Location: MSHCP > VOLUME 2 > INVERTEBRATES/CRUSTACEANS
Riverside fairy shrimp (Streptocephalus woottoni)
State: None
Federal: Endangered
The Riverside fairy shrimp is narrowly distributed in the Plan Area. It is known from five localities in deep vernal pools. In the Plan Area vernal pools supporting Riverside Fairy shrimp have identified on Murrieta stony clay loams, Las Posas series, Wyman clay loam, and Willows soils. Five known key populations occur within the Plan Area. They are located on the Santa Rosa Plateau, Skunk Hollow, Murrieta and Lake Elsinore back basin. Preservation of this species must be analyzed based on Core Areas. Riverside fairy shrimp requires specific conditions, occurs in few locations, and uses a well-defined habitat that is narrowly distributed. This species will require site specific considerations, protection of essential habitat on a landscape basis, and species specific management conditions.
The species-specific conservation objectives developed for this species are based upon the best available scientific information at the time of MSHCP preparation. Pursuant to Section 5.0 which includes Management, Monitoring and the Adaptive Management Program, the MSHCP's mitigation requirements will be monitored and analyzed to determine if they are producing the desired result. Based upon this information, the following species-specific conservation objectives will be adjusted if appropriate, as new information is gathered during Plan implementation. The Adaptive Management Program will be used to identify alternative strategies for meeting the MSHCP's general biological goals and objectives and, if necessary, adjusting future conservation strategies according to the information received.
Include within the MSHCP Conservation Area at least five Core Areas of occupied vernal pools (or vernal pool complex) and their watersheds. Core Areas include the Santa Rosa Plateau Ecological Reserve (17,188 acres), Skunk Hollow (156 acres), Murrieta (1,292 acres) and Lake Elsinore back basin (3,180 acres).
Include within the MSHCP Conservation Area at least 11,942 acres of landscape habitat area which might contain suitable vernal pool habitat for Riverside fairy shrimp (playa, basalt flows, and clay soils). These areas may support other non-mapped pools and depressions which may be suitable for Riverside fairy shrimp.
Include within the MSHCP Conservation Area additional areas within the Criteria Area identified as important for the Riverside fairy shrimp. This objective shall be met through implementation of the Protection of Species Associated with Riparian/Riverine Areas and Vernal Pools policy presented in Section 6.1.2 of the MSHCP, Volume I. Wetland mapping assembled as part of that policy shall be reviewed as part of the project review process and, if suitable Riverside fairy shrimp habitat, defined as vernal pools, stock ponds, ephemeral ponds, or other human-modified depressions, is identified on the wetland maps and cannot be avoided, a single-season dry or wet season survey for this species shall be conducted by a qualified biologist in accordance with accepted protocol. If survey results are positive, 90 percent of the occupied portions of the property that provide for long-term conservation value for the fairy shrimp shall be conserved.
As described below under Data Characterization, there are only six data points for the MSHCP Plan Area that are precise enough for evaluation, due in large part to ephemeral microhabitat characteristics, low survey effort, low population numbers, and patchy distribution. However, these data points are thought to define the species' distribution within Western Riverside County. Three (50 percent) of six precision code "1" MSHCP data points would be conserved in reserve or existing Public/Quasi-Public Lands. The unmapped Santa Rosa Plateau population would also be conserved. Other known populations at Alberhill and one of two populations at Lake Elsinore would be conserved within the MSCHP Conservation Area.
For purposes of this conservation analysis, potential habitat for the Riverside fairy shrimp includes deep, long-lived vernal pools, ephemeral ponds and human derived depressions. Vernal pools and alkali playas have been mapped to a certain extent, within the MSCHP Plan Area and coverages are presented in Table 1. However, this microhabitat may occur sporadically within a variety of mapped habitats ranging from disturbed or ruderal land coverages to chaparral. Because of this, species coverage can not be concluded based on habitat preservation alone. Instead, species coverage must be based on key population preservation combined with key population habitat preservation within the five key habitat Core Areas (i.e., Santa Rosa Plateau, Murrieta, Skunk Hollow, Lake Elsinore back bay area, and Alberhill) and general conservation of vernal pools and playas within the Plan Area.
TABLE 1
SUMMARY OF KNOWN VERNAL POOL AND HABITAT MATRIXES CONSERVATION FOR RIVERSIDE FAIRY SHRIMP
| Vegetation Type | MSHCP Plan Area (Acres) |
Within MSHCP conservation Area | Outside MSHCP conservation Area | ||||
|---|---|---|---|---|---|---|---|
| Criteria Area1 (Acres) |
Public/ Quasi-Public (Acres) |
Total Within MSHCP Conservation Area (Acres) |
Rural/ Mountainous (Acres) |
Outside MSHCP Conservation Area (Acres) |
Total Outside MSHCP Conservation Area (Acres) |
||
| Playas and Vernal Pools2 | 7,913 | 3,827 | 2,923 | 6,750 | 0 | 1,163 | 1,163 |
| Clayey (Altamont, Auld, Bosanko, Claypit, and Porterville) Soils3 | 608 | 182 | 50 | 232 | 0 | 376 | 376 |
| Basalt Flow (Santa Rosa Plateau Basalt Flow) Soils3 | 1,698 | 585 | 996 | 1,581 | 83 | 34 | 117 |
| Alkalai (Willows, Traver, and Domino) Soils3 | 7,591 | 2,591 | 788 | 3,379 | 0 | 4,212 | 4,212 |
| TOTAL | 17,810 | 7,185 | 4,757 | 11,942 | 83 | 5,785 | 5,868 |
| 1 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area. 2 Includes all vernal pool habitat inside and outside the Core Areas. 3 Only includes habitat in the Skunk Hollow, Murrieta, Alberhill, Lake Elsinore, and Santa Rosa Plateau. |
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The MSHCP Plan Area supports approximately 17,810 acres of land which may support suitable habitat for the Riverside fairy shrimp. Within that acreage, approximately 6,750 acres (85 percent) of the available vernal pool and playa habitat. 5,192 acres (52 percent) of the available habitat matrix over appropriate soils (i.e., playa, basalt flow, clayey soils) which might support pools, occurs within the Santa Rosa Plateau, Murrieta (a small (approximate 150-acre) block in Wildomar (Murrieta) just north of Clinton Keith Road), Skunk Hollow, Lake Elsinore back bay area, and Alberhill key population areas. Overall, approximately 11,942 acres (67 percent) of potential key population suitable habitat will be conserved in the MSHCP Conservation Area. It is assumed that these lands would be managed for wildlife resources including the Riverside fairy shrimp.
Five key populations (Santa Rosa Plateau, Lake Elsinore, Skunk Hollow, Alberhill, and Murrieta) will be conserved within the MSHCP Conservation Area. Additionally, the configuration of the MSHCP Conservation Area provides for conservation of other potential habitat on the Gavilan Plateau, Salt Creek, and San Jacinto River floodplains. Connectivity between the known populations is not necessary. However, it is necessary to protect the populations, the watersheds and water quality of the pools that sustain them, and provide for expansion within the pool complexes associated with the populations. Accordingly, large habitat blocks important to the Riverside fairy shrimp are located throughout MSHCP Conservation Area and the species known range within the Plan Area within the following Core Areas: Santa Rosa Plateau (Existing Core F; 17,188 acres), Murrieta (1,292 acres), Skunk Hollow (156 acres), Alberhill (3,324 acres), and Lake Elsinore back bay area (3,180 acres). All of these contain, or are expected to contain, the habitat requirements necessary to support Riverside fairy shrimp populations and associated vernal pools.
Implementation of the MSHCP, including the conservation of existing populations and Critical Habitat as described above, will maintain viable populations of the Riverside fairy shrimp and facilitate recovery of the species. The current distribution is thought to be known, however the discovery of additional populations cannot be ruled out. Breeding population size is unknown and censussing breeding populations can be problematic due to the species' ephemeral nature. However, pools can be sampled to determine cyst densities. Ensuring that the species remains viable in the MSHCP Plan Area will require a systematic monitoring program as described below.
In summary, conservation for the Riverside fairy shrimp will be achieved by the inclusion of at least 11,942 acres of suitable Conserved Habitat within five Core Areas which are composed of large blocks of habitat within the MSHCP Conservation Area. In addition, other areas within the Criteria Area identified as important for the Riverside fairy shrimp will be conserved. This objective shall be met through implementation of the Protection of Species Associated with Riparian/Riverine Areas and Vernal Pools policy presented in Section 6.1.2 of the MSHCP, Volume I. Wetland mapping assembled as part of that policy shall be reviewed as part of the project review process and, if suitable habitat for this species is identified on the wetland maps and cannot be avoided, a single-season dry or wet season survey for this species shall be conducted by a qualified biologist in accordance with accepted protocols. If survey results are positive, 90 percent of the occupied portions of the property that provide for long-term conservation value for the fairy shrimp shall be conserved. Furthermore, the Plan Area is contiguous with suitable habitat in Orange and San Diego counties.
Within the key population areas, approximately 5,868 acres (33 percent) of potential vernal pool and playa habitat and suitable soils habitat land coverages would be located outside the MSHCP Conservation Area. Any Riverside fairy shrimp present within this area would be subject to Incidental Take under the guidelines implemented as part of this Plan.
This fairy shrimp is found in deep long-lived vernal pools. The currently known distribution in Riverside County is thought to be moderately well understood. Critical Habitat designation was recently finalized by the U.S. Fish and Wildlife Service (2001), but is currently under federal review, and a Recovery Plan for southern California vernal pools was completed by the U.S. Fish and Wildlife Service (1998) which outlines the requirements for downlisting/delisting the Riverside fairy shrimp, among other vernal pool species. Existing information regarding the Riverside fairy shrimp's biology is minimal, and much needs to be studied, however the U.S. Fish and Wildlife Service determined that there was enough information available to designate critical habitat and issue recovery plan guidelines. The MSHCP database holds eight (8) records for S. wootoni. Of the eight records, six (75 percent) are precision code "1" (an "x" and "y" coordinate that allows for good precision in the location) and three are precision code "3" or "4" (relatively imprecise locations from general areas). Four of the Precision code "1" records are from 1998, one from 1992, and one from 1990. All records are considered to be recent.
S. wootoni is restricted to deep seasonal vernal pools, vernal pool like ephemeral ponds, and stock ponds and other human modified depressions (Eng, Belk, and Eriksen 1990, U.S. Fish and Wildlife Service 1993, U.S. Fish and Wildlife Service 2001). Riverside fairy shrimp prefer warm-water pools that have low to moderate dissolved solids, are less predictable, and remained filled for extended periods of time (Eriksen and Belk 1999). Basins that support Riverside fairy shrimp are typically dry a portion of the year, but usually are filled by late fall, winter or spring rains, and may persist through May (U.S. Fish and Wildlife Service 2001). All known habitat lies within annual grasslands, which may be interspersed through chaparral or coastal sage scrub vegetation. In Riverside County, Riverside fairy shrimp have been found in pools formed over the following soils: Murrieta stony clay loams, Las Posas series, Wyman clay loam, and Willows soils (U.S. Fish and Wildlife Service 2001).
Riverside fairy shrimp is restricted to southwestern California and northwestern Baja California. It occurs from Los Angeles County (L.A. Airport) south and east through Orange and western Riverside Counties to coastal San Diego County (primarily Camp Pendleton and Otay Mesa) and the vicinity of Baja Mar north of Ensenada in Baja California, Mexico. With the exception of the Riverside populations, all populations are within 15 kilometers of the coast over a north-south distance of about 140 kilometers (Eriksen and Belk 1999). All known populations lie between 30 and 415 meters in elevation.
Within Western Riverside County, the Riverside fairy shrimp is known from vernal pools on the Santa Rosa Plateau (U.S. Fish and Wildlife Service 2001); at Skunk Hollow, just east of the I-15 on the Pechanga Indian Reservation; Murrieta; Wildomar; Lake Elsinore; and Alberhill. The U.S. Fish and Wildlife Service (2001) indicate that five populations remain in Western Riverside County including the Skunk Hollow, Santa Rosa Plateau, Murrieta, Alberhill, and Lake Elsinore populations, plus an un-named location that apparently includes a series of private stockponds. Both sites along Highway 79 appear to have been graded. The type locality was graded in 1995 and another site is apparently now within the Murrieta Golf Course. Other undiscovered populations may occur in this area.
The U.S. Fish and Wildlife Service (2001) determined that the Santa Rosa Plateau and Murrieta populations were important enough for species recovery, to designate them as critical habitat. Since these areas, hold the largest known, contiguous populations of non-protected fairy shrimp, they are also considered to be key populations for this plan. Additionally, the Skunk Hollow population is considered important.
Genetics: No genetic studies have been conducted on S. wootoni to determine its relatedness to other genera/ species, or to determine the relatedness of one sub-population to another.
Diet and Foraging: Anostarcans are non-selective particle-feeding filter-feeders, or omnivores. Detritus, bacteria, algal cells, and other items between 0.3 to 100 microns may be filtered and ingested (Eriksen and Belk 1999).
Daily Activity: Literature review unfinished.
Reproduction: S. wootoni females produce between 17 and 427 cysts over their lifetime (Simovich and Hathaway 1997). Presumably because of the ephemeral and unpredictable nature of the pool resource, few of the available cysts hatch at a time (Eriksen and Belk 1999). Cysts may hatch when water temperature is at 10 degrees Celsius but develop slowly below 15 degrees Celsius (Eriksen and Belk 1999). Hathaway and Simovich (1996)found that S. wootoni hatched in 7 to 12 days when water temperature was between 10 and 20 degrees Celsius and maturity was noted between 48 to 56 days.
Survival: There is no information regarding survivorship. However, in a species dependant on an ephemeral and unpredictable resource, it is easy to assume that there is often 100 percent mortality in hatched cohorts when ponds dry.
Dispersal: Dispersal in fairy shrimp is likely caused by "vectors" such as waterfowl, cattle, sheep, dogs and other traffic or wallowing through inhabited wet or dry pools, and vehicles transporting cysts or pregnant or mature adults between dry depressions or extant pools; cysts dispersed like some plant seeds by running the length of an animal gut through ingestion of pregnant females or ingestion of cysts in drinking water and elimination over suitable depressions or pools.
Socio-Spatial Behavior: There is no information regarding the partitioning of intraspecific resources, territoriality, or other socio-spatial behaviors.
Community Relationships: Fairy shrimp forage on micro-nutrient packages, converting the micro-nutrients into usable food for larger invertebrates and vertebrates. Fairy shrimp may be eaten by a wide variety of species, including beetles, dragonfly, larvae, and other arthropods, frog, salamander, and toad tadpoles, shorebirds, ducks, and even other fairy shrimp. S. wootoni may be found swimming and competing for food resources with Branchinecta lindahli and B. sandiegonensis. S. wootoni cysts may co-occur with those of B. lynchi, however they do not swim together (Eriksen and Belk 1999).
Urban, agricultural development, modified hydrology due to adjacent road construction, and illegal trash dumping. Unpredictable natural events such as drought or fire may extirpate the Riverside fairy shrimp due to its fragmented and restricted range. Low levels of genetic variability may affect the species potential for long term viability (U.S. Fish and Wildlife Service 1993).
Riverside fairy shrimp are adapted for survival in water bodies that are relatively short-lived and their cysts (protected eggs) can withstand long dry periods. Riverside fairy shrimp require warm waters, often available only late in the rainy season for hatching (Eriksen and Belk 1999). Vulnerable to contaminants in runoff waters and watershed quality. The limited genetic information available suggests that there is very little genetic variability within populations. Dispersal of cysts thought to occur by animal vectors, either grazing animals or waterfowl. With the long distance isolation between the few remaining pools, gene flow is greatly if not completely reduced.
Brown, J. W., H.A. Wier, and D. Belk. 1993. New records of fairy shrimp (Crustacea: Anostraca) from Baja California, Mexico. The Southwestern Naturalist 38(4): 389 - 390.
Eng, L.L., D. Belk and C.H. Eriksen. 1990. California Anostraca: distribution, habitat and status. Journal of Crustacean Biology 10: 247 - 277.
Eriksen, C. and D. Belk 1999. Fairy Shrimps of California''s Puddles, Pools, and Playas. Mad River Press, Inc., Eureka, California.
Hathaway, S.A. and M.A. Simovich. 1996. Factors affecting the distribution and co-occurrence of two southern Californian anostracans (Branchiopoda), Branchinecta sandiegonensis and Streptocephalus wootonii. Journal of Crustacean Biology 16(4): 669 - 677.
Hathaway, S.A., D.P. Sheehan, and M..A. Simovich. 1996. Vulnerability of branchiopod cysts to crushing. Journal of Crustacean Biology 16(3): 448 - 452.
Simovich, M.A. and S.A. Hathaway. 1997. Diversified bet-hedging as a reproductive strategy of some ephemeral pool anostracans (Branchiopoda). Journal of Crustacean Biology 17(1): 38 - 44.
U.S. Fish and Wildlife Service. 1997. Vernal Pools of Southern California Recovery Plan. U.S. Fish and Wildlife Service, Portland, Oregon. 113+pp.
U.S. Fish and Wildlife Service. 1993. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Three Vernal Pool Plants and the Riverside Fairy Shrimp. Federal Register 58: 41384-41392.
U.S. Fish and Wildlife Service. Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for the Riverside fairy Shrimp; Final Rule. Federal Register 66: 29384-29414.
White, S. D. 1994. Vernal Pools in the San Jacinto Valley. Fremontia 22(3): 17 - 19.
Santa Rosa Plateau fairy shrimp (Linderiella santarosae)
State: None
Federal: None
The Santa Rosa Plateau fairy shrimp is narrowly distributed in the Plan Area. It is restricted to cool-water vernal pools which are formed on Southern Basalt Flows. In the Plan Area, this species, and its microhabitat are only known to occur on the Santa Rosa Plateau.
Because the Santa Rosa Plateau fairy shrimp requires specific conditions, occurs in few locations, and is confined to a well defined habitat that is very narrowly distributed, this species will require site specific considerations, protection of preferred habitat, and species specific management conditions.
The species-specific conservation objectives developed for this species are based upon the best available scientific information at the time of MSHCP preparation. Pursuant to Section 5.0 which includes Management, Monitoring and the Adaptive Management Program, the MSHCP's mitigation requirements will be monitored and analyzed to determine if they are producing the desired result. Based upon this information, the following species-specific conservation objectives will be adjusted if appropriate, as new information is gathered during Plan implementation. The Adaptive Management Program will be used to identify alternative strategies for meeting the MSHCP's general biological goals and objectives and, if necessary, adjusting future conservation strategies according to the information received.
Include within the MSHCP Conservation Area at least 32 acres of basalt flow vernal pools and a majority of their watersheds within the Santa Rosa Plateau Ecological Reserve.
Include within the MSHCP Conservation Area at least 2,134 acres of area on the basalt flow that may contain unmapped vernal pool habitat which might support Santa Rosa Plateau fairy shrimp.
Include within the MSHCP Conservation Area additional areas within the Criteria Area identified as important for the Santa Rosa Plateau fairy shrimp. This objective shall be met through implementation of the Protection of Species Associated with Riparian/Riverine Areas and Vernal Pools policy presented in Section 6.1.2 of the MSHCP, Volume I. Wetland mapping assembled as part of that policy shall be reviewed as part of the project review process and, if suitable Santa Rosa Plateau fairy shrimp habitat, defined as vernal pools, stock ponds, ephemeral ponds, or other human-modified depressions over Basaltic soils, is identified on the wetland maps and cannot be avoided, a single-season dry or wet season survey for this species shall be conducted by a qualified biologist in accordance with accepted protocols. If survey results are positive, 90 percent of the occupied portions of the property that provide for long-term conservation value for the fairy shrimp shall be conserved.
As described below under Data Characterization, there is only one data point in the MSHCP Plan Area, due in large part to ephemeral microhabitat characteristics, low survey effort, low population numbers, and patchy distribution. However, this data point is thought to define the distribution within western Riverside County. The microhabitat for this species is restricted to that locality, the Santa Rosa Plateau. The known population is conserved within the MSHCP Conservation Area.
For purposes of this conservation analysis, potential habitat for the Santa Rosa Plateau fairy shrimp includes long-lived, cool-water vernal pools which are formed on Southern Basalt Flows. This microhabitat is only known to occur on the Santa Rosa Plateau, however a number of vegetation coverages may canopy the pools. Because of this, analysis for species coverage must be based on conservation of the known population and microhabitat. The only known population area is in conservation on the Santa Rosa Plateau Ecological Reserve under the management of the Nature Conservancy. Other stakeholders of the Reserve include the U.S. Fish and Wildlife Service, California Department of Fish and Game, and the Metropolitan Water District of Southern California.
Upon reviewing basalt flow vernal pools and playa habitats, the Plan Area supports approximately 2,418 acres (32 acres as vernal pool/playa and 2,386 acres as basalt flow soils) of potential habitat for Santa Rosa Plateau fairy shrimp within the previously identified location. Table 1 shows the conservation and loss of potential habitat for the Santa Rosa Plateau fairy shrimp and additional available basalt flows on the Plateau and environs, which may support additional pools. Overall, approximately 32 acres (100 percent) of known basalt flow vernal pool and playa habitat would be conserved in the MSHCP Conservation Area. Approximately 2,134 acres (89 percent) of additional basalt flow soils, which may support more pools, would be conserved in the MSHCP Conservation Area. It is assumed that these lands would be managed for wildlife resources including the Santa Rosa Plateau fairy shrimp.
TABLE 1
SUMMARY OF KEY POPULATION HABITAT CONSERVATION FOR
SANTA ROSA PLATEAU FAIRY SHRIMP
| Vegetation Type | MSHCP Plan Area (Acres) |
Within MSHCP conservation Area | Outside MSHCP conservation Area | ||||
|---|---|---|---|---|---|---|---|
| Criteria Area1 (Acres) |
Public/ Quasi-Public (Acres) |
Total Within MSHCP Conservation Area (Acres) |
Rural/ Mountainous (Acres) |
Outside MSHCP Conservation Area (Acres) |
Total Outside MSHCP Conservation Area (Acres) |
||
| Playas and Vernal Pools2 | 32 | 0 | 31 | 32 | 0 | 0 | 0 |
| Basalt flow soils3 | 2,386 | 884 | 1,250 | 2,134 | 218 | 34 | 252 |
| TOTAL | 2,418 | 884 | 1,281 | 2,166 | 218 | 34 | 252 |
| 1 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area. 2 Includes all vernal pool habitat inside and outside the Core Areas. 3 Only includes habitat in the Skunk Hollow, Murrieta, Alberhill, Lake Elsinore, and Santa Rosa Plateau. |
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The only known population (Santa Rosa Plateau) will be conserved within the MSHCP Conservation Area. Connectivity is not an issue because this is the only known population. However, maintenance of this population and connections between occupied pools on the Plateau is requisite.
Implementation of the MSHCP, including the conservation of existing populations as described above, will maintain viable populations of the Santa Rosa Plateau fairy shrimp. The current distribution is thought to be known, but the population size is unknown and censussing reproducing populations can be problematic due to their ephemeral nature. However, pools can be sampled for cyst densities relatively easily. Ensuring that the species remains viable in the MSHCP Plan Area will require a systematic monitoring program as described below.
In summary, conservation for the Santa Rosa Plateau fairy shrimp will be achieved by the inclusion of at least 32 acres of suitable basalt vernal pool Conserved Habitat within 1 Core Area. In addition, at least 2,134 acres of Basalt flow soils, which may support suitable vernal pools within the MSHCP Plan Area will be conserved. This objective will be met through implementation of the Protection of Species Associated with Riparian/Riverine Areas and Vernal Pools policy presented in Section 6.1.2 of the MSHCP, Volume I. Wetland mapping assembled as part of that policy shall be reviewed as part of the project review process and, if suitable habitat for this species is identified on the wetland maps and cannot be avoided, a single-season dry or wet season survey for this species shall be conducted by a qualified biologist in accordance with accepted protocols. If survey results are positive, 90 percent of the occupied portions of the property that provide for long-term conservation value for the fairy shrimp shall be conserved. Furthermore, the MSHCP Plan Area is contiguous with suitable habitat in Orange, and San Diego counties.
Within the key population areas, no basalt flow vernal pool habitat would be located outside the MSHCP Conservation Area, and approximately 252 acres (11 percent) of potential vernal pool supporting basalt flow habitats would be located outside the MSHCP Conservation Area. The entire known population would be included within the MSHCP Conservation Area and therefore, no Take of populations is anticipated.
The habitat requirements are well understood and definable (Southern Basalt Flow vernal pools). It is unlikely that additional localities for this species will be discovered within the MSHCP Plan Area. However, it is possible populations may be discovered in the Santa Rosa West subregion of the MSHCP Plan Area (e.g., Redonda Mesa, Avenaloca Mesa). There is virtually nothing known about the Santa Rosa Plateau fairy shrimp's biology. The MSHCP database holds one record for L. santarosae. The record holds both x and y coordinates and is from 1998. The record is considered precise and recent enough to be useful to planning efforts.
L. santarosae is restricted to seasonal southern basalt flow vernal pools with cool clear to milky waters that are moderately predictable and remain filled for extended periods of time (Thiery and Fugate 1994, Eriksen and Belk 1999).
L. santarosae is endemic to western Riverside County (Thiery and Fugate 1994, Eriksen and Belk 1999) at an elevation of 625 meters.
The Santa Rosa Plateau fairy shrimp is known only from vernal pools on the Santa Rosa Plateau under management by the Nature Conservancy (Thiery and Fugate 1994, Eriksen and Belk 1999), particularly on the Mesa del Colorado (Keeler-Wolf et. Al. 1998). A review of 7.5 minute United States Geologic Survey topographic maps reveals other potential mesas outside the protection of the Nature Conservancy (e.g., Avenaloca Mesa, Redonda Mesa).
Santa Rosa Plateau.
Genetics: No genetic studies have been conducted on L. santarosae to determine its relatedness to other genera/ species, or to determine the relatedness of one sub-population to another.
Diet and Foraging: Anostarcans are non-selective particle-feeding filter-feeders, or omnivores. Detritus, bacteria, algal cells, and other items between 0.3 to 100 microns may be filtered and ingested.
Daily Activity: Nothing is known about its daily activity.
Reproduction: Nothing is known about its reproductive biology, except that it has large cysts (Eriksen and Belk 1999).
Survival: Nothing is known about its survivorship.
Dispersal: Dispersal in fairy shrimp is likely caused by "vectors" such as waterfowl, cattle, sheep, dogs and other traffic or wallowing through inhabited wet or dry pools, and vehicles transporting cysts or pregnant or mature adults between dry depressions or extant pools; cysts may be dispersed like some plant seeds by running the length of an animal's gut through ingestion of pregnant females or ingestion of cysts in drinking water and elimination over suitable depressions or pools
Socio-Spatial Behavior: There is no information regarding the partitioning of intraspecific resources, territoriality, or other socio-spatial behaviors.
Community Relationships: Fairy shrimp forage on micro-nutrient packages, converting the micro-nutrients into usable food for larger invertebrates and vertebrates. Fairy shrimp may be eaten by a wide variety of species, including beetles, dragonfly, larvae, and other arthropods, frog, salamander, and toad tadpoles, shorebirds, ducks, and even other fairy shrimp. L. santarosae may be found swimming and competing for food resources with Branchinecta lynchi.
There are no known immediate threats to this fairy shrimp at this time on the Santa Rosa Ecological Reserve. However, nearby mesas may also support appropriate vernal pool habitat and shrimp and may be subject to development, agricultural, or runoff pressures which may compromise survivorship.
Santa Rosa Plateau fairy shrimp are found in long-lived, cool-water Southern Basalt Flow vernal pools with low to moderate dissolved solids (Keeler-Wolf et. al. 1998, Eriksen and Belk 1999). Fairy shrimp are adapted for survival in water bodies that are relatively short lived and their cysts (protected eggs) can withstand long dry periods. Santa Rosa Plateau fairy shrimp require cool waters, often early in the rainy season for hatching. Fairy shrimp are highly susceptible to contaminants.
Eriksen, C. and D. Belk 1999. Fairy Shrimps of California's Puddles, Pools, and Playas. Mad River Press, Inc., Eureka, California.
Keeler-Wolf, T., D.R. Elam, K. Lewis, and S.A. Flint. 1998. California Vernal Pool Assessment - Preliminary Report. State of California, The Resources Agency, Department of Fish and Game.
Thiery, A. and M. Fugate 1994. A new American fairy shrimp, Linderiella santarosae (Crustacea: Anostraca: Linderiellidae), from vernal pools of California. U.S.A. Proceedings of the Biological Society of Washington 107:641-656.
U.S. Fish and Wildlife Service. 1997. Vernal Pools of Southern California Recovery Plan. U.S. Fish and Wildlife Service, Portland, Oregon. 113+pp.
vernal pool fairy shrimp (Branchinecta lynchi)
State: None
Federal: Threatened
The vernal pool fairy shrimp is narrowly distributed at relatively few locations within the MSHCP Plan Area in suitable habitat. It is present in vernal pools in three key locations in the MSHCP Plan Area. Key locations are the Santa Rosa Plateau Ecological Reserve, Skunk Hollow, and Salt Creek in west Hemet. Conservation analysis for this species must be considered based on Core Areas. Because the vernal pool fairy shrimp requires specific conditions, occurs in few locations, and uses a well defined habitat that is narrowly distributed, this species will require site-specific considerations, protection of essential habitat on a landscape basis, and species specific management conditions.
The species-specific conservation objectives developed for this species are based upon the best available scientific information at the time of MSHCP preparation. Pursuant to Section 5.0 which includes Management, Monitoring and the Adaptive Management Program, the MSHCP's mitigation requirements will be monitored and analyzed to determine if they are producing the desired result. Based upon this information, the following species-specific conservation objectives will be adjusted if appropriate, as new information is gathered during Plan implementation. The Adaptive Management Program will be used to identify alternative strategies for meeting the MSHCP's general biological goals and objectives and, if necessary, adjusting future conservation strategies according to the information received.
Include within the MSHCP Conservation Area at least 476 acres of suitable habitat by conserving vernal pool and playa habitat (does not include watershed acreages) within the West Hemet portion of Salt Creek, Santa Rosa Plateau Ecological Reserve, and Skunk Hollow.
Include within the MSHCP Conservation Area at least 2,647 acres of alkali playa (Willow, Traver and Domino soils) in the floodplain of the San Jacinto River and west Hemet portion of Salt Creek which contains suitable habitat for this species.
Include within the MSHCP Conservation Area at least three Core Areas, which include the three known occupied vernal pools (or vernal pool complexes) and their watersheds in the West Hemet portion of Salt Creek (4,043 acres), Santa Rosa Plateau Ecological Reserve (17,188 acres), and Skunk Hollow (156 acres).
Include within the MSHCP Conservation Area additional areas within the Criteria Area identified as important for the vernal pool fairy shrimp. This objective shall be met through implementation of the Protection of Species Associated with Riparian/Riverine Areas and Vernal Pools policy presented in Section 6.1.2 of the MSHCP, Volume I. Wetland mapping assembled as part of that policy shall be reviewed as part of the project review process and, if suitable vernal pool fairy shrimp habitat, defined as vernal pools, stock ponds, ephemeral ponds, or other human-modified depressions over willow soils, is identified on the wetland maps and cannot be avoided, a single-season dry or wet season survey for this species shall be conducted by a qualified biologist in accordance with accepted protocol. If survey results are positive, 90 percent of the occupied portions of the property that provide for long-term conservation value for the fairy shrimp shall be conserved.
As described below under Data Characterization, there are only 4 data points within the MSHCP Plan Area, due in large part to ephemeral microhabitat characteristics, low survey effort, low population numbers, and patchy distribution. However, these data points are thought to define the distribution within western Riverside County.
For purposes of this conservation analysis, potential habitat for the vernal pool fairy shrimp includes short lived, cool vernal pools. In particular, alkali pools appear to be important. Vernal pools and playa habitats have been mapped to a certain extent within the Plan Area and acreages for those occurring within the west Hemet portion of Salt Creek, Santa Rosa Plateau, and Skunk Hollow are presented in Table 1. However, this microhabitat may also occur sporadically within a variety of other mapped habitats ranging from disturbed or ruderal land coverages to chaparral. Because of this, species coverage can not be concluded based on habitat preservation alone. Instead, species coverage must be primarily based on population preservation. Three (75 percent) of four recorded population areas would be conserved in reserve or existing Public/Quasi-Public Lands. The Santa Rosa Plateau and Skunk Hollow populations are already conserved, while the Salt Creek population would be within the MSHCP Conservation Area. It is assumed that these lands would be managed for wildlife resources including the vernal pool fairy shrimp.
Upon reviewing vernal pool and playa habitats and alkali soils, the MSHCP Plan Area supports approximately 7,206 acres of potential habitat for vernal pool fairy shrimp within the previously identified locations. Table 1 shows the conservation and loss of potential habitat for vernal pool fairy shrimp at the three locations and additional alkali playa (Willows, Traver and Domino soils) in the floodplain of the San Jacinto River and west Hemet portion of Salt Creek. Overall, approximately 476 acres (88 percent) of potential habitat in the identified areas would be conserved in the MSHCP Conservation Area. Approximately 2,647 acres (40 percent) of potential Willows soils within the floodplain of the San Jacinto River would be conserved in the MSHCP Conservation Area. It is assumed that these lands would be managed for wildlife resources including the vernal pool fairy shrimp.
TABLE 1
SUMMARY OF HABITAT CONSERVATION FOR
VERNAL POOL FAIRY SHRIMP
| Vegetation Type | MSHCP Plan Area (Acres) |
Within MSHCP conservation Area | Outside MSHCP conservation Area | ||||
|---|---|---|---|---|---|---|---|
| Criteria Area1 (Acres) |
Public/ Quasi-Public (Acres) |
Total Within MSHCP Conservation Area (Acres) |
Rural/ Mountainous (Acres) |
Outside MSHCP Conservation Area (Acres) |
Total Outside MSHCP Conservation Area (Acres) |
||
| Playas and Vernal Pools2 | 543 | 429 | 47 | 476 | 0 | 67 | 67 |
| Willows Soils3 | 6,663 | 2,018 | 669 | 2,647 | 0 | 4,016 | 4,016 |
| TOTAL | 7,206 | 2,447 | 716 | 3,123 | 0 | 4,083 | 4,083 |
| 1 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area. 2 Includes all vernal pool habitat inside and outside the Core Areas. 3 Only includes habitat in the Skunk Hollow, Murrieta, Alberhill, Lake Elsinore, and Santa Rosa Plateau. |
|||||||
Three key populations (Santa Rosa Plateau, Salt Creek, Skunk Hollow) will be conserved within the MSHCP Conservation Area. Additionally, the configuration of the MSHCP Conservation Area provides for conservation of other potential habitat in the Gavilan Plateau, along warm springs, and in the flood plain of the San Jacinto River. However, it is necessary to protect the populations, watersheds, and water quality of the pools that sustain them, and provide for expansion within the pool complexes associated with populations. Accordingly, large habitat blocks important to the vernal pool fairy shrimp are located throughout MSHCP Conservation Area and the species known range within the MSHCP Plan Area within the following Core Areas: Santa Rosa Plateau (Existing Core F; 17,188 acres), West Hemet portion of Salt Creek ( 4,043 acres), and Skunk Hollow 156 acres). All of these contain, or are expected to contain, the habitat requirements necessary to support vernal pool fairy shrimp populations and associated vernal pools.
Implementation of the MSHCP, including the conservation of existing populations as described above will maintain viable populations of the vernal pool fairy shrimp. The current distribution is thought to be known, but population size is unknown and censussing reproducing populations can be problematic due to their ephemeral nature. However, pools can be sampled for cyst densities relatively easily. Ensuring that the species remains viable in the MSHCP Plan Area will require a systematic monitoring program as described below.
In summary, conservation for the vernal pool fairy shrimp will be achieved by the inclusion of at least 3,123 acres of suitable Conserved Habitat within three Core Areas which are composed of large blocks of habitat within the MSHCP Conservation Area. In addition, other areas within the Criteria Area identified as important for the vernal pool fairy shrimp will be conserved. This objective shall be met through implementation of the Protection of Species Associated with Riparian/Riverine Areas and Vernal Pools policy presented in Section 6.1.2 of the MSHCP, Volume I. Wetland mapping assembled as part of that policy shall be reviewed as part of the project review process and, if suitable habitat for this species is identified on the wetland maps and cannot be avoided, a single-season dry or wet season survey for this species shall be conducted by a qualified biologist in accordance with accepted protocols. If survey results are positive, 90 percent of the occupied portions of the property that provide for long-term conservation value for the fairy shrimp shall be conserved. Furthermore, the Plan Area is contiguous with suitable habitat in Orange, and San Diego counties.
About 67 acres (12 percent) of potential vernal pool and playa habitat for the vernal pool fairy shrimp within the three locations and 4,016 acres (60 percent) of Willows, Traver, and Domino soils within the floodplain of the San Jacinto River and the west Hemet portion of Salt Creek, would be outside the MSHCP Conservation Area. Any vernal pool fairy shrimp present within this area would be subject to Incidental Take under the guidelines implemented as part of this Plan
The habitat requirements are fairly well understood and definable (vernal pools or alkali vernal pools). While additional populations are likely to be found, the majority of the suitable unoccupied habitat locations are known. Much still needs to be learned regarding its biology. The MSHCP data base includes 4 records for B. lynchi. Of the four records, three (75 percent) are precision code "1" (an "x" and "y" coordinate that allows for good precision in the location) and one (25 percent) record is precision code "3" (relatively imprecise locations from general areas). Two of the precision code "1" records are from 1998 and the last is from 1990. All three records are considered to be recent.
B, lynchi is restricted to seasonal vernal pools (Eng, Belk, and Eriksen 1990; U.S. Fish and Wildlife Service 1994). The vernal pool fairy shrimp prefers cool-water pools that have low to moderate dissolved solids, are unpredictable, and often short lived (Eriksen and Belk 1999).
B. lynchi is found primarily in the Central Valley and the foothills of the Sierra Nevada in northern California from 10 to 290 meters in elevation (Eng, Belk, and Eriksen 1990, Eriksen and Belk 1999, U.S. Fish and Wildlife Service 1994). The northernmost population is found near Medford in southern Oregon (Eriksen and Belk 1999). In southern California, vernal pool fairy shrimp is known only from western Riverside County up to an elevation of 1159 meters.
The vernal pool fairy shrimp is known from four locations in the MSHCP Plan Area: Skunk Hollow, the Santa Rosa Plateau, Salt Creek, and the vicinity of the Pechanga Indian Reservation. Vernal pool fairy shrimp are most abundant on the Santa Rosa Plateau. At this time, vernal pool fairy shrimp have only been found at a single alkali vernal pool at the Salt Creek vernal pool complex but there has been relatively little survey work completed in the area and many of the pools have been degraded by human activities. The populations at Santa Rosa Plateau are within the Santa Rosa Plateau Ecological Reserve. The population at Skunk Hollow was conserved in an HCP. The Salt Creek population is on private lands. The record from the vicinity of the Pechanga Indian Reservation was not precise enough to determine its exact location.
Murrieta Hot Springs (Skunk Hollow), Salt Creek, Santa Rosa Plateau.
Genetics: No genetic studies have been conducted on B. lynchi to determine its relatedness to other genera/ species, or to determine the relatedness of one sub-population to another.
Diet and Foraging: Anostarcans are non-selective particle-feeding filter-feeders, or omnivores. Detritus, bacteria, algal cells, and other items between 0.3 to 100 microns may be filtered and ingested.
Daily Activity: There is no information regarding daily activity.
Reproduction: B. lynchi females produce an unknown number of cysts per clutch and over their lifetime (Eriksen and Belk 1999). All that is needed for cysts to hatch is for water temperatures to get below 10 degrees Celsius by a frost or cold storm (Helm 1998). Multiple broods or hatches may occur during a season (Gallagher 1996).
Survival: There is no information regarding survivorship.
Dispersal: Dispersal in fairy shrimp is likely caused by "vectors" such as waterfowl, cattle, sheep, dogs and other traffic or wallowing through inhabited wet or dry pools, and vehicles transporting cysts or pregnant or mature adults between dry depressions or extant pools; cysts dispersed like some plant seeds by running the length of an animal's gut through ingestion of pregnant females or ingestion of cysts in drinking water and elimination over suitable depressions or pools; periodic flooding transporting adults between pools; and possibly wind blown cysts may be transported between pool complexes.
Socio-Spatial Behavior: There is no information regarding the partitioning of intraspecific resources, territoriality, or other socio-spatial behaviors.
Community Relationships: Fairy shrimp forage on micro-nutrient packages, converting the micro-nutrients into usable food for larger invertebrates and vertebrates. Fairy shrimp may be eaten by a wide variety of species, including beetles, dragonfly, larvae, and other arthropods, frog, salamander, and toad tadpoles, shorebirds, ducks, and even other fairy shrimp. B. lynchi may be found swimming and competing for food resources with B. lindahli and Linderiella santarosae within the Plan Area. B. lynchi cysts may be found with Streptocephalus wootoni but not observed to swim together (Eriksen and Belk 1999).
Vernal pool fairy shrimp is threatened by urban development, water supply and flood control activities, agricultural conversion, and the direct loss of vernal pools to filling, grading, discing, leveling, as well as modification of surrounding uplands that alter vernal pool watersheds (U.S. Fish and Wildlife Service 1994). In Riverside County, the Santa Rosa Plateau population is secure and the Skunk Hollow population is protected from urban development. The Skunk Hollow population is also being managed for conservation. The Salt Creek population which has the largest potential habitat available, is threatened by discing for weed abatement and fire control, urbanization, pipeline construction, trampling by sheep, and alteration of hydrology (White 1994, Roberts 1999). Water quality may be a threat at all pool complexes.
Vernal pool fairy shrimp are found in short-lived cool-water vernal pools with low to moderate dissolved solids (Eriksen and Belk 1999). At some localities in the central valley, Skunk Hollow, and Salt Creek, they are associated with alkaline soils (U.S. Fish and Wildlife Service 1994; C. Patterson, biologist, pers. comm., 1998). Fairy shrimp are adapted for survival in water bodies that are relatively short lived and their cysts (protected eggs) can withstand long dry periods. Vernal pool fairy shrimp require cool waters, often early in the rainy season for hatching. Fairy shrimp are highly susceptible to contaminants. Vernal pool fairy shrimp are vulnerable to contaminants in runoff waters and watershed quality. The limited genetic information available suggests that there is very little genetic variability within populations. Dispersal of cysts thought to occur by animal vectors, either grazing animals or waterfowl. With the long distance isolation between the few remaining pools, gene flow is greatly if not completely reduced. This species may be difficult to detect in dry years.
Eng, L.L., D. Belk and C.H. Eriksen. 1990. California Anostraca: distribution, habitat and status. Journal of Crustacean Biology 10: 247 - 277.
Eriksen, C. and D. Belk 1999. Fairy Shrimps of California's Puddles, Pools, and Playas. Mad River Press, Inc., Eureka, California.
U.S. Fish and Wildlife Service 1994. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Three Vernal Pool Plants and the Riverside Fairy Shrimp. Federal Register 59: 48153.
U.S. Fish and Wildlife Service. 1997. Vernal Pools of Southern California Recovery Plan. U.S. Fish and Wildlife Service, Portland, Oregon. 113+pp.
U.S. Fish and Wildlife Service. 1998. Determination of endangered or threatened status for four southwestern California plants from vernal wetlands and clay soils. 63 FR 54975.
White, S. D. 1994. Vernal Pools in the San Jacinto Valley. Fremontia 22(3): 17 - 19.