Modelling geographic patterns of population density of the white‐tailed deer in central Mexico by implementing ecological niche theory

Abstract

Conservation and management of species require basic knowledge on their geographic distribution and abundance. Here, we propose a novel approach, based on the theory of the ecological niche, to model the spatial patterns of the white‐tailed deer Odocoileus virginianus population density in two regions of central Mexico (Balsas Basin and Tehuacán‐Cuicatlán Valley). We used an ecological niche model to generate binary geographic distribution maps of the white‐tailed deer in each region based on occurrence data and a set of environmental variables. Then, the centroid of the distributions was calculated in ecological space (niche centroid) and the multidimensional Euclidian ecological distance of each pixel to the niche centroid was estimated. Finally, for each region the distance to the niche centroid (DNC) was regressed against 14 independent occurrence points in each site containing white‐tailed deer density information to determine the function describing the DNC‐density relationship, which was used to generate maps describing the distribution of white‐tailed deer density. Our results indicated an inverse DNC‐density relationship in both regions (Balsas Basin: r2 = 0.90 and Tehuacán‐Cuicatlán: r2 = 0.76) that was validated via bootstrapping resulting in a predicting capacity of near 62% for Balsas Basin and 65% for Tehuacán‐Cuicatlán Valley. Our results suggest that the distance to the niche centroid method is a robust, science‐based correlative approach that resulted useful to predict the population density of the white‐tailed deer in a spatially explicit fashion. The proposed approach is suitable for predicting the distribution of density for white‐tailed deer for which occurrence data with accompanying density information exists, but relative abundance can also be estimated when no abundance data are available.

Habitat and Human Factors Associated with White-Tailed Deer Density in the Tropical Dry Forest of Tehuacán-Cuicatlán Biosphere Reserve, Mexico

“…The efforts of these committees will surely reduce the incidence of poaching. In addition, the four study sites are relatively close to a principal highway (Tehuacan to Oaxaca city), but recently Yañez-Arenas et al [49] modeling abundance distribution of white-tailed deer with a niche modeling approach, showed that higher deer densities could be expected in sites with irregular topography and lower human activities, which in the TCBR are mainly in the eastern mountainous region. Thus, the distribution of abundance is heterogeneous among locations within the TCBR.…”

“…Density estimations were obtained in a systematic way at all four sites using the fecal standing crop method [33,34], and for the estimation of population density we applied the equation proposed by Eberhardt and Van Etten [36] following the recommendations by Camargo-Sanabria and Mandujano [32]. We used this method because it was considered the most appropriate for the topography and vegetation characteristics of the region with its conditions similar to other sites, including the presence of tropical dry forest [16,17,20,48,49]. However, we recognized that pellet-group counts could produce biased estimates, especially where defecation rate is unknown [38].…”

Evaluating the Relationship between White-Tailed Deer and Environmental Conditions using Spatially Autocorrelated Data in Tropical Dry Forests of Central Mexico

“…However, unless these studies are repeated in various habitats and different regions, it is impossible to know which results are specific to each location and which can be generalized. Large-scale (regional, landscape, ecoregion) studies are therefore very important to better understand natural systems, to make inferences in non-sampled areas, and to propose improved management strategies [16]. However, such studies require statistical tools that take the spatial aspect into account when analyzing the data.…”

“…From methodological and ecological perspectives, studies of deer-habitat relationships have traditionally been conducted at small scales and have provided valuable information regarding the variables that affect local populations of this species [see [11][12][13][14][15][16][17][18]47]. However, unless these studies are repeated in various habitats and different regions, it is impossible to know which results are specific to each location and which can be generalized.…”

“…In addition, we analyzed whether differences in deer density and habitat variables existed between the two study regions. This evaluation is important because studies conducted in Mexico on the effects of different habitat variables on the density or abundance of the white-tailed deer [11][12][13][14][15][16][17][18] autocorrelation [19]. Understanding and including spatial autocorrelation can reveal more accurately the relationship between habitat and white-tailed deer population, with important repercussions for conservation and management of the white-tailed deer in Mexico.…”