DOI: 10.5061/dryad.p2ngf1vvg
title: The high cost of movement in an arid working landscape for an endangered amphibian

description: Connectivity is essential for the maintenance of genetic diversity and
 stability of wildlife populations. Drought and changing precipitation
 regimes have caused natural aquatic amphibian breeding habitats to
 disappear or become isolated and have led to the replacement of natural
 surface water with artificial livestock water tanks. Terrestrial movement
 is the only means of responding to aquatic threats in arid landscapes and
 to allow population connectivity. Aridity may present an impenetrable
 barrier in hydrologically fragmented environments. We used a facultatively
 paedomorphic and federally endangered salamander to assess the challenges
 of movement across arid working lands. Sonoran tiger salamanders
 (Ambystoma mavortium stebbinsi) are endemic to the San Rafael Valley of
 southeastern Arizona, United States of America, where they depend on
 livestock water tanks as breeding habitat. The ecology of this species’
 metamorphs outside of stock tanks is virtually unknown. To assess survival
 on the landscape during terrestrial movement we used radio transmitters to
 track 78 adult metamorphosed salamanders over two years. Sonoran tiger
 salamanders moved up to 1 km from the tank edge, and average distances
 moved of over 400 m were higher than most Ambystoma species. However,
 during the study period, none reached neighboring stock tanks. We found
 high mortality due to predation and desiccation. Individuals that
 dispersed to terrestrial habitat in summer survived longer than
 individuals that dispersed in spring. High mortality suggests terrestrial
 movement is exceptionally risky and may contribute to isolated
 subpopulations and elevated levels of inbreeding. Conservation actions
 that improve and maintain artificial aquatic habitats as well as increase
 connectivity may improve long-term management for pond-breeding amphibians
 in arid regions.
description: # The high cost of movement in an arid working landscape for an endangered
 amphibian Description of data: ID: animal ID Tank: tank where the
 salamander was originally captured HR (0/1): Home range calculated for the
 individual. 0=no; 1=yes Massb4; body mass (g) of the salamander at
 implantation day SVL: Snout–vent length (cm) Left tank (0/1): whether the
 salamander ever left the tank of origin during the survey period (1=yes)
 or not (0=no) ID_Interval: numer of days between implantation date and
 date when the salamander left the tank. na shoed if the salamander never
 left the tank Dispersal_Month: the month when the salamander left the tank
 (na if it never left the tank) Dispersal: Date when for the first time the
 salamander was recorded as away from the tank (na if it never left the
 tank) Final: last day of tracking Days_terrestrial: days in dispersion (na
 if it never left the tank) Total_Fixes: number of telemetry locations. na
 if the transmitter malfunctioned or signal was lost TD: total distance
 moved since leaving the tank (na if it never left the tank) MD: maximum
 distance moved between telemetry fixes (na if it never left the tank) SD:
 the average distance traveled per day (na if it never left the tank)
 KDE_95: home range with Kernel Density estimator (na if it never left the
 tank or if the number of locations collected was &lt; 20) KDE_50: core
 area with Kernel Density Estimator (na if it never left the tank or if the
 number of locations collected was &lt; 20) Survival (1/0):Fate of each
 salamander (0=died;1=survived) until the end of the study (na if the
 individual went missing or the transmitter malfunctioned)