Study

Return to the wild: translocation as a tool in conservation of the desert tortoise (Gopherus agassizii)

  • Published source details Field K.J., Tracy C.R., Medica P.A., Marlow R.W. & Corn P.S. (2007) Return to the wild: translocation as a tool in conservation of the desert tortoise (Gopherus agassizii). Biological Conservation, 136, 232-245.

Actions

This study is summarised as evidence for the following.

Action Category

Translocate reptiles away from threats: Tortoises, terrapins, side-necked & softshell turtles

Action Link
Reptile Conservation

Provide supplementary food or water

Action Link
Reptile Conservation
  1. Translocate reptiles away from threats: Tortoises, terrapins, side-necked & softshell turtles

    A replicated, controlled study in 1997–1998 in a site of desert scrub in southern Nevada, USA (Field et al. 2007) found that most desert tortoises Gopherus agassizii translocated away from development areas and held in pens for 2–7 years prior to release survived at least two years after their release.  Overall, six of 28 (21%) tortoises died in the first year following release, and no tortoises died in the second year. Mortality rates were similar between tortoises receiving supplementary water (4 of 15, 27%) and those not supplemented (2 of 13, 15%).   Released tortoises were held in outdoor pens for two years (juveniles) or seven years (adults) after being removed from areas undergoing urban development. One to two months prior to release, tortoises either received supplementary water (sprinklers on for 15 minutes/day and saucers placed to catch water) (6 females, 8 males, 1 juvenile) or received no water (7 females, 5 males, 1 juvenile). Tortoises were released into artificial burrows in April–May 1997, and the release site was fenced off from a nearby road. Tortoises were relocated by radio-tracking through July 1997 to November 1998.

    (Summarised by: Maggie Watson, William Morgan)

  2. Provide supplementary food or water

    A replicated, controlled study in 1997–1998 in a site of desert scrub in southern Nevada, USA (Field et al. 2007) found that translocated desert tortoises Gopherus agassizii provided with supplementary water had similar survival but moved more and grew more than non-supplemented tortoises.  Mortality rates were similar between supplemented (4 of 15, 27%) and non-supplemented (2 of 13, 15%) translocated tortoises in the year of release. No tortoises died in the second year. Water supplemented tortoises grew more (0.0014 mm/day) and moved longer distances (up to 3,800 m, males only) compared to non-supplemented tortoises (0.007 mm growth/day and 700 m, males only).  Released tortoises were held in outdoor pens for two (juveniles) to seven (adults) years, having been removed from areas undergoing urban development. One to two months prior to release, tortoises either received supplementary water (sprinklers on for 15 minutes/day and saucers placed to catch water; 6 females, 8 males, 1 juvenile) or received no water (7 females, 5 males, 1 juvenile). Tortoises were released into artificial burrows in April–May 1997, and the release site was fenced off from a nearby road. Tortoises were relocated by radio-tracking through July 1997 to November 1998.

    (Summarised by: Maggie Watson, Guy Rotem)

Output references
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