Territorial landscapes: incorporating density-dependence into wolf habitat selection studies

Abstract

Habitat selection is a process that spans space, time and individual life histories. Ecological analyses of animal distributions and preferences are most accurate when they account for inherent dynamics of the habitat selection process. Strong territoriality can constrain perception of habitat availability by individual animals or groups attempting to colonize or establish new territory. Because habitat selection is a function of habitat availability, broad-scale changes in habitat availability or occupancy can drive density-dependent habitat functional responses. We investigated density-dependent habitat selection over a 19-year period of grey wolf (Canis lupus) recovery in Michigan, USA, using a generalized linear mixed model framework to develop a resource selection probability function (RSPF) with habitat coefficients conditioned on random effects for wolf packs and random year intercepts. In addition, we allowed habitat coefficients to vary as interactions with increasing wolf density over space and time. Results indicated that pack presence was driven by factors representing topography, human development, winter prey availability, forest structure, roads, streams and snow. Importantly, responses to many of these predictors were density-dependent. Spatio-temporal dynamics and population changes can cause considerable variation in wildlife–habitat relationships, possibly confounding interpretation of conventional habitat selection models. By incorporating territoriality into an RSPF analysis, we determined that wolves' habitat use in Michigan shifted over time, for example, exhibiting declining responses to winter prey indices and switching from positive to negative responses with respect to stream densities. We consider this an important example of a habitat functional response in wolves, driven by colonization, density-dependence and changes in occupancy during a time period of range expansion and population increase.

Territoriality drives preemptive habitat selection in recovering wolves: Implications for carnivore conservation

“…long‐term growth rate ≈ 0) and density dependence has a stronger regulatory role. Although we could not confirm equilibrium in our study population, we suspect that suitable habitat was likely saturated by the end of the study (O'Neil, Beyer, & Bump, 2019). Distinguishing between theoretical models of density‐dependent habitat selection, as we did with isodar analysis, is a valuable objective for any population because the underlying distribution has important implications for population dynamics (Falcy, 2015; Mosser et al, 2009).…”

Landscape-scale giant panda conservation based on metapopulations within China’s national park system

“…To construct a conceptual framework and specific schemes for landscape-scale giant panda metapopulation conservation management, we determined each metapopulation’s status in terms of geographic range, relative abundance, relative density, and density-dependent habitat selection. This enabled us to establish biological effects such as area sensitivity ( 37 ), small population risks (i.e., genetic drift and inbreeding) ( 42 ), and intraspecific competition ( 22 , 24 ), which we classified into three categories: (i) large metapopulations with stronger intraspecific competition for habitat, (ii) small metapopulations with a larger range and weaker intraspecific competition for habitat, and (iii) small metapopulations with a smaller range and weaker intraspecific competition for habitat. Correspondingly, we used our empirical results to decide upon which priority management actions proposed in theory by previous studies should be applied.…”

“…Habitat selection can be context dependent, affected by variations in population density and resource availability ( 21 ). According to the theory of density-dependent habitat selection, individuals will increase their use of suboptimal or marginal habitat patches as population density and resultant intraspecific competition increases ( 22 , 23 ), although density-dependent habitat selection has not been thoroughly explored for territorial species ( 24 ). This theory would predict that individuals in territorial populations will select habitat according to an ideal-dominant or preemptive habitat distribution, where the best sites will be selected primarily by dominants then, and as population density increases, newly arriving, juvenile, or subordinate (secondary) individuals will increasingly reside in suboptimal or marginal habitat patches ( 22 , 23 ).…”