Impacts of Prairie Management on Insect Biodiversity — 31p — Emma Nelson, William Davis, Diane Roeder

Insects are effective bioindicators of ecosystem health because of the diversity of habitats and ecological roles they inhabit. Insect populations are declining due to habitat loss and degradation; thus insects can be used to indicate the relative quality of preserved or restored habitat patches. The goal of this study is to evaluate whether restored prairies support similar insect diversity (with a focus on ants) and ecosystem services as do undisturbed remnant prairies in western Minnesota. Because restored prairies are younger than remnants, we hypothesized that remnants persisting in a natural state will have higher levels of biodiversity and ecosystem services than do restored prairies. To measure insect diversity, we deployed 5-12 pitfall traps (scaled to patch size) at each of 30 remnants and 15 restored patches for a total of 415 traps. Traps were collected after 48 hours. We used sentinel prey stations 2-m from each pitfall trap to measure predation. These consisted of small cages containing ~50 corn earworm eggs secured to a petri dish and wrapped in wire mesh. Predation was measured as the number of eggs consumed during the 48 hour sampling period. After one year of sampling in 2023, we found a total of 11 genera of ants. On average, remnants contained more ant genera than restored patches . The genera present in restorations were a subset of those present in remnants, although no genera were exclusively found in either prairie type, suggesting that restoration efforts have been effective in restoring ant diversity in the region. There was no significant difference in sentinel prey consumption between the two prairie types, indicating similar pest control via predation. Ant and insect identification will continue in 2024, along with a second year of sampling, to determine if these results are consistent across years and across insect families.

Augustana University
Diane Roeder