Could top-down forces, such as predation, really be the driving force behind the incredible diversity on the planet? Really nice essay by John Terborgh in PNAS attempts to convince us that this is the case – thanks to ConservationBytes for the link (below). I agree that competition has been over-emphasized as the defining mechanism for diversity. However, it did cover old territory as diversity obviously is an interplay between bottom-up (competition) and top-down forces such as predation. I feel that coexistence theory has moved on from this dichotomy. I also think that environmental change and habitat heterogeneity could’ve been added to the discussion as these forces also important mechanisms. Parasites and pathogens (also top down forces) could’ve been mentioned explicitly too as they are often ignored in the literature and are of obvious importance. Nonetheless it is a really interesting and well written read and I totally agree with Corey Bradshaw that conservation of the predator guild is damn important.
The originl article: http://www.pnas.org/content/112/37/11415.abstract