A three-step approach for assessing landscape connectivity via simulated dispersal: African wild dog case study

Context Dispersal of individuals contributes to long-ter m population persistence, yet requires a suf-ficient degree of landscape connectivity. To date, connectivity has mainly been investigated using least-cost analysis and circuit theory, two methods that make assumptions that are hardly applicable to dispersal. While these assumptions can be relaxed by explicitly simulating dispersal trajectories across the landscape, a unified approach for such simulations is lacking.Objectives Here, we propose and apply a sim-ple three-step approach to simulate dispersal and to assess connectivity using empirical GPS movement data and a set of habitat covariates.Methods In step one of the proposed approach, we use integrated step-selection functions to fit a mechanistic movement model describing habitat and movement preferences of dispersing individuals. In step two, we apply the parameterized model to sim-ulate dispersal across the study area. In step three, we derive three complementary connectivity maps; a heatmap highlighting frequently traversed areas, a betweenness map pinpointing dispersal corridors, and a map of inter-patch connectivity indicating the pres-ence and intensity of functional links between habi-tat patches. We demonstrate the applicability of the proposed three-step approach in a case study in which we use GPS data collected on dispersing African wild dogs (Lycaon pictus) inhabiting northern Botswana.Results Using step-selection functions we success-fully parametrized a detailed dispersal model that described dispersing individuals' habitat and move-ment preferences, as well as potential interactions among the two. The model substantially outper-formed a model that omitted such interactions and enabled us to simulate 80,000 dispersal trajectories across the study area.Conclusion By explicitly simulating dispersal tra-jectories, our approach not only requires fewer unre-alistic assumptions about dispersal, but also permits the calculation of multiple connectivity metrics that together provide a comprehensive view of landscape connectivity. In our case study, the three derived con-nectivity maps revealed several wild dog dispersal hotspots and corridors across the extent of our study area. Each map highlighted a different aspect of land-scape connectivity, thus emphasizing their comple-mentary nature. Overall, our case study demonstrates that a simulation-based approach offers a simple yet powerful alternative to traditional connectivity modeling techniques. It is therefore useful for a variety of applications in ecological, evolutionary, and conservation research [Graphics]