How do species interactions change over biogeographic scales? Do these observations support hypotheses explaining the latitudinal diversity gradient?

One of the oldest observations in nature is the latitudinal diversity gradient. The tropics hold more species than temperate and polar zones. Why is this?

Species richness is greatest in the tropics. Figure adapted from Tittensor et al 2010 (Nature).

One hypothesis put forth is the biotic interactions hypothesis. It proposes that species interactions are stronger in the tropics, which may drive greater rates of speciation (related to the red queen hypothesis). I have conducted predation experiments in Panama, Belize, Florida, Virginia, and Connecticut within seagrass beds (one of the few consistent habitats across this range). I am currently working on a global meta-analysis examining the strength of predation in marine ecosystems as a part of my MarineGEO postdoctoral fellowship at the Smithsonian Institution.

Smithsonian’s marine field station Carrie Bow Cay in Belize.