A biologist at the Pine Bush Preserve, Steven P. Campbell, Ph.D., has coauthored a study that found butterfly populations across the United States are declining dramatically.

The total abundance of butterflies has declined by 22 percent from 2000 to 2020, according to the study, “Rapid butterfly declines across the United States during the 21st century,” published in the journal Science. Declines were present across all butterfly families.

“Numerous declines have been documented across insect groups, and the potential consequences of insect losses are dire ….,” says an abstract of the study, which goes on to comment on butterflies, “The prevalence of declines throughout all regions in the United States highlights an urgent need to protect butterflies from further losses.”

“Two-thirds of studied species showed declines of more than 10 percent,” wrote Science editor Bianca Lopez in a summary of the study. “Many insects have the potential for rapid population growth and recovery, but habitat restoration, species-specific interventions, and reducing pesticide use are all likely needed to curb population declines.”

Twenty-nine years of monitoring data on the Karner blue butterfly at the Albany Pine Bush Preserve was part of the records the study used of 12.6 million individual butterflies, from 554 species, collected from over 76,000 surveys, across 35 monitoring programs in the United States.

“This alarming state of the nation’s butterfly populations underscores how critical conservation efforts are for these important pollinators, and just what a significant example our own success with butterfly recovery has been within that same 20-year time span,” said Neil Gifford in a release from the Albany Pine Bush Preserve. Gifford is the preserve’s conservation director.

“The paper also suggests why it is important to protect and monitor the Albany Pine Bush Preserve’s entire butterfly community, an effort initiated in 2024 by our Field Ecologist & Entomologist, Alex Soldo,” said Gifford.

“A strong showing from the Karner blue butterfly (Plebejus samuelis) metapopulation in 2024 continues to indicate that our efforts to restore and maintain high-quality inland pitch pine-scrub oak barrens is also protecting the rare species it supports,” said Campbell in the release.

“The number of adult butterflies in the preserve’s metapopulation were estimated to be about 8,300 in the spring brood and 25,500 butterflies in the summer brood,” Campbell went on. “The summer brood estimate was the second largest since monitoring began in 2007.

“Although the metapopulation size fluctuates annually, it has remained above the 3,000-butterfly recovery threshold established by the U.S. Fish and Wildlife Service for the last 12 years. The preserve’s metapopulation has also exceeded our target of 7,640 butterflies in either brood for 10 of the last 11 years.

“Most notably, these brood size estimates are conservative since they apply to only 13 percent of preserve area known to support Karner blues.”

The study was completed by the Status of Butterflies in the U.S. working group, which formed to bring together all available butterfly monitoring datasets and develop a picture of the health of butterfly populations across the contiguous United States.

Nearly two dozen researchers participated in the working group, hosted by the U.S. Fish and Wildlife Service Center for Pollinator Conservation and U.S. Geological Survey John Wesley Powell Center for Analysis and Synthesis.

Upcoming events

The Pine Bush Preserve is offering two events related to butterflies:

— Science Lecture: Butterfly and moth diversity in the Albany Pine Bush Preserve

On Thursday, May 15, at 7 p.m., this lecture will explore the reasons behind the high diversity of Lepidoptera in barrens habitats, highlight the species found in the preserve, and explain how these species are managed and monitored to both protect them and to learn how management decisions are affecting the preserve overall; and

— Community Science: National Butterfly Count Volunteer Training

On Wednesday, June 25, at 7 p.m., participants will learn what butterflies can be found in the Albany Pine Bush Preserve and how to participate in the 2025 National Butterfly Count.