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Harvard Forest REU Symposium Abstract 2008
- Title: Forest canopy loss affects the competition dynamics of carabid beetles (Carabidae)
- Author: Alyssa M Hernandez (Cornell University)
- Abstract:
Forest canopy loss has been shown to greatly affect the diversity of the smaller invertebrates in the forest understory. In this experiment, beetle abundance was analyzed in order to uncover any notable changes in forest habitats. A total of eight plots were examined within the Hemlock Removal Experiment (hardwood control, hemlock control, girdled and logged plots). Random pitfall samples placed in each plot and supplemental hand sampling served as a means for collecting specimens on a monthly basis. Our results show a higher than expected abundance of carabid beetles (Carabidae) from the genus Pterostichus represented within the hardwood, hemlock and girdled plots. However, Pterostichus was almost completely absent from the logged plots. Instead, in the logged sample, we found the carabid, Cicindela sexguttata, which seemed to be exclusive to this environment. In the absence of canopy cover and increased ambient temperature of the logged plots, the highly ectothermic Cicindela sexguttata may be more prevalent because the high temperatures within this area maximize its ability to catch prey. If this is true, its competition advantage is increased significantly and it can eliminate other competitors, perhaps explaining the decrease in abundance of Pterostichus. This same theory could be applied in explaining the lack of Cicindela sexguttata in the other plots. The lack of sunlight causes it to lose its competitive advantage. Although more data is needed to firmly test this hypothesis, these initial observations show a distinct correlation that gives certain insight into carabid beetle (Carabidae) dynamics.
- Research Category: Biodiversity Studies
