Estimating handling times for herbivore diets: a statistical method using the gamma distribution

Autor:	Stephan G. Kohlmann, James H. Matis, Kenneth L. Risenhoover
Rok vydání:	1999
Předmět:	Herbivore Capra ibex biology Ecology Foraging Statistical model biology.organism_classification Nubian ibex Bite size Statistics Gamma distribution Animal Science and Zoology Capra ibex nubiana Ecology Evolution Behavior and Systematics Mathematics
Zdroj:	Journal of Animal Ecology. 68:638-645
ISSN:	1365-2656 0021-8790
Popis:	1. We present a statistical model for the prediction of handling times for different diet items of herbivores foraging in heterogeneous environments, based on the distribution of time intervals between bites. 2. We propose the gamma distribution as a convenient and appropriate model for foraging data and illustrate its use with field observations of foraging Nubian ibex (Capra ibex nubiana Linnaeus 1758) in the Negev Desert of Israel. 3. Specifically, we demonstrate how to estimate handling times from skewed frequency data of intervals between bites within patches. 4. We compared two mathematically equivalent gamma models and found a pronounced difference in the numerical results in fitting empirical data. 5. Estimated handling times varied with bite size, but not with plant category or sex of the foraging animal. 6. Fitting a gamma model to foraging data allows the efficient estimation of minimum handling constraints, mean handling times and within-patch cropping rates, which should be useful for models of the herbivore foraging process.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b89dead053d52976bced871c9f8f4b69 https://doi.org/10.1046/j.1365-2656.1999.00303.x Zobrazit plný text záznamu Plný text