A recent study reveals that some butterfly species on the brink of extinction actually fare better when their habitats are cared for by humans.
Researchers from Washington State University, led by Cheryl Schultz and Collin Edwards, examined data from 114 populations of 31 butterfly species across 10 states in the U.S. There has been a growing concern among scientists about the rapid decline in global insect populations, which is driven by climate change, loss of habitat, and the use of pesticides. The findings show that these endangered butterflies are especially at risk, with their numbers decreasing at an alarming rate of about 8% each year, which means a total reduction of approximately 50% over ten years.
The results of the study, published in the Journal of Applied Ecology, provide encouraging evidence that proper management of habitats can help slow or even reverse these steep declines.
Cheryl Schultz, a conservation biology professor at WSU and one of the lead authors of the study, expressed excitement about the findings: “We discovered that in areas where people actively work to manage habitats, the butterflies thrive. This is very encouraging because it demonstrates that habitat management can have a positive impact, even amid challenges like climate change.”
As temperatures rise due to climate change, many butterfly species have been altering their seasonal behaviors, often starting their activity earlier in the year. Ecologists are still exploring whether these shifts are beneficial, detrimental, or neutral to the species involved.
“Our research showed that significant changes in behavior were generally harmful for these butterflies. Populations that experienced larger timing shifts tended to be in decline,” stated Edwards, a co-lead author and recent postdoctoral fellow at WSU. “However, we were pleased to find that effective habitat management seemed to mitigate the impacts of climate change on the timing of butterfly activities. Populations that received more frequent management showed less drastic changes in their seasonal behaviors.”
Despite the overall negative trends observed in these butterfly populations, the connections established between population changes, timing shifts, and management strategies offer a path forward for their conservation.
Co-author Elizabeth Crone, a professor at the University of California, Davis, emphasized, “While this won’t completely eliminate the effects of climate change, we can alleviate some of its impacts. Local actions can have a positive effect on these butterfly populations.”
The study examined species including the Oregon silverspot, Taylor’s checkerspot, Karner blue, and frosted elfin butterflies. It also highlighted the Fender’s blue, a species that has become a symbol of recovery, bouncing back from a few thousand butterflies in the 1990s to around 30,000 today due to efforts from researchers like Schultz and collaboration with public land managers and private landowners, including many vineyards in the Willamette Valley.
Researchers found that the habitat management strategies employed were suitable, with techniques like controlled burns, mowing, weeding, and the active planting of nectar or host plants for caterpillars being tailored to the specific needs of each area.
Schultz noted that volunteers can play a crucial role in the active management of local natural areas by helping with plantings and removing invasive species. Individuals can also support butterflies in their own gardens.
“We strongly encourage everyone to plant a variety of wildflowers and plants that serve as both hosts for caterpillars and sources of nectar for butterflies,” Schultz said. “It’s important that these plantings are free from pesticides. Reducing pesticide use in our environment will greatly benefit butterflies and other insects.”
This research was funded by the U.S. Strategic Environmental Research and Development Program, the U.S. Fish and Wildlife Service, and the U.S. Geological Survey.
