Literaturdatenbank
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Henen, B. T. (2002). Energy and water balance, diet, and reproduction of female desert tortoises (gopherus agassizii). Chelonian Conservation and Biology, 4(2), 319–329.
Added by: Admin (14 Aug 2008 20:35:28 UTC) |
| Resource type: Journal Article BibTeX citation key: Henen2002 View all bibliographic details  |
Categories: General Keywords: Ernährung = nutrition, Fortpflanzung = reproduction, Gopherus, Gopherus agassizii, Habitat = habitat, Nordamerika = North America, Physiologie = physiology, Schildkröten = turtles + tortoises, Testudinidae Creators: Henen Collection: Chelonian Conservation and Biology |
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| Abstract |
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Gopherus agassizii Testudinidae Long-term chronic impacts upon the diet and nutrition of female desert tortoises can decrease fecundity and cause local extinctions. In this synthesis, I analyze energy budgets, water budgets, and diets to evaluate the impact of environmental variation upon reproductive output. Female desert tortoises relax homeostatic regulation of many nutrient budgets (e.g., water, energy, nitrogen, and minerals) in order to endure the extremely harsh and variable conditions of their desert clime. Their diets also reflect adjustments to the variable abundance and nutritive value of desert plants, especially winter annuals. The relaxed approach to homeostasis helps desert tortoises survive and helps females muster the resources (nutrients) to produce eggs in most years. Female desert tortoises use an approach intermediate to capital and income breeding, relying upon body reserves and spring food consumption to produce eggs. Despite the extreme tolerances effected by relaxing homeostasis, desert tortoises are vulnerable to extreme desert conditions. Extended droughts preclude drinking and greatly reduce the availability of nutritive dietary plants, decreasing survivorship and egg production. Global environmental change could exacerbate these extreme conditions, adding another anthropogenic impact upon the Threatened desert tortoise.
Added by: Admin |