Remote mountain meadow confirms global insect crisis

Insects are the tiny engines of life: flying, crawling, pollinating, and recycling. They sustain plants, hold food webs together, and enrich the soil. But despite the fact that insects are everywhere, they are quietly disappearing.

The crisis is no longer just in farmlands and cities. A new study from Colorado’s mountains shows steep declines even in wild, remote areas. That makes the warning louder: no ecosystem is safe.

Insects decline in mountains

Keith Sockman, a biologist at the University of North Carolina at Chapel Hill, spent 20 years counting flying insects in a high Colorado meadow.

The site sits above 3,000 meters, near wilderness, with little human disturbance. It has decades of weather records, which made it ideal for linking insect numbers with climate.

The results were stark. Insect numbers fell by an average of 6.6 percent every year. Over two decades, that meant a 72.4 percent drop. The main culprit was rising summer temperatures, especially warmer nights.

“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.”

When warmth lingers at night

The study found a lagged effect. Hot summers hurt insect numbers the following year. Warmer nights were the most damaging.

Over the past 38 years, summer low temperatures in the region rose by about 0.8°C per decade. That left insects with less recovery time from daytime heat.

This matches what scientists have seen with mountain butterflies. Even slight rises in nightly lows can strain species already adapted to narrow temperature ranges.

More than farmland losses

Germany’s famous study showed over 80 percent declines in farmed landscapes over 27 years. Those findings were often blamed on pesticides and habitat loss.

Sockman’s work shows something different. Insects are collapsing even in a meadow with little human pressure. Climate itself may be enough.

“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.”

Other forces at play

Climate change explains much, but not everything. Sockman points to other possibilities: shifts in vegetation as meadows change, rising carbon and nitrogen altering plant nutrition, or natural succession.

The traps used in the study also captured mainly flying insects. That means the decline may not reflect every insect group, though the loss is still severe.

Seasonal timing shifts (when insects emerge earlier or later) could also play a role. But the data showed consistent drops that timing alone could not explain. Even if some insects shifted their activity to earlier in the season, the overall counts did not recover.

Years with hotter summers still produced smaller populations the next year, which suggests the pressure is deeper than timing changes. It points toward long-term stress, not just seasonal mismatch, driving the collapse.

Why mountain insects matter

Mountain ecosystems are fragile. Insects there need traits like cold tolerance, rapid development, and resilience to harsh winds.

They pollinate alpine flowers, recycle nutrients in short growing seasons, and serve as prey for birds. If they vanish, the entire system weakens.

“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,” Sockman said.

A global signal

High mountains and high latitudes are warming faster than the rest of the planet. They act like islands, with no higher ground for species to escape to. What is happening in Colorado is likely happening elsewhere too.

The losses here are not local – they are global warnings, signaling risks for ecosystems from the Andes to the Himalayas and across Arctic regions where insects support both wildlife and human livelihoods.

Protecting insects in mountains

Insect monitoring must expand beyond farmland and suburban areas. Remote ecosystems also need attention. Long-term studies like Sockman’s are rare but essential for tracking change.

The message is urgent. Insects are not resilient enough to withstand unchecked warming. If they vanish, food webs will collapse, pollination will falter, and ecosystems will unravel. Their fate is tied to ours.

The study is published in the journal Ecology.

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