Wildlife Science News: Ants & Forest Health, Mapping Migratory Birds

Tiny ants play a big role in forest health, mapping migratory bird hotspots, prairie potholes as pollution catchers and more wildlife and science news

By Mark Wexler
Scope
Sep 27, 2023

Tiny Ants Play Big Role In Forest Health

One hallmark of old-growth northeastern deciduous forests in spring is the dazzling display of violets, trilliums, wild ginger and other wildflowers that carpet the forest floor. In newer secondary forests, such spring ephemerals tend to be scarce—and in recent research published in Ecology, scientists say one explanation may be a lack of woodland ants. According to researchers at Binghamton University, several ant species in the genus Aphaenogaster (above) are critical dispersers of the seeds of native understory wildflowers. “These plants evolved with seeds that have an appendage rich in fats, and that’s very attractive to woodland ants,” says lead author Carmela Buono, a doctoral candidate in biological sciences. The insects take the seeds to their nest—where they are safe underground from seed predators such as rodents—and later “plant” the seeds outside the nest. The scientists say low numbers of woodland ants in regenerated forests stems from several factors, including competition with invasive slugs that thrive on former agricultural lands. To restore the health of these newer forests, “we need to look beyond trees to the diversity of insects,” Buono says. Ants may not be as charismatic as pollinators like bees and butterflies, she adds, “but they are just as important.”

An image of a Blackburnian Warbler male calling.

Mapping Hotspots to Help Migrants

Princeton University researchers have produced the first comprehensive map of the most important places migratory songbirds (such as the Blackburnian warbler, above) stop to rest and refuel across the eastern United States during fall migration. The scientists identified these stopover hotspots—which include dozens of sites along the Mississippi River and in the Appalachian Mountains—by compiling data on bird densities each fall from 2015 to 2019 at 60 U.S. weather radar stations covering more than 150 million acres. The map, published in the Proceedings of the National Academy of Sciences, “gives us a powerful new tool for identifying the key habitats these birds are using during their epic migrations,” says Princeton ecologist and co-author David Wilcove. The scientists found that forests provide the most essential habitats for autumn migrants and that forest fragments in heavily deforested regions support especially large numbers of the birds. Unfortunately, these “small pockets of deciduous forest are often neglected in conservation planning,” says Princeton ecologist and lead author Fengyi Guo, who hopes the new migration stopover map will help to change that.

An image of a sunset over prairie potholes in South Dakota.

Pollution-Catching Power

Often isolated from larger waterways, seasonal wetlands such as prairie potholes (above) are frequently drained for agriculture or development. But according to a recent study in Environmental Research Letters, such wetlands are “pollution-catching powerhouses” twice as effective at protecting downstream rivers and lakes from nitrogen, phosphorous and other contaminants as wetlands connected to larger water bodies. To reach that conclusion, environmental engineers at Canada’s University of Waterloo combined computer modeling with 30 years of satellite imagery to calculate pollution retention. They then measured water levels at different times of year in 3,700 wetlands nationwide. “Being disconnected can be better because the wetlands are catching the pollutants and retaining them as opposed to leaking them back into streams,” says lead author Frederick Cheng, now at Colorado State University. Draining wetlands also destroys wildlife habitat and increases the risk of floods, drought and other impacts of climate change.

An image of a black-tailed prairie dog.

Microscope

Wide-Open Spectrum

After analyzing vision research on nearly 450 species, University of Arkansas biologists report in the Proceedings of the Royal Society B that wildlife adapted to open habitats (such as prairie dogs, pictured) see a wider range of colors than forest animals.