987). Surveys of the Salt Creek drainage conducted by California Department of Fish and Game (DPG) in April and May 1986. resulted in the capture of 70 pupfish along a 750-foot stretch of Salt Creek This number represent the minimum size of the population in Salt Creek. In June 1987, DFC personnel again noted the presence of desert pupfish in Salt Creek; however, trapping was not conducted at that time. Desert pupfish also occur at Oasis Springs approximately 2 miles east of Salt Creek
It is believed that before 1982, the upper portion of Salt Creek contained mostly desert pupfish with very few exotics due to a natural fish barrier in the Stream channel (BLM, 1982). Presently, the vast majority of fish in the upper section of Salt Creek are exotics dominated by tilapia (Talipia sp.) (Environmental Science and Engineering, 1983). The mechanism for the recent introduction of exotic fish into upper Salt Creek is not known.
Razorback Sucker (Xyrauchen taxanus)
The razorback sucker is endemic to the Colorado River drainage from Wyoming to Mexico and was historically distributed throughout the mainstream of the river and along its major tributaries. At present, the species is found in isolated segments of the Green and Colorado Rivers in the upper basin. in portions of Lakes Mead, Mojave, and Havasu, and in Senator Wash Reservoir in the lower basin (Minckley et. al. 1983). Most of the individuals found in the reservoirs are quite large, possibly indicating low reproductive success (Minckley et. al., 1983).
DFG and the U.S. Fish and Wildlife Service (FWS) conducted a reintroduction program for razorback suckers in the lower Colorado River in recent years, which may account for small numbers of the species Subsequently captured in irrigation canals along the lower Colorado River drainage. Razorback suckers have also been found in small numbers in the cement-lined Granite Reef Aqueduct.
The razorback sucker was not found in inventories of the Coachella Canal in 1980 and 1984 (Mueller et al., 1984). There have been no recorded occurrences of razorback suckers in the Coachella Canal; however, the species has been reported in the reservoirs off the canal (Richard Thiery, personal communication).
Preferred habitat of the razorback sucker is warm flowing water over sand, gravel, or rocky bottom. The species is a bottom feeder and forages on microscopic organisms, filamentous algae, and insect larvae. Spawning occurs in January through May. over gravelly bottoms, in tributary streams, and in shallow waters of reservoirs (Minckley et. al.. 1983).
Desert Tortoise (Xerobates agassizii)
The desert tortoise is an extremely long-lived, herbivorous reptile occurring throughout most of the Mojave and Sonoran Deserts. It is known to occur in the general project area. especially in the Chocolate Mountains.
Surveys for desert tortoise were conducted on the Chocolate Mountains Aerial Gunnery Range in 1981 where the highest kown tortoise populations of 100 - 250 per square mile were found on Chuckwalla Bench. Low populations of 0 - 25 per square mile were found on the western portion of the Gunnery Range nearest the Coachella Canal during the same surveys. Optimum tortoise habitat was found primarily in sandy soils where there is a mosaic of desert pavement, desert washes, and rolling hills at elevations ranging from 1150 to 2050 feet.
Areas adjacent to the Coachella Canal were surveyed in May 1981 for tortoise habitat suitability (FWS. 1988). Most of the area adjacent to the unlined portion of the Coachella Canal was determined to be poor quality habitat due to rocky substrate, scarce vegetation and low elevations. The areas between siphons 22-23 and 29-31 could provide at least marginal habitat due to a sandy loam substrate. However, this area with an elevation of around sea level is probably too low for tortoises. No tortoise burrows or other signs were observed during these surveys. The results of the 1988 tortoise surveys are summarized in the FWS memorandum dated July 16, 1988.
Although candidate specles do not have protection in accordance with Section 7(c) of the Endangered Species Act of 1973, as amended, they are included in the assessment in the event that their status changes during the course of construction.
Yuma Puma (Felus concolor browni)
The Yuma puma is not well studied and little is known about the status and distribution of this subspecies of the mountain lion. records of the Yuma puma since 1969 have included sporadic sightings of the Yuma puma along the Coachella Canal and in the Chocolate Mountains (Harvey and Stanley 1987). It is generally assumed that the distribution of pumas is closely related to the distribution of the burro deer (Odocoileus hemionus eremicus) populations. Studies of desert mule deer (O.h. crooki) along the lower Colorado River showed deer population movements through desert washes from riparian zones to desert mountain ranges. after commencement of the summer monsoon season, with returns to the reparian zone by late spring (Celentano and Garcia. 1984; Haywood et al.. 1984). Pumas are likely to have similar movements as they follow their prey.
The status of bats in California is not Well known; However, there is increasing evidence of significant declines in the populations of a number of species. Ongoing studies by DFG will provide information on Statewide occurrence and population trends for special status species (Caryla Larsen, personal communication). There are five candidate species of bats that may occur in the project area and are described as follows.
Spotted Bat (Euderma maculata)
Little information is available on the spotted bat This species used to be quite common in coastal and central California. There is one record for the spotted bat in Riverside County, a dead bat found near Mecca in 1903 (Pat Brown, personal communication) There is no evidence that populations of spotted bats occur in the project area.
Greater Western Mastiff Bat (Eumops perotis californicus)
This species has declined in numbers over the years arid is considered by some to be the highest priority bat species in California. The mastiff bat ranges from the central California coast into the desert southwest It prefers rugged rocky canyons where crevices on high cliff faces provide preferred roost sites (Barbour and Davis. 1969). It is also known to roost in trees, buildings, and tunnels. It emerges at late dusk to feed on hymenopterous insects (Burt arid Grossenheider, 1964).
Occult Little Brown Bat (Myotis occultus)
The occult bat roosts colonially in caves, mine tunnels, hollow trees, and buildings. It emerges at dusk to feed on insects near water (Burt arid Crossenheider, 1964). It is known from riparian areas along the lower Colorado River, and is more common in Arizona than in California (Pat Brown, personal communication).
Nine candidate species of birds were indicated by the FWS to be of concern in the project area; California black rail (Latterallus jamaicensis coturniculus), white-faced ibis (Plegadis chichi), Eulvous whistling duck (Dendrocygna bicolor), Swainson's hawk (Butto swainsoni), ferruginous hawk (Buteo ragalis), western snowy plover (Charadrius alexandrinus nivosus), mountain plover (Charadrius montanus), long-billed curlew (Numenius americanus), and tricolored blackbird (Agelaius tricolor). Surveys for California black rails were conducted during March and April 1988, concurrent with Yuma clapper rail surveys (Reclamation, 1988a). The status and distribution of the other eight candidates is based on existing information, although these species wore looked for during gen~al bird surveys of the area.
California Black Rail
This subspecies occurs along the California coast from Tomales Bay in Mann County, south to San Diego Bay and Baja California. It also occurs in interior southern California and in Arizona. The overall status of the California black rail is at present, unknown; however, it is generally believed that overall numbers of California black rails have declined due to degradation and elimination of fresh and salt water wetland habitat (Wilbur, 1924). Few surveys have been performed for the California black rail in the Imperial Valley. Jurek's (1975) and other investigations of 1974 and 1925 included marsh habitats between the Coachella and East Highline Canals only. Jurek (1975) detected 20 to 26 black rails, which were fairly evenly distributed in all marshes except for those with little surface water. Along the All - American Canal, Kasprzyk et al. (1987) recorded 30 to 50 California black rails in the marsh located between drops 3 and 4.
Preferred habitat of California black rails is in areas with minimum water fluctuations, providing moist surfaces or very shallow water, gently sloping shorelines and dense stands of marsh vegetation (Repking and Ohmart, 1977). During Reclamation's surveys. black rails appeared to be associated with types 1.2.3. and 4 marshes.
California black rails were cerisused during Mardi and April 1988, concurrently with Yuma dapper rail surveys (Reclamation, 1988a). Tape recordings of their song were played and responses noted. The results of these surveys revealed the presence of this species in the western portions of the Salt Creek marsh, as well as in other marshes downstream from the Hot Mineral Spa. During March 1989, black rails were heard in the eastern portions of Salt Creek Marsh in marsh type 4 (Jim Rorabaugh, personal communication).
White-Faced Ibis (Plegadis chichi)
The white-faced ibis is a fairly common transient and summer visitor in the Salton Sea area, breeding locally and irregularly (Garrett and Dunn~. 1981). Personnel from Salton Sea National Wildlife Refuge report flocks of 4,000 to 5,000 in the winter at the Salton Sea, where they feed in flooded alfalfa fields. The ibis feeds on crayfish, other invertebrates, and small fish in marshes, irrigated fields, and shallow backwaters. It has not been reported in the project area.
Fulvous Whistling Duck (Dendrocygna bicolor)
The fulvous whistling duck is an uncommon breeder in the Salton Sea area, preferring dense stands of cattails with adjacent shallow water (Garrett and Dunn, 1981). Salton Sea National Wildlife Refuge reports 40 to 50 pairs of fulvous whistling ducks (B. Henry, personal communication). It also is known to forage in irrigated fields in the Imperial Valley. This species has not been observed.
Swainson's Hawk (Buteo swainsoni)
The Swainson's hawk is observed occasionally in the Imperial Valley during spring and particularly during fan migration (Garrett and Dunn. 1981; B. Henry, personal communication). This hawk is not known to breed in the general project area and has riot been observed in the affected environment. It winters in South America.
Ferruginous Hawk (Buteo regalis)
Migrating ferruginous hawks are observed with greater frequency than Swainson's hawks during spring in the vicinity of Salton Sea National Wildlife Refuge (B. Henry. personal communication). The species is also known as a winter visitor in the Imperial Valley (Garrett and Dunn, 1981) but is not known to breed in the desert southwest. It is usually associated with agricultural land but has not been observed in the project area.
Western Snowy Plover (Charadrius alexandrinus nivosus)
The snowy plover is primarily a summer resident in the Imperial Valley. It nests at the Salton Sea along gravelly beaches, salt pans, and alkali flab. It feeds in very shallow water not far from the nest area (Garrett and Dunn. 1981; B. Henry, personal communication). It also feeds in agricultural fields. This species has riot been observed in the project area-
Mountain Plover (Charadrius montanus)
Mountain plovers are fairly common winter residents in the Imperial Valley (Garrett and Dunn. 1981). congregating in flocks of up to 1,000 in Bermuda grass and plowed fields (B.Henry, personal communication). This species has not been observed in the project area.
Long-Billed Curlew (Numenius americanus)
The long-billed curlew is present most of the year in the Imperial Valley, foraging in flooded alfalfa fields. There are no documented breeding records of this species for die area (B. Henry, personal communication).
Tricolored Blackbird (Agelaius tricolor)
Personnel from the Salton Sea National Wildlife Refuge regard the tricolored blackbird as accidental in its occurrence in the area (B. Henry, personal commumication). Reports of large flocks near the north end of the Salton Sea have been nonconlusive (Garrett and Dunn, 1981). However, this species is associated with wetlands of the desert southwest (Ray Bransfield, personal communication) This species has not been observed in the project area.
Flat-Tailed Horned Lizard (Phrynosoma m'callii)
The fiat-tailed horned Lizard occurs in the desert lowlands of Imperial, Riverside, and San Diego Counties; south to Baja California, and Sonora, Mexico; and in the extreme southwestern portion of Arizona (Turner et al. 1980). The original range of the species has diminished in recent years due to human activities (Turner et al., 1980).
Flat-tailed horned lizard habitat is characterized by areas of low relief with surface soils of fine, packed sand, or pavement, overlain with loose, fine, windblown sand (Turner et al., 1980). Optimal habitat is found in the desert saub commnnity; however, the species is also known to occur at the edges of vegetated sand dunes, on barren clay soil, and in saltbush communtities. Diet of the flat-tailed homed lizard consists almost exclusively of harvester ants. Observations of the species were correlated with numbers of black harvester ant nests (Turner and Medica, 1982).
During April 1988, Reclamation biologists conducted surveys for flat-tailed horned lizards along a 38-mile stretch of the Coachella Canal (Reclamation. 1988b). No evidence of the horned lizard was found. The necessary habitat of fine, sandy substrate and simple, scarce flora was absent along the canal alignment
Colorado Desert Fringe-Toed Lizard (Uma notata notata)
The range of this species is extreme southeastern California, west to extreme eastern San Diego County, and northeastern Baja California. The Colorado desert fringe-toed lizard is highly adapted to living in areas of windblown sand and is not known to occur elsewhere (Smith. 1971). Distribution is restricted to flne, loose, windblown sand of dunes, flats, riverbanks, and washes (Stebbins. 1985).
Five speces of plants were indicated by FWS to be of concern in the project area:
California ditaxis, (Ditaxis california), Orocopia sage (Salvia greatae), desert sunflower (Helianthus niveus spp. tephrodes), giant Spanish needles (Pa1afoxia arida var. gigantea) and Peirson's milkvetch (Astragallus magdalene var.peirsonii). In addition, California Department of fish and Game personnel suggested that two additional spacies, Wiggin's croton (Croton wigginsii), and fairyduster, (Calliandra eriophylla) may also be present The only species that has been reported from the general project area is the Orocopia sage.
California ditaxis is a candidate species for Federal listing and a listed by the California Native Plant Society (CNPS). This species is a woody perennial member of the spurge family, inhabiting sandy washes and canyon floors in the desert scrub community at elevations between 400-3000 feet.
Desert Sunflower (Helianthus niveus spp.tephrodes)
Desert sunflower is a candidate species for Federal listing, listed as endangered with the State of California, and is also listed with CNPS. This species is restricted to unconsolidated and fairly mobile sand dunes.
Orocopia sage is a candidate species for Federal listing and is listed by CNPS. This is a woody perennial of the mint family, typically found in desert washes and on alluvial fans at the base of the Orocopia and Chocolate Mountains below 600 feet. The type locality is Salt Creek Wash. There are recent records of Orocopia sage in the general project area (Imperial Irrigation District and ELM. 1987). Because of distribution records, this species has the greatest potential to occur at the project site.
Giant Spanish Needles (Palafoxia arida var.gigantea)
The giant Spanish needle is a candidate species for Federal listing arid is also listed by CNPS. This species is a woody perennial. res~icted to stable arid active sand dunes in southeast California.western Arizona, and Baja California.
Peirson's Milkvetch (Astragalus magdalene var.perisonii)
Peirson's milkvetch is a candidate species for Federal listing and is listed as endangered by the State of California. This species is a woody perennial member of the pea family, restricted to slopes and hollows of mobile dunt systems in the Algodones system and Borrego Valley, California.
Fairyduster is localized in its California distribution and is therefore listed with CNPS.
This species is a 2ow shrub of the pea family, found in shallow, sandy washes and gullies in desert pavement areas and on alluvial fans below 1000 feet in southeastern California.
It has been reported to be relatively abundant on the east side of the Chocolate Mountains (Jaeger, 1969).
Wiggin's Croton (Croton wigginsii)
Wiggin's croton is listed as endangered with the State of California. In California, this woody perennial inhabits stable and active sand dunes and sandy washes in the Algodones dune system.
Results of Surveys for Sensitive Plant Species
Surveys for the seven species were conducted in the project area by Reclamation and Fish and Wildlife Service personnel in March 1988. Because of the large size of the project area, a complete survey was not conducted, but 10 percent of the directly affected desert scrub community type was sampled. Additionally, 15 desert washes located perpen-dicular to the canal siphons was surveyed.
The seven species of concern were not found during the surveys. Three species, desert sunflower, giant Spanish needles, and Pairsan's milkvetch are highly restdricted to dune systems, which are not present in the project area. Localized populations of the species not restricted to dune systems could be present in the project area. Wiggin's crotan is most commonly found in dunes systems, although it has been found on sandy soils in the desert scrub community. The other three species, California ditaxis. Orocopia sage, and fairyduster are known from desert washes or alluvial fans; therefore, it is possible that small populations could exist in the study area.
Brown-Tassel Trigonoscuta Weevil (Trigonoscuta brunotesselata)
This species is known only from the Kelso Dunes in San Bernardino County, California (Dr. Albert Sleeper, Long Beach Sate University, California, personal communication).
Andrew's dune scarab beetle is presumed to be endemic to the Sand Hills, Imperial County, California. and probably in portions of the sand dune system in Baja California Norte, Mexico. Distribution of the species is apparently widespread across the main dune mass. However, there is no evidence that it inhabits areas other than the main dunes
(Hardy and Andrews, 1979).