A Disease-Mediated Trophic Cascade in the Serengeti and its Implications for Ecosystem C

• DOI: 10.1371/journal.pbio.1000210
• Publication Date: 2009-09-28T17:43:45Z
• Authors: Ricardo M. Holdo; Anthony R. E. Sin...; Andrew P. Dobson; Kristine L. Metzger; Benjamin M. Bolker; Mark E. Ritchie; Robert D. Holt
• Keywords: Trophic cascade; Wildebeest; Mesopredator release hypothesis

Tree cover is a fundamental structural characteristic and driver of ecosystem processes in terrestrial ecosystems, trees are major global carbon (C) sink. Fire herbivores have been hypothesized to play dominant roles regulating African savannas, but the evidence for this conflicting. Moving up trophic scale, factors that regulate fire occurrence herbivores, such as disease predation, poorly understood any given ecosystem. We used Bayesian state-space model show wildebeest population eruption followed (rinderpest) eradication Serengeti East Africa led widespread reduction extent an ongoing recovery tree population. This supports hypothesis has played key role regulation then link our with theoretical empirical results quantifying effects grazing on soil predict cascade may important shifts size pools C stored biomass. Our suggest dynamics tightly coupled at landscape scales, exerts clear top-down density, outbreaks can lead complex cascades savanna ecosystems. propose long-term status other intensely grazed savannas sources or sinks be fundamentally linked control poaching.