Spatial variation in abundance parameters of a federally threatened groundwater salamander within and among central Texas headwater creeks

Semi-arid conditions in central Texas relegate Eurycea salamanders to aquatic habitats influenced by groundwater (i.e., springs, spring-fed creeks, and subterranean water in alluvium and aquifers). Many studies have noted that epigean (surface) populations of central Texas Eurycea occur near spring outlets. Consequently, the U.S. Fish and Wildlife Service designated surface critical habitat units for three species as a uniform distance up and downstream of occupied spring outlets. Here, we used data from visual encounter and quadrat surveys to model relative abundance and relative density, respectively, of federally threatened Jollyville Plateau Salamanders (E. tonkawae) in relation to downstream distance from a spring outlet in headwater creeks. We additionally use recapture data to investigate movement within these systems and in relation to the critical habitat units. Consistent with other studies, E. tonkawae relative abundance and relative density decreased with increasing distance..., , , # Spatial variation in abundance parameters of a federally threatened groundwater salamander within and among central Texas headwater creeks

[https://doi.org/10.5061/dryad.n5tb2rc5b](https://doi.org/10.5061/dryad.n5tb2rc5b)

## Description of the data and file structure

**Spatial variation in abundance parameters of a federally threatened groundwater salamander within and among central Texas headwater creeks**

Zachary C. Adcock, Andrew R. MacLaren, Michelle E. Adcock, and Michael R.J. Forstner

This document contains a description of the metadata, data, and notes for all analyses and results included in the associated manuscript. These items are organized by topic, and for each set of results, the associated data file and R code file are provided.

Metadata notes

We conducted the study between May 2013 and August 2016. Survey and salamander capture dates are included in the accompanying data files.

All salamanders included in the study are Jollyville Plateau Salamanders (*Eurycea t...,