PORTLAND, Ore.— The Center for Biological Diversity filed a legal petition today with the U.S. Fish and Wildlife Service to protect the wonder caddisfly under the Endangered Species Act.

The wonder caddisfly is one of the rarest of the Columbia River Gorge’s caddisflies, many of whom live nowhere else on Earth. Due to prolonged drought in the region, the species has disappeared from one of only two streams where it occurred and now survives in a single 110-yard stretch of river below a waterfall on the Oregon side of the gorge.

“The wonder caddisfly and its home are both so unique and delicate, and they desperately need protection from humans and our changing climate,” said Meg Townsend, a freshwater species attorney at the Center. “An endangered listing will give the caddisfly a fighting chance at survival, along with more funding for conservation that can help protect not only the caddisfly but the rivers it lives in.”

Caddisflies begin their lives as river-dwelling larvae, constructing a portable protective case out of stream sediments like fine sand and plant material, and emerge from the water as winged, moth-like adults.

The wonder caddisfly lives only in Wonder Creek, below Lancaster Falls; immediately below the waterfall, a trail crossing the creek and a clear-cut powerline corridor prevent its population from expanding downstream. Although the species was first discovered below nearby Cabin Creek Falls, it’s already gone from Cabin Creek, and extensive survey efforts have failed to find other populations.

Requiring very specific habitat to survive, and with only one population in a heavily trafficked area, these tiny underwater builders are particularly vulnerable to extinction. Climate change is also a significant threat, since it increases drought severity and the risk of wildfire. Although these caddisflies live outside the area affected by the 2017 Eagle Creek wildfire, future fires in the gorge could harm their home.

Up to 40% of all insect species may be threatened with extinction, and caddisflies are the most imperiled aquatic insect — a group that also includes mayflies, stoneflies, dragonflies and damselflies — and an important part of the web of life, providing food for fish, birds, bats, spiders, frogs and small mammals like voles. Since they need clean water, their presence in a stream is a good indicator of water quality.

“The wonder caddisfly is one small part of what makes the Columbia Gorge magical,” said Townsend. “If we lose this little animal, we lose a little bit of the history of our world.”