Summary:
Insects are vanishing at alarming rates even in remote, undisturbed landscapes, according to research published in Ecology. A study led by Keith Sockman, associate professor of biology at the University of North Carolina at Chapel Hill, tracked flying insect populations over 20 years in a subalpine meadow in Colorado that has experienced minimal direct human impact. The results show an average annual decline of 6.6%, amounting to a 72.4% drop between 2004 and 2024.
The long-term monitoring effort used 38 years of weather data to explore possible drivers of this decline. Sockman found that rising summer temperatures, particularly warmer daily lows, were strongly associated with the losses. The findings indicate that climate change may be a key factor even where ecosystems remain relatively untouched by human land use.
“Insects are necessary for terrestrial and fresh-water ecosystems to function,” Sockman said. He noted their critical role in nutrient cycling, pollination, and maintaining food webs.
While most reports of insect decline focus on habitats altered by human activity, this study demonstrates that steep losses can occur even in pristine environments. The results raise concerns about the resilience of mountain ecosystems, which host many locally adapted and endemic species.
Even untouched ecosystems are losing insects at alarming rates
Keith Sockman, associate professor of biology at UNC-Chapel Hill, quantified the abundance of flying insects during 15 seasons between 2004 and 2024 on a subalpine meadow in Colorado, a site with 38 years of weather data and minimal direct human impact. He discovered an average annual decline of 6.6% in insect abundance, amounting to a 72.4% drop over the 20-year period.
The study also found that this steep decline is associated with rising summer temperatures.
“Insects have a unique, if inauspicious position in the biodiversity crisis due to the ecological services, such as nutrient cycling and pollination, they provide and to their vulnerability to environmental change,” Sockman said. “Insects are necessary for terrestrial and fresh-water ecosystems to function.”
The findings address a critical gap in global insect research. While many reports of insect declines focus on habitats altered by human activity, few examine populations in relatively pristine areas. This study demonstrates that dramatic losses can occur even where direct human impacts are minimal, suggesting climate change may be a key driver.
“Several recent studies report significant insect declines across a variety of human-altered ecosystems, particularly in North America and Europe,” Sockman said. “Most such studies report on ecosystems that have been directly impacted by humans or are surrounded by impacted areas, raising questions about insect declines and their drivers in more natural areas.”
Sockman emphasizes the urgency of these results for biodiversity conservation: “Mountains are host to disproportionately high numbers of locally adapted endemic species, including insects. Thus, the status of mountains as biodiversity hotspots may be in jeopardy if the declines shown here reflect trends broadly.”
This research highlights the need for more comprehensive monitoring of insect populations in a variety of landscapes and adds urgency to addressing climate change. By showing that even remote ecosystems are not immune, the study underscores the global scale of the biodiversity crisis.
Journal Reference:
Sockman, Keith W., ‘Long-Term Decline in Montane Insects under Warming Summers’, Ecology 106 (9): e70187 (2025). DOI: 10.1002/ecy.70187
Article Source:
Press Release/Material by University of North Carolina at Chapel Hill (UNC-Chapel Hill)
Featured image: Colorado meadow used for Keith Sockman’s 20 year study. Credit: Keith Sockman | UNC-Chapel Hill
