SPECIES NAME AND GROUP DESIGNATION

Common Name and Scientific Name:

California red-legged frog (Rana aurora draytonii)

Status:

State: Species of Special Concern, California Protected Species

Federal: Threatened

GROUP DESIGNATION AND RATIONALE

Group 3

The California red-legged frog has narrow habitat requirements and limited distribution within the Plan Area, typically being restricted to the lowland streams, wetlands, and pools where dense vegetation surrounds relatively deep water with small (<300 km²) watersheds. They also require adjacent upland areas to move between suitable breeding sites. Currently, the known distribution of red-legged frogs within the Plan Area is limited to the Santa Rosa Plateau (Cole Creek). Suitable plateau and drainage habitat and connections to other suitable habitat in the southern Santa Ana Mountains has been delineated for this species. Primary breeding habitat for this species includes suitable wetland habitat as described below, with secondary habitats including adjacent upland areas. Because the red-legged frog requires very specific breeding habitat conditions, only occurs within a single location, and uses a well defined habitat that is narrowly distributed, this species will require site specific considerations, protection of primary breeding habitat and adjacent upland areas, and species-specific conservation measures.

This is a species on the Additional Survey Needs and Procedures (Section 6.3.2) list and surveys for California red-legged frog will be conducted as part of the project review process for public and private projects within the amphibian species survey area where suitable habitat is present (see Amphibian Species Survey Area Map, Figure 6-3 of the MSHCP, Volume I). California red-legged frogs located as a result of survey efforts shall be conserved in accordance with procedures described within Section 6.3.2, MSHCP, Volume 1. Other species survey requirements associated with the MSHCP are documented in Sections 6.1.2 and 6.1.3. A complete summary of all MSHCP species survey requirements is provided in Appendix E of Volume I.

SPECIES CONSERVATION OBJECTIVES

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.

Objective 1

Include within the MSHCP Conservation Area at least 766 acres of occupied and historic breeding habitat (riparian scrub, woodlands and forests, open water, and playas and vernal pools). Breeding habitat for the red-legged frog includes cool, deep pools, lowland streams, and other wetlands where dense vegetation surrounds relatively them. These areas generally have a small (<300 km²) watershed.

Objective 2

Include within the MSHCP Conservation Area the Core Areas in the Santa Rosa Plateau (9,028 acres) and the southern Santa Ana Mountains (30,964 acres), and the intervening lands which shall provide movement between the Core Areas. The intervening lands are primarily situated around Avenoloca Mesa, Redonda Mesa, slopes and foothills of Squaw Mountain, and Alamos Canyon.

Objective 3

Include within the MSHCP Conservation Area at least 39,147 acres of upland habitat adjacent to occupied or suitable breeding habitat. These areas are situated around the Santa Rosa Plateau, southern Santa Ana Mountains, and intervening lands including Avenoloca Mesa, Redonda Mesa, slopes and foothills of Squaw Mountain, Alamos Canyon and environs. Upland habitats include woodlands and forests, chaparral, coastal sage scrub, and grasslands.

Objective 4

Surveys for this species will be conducted as part of the project review process for public and private projects within the amphibian species survey area where suitable habitat is present (see Amphibian Species Survey Area Map, Figure 6-3 of the MSHCP, Volume I). Red-legged frog locations identified as a result of survey efforts shall be conserved in accordance with procedures described within Section 6.3.2, MSHCP, Volume I.

Objective 5

Within the MSHCP Conservation Area, Reserve Managers shall maintain or, if feasible, restore ecological processes within occupied habitat and suitable new areas within the Criteria Area. At a minimum, these areas will include the Santa Rosa Plateau, San Mateo Wilderness area of the Cleveland National Forest, Squaw Mountain, Avenacola Mesa Redondo Mesa, Alamos Canyon, and surrounding areas.

Objective 6

Within the MSHCP Conservation Area, determine if successful reproduction is occurring as measured by the presence/absence of tadpoles, egg masses, or juvenile frogs once a year for the first five years after permit issuance and then as determined by the Reserve Management Oversight Committee as described in Section 6.6, MSHCP Volume I (but not less frequently than every 8 years).

SPECIES CONSERVATION ANALYSIS

Conservation Levels

For purposes of this conservation analysis, potential habitat for the California red-legged frog includes relatively deep (>0.7 meter deep), cool pools or ponds with emergent and submergent vegetation and associated uplands. Vernal pools and alkali playas have been mapped to a certain extent within the MSCHP plan, but are only used for this analysis within the Santa Rosa Plateau and southern Santa Ana Mountains. This is because red-legged frogs also use stock ponds and streams with suitable characteristics, therefore conservation based on vernal pool coverage alone is not appropriate. Instead, species coverage must be primarily based on population preservation and suitable occupied and potential habitat preservation within historically occupied areas.

The Plan Area supports approximately 813 acres of land which is determined to be primary breeding habitat and includes both occupied and historically occupied suitable breeding habitat. The Plan Area also supports approximately 48,518 acres of secondary upland movement habitat. As stated below under Data Characterization and Key Populations, suitable breeding habitat is described over the Santa Rosa Plateau, southern Santa Ana Mountains (San Mateo Wilderness area of the Cleveland National Forest) and intermediate areas around Rdonda Mesa, Avenacola Mesa, Squaw Mountain, and Los Alamos Canyon. As shown in Table 1, suitable primary habitats preserved include riparian scrub, woodlands, and forests; open water; playas and vernal pools, and; alluvial fan scrubs. Suitable upland habitats (Table 2) include chaparral; coastal sage scrub; woodlands and forests, and; grasslands. Overall, approximately 766 acres (94 percent) of suitable primary occupied and potential historical breeding habitat and 39,147 acres (81 percent) of suitable secondary upland movement habitat (39,913 acres total [81 percent]) will be conserved in the MSHCP Conservation Area. It is assumed that these lands would be managed for wildlife resources including the California red-legged frog.

TABLE 1
SUMMARY OF PRIMARY HABITAT CONSERVATION
FOR THE CALIFORNIA RED-LEGGED FROG

		Within MSHCP Conservation Area			Outside MSHCP Conservation Area
Vegetation Type	Plan Area1 (Acres)	Criteria Area2 (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 Pools	32	1	31	32	0	0	0
Riparian Scrub, Woodland and Forest	773	34	699	733	37	3	40
Riversidean Alluvial Fan Sage Scrub	1	0	1	1	0	0	0
Open water	7	0	0	0	7	0	7
TOTAL	813	35	731	766	44	3	47
1 Includes occupied, historically occupied, and other proximate suitable breeding habitat within Santa Rosa Plateau, southern Santa Ana Mountains, and potential movement areas between them. 2 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area.

TABLE 2
SUMMARY OF SECONDARY HABITAT CONSERVATION
FOR THE CALIFORNIA RED-LEGGED FROG

		Within MSHCP Conservation Area			Outside MSHCP Conservation Area
Vegetation Type	Plan Area1 (Acres)	Criteria Area2 (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)
Agricultural Land	301	6	3	9	280	12	292
Chaparral	36,643	495	30,993	31,488	4,411	744	5,155
Coastal Sage Scrub	1,185	34	991	1,025	139	21	160
Grassland	6,721	338	3,971	4,309	2,256	156	2,412
Woodlands and Forest	3,668	117	2,199	2,316	1,246	106	1,352
TOTAL	48,518	990	38,157	39,147	8,332	1,039	9,371
1 Includes occupied, historically occupied, and other proximate and interstitial upland movement habitat within Santa Rosa Plateau, southern Santa Ana Mountains, and potential movement areas between them. 2 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area.

As described below under Data Characterization, there are only seven current data points for the MSHCP Plan Area that are precise and recent enough for evaluation; all of which occur on the Santa Rosa Plateau within Public/Quasi-Public Land designations. These data points are thought to define the population within western Riverside County.

MSHCP Conservation Area Configuration Issues

Two key core habitat blocks are conserved under the Plan. The Santa Rosa Plateau population area (Existing Core F; 9,028 acres) and the southern Santa Ana Mountains U.S. Forest Service area (southern portion of Existing Core B; 30,964 acres), are connected by a wide (2- to 3-mile wide) linkage/habitat block area (10,334 acres). This runs through approximately 4 miles of non-reserve and non-public/quasi-public, rural/mountainous land. Maintaining viable connectivity between the two MSHCP Conservation Areas within non-reserve areas will be crucial to maintaining successful existing and re-introduced populations. The Cleveland National Forest protects much of the Los Alamos Creek watershed within the San Mateo Canyon Wilderness and the Santa Rosa Plateau population/suitable habitat is protected by the Santa Rosa Plateau Ecological Reserve.

Implementation of the MSHCP, including the conservation of the existing populations and suitable habitat as described above, will maintain viable populations of the California red-legged frog and facilitate recovery of the species. The current distribution is thought to be known, however some areas which may support the frog are relatively inaccessible and are visited sporadically at best. However, surveying for existing and new populations is relatively easy if access is available. Ensuring that the species remains viable in the MSHCP Plan Area will require a systematic monitoring program.

Conservation Strategy Summary

In summary, conservation for the California red-legged frog will be achieved by the inclusion of at least 39,913 acres of suitable Conserved primary breeding Habitat and Conserved secondary upland Habitat within 2 Core Areas which are composed of large blocks of habitat within the MSHCP Conservation Area. The Core Areas are connected by a large interstitial area which has small drainages and large upland areas which will need to be protected as they are determined to be important to red-legged frog. In addition, surveys for this species will be conducted as part of the project review process for public and private projects within the amphibian species survey area where suitable habitat is present (see Amphibian Species Survey Area Map, Figure 6-3 of the MSHCP, Volume I). Red-legged frog locations identified as a result of survey efforts shall be conserved in accordance with procedures described within Section 6.3.2, MSHCP, Volume 1. Other species survey requirements associated with the MSHCP are documented in Sections 6.1.2 and 6.1.3. A complete summary of all MSHCP species survey requirements is provided in Appendix E of Volume I. Within the MSHCP Conservation Area, Reserve Managers shall maintain or, if feasible, restore ecological processes within occupied habitat and suitable new areas within the reserve. At a minimum, these areas will include the Santa Rosa Plateau, San Mateo Wilderness area of the Cleveland National Forest, Squaw Mountain, Avenacola Mesa Redondo Mesa, Alamos Canyon, and surrounding areas. Within the MSHCP Conservation Area, Reserve Managers shall determine if successful reproduction is occurring as measured by the presence/absence of tadpoles, egg masses, or juvenile frogs once a year for the first 5 years after permit issuance and then as determined by the Reserve Management Oversight Committee (but not less frequently than every 8 years). Furthermore, the Plan Area is contiguous with suitable habitat in Orange and San Diego counties.

INCIDENTAL TAKE

Incidental Take of the California red-legged frog is difficult to quantify due to a relative lack of species occurrence data. However, the maximum level of Take of the red-legged frog can be anticipated by the loss of the number of acres of habitat that will become unsuitable for this species, and individuals within these areas will be subject to Incidental Take consistent with the Plan. Approximately 47 acres (6 percent) of probable suitable primary breeding habitat and 9,371 (19 percent) of suitable secondary upland movement habitat (9,418 acres total [19 percent]), would be located outside the MSHCP Conservation Area.

SPECIES ACCOUNT

Data Characterization

The California red-legged frog is currently restricted to pool complexes on the Santa Rosa Plateau Ecological Reserve. The only known population within the Plan Area is comprised of a couple of males on the Santa Rosa Plateau. The species was federally-listed in May 1996 (U.S. Fish and Wildlife Service 1996) and final Critical Habitat was designated in March 2001 (U.S. Fish and Wildlife Service 2001). Abundant information exists in the literature, for the red-legged frog. However, there is no information available regarding genetics, survivorship, dispersal, and socio-spatial behavior. The MSHCP data base holds 22 records for R. a. draytonii. Of the 22 records, 7 (32 percent) are precision code "1" (an "x" and "y" coordinate that allows for good precision in the location), 5 (23 percent) are precision code "2" (one "x" or "y" data point or equivalent), and 10 (46 percent) "3" or "4" (relatively imprecise locations from general areas). Five of the Precision code "1" records are from 1998, one from 1997, and one precision code "2" record from 1995. These are considered to be the only recent records.

Habitat and Habitat Associations

The California red-legged frog inhabits lowland streams, wetlands, riparian woodlands, and livestock ponds (Hayes and Jennings, 1988; Jennings, 1988). The species may also occur in uplands near breeding areas and along intermittent drainages connecting wetlands. The adults often use dense, shrubby or emergent riparian vegetation closely associated with deep (>0.7 meters), still or slow moving water (Hayes and Jennings, 1988). Red-legged frogs require cold water pond habitats (including stream pools) with emergent and submergent vegetation (Storer, 1925).

Habitats with the highest densities of frogs are deep water ponds with dense stands of overhanging willows (Salix sp.) and a fringe of cattails (Typha latifolia) between the willow roots and overhanging willow limbs (Jennings 1988; Rathburn, et al., 1993). Red-legged frogs are closely tied to plunge pool habitats next to willows (Hayes and Jennings, 1988). California red-legged frogs have also been found in association with stock ponds throughout its range, wildlife "guzzlers," marsh habitat, and can occur in ephemeral ponds or permanent streams and ponds, however populations probably cannot persist in ephemeral streams (Jennings and Hayes, 1985).

California red-legged frogs appear to be more closely tied to small drainage areas (<300km²) and their intermittent water flow as opposed to large drainage areas (>300km²) and their perennial water flow, due to restricted access by aquatic macrofaunal predators (Hayes and Jennings, 1988). Two thirds of their localities are from drainage areas < 40 square kilometers and they were most frequently recorded at sites having a low local gradient, and in streams having a low stream order. Hayes and Jennings (1988) reported that red-legged frogs have been recorded in 1st to 6th order streams, but 94 percent (n=115) are 4th or lesser-order streams and 42 percent are 1st order streams. Good water quality is also important (Jennings, 1988; Bradford et al., 1994) and water salinity should be at or below 4.5 percent to ensure survival of embryonic stages (Hayes and Jennings, 1988).

Biogeography

According to Jennings and Hayes (1985), the historic range of the California red-legged frog extends through Pacific slope drainages from the vicinity of Redding (Shasta County: Storer, 1925) inland and to Point Reyes (Marin County), California (coastally) southward to the Santo Domingo River drainage in Baja California, Mexico. It has also occupied habitat in a few desert slope drainages in southern California (Jennings and Hayes, 1994). Currently, a large number of California red-legged frogs are only found in coastal fog belt localities; most inland populations appear to be extirpated (Jennings, 1991).

Significant breeding populations (>350 adults) are currently known at Pescadero Marsh Natural Preserve, Point Reyes National Seashore, and the canals west of the San Francisco Airport. In southern California, south of Ventura to the Mexican border, only one population (Santa Rosa Plateau Preserve) is protected. Introduced populations occur in central southern Nevada (Green, 1985). An introduced population also occurred on Santa Cruz Island (Jennings, 1988). The species is known from sea level to approximately 1,500 meters.

Known Populations Within Western Riverside County

The red-legged frog is very rare in Riverside County. One small population occurs on the Santa Rosa Plateau which consists of four males and one female. During the spring of 1998 the female was not observed (Scott Harris, CDFG, pers. comm.). The Santa Rosa Plateau (Cole Creek) population is the only known population within western Riverside County. This population is the only known extant population south of Ventura County.

Key Populations in Plan Area

The currently known extant population includes three individuals located at the Santa Rosa Plateau Ecological Reserve. Other historical or suspected locations include the vicinity of Temescal, Vail Lake, Kolb Creek, Murrieta Creek, Santa Ana River, Santa Ana Mountains, Anza, Glen Ivy, Pedley, and the City of Riverside.

On March 2001, the USFWS issued a proposal the final designated critical habitat for this species. The only area within the Plan Area is situated on and around the Santa Rosa Ecological Reserve. Specifically, it includes portions of the Reserve, the Santa Rosa Plateau, and the southern extent of the Santa Ana Mountains including portions of DeLuz Creek, Murrieta and San Mateo Canyon watersheds. Sixty-six percent is managed by the USFS, the rest is privately owned or managed by the State of California.

Biology

Genetics: There is no available information regarding genetics.

Diet and Foraging: After examining the digestive contents of 35 red-legged frogs, Hayes and Tennant (1985) found that the most frequently encountered prey groups were carabid and tenebrionid beetles, water striders (Gerridae), lycosid spiders, and larval neuropterans. The most frequently encountered prey species were larval alderflies (Sialis californica), pillbugs (Aramadillidium vulgare), and water striders (Gerris sp.). Algae is probably the food item eaten by larvae (Jennings et al., 1992). Small vertebrates such as Pacific tree frogs (Pseudacris regilla) and California mice (Peromyscus californicus) represented over half the prey mass eaten by larger frogs and were found to be the largest prey items in Hayes and Tennant's sample. As expected, the data suggest that a greater range of prey sizes is available to larger frogs. A large female red-legged frog was observed swallowing a California mouse by pressing it against the substrate and using its forelimbs. This resulted in the frog's ingestion of a considerable amount of sand with the prey item.

Hayes and Tennant (1985) emphasize that prey composition appears largely influenced by variation in habitat. Their observations indicate that frogs appeared to recognize potential prey by continuous movement. Dickerson (1906) stated that the red-legged frog can take prey underwater, emphasizing its cannibalistic nature and fish-eating habits in addition to its diet of aquatic and terrestrial insects, tadpoles, worms, and a preference for sow bugs. Feeding was observed during both day and night time for juveniles, but only at night for adults and sub-adults.

Daily Activity: California red-legged frogs found in coastal areas are rarely inactive (Jennings et. al., 1992), whereas those found at interior sites may hibernate (Storer, 1925). R. a. draytonii may estivate in small mammal burrows and moist leaf litter, and can be found up to 30 meters from water in adjacent dense riparian vegetation for up to 77 days (Rathburn, et al., 1993). Adults are largely nocturnal, whereas juveniles can be active either diurnally or nocturnally (Hayes and Tennant, 1985; Jennings, 1988). In addition, time of feeding does not differ from time of activity for either adults or juveniles, suggesting that juveniles have a broader range of activity and probably longer feeding periods than adults or sub-adults.

Reproduction: R. a. draytonii breed from November through April, with earlier breeding records occurring in southern localities (Storer, 1925). R. a. draytonii can only reproduce when conditions are optimal, and consequently, this taxon is an explosive breeder. Within a narrow window (1-3 weeks) between late December and early April, females normally lay loose, oval, floating egg clusters of about 2,000-5,000 eggs in quite waters (Storer, 1925). Egg masses are generally attached to vertical emergent vegetation so that they are near the surface of the water (Hayes and Miyamoto, 1984). Eggs hatch in 6-14 days (Jennings, 1988), and metamorphosis occurs 3.5 to 7 months after hatching (Storer, 1925; Jennings and Hayes, 1990). There is no evidence to suggest that they lay more than one clutch per year like some eastern ranids (e.g., see Emlen, 1977).

Developing eggs and embryos of this taxon are unable to survive salinities of >4.5 0/00 (Hayes and Jennings, 1988) and probably temperatures >21 degrees Celsius [this figure is based on the critical thermal maximum for closely related R. a. aurora (Licht, 1971)]. Larvae require cold water (<18.3 degrees Celsius) to develop properly (Jennings, 1988); and likely experience the highest mortality rates, with less than 1 percent of eggs laid reaching metamorphosis (Jennings et al., 1992). Two years after metamorphosis, males reach sexual maturity, while females require three years to attain sexual maturity (Jennings and Hayes, 1985). R. a draytonii may live up to 10 years (Jennings et al., 1992).

Survival: Survival rates for red-legged frogs from hatching to metamorphosis range from one to less than five percent for frogs co-occurring with bullfrogs and 30 to 40 percent for those without bullfrogs (USFWS 2000). Adults live 8 to 10 years (USFWS 2000).

Dispersal: According to USFWS 2000, red-legged frogs can be found living in streams away from breeding habitat and distances exceeding 2.9 km and have ben found over 100 m away from water in dense riparian vegetation. During wet weather, some frogs make overland excursions over upland habitat, mostly at night. Movements ranging from 0.4 to over 3.2 km are known to occur without regard to topography or vegetation type. Frogs may or may not use riparian corridors for movements, instead they may move directly to their goal. Juveniles may disperse locally between July and September.

Socio-Spatial Behavior: There is no available information.

Community Relationships: Hayes and Jennings' data (1988) reveal that R. a. draytonii was more frequently found at sites with native fishes and with substrate alteration (at least 25 percent of either direct or indirect impact by humans (e.g., rip-rap, vegetation removal, trampling of banks by cattle, etc.), and less frequently at sites with introduced fish. At 52 sites that supported R. a. draytonii in the central valley of California, the most frequently co-occurring native fish species were the California roach (Lavinia symmetricus; present at 47 percent of examined sites), hitch (Lavinia exilicauda; present at 25 percent of examined sites), green sunfish (Lepomis cyanellus; present at 15 percent of examined sites), and mosquitofish (Gambusia affinis; present at 15 percent of examined sites) (Hayes and Jennings, 1988).

Threats to Species

The California red-legged frog has sustained a 70 percent reduction in its geographic range in California as a result of habitat loss or alteration due to over-collecting, introduced predators, reservoir construction, stream channelization, urbanization, overgrazing, and drought (Jennings, 1988). More specifically, any projects within suspected habitats of the species that affect suitable stream and wetland habitats, as well as adjacent upland areas, could result in significant impacts to the species. Examples of projects in western Riverside County that could result in a significantly negative impact on this species include a wide range of water management activities, including construction, operation, and maintenance activities associated with dams and reservoirs, irrigation diversion activities, wastewater discharge, flood control, and aggregate mining activities (Fisher and Shaffer, 1996). Pesticides, herbicides and lead can negatively affect frogs and other amphibians. Predation by introduced fishes (Jennings, 1988; Moyle, et al. 1986; Hayes and Jennings, 1986), bullfrogs (Jennings and Hayes, 1985; Hayes and Jennings, 1986), and crayfish, as well as disease (Jennings and Hayes 1988), and parasites (Lefcort and Blaustein, 1995) all have been known to affect red-legged frog populations. Catastrophic events, and recreational activities also can contribute to the decline of R. a. draytonii.

Long-term cumulative effects of multiple factors are usually the cause of the declines such as these. When natural low points in amphibian population cycles synergize with widespread environmental alterations, extinction events occur. Because true frogs fit classic models of metapopulation dynamics, they are uniquely vulnerable to these cumulative environmental effects. Typically, disjunct populations undergo continuous cycles of extinction and recolonization from nearby sources (see Harrison, 1991). Such recolonization events are now impossible for many native frogs in the Sierra Nevadas because of the introduction of predatory fishes in formerly suitable habitats and the widespread extinction of many local source frog populations (Bradford, et al. 1993).

The rapid decline of the red-legged frog over most of its historic range has not been prevented by State protection which has been provided since 1971. The required habitat of the red-legged frog (Riparian habitats with deep pools) has been severely reduced by drought and land use practices over the past 50 years throughout California. This has resulted in habitat less suitable for reproduction and survival for the species. Jennings (1991) cited the following niche-specific effects resulting from the above practices: (1) creation of lotic warm water microhabitats; (2) the removal of native streamside vegetation which allows the growth of emergent vegetation; (3) modification of riparian zones which allows increased solar input, thus raising ambient temperatures and providing access for predators of all life stages; and (4) reducing or elimination of undercut banks, underwater holes, tree root masses, and gravel substrates by increased erosion and siltation.

Special Biological Considerations

Immediate management considerations need to be applied to R. a. draytonii if the remaining or suspected populations are to remain viable. The goal of management should be to isolate the taxon from introduced predators (Hayes and Jennings, 1988). In addition, preservation of modal conditions for habitat variables identified as associated with the species is likely to promote isolation and would be a suitable interim strategy (Hayes and Jennings, 1988).

Although exploitation as food has been linked to the historical disappearance of red-legged frogs (Hayes and Jennings, 1986, 1988), the severe decline in the population since the mid-1970's, despite unperceived changes in habitat, remain poorly understood (Jennings, 1991). Wernette et. al. (1982) reported that over half of the remaining populations are located in areas projected to be flooded by reservoirs proposed for the Coast Range slope of the Central Valley. Six years after Wernette's, et. al. 1982 report, Hayes and Jennings (1988) reported that R. a. draytonii had become extinct on the floor of the Central Valley, and was probably extinct from over half of the drainage systems in the Central Valley from where it was historically recorded.

The recent USFWS final critical habitat document (USFWS 2001) states that critical habitat will provide breeding and non-breeding habitat for dispersal between the habitats and also allows for expansion fo red-legged frog populations. The proposal continues to state the primary constituent elements of critical habitats: (1) suitable aquatic habitat, (2) associated upland habitats; and (3) suitable dispersal habitat connecting suitable aquatic habitat. Suitable aquatic habitat is defined as all natural or man-made still or slow-moving freshwater bodies that are void of non-native predators and are year-round. Suitable breeding water bodies must have a minimum water depth of 8 inches and maintain water levels from March through July at a minimum. There must be 2 or more breeding sites within 2 km. Suitable upland habitats include all upland habitats within 150 m of the edge of suitable aquatic habitat. Suitable dispersal habitat must be free of barriers and at least 150 m wide. Dispersal corridors include upland and wetland habitats which are free of barriers and connect suitable aquatic habitat within 2 km of one another. Dispersal barriers are defined as heavily traveled roads (more than 30 cars per hours), moderate to high density urban or industrial developments, and large reservoirs. Agricultural lands and pastures are not barriers.

LITERATURE CITED

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Bradford, D.M. Graber, and F. Tabatabai. 1993. Isolation of remaining populations of the native frog, Rana mucosa, by introduced fish in Sequoia and Kings Canyon National Parks, California. Conservation Biology 7(4):882-88.

Dickerson. 1906. The frog book. Doubleday, Page and Co., New York.

Emlen, S.T. 1977. "Double clutching" and its possible significance in the bullfrog. Copeia, 1977(4):749-751.

Fellers, G.M. and C.A. Drost. 1993. Disappearance of the Cascades frog, Rana cascadae at the southern end of its range, California, USA. Biological Conservation 65(2): 177-81.

Fisher, R.N. and H.B.Shaffer. 1996. The decline of amphibians in California's great central valley. Conservation Biology 10: 1387-1397.

Green, D.M. 1985. Differentiation in amount of centromeric heterochromatin between subspecies of the red-legged frog rana-aurora. Copeia 1985: 1071-1074.

Harris, Scott. 1999. Personal Comment.

Harrison, S. 1991. Local extinction in a metapopulation context: An empirical evaluation. Biological Journal of the Linnean Society 42(1&2):73-88.

Hayes, M.P. and M.R. Jennings. 1986. Decline of ranid frog species in western North America: are bullfrogs (Rana catesbeiana) responsible? J. Herpetology, 20(4):490-509.

Hayes, M. P., and M. R. Jennings. 1988. Habitat correlates of distribution of the California red-legged frog (Rana aurora draytonii) and the foothill yellow-legged frog (Rana boylii): Implications for management. Pages 144-158 In: R. Sarzo, K. E. Severson, and D. R. Patton (technical coordinators). Proceedings of the Symposium on the Management of Amphibians, Reptiles, and small mammals in North America. U.S.D.A. Forest Service General Technical Report RM-166.

Hayes, M. P., and M. M. Miyamoto. 1984. Biochemical, behavioral and body size differences between Rana aurora aurora and R. a. draytonii. Copeia 1984(4):1018-1022.

Hayes, M. P., and M. R. Tennant. 1985. Diet and feeding behavior of the California red-legged frog, Rana aurora draytonii (Ranidae). The Southwestern Naturalist 30(4):601-605.

Jennings, M. R. 1988. Natural History and decline of native ranids in California. Pages 61-72 In: H. F. DeLisle, P. R. Brown, B. Kaufman, and B. M. McGurty (editors). Proceedings of the conference on California herpetology. Southwest Herpetologists Society, Special Publication (4):1-143.

Jennings, M. R., and M. P. Hayes. 1990. Status of the California red-legged frog (Rana aurora draytonii): The inducement of bullfrog (Rana catesbeiana) introduction. Herpetologica 41(1):94-103.

Jennings, M.R. and M.P. Hayes. 1985. Pre-1900 overharvest of California red-legged frog (Rana aurora draytonii): The inducement for bullfrog (Rana catesbeiana) introduction. Herpetologica, 41(1):94-103.

Jennings, M. R., M. P. Hayes, and D. C. Holland. 1992. A petition to the U.S. Fish and Wildlife Service to place the California red-legged frog (Rana aurora draytonii) and the western pond turtle (Clemmys marmorata) on the list of endangered and threatened wildlife and plants. 21 pp.

Jennings, M.R. 1991. Preliminary Summary of Information Regarding Four Species of Potentially Endangered Amphibians in Southern California. California Academy of Sciences. Department of Herpetology. San Francisco, California.

Jennings, M.R. 1996. Sierra Nevada Ecosystem Project: Final report to Congress, vol. II. Assessments and scientific basis for management options. Davis: Univ. of California, Centers for Water and Wildland Resources. Ch 31. Status of Amphibians.

Lefcort, H. and A.R.Blaustein. 1995. Disease, predator avoidance, and vulnerability to predation in tadpoles. Oikos 74: 469-474.

Licht, L.E. 1971. Breeding habits and embryonic thermal requirements of the frogs, Rana aurora aurora and Rana pretiosa pretiosa, in the Pacific Northwest. Ecology, 52(1):116-124.

Moyle, P.B. and H.W.Li and B.A.Barton. 1986. The Frankenstein effect: impact of introduced fishes on native fishes in North America. in Fish culture in fisheries management, edited by R.H.Stroud (Bethesda, Maryland: American Fisheries Society), pp. 415-26.

Rathburn, G.B., M. R. Jennings, T. G. Murphy, and N. R. Siepel. 1993. Status and ecology of sensitive aquatic vertebrates in lower San Simeon and Pico creeks, San Luis Obispo County, California. U.S. Fish and Wildlife Service, National Ecology Research Center, San Simeon, California. Prepared for the California Department of Parks and Recreation. 103 pp.

Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Company, Boston, MA. 336 pp.

Storer, T. I. 1925. A synopsis of the amphibia of California. University of California Publications in Zoology 27:1-342.

U.S. Fish and Wildlife Service. Federal Register 61: 25832, May 23, 1996.

U.S. Fish and Wildlife Service. September 11, 2000. Federal Register 65:54892.

Wernette, F.G., F.A. Hall Jr., C.J. Brown Jr., C.L. Mayer, and N.A. Villa. 1982. Los Vaqueros project- fish and wildlife impacts. 263 p. California Department of Fish and Game, Status Report.

 

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SPECIES NAME AND GROUP DESIGNATION

Common Name and Scientific Name:

coast range newt (Taricha tarosa tarosa)

Status:

State: Species of Special Concern (CDFG)

Federal: None

GROUP DESIGNATION AND RATIONALE

Group 3

The coast range newt has narrow habitat requirements and limited distribution within the Plan Area, typically being restricted to "pools and runs" stream configurations and adjacent upland habitats within the Santa Ana Mountains Bioregion. Currently, the known distribution of coast range newt within the Plan Area is restricted to the Santa Ana Mountains. Because the coast range newt requires very specific breeding habitat conditions, only occurs within a few locations, and uses a well defined habitat that is narrowly distributed, this species will require site specific considerations, protection of primary breeding habitat and adjacent upland areas, and species-specific conservation measures.

SPECIES CONSERVATION OBJECTIVES

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.

Objective 1

Include within the MSHCP Conservation Area at least 8,441 acres of primary breeding habitat (playa and vernal pools, riparian scrub, woodland, and forest, and water) within the Santa Ana Mountains bioregion. Within the greater habitat categories, coast range newt breeding activities are limited to streams and creeks which may form "pool and runs" hydrology.

Objective 2

Include within the MSHCP Conservation Area at least 76,579 acres of the secondary habitat (chaparral, coastal sage scrub, grassland, Riversidean alluvial scrub, and oak woodlands and forests) within the Santa Ana Mountains Bioregion. Secondary habitat is limited to a 2 km buffer around streams and creeks.

Objective 3

A 100-meter buffer, where possible, will be established around emergent vegetation areas identified in Objective 1 as they are incorporated into the MSHCP Conservation Area for water quality purposes.

Objective 4

Within the MSHCP Conservation Area, Reserve Managers shall maintain or, if feasible, restore ecological processes within occupied habitat and suitable new areas within the MSHCP Conservation Area. At a minimum, these areas will include creeks, streams, ponds, and other wetland habitat in the Cleveland National Forest (Santa Ana Mountains Bioregion) and Santa Rosa Plateau (includes portions of Cole Creek).

Objective 5

Within the MSHCP Conservation Area, maintain occupancy of at least 75 percent of the occupied coast range newt habitat and determine if successful reproduction is occurring within the MSHCP Conservation Area as measured by the presence/absence of larvae or egg masses once a year for the first five years after permit issuance and then as determined by the Reserve Management Oversight Committee as described in Section 6.6, MSHCP Volume I (but not less frequently than every 8 years).

SPECIES CONSERVATION ANALYSIS

Conservation Levels

For purposes of this conservation analysis, suitable habitat for the coast range newt includes most upland habitats and water bodies within the Santa Ana Mountains Bioregion below an 1,830 m elevation. Specifically, breeding habitat is associated with "pools and runs" stream courses (i.e., playa and vernal pools, riparian scrub, woodland and forest, and water), and secondary upland habitat consists of adjacent uplands within 2 kilometers of stream courses (i.e., chaparral, coastal sage scrub, grasslands, Riversidean alluvial sage scrub, and oak woodlands and forests). Because of the apparently abundant seasonal streams available within the Santa Ana Mountains Bioregion, the entire Bioregion is considered to act as suitable secondary upland habitat. Because there are very few data points, and most of the points that are available are old or undated, species coverage must be primarily based on suitable habitat preservation within the Santa Ana Mountains Bioregion. As described below under Data Characterization, there is only one current data point for the Plan Area that is precise and recent enough for evaluation, however this and the other points are all located within the Santa Ana Mountains. These data points are thought to roughly define the limits of the population within western Riverside County. This data is presented in Tables 1 and 2 below.

TABLE 1
SUMMARY OF PRIMARY HABITAT CONSERVATION
COAST RANGE NEWT

		Within MSHCP Conservation Area			Outside MSHCP Conservation Area
Vegetation Type	Plan Area1 (Acres)	Criteria Area2 (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 Pools	31	0	31	31	0	0	0
Riparian Scrub, Woodland and Forest	1,287	123	933	1,056	175	55	230
Water	37	1	0	1	23	14	37
Woodlands and Forest	11,099	981	6,372	7,353	3,219	525	3,744
TOTAL	12,456	1,107	7,304	8,441	3,417	595	4,011
1 Total acres only include Santa Ana Mountains Bioregion. 2 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area.

TABLE 2
SUMMARY OF SECONDARY UPLAND HABITAT CONSERVATION
COAST RANGE NEWT

		Within MSHCP Conservation Area			Outside MSHCP Conservation Area
Vegetation Type	Plan Area1 (Acres)	Criteria Area2 (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)
Chaparral	85,516	3,458	62,480	65,938	16,599	2,978	19,577
Coastal Sage Scrub	12,506	342	5,007	5,349	6,238	918	7,156
Grassland	10,297	743	4,338	5,081	4,338	877	5,215
Riversidean Alluvial Fan Sage Scrub	334	142	69	211	26	95	121
TOTAL	108,653	4,685	71,894	76,579	27,201	4,868	32,069
1 Total acres only include Santa Ana Mountains Bioregion area. 2 Acres refer to Additional Reserve Lands to be assembled from within the Criteria Area.

Based on these habitats, the Plan Area within the Santa Ana Mountains Bioregion supports approximately 121,109 acres of potential habitat for the newt. Approximately 8,441 acres (68 percent) of primary wetland (breeding) habitat and 76,579 acres (70 percent) of secondary upland habitat would be conserved within the MSHCP Conservation Area. It is assumed that these lands would be managed for wildlife resources, including the coast range newt. Management actions will be incorporated into the conservation strategy so that habitat conditions will be maintained.

As described below under Data Characterization, all data points are considered too few and mostly too old, therefore preservation based on species occurrence is not feasible. All data points and known locations are situated within the Santa Ana Mountains Bioregion. Regardless, 4 (57 percent) of 7 precision code "1" or "2" data points will remain within the MSHCP Conservation Area, including the only recent data point from 1995. A review of various roadless areas and range allotments indicates the following: The Cleveland National Forest has portions of four roadless areas (Ladd, Coldwater, Trabuco, and Wildhorse) that occur from the vicinity of Corona south to the vicinity of Sedco Hills, and; portions of three cattle ranges (El Cariso, Verdugo, and Tenaja) occur between Lakeland Village and the Santa Rosa Plateau. Based on communications from the U.S. Fish and Wildlife Service, newts are also known from the Cole Creek area within the Santa Rosa Plateau Ecological Reserve and possibly to the northwest.

MSHCP Conservation Area Configuration Issues

Only one large contiguous block of habitat supporting the coast range newt is present within the MSHCP Plan Area. This area is located in the Santa Ana Mountains, primarily on U.S. Forest Service land and the Santa Rosa Plateau Ecological Reserve. Protection is provided by the Forest Service and existing wetland regulations and the Plan's wetland policies. Management of watersheds will be important in maintaining breeding populations. Because newts are known to travel up to 2 km from breeding sites, connectivity between suitable breeding areas must be maintained. Very little is known about genetic relationships between coast range newts within the Plan Area. in order to retain important genetic variation, it is important to conserve representative populations at the limits of the species distribution and range, including longitude, latitude, and elevation. To this end, the Plan Area contains a relatively large and contiguous area with a wide elevational range within habitat that is suitable for the species.

The Forest Service will need to address development, hydrology maintenance, fish stocking practices, firewood harvesting, commercial timber harvesting, fire management, grazing leases, and land exchanges to avoid discussed threats to the species.

Implementation of the MSHCP, including the conservation of the existing population and suitable habitat as described above, will maintain viable populations of the Coast range newt. The current population size and local distribution of the coast range newt is unknown and censussing populations may be difficult due to steep terrain and habitat preferences of the species. Ensuring that the species remains viable in the MSHCP Plan Area will require a comprehensive management plan and general monitoring.

Conservation Strategy Summary

In summary, conservation for the coast range newt will be achieved by the inclusion of at least 8,441 acres of suitable primary Conserved Habitat and 76,579 acres of secondary upland Conserved Habitat within one Core Area (Santa Ana Mountains Bioregion) within the MSHCP Conservation Area. The Core Area provides connections between seasonally preferred habitats. In addition, the MSHCP Plan will maintain a 100-meter buffer around breeding habitat areas identified above; maintain or, if feasible, restore ecological processes within occupied habitat and suitable new areas within the MSHCP Conservation Area, minimally these areas will include creeks, streams, ponds, and other wetland habitat in the Cleveland National Forest (Santa Ana Mountains Bioregion) and Santa Rosa Plateau (includes portions of Cole Creek); and maintain occupancy of at least 75 percent of the occupied coast range newt habitat and determine if successful reproduction is occurring within the MSHCP Conservation Area, as measured by the presence/absence of larvae or egg masses once a year for the first five years after permit issuance and then as determined by the Reserve Management Oversight Committee. The current population size and distribution of the coast range newt is unknown. Furthermore, the Plan Area is contiguous with suitable habitat in Orange and San Diego counties.

INCIDENTAL TAKE

Incidental Take of the coast range newt is difficult to quantify due to our limited knowledge of the species distribution within the Plan Area, and the fact that losses may be masked by fluctuations in abundance and distribution during the life of the permit. However, the maximum level of Take of the coast range newt can be anticipated by the loss of the number of acres of habitat that will become unsuitable for this species and individuals within these areas will be subject to Incidental Take consistent with the Plan. Approximately 4,011 acres (32 percent) of potential primary breeding habitat and 32,069 acres (30 percent) of secondary upland habitat for the coast range newt would be outside the MSHCP Conservation Area.

SPECIES ACCOUNT

Data Characterization

The coast range newt is restricted to the Santa Ana Mountains from the Santa Ana River to the Santa Margarita River, utilizing a variety of upland habitats but relying on bodies of water for breeding purposes. There is a moderate amount of information known about the western newt. The MSHCP data base holds 23 records for T. t. tarosa. Of the 23 records, 2 (8 percent) area precision code "1" (an "x" and "y" coordinate that allows for good precision in the location), 9 (39 percent) are precision code "2" (one "x" or "y" data point or equivalent), and 12 (31 percent) are precision code "3" or "4" (relatively imprecise locations from general areas). Both of the precision code "1" and seven of the precision code "2" records are undated. Only one precision code "2" is dated from 1990 to 2001 (1995). This is considered to be the only recent record. However, all data are considered pertinent and useful to conservation analysis.

Habitat and Habitat Associations

T. t. tarosa frequents terrestrial habitats (grassland, woodland and forest) but breeds in ponds, reservoirs, and slow moving streams (Stebbins, 1985).

Biogeography

The western newt (T. t. torosa) ranges along the western coast of California from Humboldt County, to the Mexican border (Tan and Wake, 1995). Populations in southern California appear to exhibit a high level of historic fragmentation. The known elevation range of this taxon extends from near sea level to 1,830 meters. T. t. torosa has been depleted in southern California, including extirpation of the southern most populations in San Diego County. It is one of two species of California newt; the other being T. t. sierrae which is found in the Sierra Nevada Mountains.

Known Populations Within Western Riverside County

T. t. torosa occurs in coastal drainages of the western most portions of Riverside County. Lands adjacent to Forest Service southeast of Lake Elsinore, and along Highway 74, and southwest of Corona. Southeast of Lake Norconian and west of Highway 15. Several known citations on Forest Service lands, and at the Santa Rosa Plateau.

Key Populations in Plan Area

Entire known range in western Riverside County including the Santa Ana Mountains from the Santa Ana River south to the Santa Margarita River.

Biology

Taxonomic Systematics: Newts of the genus Taricha form a monophylitic group of three species (Riemer, 1958). Earlier studies recognized more species, but the taxonomy has been stable since Riemer's study in 1958. Tan and Wake (1995) studied mtDNA sequences of the California newt to test the previous phylogeographic hypothesis of the two subspecies T. t. torosa and T. t. sierra. They found the southern sierrae cluster has an mtDNA lineage derived from the coastal torosa. Additionally, the southern and central populations of torosa displayed more differentiation than the northern populations, suggesting a longer independent history (Tan and Wake, 1995). Phylogenetically, this places the southern torosa more basal to both the northern torosa and southern sierrae clusters. Tan and Wake (1995) concluded that the Taricha torosa complex is composed of five clusters: three clusters of T. t. sierrae (northern, central and southern Sierra Nevada); and two clusters of T. t. torosa (southern coastal and central coastal). Furthermore, the data suggests that the sierrae taxon is diphyletic.

Diet and Foraging: Typically, newts feed on earthworms, insects, snails and other small invertebrates (Stebbins, 1972). Hanson, et al. (1994), reported the stomach contents of a single female newt captured in the Santa Monica Mountains. They found several insects including 2 coleopterans, 11 lepidopteran, and 1 plecopteran; 5 conspecific newt larvae and an intact nestling bird. Additionally, newts are known to cannibalize their own or conspecific's egg masses (Marshall, et al., 1990). The study conducted by Marshall et al. (1990) determined that the majority of intraspecific oophagy occurred in the female newt.

Daily Activity: T. torosa has been found to be active in all hours of the day (Marshall, et al., 1990). Much of its daily activity revolves around feeding, both in aquatic and terrestrial habitats. It has a well developed tongue-projection system for use in terrestrial feeding, and relies almost entirely on prey movement to detect food items. Without movement, prey within reach are ignored. Feeding consists of orientation and approach to prey, and the strike (Findeis and Bemis, 1990). An alert posture and elevated head characterize approach which is rapid. Within 5-10 mm of prey the newt halts and may shift position slowly in preparation of the strike. Successful strikes occur only when prey is directly in front of the newt's head and within 10 mm (Findeis and Bemis, 1990). At the instant the tongue is substantially deployed, the newt lunges forward to contact the tongue pad to the prey item and retract the item deep into the oral cavity. Findeis and Bemis (1990) found that in captivity, strikes were 56 percent successful with maggots as the prey item.

Reproduction: The mating season for the western newt occurs between January and May, depending on location (Stebbins, 1962; Twitty, 1942). The reproductive cycle begins with males migrating in large numbers to the breeding area. The preferred breeding and oviposition sites of T. torosa are the largest and deepest pools, and slow-moving runs available in streams (Gamradt and Kats, 1997). Prior to entering the water, males undergo physiological changes which adapt them to aquatic life and acquire secondary sex characteristics (i.e., skin becomes engorged with fluid and loses its rough texture, becoming highly vascularized; the tail develops a broad blade; and the cloacal lips become enlarged). Attractants released into the water by the female's skin attract males (Twitty, 1955). Movement also attracts attention at close range. Several males may be attracted to a single female, especially during the early part of the breeding season. At times a single female may become entangled in a compact mass of 20 or more males. Breeding occurs 24 hours a day (Marshall, et al., 1990).

After courting behaviors, the male deposits a spermatophore on the aquatic substrate. The spermatophore is composed of a gelatinous stalk with a rounded sperm mass perched on the apex. Once the spermatophore is in place, the male assumes the final courting position, orienting his hips away from the female in an arc, forming a deep lateral curvature of his pelvic region, with the concavity directed toward the female (Davis and Twitty, 1964). The female maintains her axial position to that of the male, moving sideways along the male''s flank until her snout penetrates the hollow of the sacral curvature, bringing her cloaca in close proximity to the spermatophore without any apparent visual guidance (Davis and Twitty, 1964). She then depresses her vent against the spermatophore to complete the ritual. After fertilization, females ovideposit 7-30 eggs (Brame, 1968), attaching them to the aquatic substrate. A female may take several weeks to deposit a single clutch (Marshall et al., 1990). In a study conducted by Gamradt and Kats (1997), 89 percent of egg masses observed were oviposited in pools and 9.5 percent were oviposited in runs of a stream in the Santa Monica Mountains.

Survival: Coast range newts are more resistant to desiccation due to their large bladder capacity, thick skin, high temperature tolerance, and frequent behavior of maintaining body contact with the substrate (Cohen, 1952; McFarland, 1955; Brattstrom, 1963; Brown and Brown, 1980). Their natural life span ranges from 10-15 years and they are very site tenacious (Twitty, 1942).

Stromberg (1997) documented a survival mechanism in response to a prescribed burn on the Hastings Natural History Reservation, Carmel Valley, Monterey Co., California. He observed a pair of newts walk through flames (5-10 cm high) without pausing. The slime covering their bodies foamed up, and within 20-30 seconds, they were through the flames and onto the ashes of the litter. Upon close examination, the now crusty white coating easily wiped off, and the skin was free of blisters or discoloration. He released the newts which continued to walk normally, proceeding at near record newt speed. As they walked, leaves and litter removed nearly all of the thin white crust covering their bodies. Foaming of the skin would dissipate heat and may be a mechanism used to escape natural wildfires (Stromberg, 1997).

Newt larvae have the ability to recognize the chemical cues of conspecific and native predators with which they have coevolved (i.e., snakes, raccoons, birds, coyotes, foxes; Diamond, 1996; Kats et al., 1994), but apparently this defense is ineffective against introduced predators such as mosquitofish and crayfish (Gamradt and Kats, 1996). The newt has the ability to repel some predators with toxic glands on its skin and eggs (Brodie et al., 1974). Adults produce a potent neurotoxin from dorsal skin, and when in the presence of predators display an Unken Reflex, curving the body upward to display the bright orange ventral skin. The bright ventral coloration of T. t. torosa is thought to be a warning to predators (Brodie, 1977).

Dispersal: Newts travel great distances relative to their body size (>1 km) during migrations between breeding sites and terrestrial habitats (Stebbins, 1951).

Socio-Spatial Behavior: The movement ecology of T. t. torosa is essentially unknown. Newts spend most of the year on land and typically engage in often lengthy (>1 km) overland migrations to breeding sites where breeding may occur between (December) January and April (Stebbins, 1951; Miller and Robbins, 1954). Electronically tagged newts have been found to return within a few meters of capture sites in subsequent years (Gamradt and Kats, 1997).

Threats to Species

T. t. torosa has been depleted by large-scale historical commercial exploitation coupled with the loss and degradation of stream habitats, especially in Riverside and other south coastal counties (Jennings and Hayes, 1994). The breeding habitat of this taxon has been severely degraded over much of its range, largely due to a shift in sedimentation dynamics that has resulted in more filling and less scouring of pools (Jennings and Hayes, 1994).

By far, the largest threat to T. t. torosa is introduced crayfish (Procambarus clarkii) and mosquito fish (Gambusia affinis), as these exotic species are apparently unaffected by the potent neurotoxin produced by T. t. torosa. Data collected by Gamradt et al. (1997) indicates that aggression by crayfish directly affects newt behavior, breeding, and egg mass production.

Gamradt and Kats (1996) conducted a study on the effect of introduced predators on the western newt in the Santa Monica Mountains. Of the ten streams surveyed, three had mosquitofish and/or crayfish and contained no California newt eggs, larvae or adults. The remaining seven streams all contained California newts. In laboratory studies, they found that both predators studied prey on newt eggs and larvae, and that newt breeding behavior may be altered by predator presence, preventing successful mating and oviposition. Additionally, they found that in 1995, one stream was cleansed of crayfish by heavy rains. The following spring, the stream contained newt eggs where no evidence of newt presence was detected previously.

Wildfire is another threat to the western newt. Gamradt and Kats (1997) studied the effects of chaparral wildfire on Taricha torosa in a Santa Monica Mountain stream. They found major changes in stream morphology following the 1993 wildfire. The preferred habitat of the newt (pools and runs) was drastically reduced by landslides and sediment loads. The result was a drastic reduction in the amount of suitable habitat for oviposition. This likely occurred at two spatial scales: available oviposition microsites were covered with sediment and pool area decreased (Gamradt and Kats, 1997). Prior to the fire, pools and runs comprised 40-50 percent of the Plan Area. The following spring, the post-fire area contained less than 20 percent runs and pools; and approximately 1/3 the number of egg masses as compared to pre-fire surveys. Three years after the post-fire survey, the number of egg masses observed increased from 51 (1994) to 67 (1996), a possible indication that recovery had begun.

Special Biological Considerations

The continued policy driven release of mosquitofish will destroy the remaining populations of the western newt unless a management plan is implemented. Management should include the preservation of streams that are currently free from the introduced predator.

LITERATURE CITED

Brattstrom, B. H. 1963. A preliminary review of the thermal requirements of amphibians. Ecology 44(2):238-255.

Brown, S. C., and P. S. Brown. 1980. Water balance in the California newt, Taricha torosa. American Journal of Physiology 238(1):R113-118.

Brodie, E. D., Jr., J. L. Hensel, Jr., and J. A. Johnson. 1974. Toxicity of the urodele amphibians Taricha, Notophthalmus, Cynops, and Paramesotriton (Salamandridae). Copeia 1974(4):506-511.

Brodie, E. D., Jr. 1977. Salamander antipredator postures. Copeia 1977(3):523-535.

Cohen, N. W. 1952. Comparative rates of dehydration and hydration in some California salamanders. Ecology 33(4):462-479.

Davis, W.C., and V.C. Twitty. 1964. Courtship behavior and reproductive isolation in the species of Taricha (Amphibia, Caudata). Copeia 1964, No 4, pp 601-610.

Diamond, J.E. A-bombs against amphibians. Nature. Vol 383, pp 386-387.

Findeis, E.K., and W.E. Bemis. 1990. Functional morphology of tongue projection in Taricha torosa (Urodela: Salamandridae). Zoological J. of the Linnean Soc. 99:129-157.

Gamradt, S.C., and L.B. Kats. 1996. Effect of introduced crayfish and mosquitofish on Calfornia newts. Conservation Biology. Vol 10, No 4, pp1155-1162.

Gamradt, S.C., and L.B. Kats. 1997. Impact of chaparral wildfire-induced sedimentation on oviposition of stream-breeding California newts (Taricha torosa). Oecologica. 110:546-549.

Grey, J.E. 1850. Catalogue of the specimens of Amphibia in the collection of the British Museum, part II. Batrachia Gradientia, etc. (British Museum), London.

Hanson, K., J. Snyder, and L. Kats. 1994. Taricha torosa (California newt) Diet. Natural History Notes. Herpetological Review. 25(2):62.

Jennings, M. R., and M. P. Hayes. 1994. Amphibian and reptile Species of Special Concern in California. Final report submitted to California Department of Fish and Game, Inland Fisheries Division, Rancho Cordova, California, under Contract 8023.

Kats, L.B., J.A. Breeding, K.M. Hanson, and P. Smith. 1994. Ontogenic changes in California newts (Taricha torosa) in response to chemical cues from conspecific predators. J. N. Amer. Benthol. Soc. 13(2):321-325.

Marshall, C.J., L.S. Doyle, and R. H. Kaplan. 1990. Intraspecific and sex-specific oophagy in a salamander and a frog: Taricha torosa and Bombina orientalis. Herpetologica. 46(4):395-399.

McFarland, W. N. 1955. Upper lethal temperatures in the salamander Taricha torosa as a function of acclimation. Copeia 1955(3):191-194.

Miller, M. R., and M. E. Robbins. 1954. The reproductive cycle in Taricha tarosa (Triturus torosus). Journal of Experimental Zoology 125(3):415-445.

Riemer, W.J. 1958. Variation and systematic relationships within the salamander genus Taricha. Univ. Cal. Publ. Zool. 56:301-390.

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Stebbins, R.C. 1962. Amphibians of western north America. Univ. Of Cal. Press, Berkeley, CA.

Stebbins, R.C. 1972. California Amphibians and Reptiles. Univ. Of Cal. Press, Berkeley, CA. 152 pp.

Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. McGraw Hill Book Company, New York, New York.

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Twitty, V.C. 1955. Field experiments on the biology and genetic relationships of the California