Earth Notes: Arthropods and Long-Term Climate Change

Nov 20, 2019

A rapidly changing climate means there’s no longer a “typical” year on the Colorado Plateau. That’s confirmed by a long-term study of bugs in the Jemez Mountains of New Mexico.

A Harpalus ground beetle, found throughout New Mexico
Credit D.C. Lightfoot/UNM

Since 1992, the U.S. Geological Survey, National Park Service and University of New Mexico have been studying ground-dwelling bugs at three different elevations within Bandelier National Monument, in habitats ranging from Pinon-Juniper woodland to mixed conifer forest.

Researchers are using lines of nine-once Dixie cups sunk into the ground as pitfall traps to catch all kinds of arthropods, the scientific term for everything from beetles and spiders, to crickets, scorpions and even mites.

The cups contain non-toxic propylene glycol and act like miniature mausoleums. They drown and preserve any critter that bumbles in—revealing the abundance and species diversity of bugs at each site.

David Lightfoot, with the University of New Mexico, says the trend to warmer and drier conditions with more variable precipitation is clearly affecting bug populations.

Lower elevation arthropods are better adapted to varying rainfall than their loftier cousins, making them more able to survive continued episodes of warming and drying. By contrast, higher elevation bugs are less responsive to warmer temperatures, variable precipitation and lower snow pack.

That likely spells sad news for flightless mountain-top arthropod species. Many of these residents of the last Ice Age may go extinct in the next 100 years as their lower elevation relatives move in.