North-Central Section–40th Annual Meeting (20–21 April 2006)
Paper No. 11-1
Presentation Time: 1:20 PM-1:40 PM


WANG, Steve C., Mathematics and Statistics, Swarthmore College, 500 College Ave, Swarthmore, PA 19081,, ANGIELCZYK, Kenneth D., Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, United Kingdom, and ROOPNARINE, Peter D., Invertebrate Zoology and Geology, California Academy of Sciences, 875 Howard St, San Francisco, CA 94103

The end-Permian extinction was the most severe mass extinction of the Phanerozoic, yet its causes remain mysterious. Here we use probabilistic food web models to explore how disruption of primary production (e.g., extinction of green plants) could have caused the collapse of end-Permian terrestrial ecosystems. First, we simulate food webs (trophic networks) reconstructed for the Dicynodon Assemblage Zone community of the Karoo Basin. Next, we perturb these food webs using simulated extinctions of taxa at varying levels of intensity, according to three modes of extinction: top-down, bottom-up, or uniform. This probabilistic forward model allows us to estimate the effects of such perturbations on terrestrial communities. We then use tree-based statistical methods (recursive partitioning) to estimate the intensity and mode of extinction from the actual extinction levels observed in Karoo Basin fauna. Our results suggest that the mode of extinction was bottom-up, implying that disruption of primary production was responsible for the collapse of late Permian terrestrial communities. Furthermore, relatively high levels of primary production loss are needed to account for observed levels of extinction among Karoo Basin consumers.

North-Central Section–40th Annual Meeting (20–21 April 2006)
General Information for this Meeting
Session No. 11
All Things Paleo: Diversity, Ecology, Morphology, Phylogeny and Taphonomy
Student Center, University of Akron: Theater
1:20 PM-5:40 PM, Thursday, 20 April 2006

Geological Society of America Abstracts with Programs, Vol. 38, No. 4, p. 15

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