Modeling the Relationship Between Fecal Pellet Indices and Deer Density |
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Authors: | DAVID M FORSYTH RICHARD J BARKER GRANT MORRISS MICHAEL P SCROGGIE |
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Institution: | 1. Department of Mathematics and Statistics, University of Otago, P.O. Box 56, Dunedin, New Zealand;2. Landcare Research, P.O. Box 40, Lincoln 7640, New Zealand;3. Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment, 123 Brown Street, Heidelberg, Victoria 3084, Australia |
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Abstract: | Abstract: Although fecal pellet counts have been widely used to index changes in deer abundance in forests, few studies have modeled the relationship between the indices and deer density. We examined the relationships between 3 fecal pellet indices (total pellets, pellet groups, and pellet frequency) and the density of deer (primarily red deer Cervus elaphus scoticus]) in 20 enclosures in the North and South islands of New Zealand. In each enclosure we estimated the 3 indices on 30 randomly located 150-m transects, with each transect having 30 circular plots of 3.14 m2. We developed 4 candidate models (1 linear and 3 nonlinear) to describe the relationship between the indices and deer density. We used a Bayesian analysis to account for uncertainty in the estimates of deer abundance and to facilitate fitting models that included random transect effects. The 4 models explained the relationship between the 3 indices and deer density similarly well. The slopes of the linear relationships between the 3 indices and deer density were positive. Our results suggest that fecal pellet counts may be useful indices of deer abundance. |
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Keywords: | Bayesian analysis Cervus elaphus deer dung counts indices monitoring New Zealand pellet frequency pellet group counts |
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