State of the Butterflies: A US Roadmap for Butterfly Conservation in the 21st Century

Kevin Burls, Endangered Species Conservation Biologist, Xerces Society for Invertebrate Conservation

Session Description

Declines in insect abundance have been documented for various regions and for various insect groups in recent years, but the geographic extent of these declines is still being investigated. Among insect fauna, butterflies have some of the richest and most geographically widespread data available in the United States thanks to long-term single species and multispecies monitoring programs across the country. As part of a US Fish and Wildlife Service (USFWS) - US Geological Survey (USGS) Powell Center Working Group, The Status of Butterflies in the United States evaluated trends in abundance for all butterfly species for which we have adequate data. This analysis, spanning the contiguous U.S., included 35 monitoring programs and over 12.6 million individual butterfly observations. The data were sufficient to analyze national trends in abundance from 2000-2020 for 342 species of the 554 species included in the combined dataset. We also completed regional analyses for species with sufficient data, including for 101 species in the Mountain-Prairie U.S. Fish & Wildlife Service Region, which includes Colorado. Overall, butterflies across the United States are declining at a rate of -1.2% per year, approximately 22% in 20 years. Species with steep declines represent new targets for conservation efforts and reflect the fact that geographically widespread species are vulnerable to multiple threats that can influence population trends over a large area. This talk will summarize the working group analysis and discuss how these findings can complement existing targets of conservation efforts.