OOS 44-10 - Interaction cascades in anthropogenic glades: Adding habitat heterogeneity in an otherwise homogenous landscape across multiple spatial scales and trophic levels

Thursday, August 11, 2011: 4:40 PM
15, Austin Convention Center
Colin M. Donihue, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, Robert M. Pringle, Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, Johannes Foufopoulos, School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI, Lauren E. McGeoch, Graduate Group in Ecology and Department of Plant Sciences, University of California, Davis, Davis, CA and Corinna Riginos, Conservation Research Center, Teton Science Schools, Jackson, WY

After abandonment, livestock corrals in East African savannas develop into nutrient-rich, treeless “glades” that persist for decades. Other research has shown that glades have significantly higher concentrations of soil nutrients including nitrogen, potassium and carbon, which attract several specialist grass species, making these patches long-term primary productivity hotspots. Using extensive sampling, and experimental manipulations, we demonstrate that these effects on primary productivity cascade up two trophic levels to increase abundance of insects and the arboreal, insectivorous gecko Lygodactylus keniensis.


We found that Acacia drepanolobium trees close to glade edges are larger on average and grow faster than those farther from the glade. Furthermore, we showed that grasshoppers grow significantly faster inside glades than far away from glade edges and that arboreal insect abundance, biomass and diversity show the same significant trend. Finally, we find that geckos are more abundant in trees close to the glade edge than far away. Our results show that these traditional pastoral methods have significant positive impacts on the abundance of species across multiple trophic levels and add important habitat heterogeneity to an otherwise homogenous landscape.

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