Patterns of richness in a long-term citizen science butterfly dataset from Cuyahoga Valley National Park

Insect populations are experiencing ongoing declines in abundance and diversity, but their population dynamics are often complex and trends are difficult to identify. Butterflies are an important, convenient, and useful insect group to monitor. They are a well-recorded group of insects, play important ecological roles as both pollinators and herbivores, and there is a large community of amateur lepidopterists that contribute to citizen science butterfly monitoring programs. In the present study, we analyzed 27 years of citizen science butterfly monitoring data collected across four sites in Cuyahoga Valley National Park, Ohio. We aimed to investigate patterns of species richness and abundance across years and sites and elucidate potential climatic variables that influence the butterfly community. We found similar levels of estimated butterfly species richness at three sites, yet one site had noticeably higher estimated species richness. Abundance fluctuated annually and was relatively consistent across sites. Further, based on Non-metric Multi-Dimensional Scaling (NMDS) results, we found that the butterfly communities changed directionally over time across all sites. NMDS analysis also identified degree days and average daily precipitation as drivers of butterfly community variability. Overall, this work identified patterns of richness and abundance patterns in a unique national park and identified potential climatic drivers of butterfly community variability.