Poster Presentation Society for Freshwater Science 2025 Annual Meeting

Impacts of chemical control of Red Swamp Crayfish on macroinvertebrate communities  (117859)

William Ota 1 , Charlotte Caldon 2 , M. Eric Benbow 2 3 , Brian Roth 1
  1. Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, United States
  2. Department of Entomology, Michigan State University, East Lansing, MI, United States
  3. Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, United States

Aquatic invasive species have the potential to disrupt the stability of native ecosystems. Following the establishment of invasive Red Swamp Crayfish (Procambarus clarkii) within Michigan in 2017, the Michigan Department of Natural Resources began an ongoing monitoring and control program to understand non-target effects of pyrethrin control of this invasive species. Pyrethrin chemical control of Red Swamp Crayfish was implemented in urban ponds across Southeast Michigan and this project focused on evaluating the effects of this chemical control on macroinvertebrate community diversity and composition. Macroinvertebrates were sampled from P. clarkii invaded and uninvaded ponds pre- and post-treatment using standardized Ponar grab and D-frame dip net techniques, and identified to order and family. Differences in Shannon and Simpson diversity between pre- and post-treatment ponds were compared using Student’s T-tests. Mean Shannon and Simpson diversity metrics were both significantly higher in post-treatment compared to pre-treatment communities (both p < 0.001). Multivariate analyses (e.g., PERMANOVA and GLMM) will be used to test how invasive species chemical control affects macroinvertebrate community composition. These early results suggest chemical control of P. clarkii may help to mitigate the threat this invasive species poses to macroinvertebrate biodiversity. This project will generate new knowledge on concurrent non-target effect monitoring within invasive species management. Future work will focus on how differences in P. clarkii chemical control application intensity or techniques impact effects on macroinvertebrate communities.