Even untouched ecosystems are losing insects at alarming rates, new study finds

A new study by the University of North Carolina in Chapel Hill shows that insect populations are decreasing quickly even in relatively unstruized landscapes, which raises concerns about the health of ecosystems that depend on it.

Keith Sockman, an associate professor of biology at UNC-Chapel Hill, quantified the abundance of flying insects for 15 seasons between 2004 and 2024 on a subalpine prairie in Colorado, a site with 38 years of meteorological data and a minimal human impact. He discovered an average annual decrease of 6.6% in abundance of insects, a drop of 72.4% over the period of 20 years. The study also revealed that this sharp decline is associated with the increase in summer temperatures.

“Insects have a unique position, but not very favorable in the biodiversity crisis because of ecological services, such as nutrient cycling and pollination, they provide and their vulnerability to environmental change,” said Sockman. “Insects are necessary for land and freshwater ecosystems to work.”

The results fill a critical gap in the global research of insects. While many insect reports decrease to focus on habitats modified by human activity, little examine the populations in relatively virgin areas. This study shows that spectacular losses can occur even when direct human impacts are minimal, which suggests that climate change can be a key engine.

“Several recent studies report significant insect reductions through a variety of ecosystems altered by humans, in particular in North America and Europe,” said Sockman. “Most of these studies report ecosystems that have been directly affected by humans or surrounded by impacted areas, raising questions about declining insects and their engines in more natural areas.”

Sockman emphasizes the urgency of these results for the conservation of biodiversity: “The mountains are hosted by a disproportionate number of endemic species adapted locally, including insects. Thus, the status of the mountains as hot spots of biodiversity can be in danger if the declins indicated here reflect the trends overall.”

This research highlights the need for more complete monitoring of insect populations in a variety of landscapes and adds urgency to the fight against climate change. By showing that even distant ecosystems are not immune, the study underlines the global scale of the biodiversity crisis.

The search document is available online in the journal Ecology.