SPATIAL STRUCTURE: THE "FINAL FRONTIER" IN ECOLOGY, BIOGEOGRAPHY, AND EVOLUTION

Synthetic studies are increasingly recognized as paramount for understanding complex evolutionary patterns and processes. The integration of ecology, biogeography, and evolution is one area where investigations using fossil data can significantly inform evolutionary theory. A central component of such investigations is the role that species’ abiotic requirements (i.e., fundamental niche, FN) play in influencing patterns of speciation, extinction, and geographic distribution through time, especially during episodes of environmental change. Geographic range has often been used as a proxy for estimates of the breadth of a species’ FN; however, the relationship between a species’ FN as defined by environmental variables (i.e., configuration in E-space) and how those requirements map geographically (i.e., configuration in G-space) has yet to be fully explored. Analyses of virtual species show that this relationship (E-space --> G-space) is not 1:1. That is, the structure of a species’ FN in E-space does not capture the complexity of a species’ spatial distribution geographically. This has significant implications for the structure of species’ distributions through time, including the effects of spatial structure on speciation, extinction, and invasion potential.

Ecological Niche Modeling (ENM) is one method to quantitatively test the effects of E-space --> G-space translation on evolutionary patterns. ENM is frequently applied in the modern to elucidate microevolutionary phenomena and is beginning to be applied to fossil data. With the latter, there is great potential to test hypotheses of process behind macroevolutionary patterns. Paleontologists are able to track the effects of environmental and biotic changes on species’ FN and geographic distributions across the entire lifetime of a given species or clade compared to the shorter, albeit more detailed, snapshot available in the modern. In this regard, analyses of the fossil record can provide unique insight into the influence of the FN on evolution.