Shifting Dispersal Networks

To sustain biodiversity and ecosystem services in Earth’s future ecosystems, many species must track suitable climate with range shifts. Interactions among species within their shifting ranges will affect whether and how species keep pace with climate change. This poses a challenge for ecologists to predict the nature and outcome of changing species interactions and for managers to sustain species interactions necessary for range shifts. Roughly half of plant species are dispersed by animals, and plant-animal seed dispersal interactions will therefore be critical for plant species’ capacity to keep pace with climate change. Seed dispersal and vegetation dynamics are heavily shaped by human impacts on climate, land use, and animal populations; climate change influences where and how quickly species need to move to track suitable habitat, land use affects how and where species can move, and defaunation affects what animals are present to move seeds. Complex feedbacks between climate, species composition within ecosystems, and the biotic and anthropogenic constraints on seed dispersal make predicting and facilitating vegetation shifts a challenging socio-environmental problem. Several new tools help tackle individual components of this problem including 1) novel applications for ecological network concepts, 2) increasingly robust data on land use and on species’ traits, interactions, and occurrence, and 3) conceptual advances in species distribution modeling. This project synthesizes these new tools, using computationally intensive approaches to 1) predict the reassembly of seed dispersal networks, 2) assess whether plants will have seed dispersers in their shifting ranges, and 3) develop a spatially explicit modeling framework to link seed dispersal networks and land use to understand vegetation dynamics at broad scales.