Longhorned beetle (Coleoptera: Cerambycidae) species diversity and community structure in a fragmented temperate forest landscape

Background/Question/Methods

Longhorned beetles, or cerambycids (Coleoptera: Cerambycidae) are important species in temperate forest ecosystems, due to their feeding impacts on trees.  Many cerambycids feed on dead wood and therefore assist in the decomposition of dead  trees in forest ecosystems.  Saproxylic cerambycids  (dead wood dependent) and other saproxylic beetles are thought to be useful indicators of  forest biodiversity.  We were interested in testing the hypothesis that larger forests have greater cerambycid species diversity than smaller forests in NW Ohio, a highly fragmented landscape in terms of forest ecosystems.

Three types of traps (a Lindgren funnel trap, an Intercept Panel trap, and a window trap) were set up in each of 8 forests in northwestern Ohio.  Ninety-five percent ethanol was used to attract beetles. Four forests were large (>100 hectares) and four forests were classified as small (<20 hectares). Beetles were collected beginning in early June; collecting continued into early October.

Results/Conclusions

Large forests had a significantly greater cerambycid species richness than small forests (t = 3.16. P = 0.02). There was a significant relationship between forest fragment size and cerambycid species richness; as forest fragment size increased, so did cerambycid species richness (F = 12.07, P = 0.013). Many other beetle species from other families were also captured (e.g., Elateridae, Curculionidae), so these data should also be examined.  Future research should focus on the landscape matrix and degree of isolation of forests, especially isolation of smaller forests.