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Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter
Published on: March 12, 2013
14.0K
Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure
Elizabeth J Roberson1, Michael J Chips2,3, Walter P Carson2
1Department of Biological Sciences, Wright State University, Dayton, OH, United States.
Peerj
|October 6, 2016
Summary
White-tailed deer browsing significantly impacts forest spider communities. Deer exclusion increased spider web abundance and habitat availability, revealing indirect ecological effects on arthropod food webs.
Area of Science:
- Ecology
- Zoology
- Forestry
Background:
- Indirect ecological effects occur when one species influences interactions between others.
- White-tailed deer (Odocoileus virginianus) populations have increased in eastern North America.
- Forest structure is influenced by herbivore browsing pressure.
Purpose of the Study:
- To investigate how white-tailed deer browsing indirectly affects web-building spider guilds.
- To determine the impact of deer on spider abundance and community composition via vegetation structure changes.
- To assess the relationship between deer exclusion, habitat structure, and spider populations in northern hardwood forests.
Main Methods:
- Paired plots (deer-free vs. control) were established in Pennsylvania and Wisconsin.
- Spider web abundance (seven types) and vegetation structure were quantified.
- Web scaffold availability index (WSAI) and prey availability were measured.
Main Results:
- Spider webs were twice as abundant in deer-free plots compared to control plots.
- Web scaffold availability index (WSAI) was significantly higher (7-12 times) in deer-free plots.
- Most spider web types, excluding funnel web-builders, were more abundant in deer-free areas, indicating deer exclusion positively impacts spider communities.
Conclusions:
- Deer browsing reduces habitat structure, negatively impacting web-building spider abundance and diversity.
- Forest management strategies should consider deer impacts on arthropod communities.
- Spider recruitment may be linked to forest disturbance events that promote shrub and tree regeneration.
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