Thermal utility of desert vegetation for the Egyptian tortoise and its conservation implications |
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| Institution: | 1. Environmental Consultant, Overgaard, Arizona, and Retired Utah State Rangeland Management Specialist, Bureau of Land Management, U.S. Department of Interior, Overgaard, Arizona, United States of America;2. Environmental Consultant, Arizona, and Retired. Rangeland Management Specialist, Bureau of Land Management, U.S. Department of Interior, Kingman, Arizona, United States of America;3. Environmental Consultant, Nevada, and Retired Nevada State Range Conservationist, Natural Resource Conservation Service, U.S. Department of Agriculture, Fallon, Nevada, United States of America;4. Soil Scientist, Natural Resources Conservation Service, U.S. Department of Agriculture, Henderson, Nevada, United States of America;5. Environmental Consultant, Idaho, and Retired Riparian Ecologist/Grazing Management Specialist, National Riparian and National Soils and Range Teams, Bureau of Land Management, U.S. Department of Interior, Midvale, Idaho, United States of America |
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| Abstract: | We examined the monthly shrub use and the thermal utility of the desert shrub, Artemisia monosperma, by the globally endangered Egyptian tortoise, Testudo kleinmanni, in Sinai, Egypt. A. monosperma is a common desert shrub that is often used by the Egyptian tortoise as a refuge. Egyptian tortoises had the highest mean carapace temperature and lowest carapace temperature range during summer months, which coincided with the aestivation period and the Egyptian tortoise's use of larger shrubs. Our results suggest that the thermal characteristics of larger shrubs are important to the microhabitat use of the Egyptian tortoise and likely long-term survival. Larger shrubs were effective as thermal refuges that ameliorated and stabilized micro-climatic variation. Smaller shrubs were not an adequate thermal refuge in the summer because the mean temperature, and its fluctuation range beneath them was too high to offer adequate refuge during aestivation. The tortoises used the smaller shrubs in the fall, winter, and spring seasons for basking, thermoregulation, and concealment and used shrubs with a cover diameter greater than one meter during the aestivation season. The future conservation of the Egyptian tortoise should focus on protecting and restoring existing habitat by maintaining large perennial shrubs for refuge and aestivation sites. |
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| Keywords: | Aestivation Desertification Microclimate Thermal ecology |
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