Evaluation of terrestrial and streamside salamander monitoring techniques at Shenandoah National Park
Jung RE. 2000. Evaluation of terrestrial and streamside salamander monitoring techniques at Shenandoah National Park. Environmental Monitoring and Assessment. 63:65-79
In response to concerns about amphibian declines, a study evaluating and validating amphibianmonitoring techniques was initiated in Shenandoah and Big Bend National Parks in thespring of 1998. We evaluate precision, bias, and efficiency of several sampling methods for terrestrialand streamside salamanders in Shenandoah National Park and assess salamander abundance inrelation to environmental variables, notably soil and water pH. Terrestrial salamanders, primarilyredback salamanders {Plethodon cinereus), were sampled by searching under cover objects duringthe day in square plots (10 to 35 m2). We compared population indices (mean daily and total counts)with adjusted population estimates from capture-recapture. Analyses suggested that the proportionof salamanders detected (p) during sampling varied among plots, necessitating the use of adjustedpopulation estimates. However, adjusted population estimates were less precise than population indices,and may not be efficient in relating salamander populations to environmental variables. In futuresampling, strategic use of capture-recapture to verify consistency of p's among sites may be areasonable compromise between the possibility of bias in estimation of population size and deficienciesdue to inefficiency associated with the estimation of p. The streamside two-lined salamander(Eurycea bislineata) was surveyed using four methods: leaf litter refugia bags, 1 m2 quadrats,50 x 1 m visual encounter transects, and electric shocking. Comparison of survey methods at ninestreams revealed congruent patterns of abundance among sites, suggesting that relative bias amongthe methods is similar, and that choice of survey method should be based on precision and logisticalefficiency. Redback and two-lined salamander abundance were not significantly related to soil orwater pH, respectively.
- Type
- Journal Article
- Authors
- Jung, Robin
- Units
- SHEN
- Keywords
- Monitoring, Salamander, Shenandoah, streamside, Terrestrial