Rapidly shifting climates will lead to species range shifts over the next century. Artificially introducing species in new locations to enhance species migration, termed assisted migration (AM), has been suggested as one possible strategy to avoid species extinction. While current methods are used to explore future areas of introduction, we lack a method able to identify the best sets of locations and timing for species introductions that maximizes AM outcomes.

We developed a novel method to explore the effects of species Introduction Effects in Space and Time on species Range dynamics (IESTR). The method uses transition matrices that combine spatial and temporal species suitability changes and dispersal information. A metaheuristic algorithm is run to achieve an objective target of range area optimizing introduction locations and times, while minimizing spatially explicit cost surfaces. We apply the method to a virtual species to showcase the potential of IESTR to explore range dynamics with artificial introductions. We assess optimal AM strategies under climate change and with different land use cost scenarios. We found a strong effect of early introductions enhancing species range shifts, as well as differences in introduction sites and timing under different cost scenarios.

IESTR is a fast and efficient technique for exploration of range shifts under artificial introductions, tackling both the spatial and temporal dimensions. The method has been developed in Cpp, available as an R package. Given the heated debate around AM and introductions, our method provides a new tool to explore strategies in spatial conservation planning in the Anthropocene.