Absence of burrows around potential breeding pond does not discount habitat b/c they move up to one kilometer . Disking does not discount CTS presence-depends on level of land management.
Ellen: Adults were captured more often closer to ponds, subadults were captured at greatest distance from pond and less frequently.
USFWS currently requiring mitigation for ag land depending on intensity of management.
Ellen and Deb did a study in 2004 behind Moss Landing power plant (before CTS listing) to determine if co. vehicles actually did crush burrow. We did multiple runs with various weight vehicles. We measured entrance to burrow before and after each run of each type of vehicle, as well as endoscoped to determine if any internal collapse occurred. All burrows were in Sand.
Biology and Conservation of the California Tiger Salamander ( Ambystoma californiense ) Alameda County Conservation Partnership Workshop Tri-Valley Mitigation Monitoring Summary
M ITIGATION AND M ONITORING E FFORTS FOR C ALIFORNIA RED-LEGGED FROG ( R ANA DRAYTONII ) AND C ALIFORNIA TIGER SALAMANDER ( A MBYSTOMA CALIFORNIENSE ): S UCCESSFUL B REEDING IN A C ONSTRUCTED P OND KEVIN D. WISEMAN 1 , DEBIE MONTANA 2 , JOSEPH E. DRENNAN 1 , AND KARLA R. MARLOW 1 1 Garcia and Associates (GANDA) 2601 Mission St., Suite 600, San Francisco, California 94110 2 Pacific Gas and Electric Company (PG&E), 3401 Crow Canyon Road, San Ramon, California 94583 INTRODUCTION SURVEY METHODS RESULTS DISCUSSION Pacific Gas and Electric Company’s (PG&E) Tri-Valley 2002 Capacity Increase Project facilitated increased current and future demand for electricity by constructing and operating two new distribution substations, 13.4 miles of 230 kilovolt (kV) transmission lines, and related upgrades to existing facilities in the Cities of Dublin, Livermore, Pleasanton, and San Ramon, and in portions of unincorporated Alameda and Contra Costa Counties adjacent to these cities. As part of mitigation requirements by the United States Fish and Wildlife Service (USFWS) for this project, PG&E was required to construct and manage a 0.29 acre (~20 x 80 m) pond and 3.9 acres of surrounding upland habitat to enhance populations of federally threatened California red-legged frog ( Rana draytonii ) and California tiger salamander ( Ambystoma californiense ). The objectives of the survey effort were to evaluate colonization and breeding success of both amphibian species using the mitigation pond by conducting annual surveys and monitoring. The mitigation pond was created in the dry season (late fall) in 2005, adjacent to an unnamed tributary of Tassajara Creek near Dublin, California (Figure 2). The pond is located approximately 0.6 km northeast of the North Dublin Substation by way of an unpaved access road within open annual grassland habitat that is grazed and largely undeveloped. Currently, the pond is surrounded by a barbed wire fence which excludes cattle from entering the pond. An unnamed, ephemeral drainage to Tassajara Creek runs adjacent to the pond. Rana draytonii were known from the immediate area, and were documented breeding in a nearby pond, located approximately 80 m to the southeast (CDFG 2008). Ambystoma californiense is also known to occur within the area, and one adult was discovered during the grading of an unpaved access road to the site in July 2005. Figure 1. Location of the Tri-Valley Mitigation Pond. Figure 2. The Tri-Valley Mitigation Pond, February 12, 2008. REFERENCES ACKNOWLEDGEMENTS Following the pond’s creation in 2005, annual surveys for R. draytonii and A. californiense were initiated in 2006 and continued in 2007-2008. Surveys consisted of daytime surveys focused on detecting egg masses, salamander larvae and tadpoles (Fig. 3), and nighttime surveys focused on detecting adult frogs when they are most likely to be observed (Fellers and Kleeman 2006). Surveys were conducted in accordance with standard protocols for both species (USFWS 2003, 2005). Survey Area. In addition to the mitigation pond, the study area also included a 1000 m reach of an unnamed tributary to Tassajara Creek (see Figure 7) which is a relatively narrow (~1-3 m), ephemeral, low-gradient drainage. Mark-recapture study. In 2008, a mark-recapture study of California red-legged frogs was initiated at the Tri-Valley Mitigation Site in order to identify individual frogs and facilitate population estimation. We implanted passive integrated transponder (PIT) tags (Biomark ® 8.5 mm, #TXP148511B; Figure 4A) into adult frogs (Figure 4B) following methods used by Fellers and Kleeman (2007) and Bulger et al. (2003). During subsequent surveys, frogs are captured, measured (SUL, weight) and the frogs serial identification number is recorded using a reader device (Biomark ® Pocket Reader) which detects the signal of the PIT tag. Figure 3. Larval surveys at the Tri-Valley Mitigation Pond, March 11, 2008. Figure 4A. Figure 4B. We observed successful breeding by both California red-legged frog and California tiger salamander for the first time in the mitigation pond in 2008. Rana draytonii adults were observed in the mitigation pond during surveys conducted in 2006 (n=1) and 2007 (n=5), however both species did not use the mitigation pond for breeding until the third wet season, despite favorable habitat conditions in 2006 and 2007. CALIFORNIA RED-LEGGED FROG On February 12, 2008, ten R. draytonii egg masses were observed at the southeastern end of the mitigation pond, estimated to have been deposited between January 31 and February 9 (Figure 5). Egg masses were deposited 170-410 cm (mean=321 cm) from shore and maximum depths at egg mass locations ranged from 26-50 cm (mean=38.7 cm) (Figure 6). Nine of ten egg masses were attached to dead bulrush fronds near the water surface. One egg mass was apparently unattached. Egg masses were located at the northeast and north edges of the mitigation pond (Figure 7). No evidence of breeding (egg masses or tadpoles) was observed in the tributary. Fig. 5. Rana draytonii egg mass. Fig. 6. Microhabitat of 10 R. draytonii egg masses. Figure 7. Locations of R. draytonii observed during surveys in 2008. CALIFORNIA TIGER SALAMANDER A total of five tiger salamander larvae were observed during dip-netting surveys conducted on May 18, 2008, which confirms successful breeding in the mitigation pond. Four larvae were found in the mitigation pond and one was found in a small (~1m 2 ; 25 cm deep) isolated pool in the tributary downstream of the mitigation pond (Figures 9, 10). The larva found in the tributary was much smaller (70 mm total length [TL]) than those in the mitigation pond (92, 93, 98, and 132 mm TL), perhaps due to higher productivity found in the pond compared to the tributary, or temporally separated breeding periods between habitats. A total of 30 adults (>55 mm SUL) were observed during seven surveys in 2008, some of which are likely repeat observations of individual frogs (Figure 7). However surveys conducted on February 21, March 11, May 18, and June 12 resulted in eight, 15, one, and six individual adult CRLF, respectively. Captured adult frogs ranged in size from 72-117 mm SUL (mean=96.9 ± 16.1 mm, N=11) and weighed 50-200 g (mean=104.5 ± 49.5 g; Figure 8). Fourteen adult frogs were observed in the mitigation pond and 16 frogs were observed in the tributary (Figure 7). Thirteen of 16 (81%) adult frogs observed in the tributary were located in the reach downstream of the mitigation pond, where bank gradients are higher and pools are more abundant than the reach upstream of the pond (Figure 7). Only one California-red legged frog was observed during daytime conditions, as compared to 29 individuals observed during nighttime surveys, similar to results observed by Fellers and Kleeman (2006). Three adult female California red-legged frogs were PIT-tagged during a nighttime survey on June 12 at the mitigation pond, none of which were recaptured during subsequent surveys. Tadpoles were commonly observed during surveys conducted in February, March, and May. On August 13, three juvenile CRLF were observed in a small pool (~1m 2 ) located within the tributary adjacent to the mitigation pond (Figure 7). The juveniles were found in 8 cm of water that was completely covered in duckweed ( Lemna sp.), and appeared to be the only source of standing water within the one kilometer reach of the tributary and the mitigation pond, which had completely dried by August 13. Fig. 8. Length and weight of captured R. draytonii adults (n=11). Figure 9. Locations of A. californiense larvae observed during surveys in 2008. Figure 10. A. californiense larva We would like to thank the many individuals who contributed to this project in numerous ways including: Mark Schexnayder, Ken DiVittorio, John and Carol Garcia, Daniel Marquez, Betsy Bolster, Jones and Stokes, Brian Galey, Jeff Steinman, Pierre Fidenci, Jeff Alvarez, and Brad Shaffer. The three-season lag time between pond creation and successful breeding by R. draytonii we observed at the Tri-Valley Mitigation Site is consistent with results from other studies conducted in the San Francisco Bay Area. For example, Alvarez et al. (in press) found that for 22 constructed ponds at Los Vaqueros Reservoir, R. draytonii eventually bred in all but one pond within 1-108 months (mean=23.9 months). At a mitigation pond created in 2006 near Montara, California, R. draytonii eventually bred on the second wet season in 2008 (Jason Minton, pers. comm.). Alvarez, J.A., M.A. Shea, and C. Dunn. In Press . Colonization of constructed mitigation ponds by California red-legged frogs. J. of Herpetology. Bulger, J.B., N.J. Scott Jr., and R.B. Seymour. 2003. Terrestrial activity and conservation of adult California red-legged frogs ( Rana aurora draytonii ) in coastal forests and grasslands. Biol. Conservation (110):85-95. California Department of Fish and Game (CDFG). 2008. California Natural Diversity Database, October update. Fellers, G.M. and P.M. Kleeman. 2006. Diurnal versus nocturnal surveys for California red- legged frogs. Journal of Wildlife Management 70(6):1805-1808. Fellers, G.M. and P.M. Kleeman. 2007. California red-legged frog ( Rana draytonii ) movement and habitat use: implications for conservation. J. of Herpetology 41(2):276-286.