Literaturdatenbank
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Walde, A. D., Delaney, D. K., & Pater, L. L. , Microhabitat selection by desert tortoises (gopherus agassizii) in the mojave desert. Paper presented at Turtle Survival Alliance 2006 Annual Meeting.
Added by: Admin (13 Dec 2008 22:23:58 UTC) |
| Resource type: Proceedings Article BibTeX citation key: Walde2006 View all bibliographic details  |
Categories: General Keywords: Gopherus, Gopherus agassizii, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises, Testudinidae Creators: Delaney, Pater, Walde Collection: Turtle Survival Alliance 2006 Annual Meeting |
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| Abstract |
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Testudinidae Gopherus agassizii Desert Tortoises utilize burrows for predator avoidance, nesting sites, loci of social interactions, hibernation sites, and thermoregulation. The burrow is of crucial importance as temperatures inside the burrow are more constant and therefore provide a refugium from high lethal surface temperatures in the summer and low temperatures in the winter. Burrows are also higher in humidity and therefore aid in reducing water loss. Consequently, we tested the hypothesis that Desert Tortoise burrows have a non-random spatial distribution within the landscape. Desert Tortoise burrows were located and we recorded if they were under a shrub or out in the open. If the burrow was under a shrub, we recorded the species and measured its size. Shrub availability as a comparative data set was assessed by conducting belt transects. A total of 946 burrows was identified, 62.8% (n=594) were located under shrubs, yet shrub cover on the study site represented only 11.5%. Desert Tortoises were highly selective of the species of shrub under which their burrows were placed. Creosote bush (Larrea tridentata) and Nevada Jointfir (Ephedra nevadensis) represented 48.5% and 27.0% of shrubs used by tortoises, compared to availability of only 13.7% and 6%, respectively. Additionally, tortoises selected larger shrubs for burrow placement, as shrubs greater than 1 m3 accounted for 66.7% of shrubs selected by tortoises compared with only 8.5% of shrubs available. The relationship between Desert Tortoise burrows and surrounding vegetation can aid in understanding and assessing the quality of Desert Tortoise habitat. Furthermore, it demonstrates the importance of large shrubs and thus strongly supports the conclusion that protection of mature desert scrub habitats, particularly creosote shrub communities, has important management implications for the Desert Tortoise.
Added by: Admin |