Accounting for dispersal and intraspecific variation in forecasts of species distribution under climate change

Abstract

Dispersal and local adaptation play an important role in driving species distributions under climate change. Many studies aim to estimate relationships between species occurrences and environmental variables to predict range shift and biodiversity loss, ignoring dispersal and intraspecific variation contributing to complex spatial and temporal dynamics. We accounted for dispersal and intraspecific variation in forecasts of species distribution under climate change with species distribution models (SDMs) using two cold-adapted, low-dispersal Platycerus species (Coleoptera: Lucanidae), each with distinct subspecies distributions, as focus species. The results showed that the subspecies-level model performed significantly better than the species-level model when considering dispersal constraints in SDMs. Whether or not dispersal or intraspecific variation is accounted for, the predicted species range of Platycerus albisomni is expected to decrease in the future. For Platycerus takakuwai, accounting for dispersal constraints in SDMs indicated that its potential distribution area would increase at the subspecies level under climate change, but decrease at the species level. These divergent results show that SDMs at the subspecies level can detect impacts of climate change that may be overlooked in species-level models. Therefore, models that consider intraspecific variation and dispersal constraints may provide a more realistic perspective on the impacts of climate change. Because accurate mapping of potential habitats is needed for conservation purposes, demographic studies should include dispersal explicitly and explore how and when intraspecific variation in dispersal affects local population dynamics. This approach could help evaluate species' habitat shifts, thus enabling suitable conservation strategies.