Functional responses in the habitat selection of a generalist mega‐herbivore, the African savannah elephant

Abstract

Resource selection function (RSF) models are commonly used to quantify species/habitat associations and predict species occurrence on the landscape. However, these models are sensitive to changes in resource availability and can result in a functional response to resource abundance, where preferences change as a function of availability. For generalist species, which utilize a wide range of habitats and resources, quantifying habitat selection is particularly challenging. Spatial and temporal changes in resource abundance can result in changes in selection preference aff ecting the robustness of habitat selection models. We examined selection preference across a wide range of ecological conditions for a generalist megaherbivore, the African savanna elephant Loxodonta africana , to quantify general patterns in selection and to illustrate the importance of functional responses in elephant habitat selection. We found a functional response in habitat selection across both space and time for tree cover, with tree cover being unimportant to habitat selection in the mesic, eastern populations during the wet season. A temporal functional response for water was also evident, with greater variability in selection during the wet season. Selection for low slopes, high tree cover, and far distance from people was consistent across populations; however, variability in selection coeffi cients changed as a function of the abundance of a given resource within the home range. Th is variability of selection coeffi cients could be used to improve confi dence estimations for inferences drawn from habitat selection models. Quantifying functional responses in habitat selection is one way to better predict how wildlife will respond to an ever-changing environment, and they provide promising insights into the habitat selection of generalist species.

Functional connectivity within conservation networks: Delineating corridors for African elephants

“…In general, the wet season habitat selection patterns of male and female elephants were similar and supported the relevance of previously reported habitat covariates (see Harris et al 2008;Hoare and Du Toit 1999;Loarie et al 2009a;Roever et al 2012;Wall et al 2006). Both sexes had a nonlinear relationship with water, selecting for areas both near and far from water relative to availability (Table 2).…”

“…All habitat variables were used to assess elephant habitat selection, as they are all known to influence elephant habitat selection (Roever et al 2012). No variables were highly correlated when examined using Pearson's correlation coefficient (r > 0.6).…”

A different angle: comparative analyses of whole-animal transport costs running uphill

“…The movements of many groups of elephants observed in southern Africa are apparently constrained by the topography of their home ranges in that they rarely walk on ground where the incline is more than about 4 deg (Roever et al, 2012). Wall et al (2006) argue that this selective behaviour against walking uphill is due to the massive energy costs of doing so for an animal typically weighing several tonnes.…”

Incorporating mortality into habitat selection to identify secure and risky habitats for savannah elephants

“…Covariates used in the estimation of the three habitat selection models pertained to water, slope, tree cover, human presence, and roads (based on Roever et al, 2012). Surface water was located using data from Tracks4Africa (2010) and was visually validated against Landsat imagery.…”