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Trophic network models explain instability of Early Triassic terrestrial communities
Peter D Roopnarine1, Kenneth D Angielczyk, Steve C Wang
1Department of Invertebrate Zoology and Geology, California Academy of Sciences, 875 Howard Street, San Francisco, CA 94103, USA. proopnarine@calacademy.org
Proceedings. Biological Sciences
|July 5, 2007
Summary
Early Triassic ecosystems were less stable than Permian ones due to altered community structures, impacting extinction patterns. This study models ecological crises after mass extinctions.
Area of Science:
- Paleontology
- Ecology
- Systems Biology
Background:
- Mass extinctions are often studied for abiotic causes and direct biotic impacts.
- Secondary extinctions driven by ecological crises and community structure effects receive less attention.
- Understanding long-term extinction trends requires analyzing community dynamics.
Purpose of the Study:
- To investigate the role of community structure in secondary extinctions following the end-Permian mass extinction.
- To model the impact of primary productivity disruptions on palaeocommunities.
- To compare the stability of Permian and Early Triassic ecosystems in the Karoo Basin.
Main Methods:
- Utilized a trophic network model combining topological and dynamic approaches.
- Simulated disruptions of primary productivity in Permian and Triassic palaeocommunities.
- Applied the model to fossil data from the Karoo Basin, South Africa.
Main Results:
- Permian communities showed no particular susceptibility to extinction.
- Early Triassic communities exhibited inherent instability.
- Instability in the Early Triassic was linked to faster amphibian guild diversification compared to amniotes.
- Post-extinction communities had fundamentally different structures than their Permian predecessors.
Conclusions:
- Community structure significantly influences ecosystem stability and extinction susceptibility.
- Differential diversification rates of ecological guilds can lead to less stable ecosystems.
- Changing community structures over geological time may explain declining background extinction rates.
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