Diet and Mesohabitat Association of the Threatened San Marcos Salamander (Eurycea Nana)
Date
2010-05
Authors
Diaz, Peter H.
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Abstract
The Endangered Species Act was created to aid in the
conservation and protection of species under threat of extinction through all or part of their range. Data regarding habitat associations and dietary needs are required for the efficient recovery and maintenance of endangered or threatened species populations. The San Marcos salamander (Eurycea nana) is a spring-associated organism which exhibits a geographic range limited to the headwaters of the San Marcos River in central Texas, USA. The USFWS and the state of Texas currently list the SMS as threatened and its designated critical habitat includes the
headwaters (Spring Lake) and the first 50 m of the river. The
present study determined mesohabitat associations and the trophic ecology of the San Marcos salamander in its critical habitat. San Marcos salamander habitat associations were determined over a 1-year period and it was determined that San Marcos salamanders are associated with mesohabitats containing cobble and gravel substrates with coverage of Amblystegium and filamentous algae. In addition, these mesohabitats account for about 14% of the area within the designated critical habitat. To examine the trophic ecology of the San Marcos salamander, gut contents were collected from salamanders and invertebrate samples from the lake and river
were collected. Dietary analyses suggest that the San Marcos
salamanders in Spring Lake and the San Marcos River are generalist predators of aquatic invertebrates and the composition of their diets closely follows temporal changes in the invertebrate
community. I conclude that due to the generalist and flexible diet
of the San Marcos salamander, conservation and recovery issues
related to the diet and food availability is likely to be a less
substantial issue than mesohabitat availability and quality.
Peter Diaz received his first Bachelor of Science degree from
Texas State in Aquatic Biology. After completion he returned to
pursue a Masters degree under Dr. Weston Nowlin in Aquatic
Resources. At this time he is awaiting the births of his first
child, Zoe Elizabeth Diaz.
Description
Keywords
salamander, eurycea, invertebrates, Spring Lake
Citation
Diaz, P. H. (2010). Diet and mesohabitat association of the threatened San Marcos salamander (Eurycea Nana) (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.