Approximately 20% of butterflies present in the United States have vanished over the past two decades
In a recent study published in the journal Science, a team of scientists have revealed concerning trends in the population of butterflies across the United States over the last 20 years. The research, which involved participation from over 100 species experts and volunteers, sheds light on the declining abundance of butterflies and the factors contributing to this trend.
The study found that agricultural fields have become 48 times more toxic to bees, a worrying statistic that may also be affecting butterfly populations. This, along with habitat loss, climate change, and pesticide use, are identified as key factors in the declines reported.
Sadly, the declines reported in the study do not come as a surprise to Monika Böhm, co-chair of International Union for Conservation of Nature's SSC Butterfly & Moth Specialist Group. The total butterfly abundance in the U.S. has declined by 22 percent across all species between 2000 and 2020. This decline was most prominent in the Southwestern region of the U.S., while the Pacific Northwest was declining the least.
Three billion birds have been lost in North America since 1970, and the study indicates that butterflies may be following a similar trajectory. Mayfly numbers have been cut in half, and more than 100 species saw drops greater than 50 percent over the twenty-year timespan. Among the butterfly species that have declined more than 90 percent are the Hermes copper, tailed orange, West Virginia white, California patch, and sandhill skipper.
Despite these concerning findings, the study also highlights the importance of butterfly monitoring programs in conservation efforts. Across 35 monitoring programs, scientists and volunteers have identified 12.6 million butterflies from 554 species at 2,478 unique locations. Improving habitat for butterflies can have a huge impact on their population due to their short generation spans.
However, the study also points out that scientists only had enough data to conduct species-level analyses for slightly over half of the butterflies found in the U.S. This underscores the need for continued monitoring and research to fully understand the factors contributing to the declines in butterfly populations and to develop effective conservation strategies.
Eliza Grames, a conservation biologist at Binghamton University in New York, is a coauthor of the study. The search results do not provide the names of the authors of the landmark study investigating the decline of the total butterfly population in the United States over the last 20 years.
The declines in butterfly populations are a clear indication of the urgent need for action to protect these important species and their habitats. As we continue to learn more about the factors contributing to these declines, it is essential that we take steps to preserve and restore the habitats that butterflies need to thrive. Participating in butterfly monitoring programs can make a difference in these conservation efforts, and everyone can play a role in supporting the conservation of butterflies and other pollinators.
