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Host-parasitoid extinction and colonization in a fragmented prairie landscape
1Department of Biological Sciences, Louisiana State University, 206 Life Sciences Building, Baton Rouge, LA 70803, USA. jcronin@lsu.edu
Oecologia
|April 20, 2004
Summary
Local extinction and colonization dynamics in prairie ecosystems are influenced by patch size, isolation, and surrounding habitat. Parasitoid extinction risk is higher due to multi-trophic interactions, impacting metapopulation persistence.
Area of Science:
- Ecology
- Population Dynamics
- Metapopulation Biology
Background:
- Few studies examine local extinction and colonization factors for prey and predator species in natural habitats.
- Understanding these dynamics is crucial for conservation in fragmented landscapes.
Purpose of the Study:
- To investigate factors influencing local extinction and colonization of planthoppers (Prokelisia crocea) and their parasitoid (Anagrus columbi) in a tall-grass prairie.
- To assess the role of patch characteristics and matrix composition on metapopulation dynamics.
Main Methods:
- Conducted a seven-generation census of planthopper and parasitoid populations across 147 Spartina pectinata patches.
- Analyzed relationships between patch-specific variables (density, size, isolation, host-plant density, parasitism) and extinction/colonization probabilities.
Main Results:
- Both planthopper and parasitoid extinction likelihood were influenced by patch variables, including size, isolation, and matrix composition.
- Parasitism by Anagrus columbi did not significantly affect planthopper extinction, suggesting a limited role in local dynamics.
- Parasitoid extinction risk was higher than the host's, influenced by multiple trophic levels and matrix habitat.
Conclusions:
- Patch turnover was high, with significant extinction and colonization rates for both species.
- Patch size and matrix composition are key drivers of planthopper dynamics.
- Anagrus columbi's metapopulation dynamics are complex, influenced by multiple trophic levels and habitat features, potentially increasing its vulnerability to landscape changes.
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