DOI: 10.5061/dryad.ds8j3
title: Data from: Habitat drives dispersal and survival of translocated juvenile desert tortoises

description: In spite of growing reliance on translocations in wildlife conservation,
 translocation efficacy remains inconsistent. One factor that can
 contribute to failed translocations is releasing animals into poor-quality
 or otherwise inadequate habitat. Here, we used a targeted approach to test
 the relationship of habitat features to post-translocation dispersal and
 survival of juvenile Mojave desert tortoises Gopherus agassizii. We
 selected three habitat characteristics – rodent burrows, substrate texture
 (prevalence and size of rocks) and washes (ephemeral river beds) – that
 are tied to desert tortoise ecology. At the point of release, we
 documented rodent burrow abundance, substrate texture and wash presence
 and analysed their relationship to the maximum dispersal. We also
 documented the relative use by each individual for each habitat
 characteristic and analysed their relationships with survival and fatal
 encounters with a predator in the first year after release. In general,
 the presence of refugia or other areas that enabled animals to avoid
 detection, such as burrows and substrate, decreased the overall mortality
 as well as predator-mediated mortality. The presence of washes and
 substrate that enhanced the tortoises’ ability to avoid detection also
 associated with the reduced dispersal away from the release site. These
 results indicate an important role for all three measured habitat
 characteristics in driving dispersal, survival or fatal encounters with a
 predator in the first year after translocation. Synthesis and
 applications. Resource managers using translocations as a conservation
 tool should prioritize acquiring data linking habitat to fitness. In
 particular, for species that depend on avoiding detection, refuges such as
 burrows and habitat that improved concealment had notable ability to
 improve the survival and dispersal. Our study on juvenile Mojave desert
 tortoises showed that refuge availability or the distributions of habitat
 appropriate for concealment are important considerations for identifying
 translocation sites for species highly dependent on crypsis, camouflage or
 other forms of habitat matching.
description: Habitat variables
 associated with survival and dispersal of translocated juvenile desert
 tortoises• Recipient site (column
 B): describes four geographic locations in which tortoises were released:
 Boulder City Conservation Easement (BCCE), Eldorado Valley (EV), Hidden
 Valley (HV), and Trout Canyon (TC) with their associated elevations
 (Column D) and the "release zone" (Column C). • Longevity
 (column E): describes the number of days that the tortoise survived (if
 died or went missing) or the number of days the tortoise was monitored (if
 survived to close of study). • Status at close of study is 0 if animal
 died, 1 if animal lived, and a - if the animal was lost. Cause of death
 (column F) is 0 if the animal was found with signs of depredation (e.g.
 tooth marks, partially consumed carcass) and 1 if the animal was living or
 dead with no signs of consumption at close of study. • MCL: midline
 carapace length in mm. • Max Distance (Column J): maximum linear straight
 line distance a tortoise moved away from its release point before settling
 into an area reminiscent of a home range. For those tortoises that did not
 appear to establish a home range before mortality occurred a dash is
 present. • Wash present (Release): indicates whether the animal was
 released in a wash (ephemeral river bed) by a 1 or over 2 m from one by a
 0. • Proportion wash encounters: frequency with which an animal was found
 in or within 2 m of a wash across all tracking events during the study
 period. • Burrow Number (release): total number of usable rodent burrows
 (entire body of tortoise fits inside with minimal excavation) within a 2 m
 radius of the release point. • Mean Burrow Number (across year): total
 number of usable rodent burrows or burrows constructed by the tortoise
 within 2 m averaged across all tracking events during the monitoring
 period. • Substrate (release): substrate category ranked between 0 – 5
 measuring the prevalence of rocks on the surface as well as the size of
 the largest rocks present (e.g. small pebbles, or large pebbles and
 cobble) in the 2 m area surrounding the release point for each individual.
 In all instances in which larger rocks were present, smaller rocks were
 also present. • Mean substrate (year): Substrate category within 2 m of
 the tortoises averaged across all tracing events during the monitoring
 period.Dryad Data
 Repository.xlsx