Literaturdatenbank
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Jennings, B. W. (1997). A methodology for determining tortoise food habits in arid regions. Proceedings: Conservation, Restoration, and Management of Tortoises and turtles - An International Conference.
Added by: Admin (17 Aug 2008 18:17:19 UTC) |
| Resource type: Journal Article BibTeX citation key: Jennings1997 View all bibliographic details  |
Categories: General Keywords: Ernährung = nutrition, Gopherus, Gopherus agassizii, Schildkröten = turtles + tortoises, Testudinidae Creators: Jennings Collection: Proceedings: Conservation, Restoration, and Management of Tortoises and turtles - An International Conference |
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| Abstract |
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Testudinidae Knowledge of tortoise food habits can provide insights into tortoise dietary and habitat requirements, and it is therefore important in management of tortoise populations. The purpose of this paper is to present a methodology that was successful in elucidating desert tortoise, Gopherus agassizii, food habits in the western Mojave Desert. These methods are also applicable to studies of other tortoise species living in arid regions. The methodology is useful in estimating tortoise diet and plant abundance, both of which are needed to quantitatively assess whether tortoises are selective foragers. To determine whether tortoises are selective foragers, a null model incorporating diet and plant abundance (i.e., Ho : plant abundance = food choice) can be statistically evaluated. Moreover, other questions can be addressed such as whether tortoises prefer succulent to dried forage, and whether tortoises prefer native to exotic plant species. Diet is estimated by direct observation of tortoises while plant abundance is estimated by following a stratified random sampling methodology. Estimating plant abundance in deserts is complicated because the investigator must make many subjective choices when formulating a sampling scheme. One must choose the number of unique vegetational/topographical strata; sample size; allocation of samples among habitat strata; quadrant size, shape, and number; when and how often to sample; whether herbaceous perennials are considered annuals or perennials; etc. The approach to each of these choices to achieve a satisfactory sampling methodology is discussed and results are presented.
Added by: Admin |