Refining model estimates of potential species’ distributions to relevant accessible areas

Abstract

Dispersal is an important, yet overlooked phenomenon when studying species’ distributions using ecological niche models (ENMs). Here, we use species’ dispersal limits to evaluate and refine ENM estimates only to the areas accessible to the species within the study region and, thereby, enhance the model interpretations. First, we ran multiple ENMs to estimate the distribution of sea krait species in both marine and terrestrial environments. Second, we estimated dispersal of the sea kraits using a cost analysis approach. Finally, we outline a new approach that combines dispersal models and ENMs with the purpose of estimating the accessible range when projecting species’ distribution estimates outside the known species range. We found that only a small proportion of the area the ENMs were projected over was accessible to sea kraits. The majority of the suitable areas for sea kraits are within the accessible area. Outside the accessible area, there is only a very limited suitable area for sea kraits. Our results suggest that when dispersal is taken into account, sea kraits seem to occupy most of their suitable available niche and that they may be unable to colonize much of the area outside of their dispersal ranges. Using dispersal estimates to refine species’ distribution predictions is a useful tool for refining the area of focus when ENM results are interpreted. Estimating species’ dispersal also helps evaluate the ability of the models to predict the species’ distributions in areas that are not accessible to the species and, hence, the potential commission error represented by overprediction.