Prior to European settlement, fire was a common natural disturbance that recycled nutrients in both prairie and oak savanna ecosystems. Luther College has implemented fire regimes for their prairie and woodland natural areas that surround campus. Past research on the effects of fire on ground beetles in prairies at Luther College have shown a mixed impact on their diversity, with some species being impacted negatively by fire, while other species respond positively to fire. Prior studies in Luther College’s woodlands have shown that invasive European Buckthorn (Rhamnus cathartica) negatively affects ground beetles. In the fall of 2015, a prescribed woodland burn took place in Flying Squirrel Forest burning roughly 14 acres. This study aimed to see what affect this first prescribed fire had on ground beetle abundance and species richness. In order to understand the effect of fire on ground beetles, five paired transects were established between the burned and unburned sites. Pitfall traps were used to collect ground beetles on a biweekly basis from both burned and unburned forest plots from May 23-September 29, 2016. Leaf litter and temperature data were both collected to observe habitat differences between burned and unburned plots. Percent cover of buckthorn, honeysuckle, other woody species, leaves, and bare ground between treatments was also collected using a 0.5 m2quadrat.
Results/Conclusions
Over the nine collection periods, 1,507 ground beetles representing 40 species were collected, identified, and quantified. Between burned and unburned transects, there was no significant difference in beetle abundance, species richness, or beetles/trap/day. Ground beetle communities were found to be more similar to each other based on location in the woodland rather than by treatment. Shannon diversity (H’) was found to be significantly different for ground beetles between burned and unburned treatments, which may be attributed to different ground beetle strategies and abundances. Leaf litter and temperature were significantly different between burned and unburned plots. The percent cover of woody species was also significantly different between treatments, and although the percent cover of buckthorn was not significantly different, unburned plots had a much larger range of buckthorn cover, suggesting that fire could be having a positive impact on the removal of buckthorn. These results suggest that fire does not negatively affect ground beetle diversity while suppressing buckthorn in an attempt to restore historical levels of diversity.