Assessing the Permeability of Landscape Features to Animal Movement: Using Genetic Structure to Infer Functional Connectivity

Abstract

Human-altered environments often challenge native species with a complex spatial distribution of resources. Hostile landscape features can inhibit animal movement (i.e., genetic exchange), while other landscape attributes facilitate gene flow. The genetic attributes of organisms inhabiting such complex environments can reveal the legacy of their movements through the landscape. Thus, by evaluating landscape attributes within the context of genetic connectivity of organisms within the landscape, we can elucidate how a species has coped with the enhanced complexity of human altered environments. In this research, we utilized genetic data from eastern chipmunks (Tamias striatus) in conjunction with spatially explicit habitat attribute data to evaluate the realized permeability of various landscape elements in a fragmented agricultural ecosystem. To accomplish this we 1) used logistic regression to evaluate whether land cover attributes were most often associated with the matrix between or habitat within genetically identified populations across the landscape, and 2) utilized spatially explicit habitat attribute data to predict genetically-derived Bayesian probabilities of population membership of individual chipmunks in an agricultural ecosystem. Consistency between the results of the two approaches with regard to facilitators and inhibitors of gene flow in the landscape indicate that this is a promising new way to utilize both landscape and genetic data to gain a deeper understanding of human-altered ecosystems.

Evaluating the influence of life‐history characteristics on genetic structure: a comparison of small mammals inhabiting complex agricultural landscapes

“…Combined with the Bayesian clustering results and previous fine‐scale studies (Anderson et al. ), our landscape genetic analysis suggests that forests promote gene flow between study cells for chipmunks. Complexity of forested habitat within study cells may also play a role in explaining patterns of genetic differentiation in chipmunks.…”

“…Previous studies have documented that landscape configuration between populations impact gene flow in both chipmunks (Anderson et al. ) and white‐footed mice (Munshi‐South ), so we expected configuration to be correlated with genetic differentiation in both species. Within the UWB, chipmunks and white‐footed mice are fairly ubiquitous (Moore and Swihart ), but multiple measures of landscape complexity within study cells have been related to variance in abundance (Rizkalla and Swihart ) and occupancy (Moore and Swihart ) within the study area.…”

“…; Anderson et al. ). These studies have confirmed that both landscape heterogeneity and life‐history traits, particularly ecological specialization, influence patterns in occupancy and abundance (Nupp and Swihart ; Swihart et al.…”

Genetic effects of anthropogenic habitat fragmentation on remnant animal and plant populations: a meta‐analysis

“…Nevertheless, we were only able to use coarse categories of matrix types because in most cases fragments are surrounded by a mosaic of different habitat types and most studies did not provide sufficient details. Thus, permeability studies contribute to explain species-specific genetic patterns in fragmented landscapes (Anderson et al 2015, Cooney et al 2015. This complexity may partially explain why studies rarely provided detailed information on matrix type.…”

Influence of environmental heterogeneity on the distribution and persistence of a subterranean rodent in a highly unstable landscape

“…The ability of 57 an animal to use resources within a landscape patch is determined not only by the distance between 58 patches but also by the nature of the routes connecting them (Taylor et al 1993). Consequently, the 59 degree of isolation between subpopulations depends on the actual capacity of movement of the 60 species in relation to the landscape heterogeneity (Bowne & Bowers 2004; Anderson et al 2015). 61…”