Biogeography: Where do we go from here?

Biogeography is a multidisciplinary science concerned with how and why organisms are distributed as they are on Earth. It links fields such as systematics, ecology, paleontology, and climatology, and occupies a central position in evolutionary biology, being fundamental to the study of processes such as speciation and adaptive radiation. Here we provide a brief overview of some particularly dynamic areas of inquiry and offer some perspectives on future directions for the field. We hope that some historical debates, such as those over the importance of dispersal, or the validity of molecular dating, are finally being put to rest. Over the last decade, biogeography has become increasingly integrative, and has benefited from advances in statistical methods for inferring geographic range dynamics in a phylogenetic context, molecular estimation of lineage divergence times, and modeling lineage birth and death. These are enabling greater insights into patterns of organismal diversification in time and space. In the next decade, analytical challenges are emerging on several fronts. For example, phylogenies are increasing in size and taxonomic breadth and new sequencing technologies enabling phylogenetic and phylogeographic datasets are increasingly genomic in depth. In addition, geographic occurrence data are accumulating in online repositories, yet tools for data mining and synthetic analysis are lacking for comparative multi-lineage studies. Biogeography is thus entering an era characterized by phylogenomic datasets, increasingly comprehensive sampling of clades, and interdisciplinary synthesis. We anticipate continued progress in our understanding of biodiversity patterns at regional and global scales, but this will likely require greater collaboration with specialists in bioinformatics and computational science. Finally, it is clear that biogeography has an increasingly important role to play in the discovery and conservation of biodiversity. Lessons learned from biogeographic studies of islands are being applied to better understand extinction dynamics as continental ecosystems become more fragmented, and phylogeography and ecological niche modeling offer innovative paths toward the discovery of previously unknown species distributions and priority areas for conservation. The future of biogeography is bright and filled with exciting challenges and opportunities.