Setting Fire to the Field: The Effects of a Prescribed Burn on Arthropod Abundance and Diversity in a Contiguous Grassland Field, Edge, and Forest Area

Edges (transitional zones) can be a combination of faunas of adjacent environments or can have their own unique subset of organisms. Edges are heavily traveled by organisms looking for food sources or refuge from the elements, and they have a greater diversity in vegetation. Arthropods in or adjacent to controlled burn areas are heavily understudied; holistic studies examining insect diversity and abundance in such systems are not common. By sampling an area with an edge, a basic understanding can be gained of its contribution to diversity and its value as a reservoir for repopulation of burned areas. It was hypothesized abundance and diversity would be higher in an edge (transitional) site than in the forest or burned sites, and that within the burn area abundance would decrease but diversity would increase over time. This study was composed of six contiguous sampling sites at Arnold Air Force Base, Tullahoma, TN: two in the forest, two on the edge, and two within a field that was subject to a prescribed burn in March 2023. Each of the sampling sites was equipped with one SLAM (Sea -Land- Air Malaise) trap and five pitfall traps. These traps operated for 10 -14 days, and all sites were sampled every other month for one year. Sweep-net sampling and organic litter collection for extraction in Tullgren funnels were performed. Data was analyzed using the Shannon-Wiener diversity index, Sørensen index, and a generalized linear mixed model was created to assess significance. Edge habitats had the highest arthropod abundance, but diversity was not statistically different. SLAM trap results and precipitation were correlated with arthropod abundances and diversity values. Repopulation of the burn area was most likely coming from the edge habitat rather than another source. The controlled burn did not significantly decrease arthropod numbers or diversity. In conclusion, a study such as this one provides invaluable information on the role of edges in arthropod biodiversity and effects of anthropogenic disturbance.