Species Dispersal and Connectivity in Conservation Landscapes

Resources and risk for species are heterogeneous across space, more so than ever today because of a pervasive human footprint. How do animals perceive and move through risky, heterogeneous lands to access resources and mates? What are the implications of animal movement decisions for successful establishment of linkages among populations and habitats in increasingly human-dominated landscapes? I will delve into these important questions by first looking at why we need to think about dispersal, and reviewing existing evidence across taxa that highlights multiple detrimental impacts of the loss of connectivity to species and communities. I will then discuss limits to successful dispersal in heterogeneous landscapes, placed within a framework that allows us to both question where animals move, as well as why they choose certain areas to move through while avoiding others. In many contexts, dispersal only becomes effective on successful reproduction of dispersers; by extension, factors limiting post-dispersal reproduction also impact effective dispersal or connectivity. I will show that mate choice, in the form of preference or avoidance of dispersers as compared to residents, can bring about connectivity patterns that we often see in real-world landscapes. Further, under certain conditions, impacts of mate choice can override those brought about by movement limitations. In many conservation landscapes, dispersers often move through risky lands where they frequently interact, and may come into conflict, with people. I will present findings on the implications for this perception of risk on connectivity for the Asian elephant Elephas maximus. I do so through a novel adaptation of the occupancy modelling framework such that we can now explicitly model matrix impacts on the probability of successful dispersal of elephants, while accounting for our inability to perfectly detect infrequent dispersal events. Certain strategies aimed at mitigating conflict can also increase perceived risk from humans, thus impeding connectivity and reducing long-term viability of species. I will present ongoing efforts that aim to scientifically implement conservation strategies to facilitate connectivity, while minimizing conflict for species such as the Asian elephant. I will conclude by reiterating the implications of scientific inference on connectivity for both ecology and conservation.