Literaturdatenbank
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Nussear, K. E., Tracy, R. C., Field, K. J., Medica, P. A., Corn, S., Marlow, R. W., & Esque, T. C. , The translocation of desert tortoises in the northeast mojave: an overview. Paper presented at Turtle Survival Alliance 2007 Annual Meeting.
Added by: Admin (13 Dec 2008 22:23:49 UTC) |
| Resource type: Proceedings Article BibTeX citation key: Nussear2007a View all bibliographic details  |
Categories: General Keywords: Gopherus, Gopherus agassizii, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises, Testudinidae Creators: Corn, Esque, Field, Marlow, Medica, Nussear, Tracy Collection: Turtle Survival Alliance 2007 Annual Meeting |
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| Abstract |
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Testudinidae Translocation of desert tortoises (Gopherus agassizii) from harm`s way is a biological, economic, and political decision for conservation. Ideally the conservation of habitat should always take precedence for conservation planning, but when habitat loss is inevitable due to political or economic decisions, only two choices remain: (1) leave tortoises in harm’s way (potentially left to die), or (2) collect the animals to use them in ways potentially important as conservation actions. Collected desert tortoises have been used for public education and outreach, scientific research, and even adopted as pets. Collectively these activities are thought to increase public understanding and support for conservation efforts. The research and education value also potentially increases our understanding of these animals and their ecosystems. However, as more-and-more tortoises are collected, facilities for housing them can become saturated. Then agencies managing these animals must expand existing research and/or holding facilities, to euthanize the tortoises (generally politically and ethically untenable), or to return the animals to the wild. The most direct means by which displaced tortoises can contribute to recovery is to return them to the wild, and in some cases, translocation is the last and only biological and economic alternative after animals have been displaced from natural habitat. What defines successful translocation has been subject of intense debate. In our studies at five sites in the northeast Mojave, we have shown that there were no adverse effects due to translocation in terms of survivorship, reproduction, and animal movements after animals become used to the new habitat. We have examined effects of pre-release care conditions, and the season-of-release on translocated animals, and all results so far suggest no negative effects of translocation. Our experiments translocating tortoises have been successful by all reasonable short-term measures. Long term monitoring of populations has been recommended, but we find little interest in long-term research on the part of agencies, and as time goes on there is likely very little influence of an event many years past, relative to the annual variation in drought, predation and habitat changes. One often overlooked measure to ensure the long-term success of translocation is that of preserving the habitat into which animals are translocated. Increasingly the persistence of the habitat is likely to be more vulnerable than persistence of the population. Protection of habitat in perpetuity is necessary, if translocation is not to become just a convenient way to store animals while gaining credit for conservation until that habitat is later developed in different political and economic climates. Thus, translocation of tortoises can be a means to keep habitat classified as important to recovery of the species, but land management agencies have to recognize this to make this a viable strategy. Unfortunately, habitats into which we have translocated tortoises have different levels of protection from urban development where National Park Service, and other areas with “Reserve” level protection have a higher level of protection from future development than to areas managed by the Bureau of Land Management, which can be auctioned and ultimately subjected to private sector development. For example, only 10 years since our first translocation in Nevada, and with > 5000 tortoises currently moved to a large scale translocation site – so publicized that the Secretary of the Interior cut the ribbon on the first tortoise burrow – that area is faced with development of adjacent lands into residential housing, and a major airport and of our sites is being used as a flood control basin. How long will these translocation areas be protected, or contain viable habitat for tortoises? All existing evidence indicates that translocation can be a remarkably efficacious tool for conservation of desert tortoise, but we must preserve the tortoise and the habitat for this to be a viable long-term conservation solution.
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