LEE VINING, Calif. (AP) — Federal firefighters have set fire to invasive non-native weeds on an island in the Sierra Nevada's Mono Lake in an effort to clear space for California gulls to build their nests on the ground.
The burn Friday cleared nearly half of 11-acre (4.45-hectare) Twain Island, the Los Angeles Times reported.
The lake is an important nesting ground for gulls but the recent arrival of a Eurasian bush known as five-horn smotherweed has left little room for nesting.
About 32,000 gull nests were counted at Mono Lake in the early 1990s. A gradual decline began in 2004, then steepened when the weed arrived in 2016 and quickly covered about 70% of the breeding grounds.
Last year, there were 11,705 nests, the lowest number in 34 years of study.
Use of fire to get rid of the weeds was decided upon after herbicides were ruled out and the idea of pulling the weeds was determined to be too large a task and not a permanent solution.
But the burn was postponed for three years due to extreme fire seasons, winter storms, deep snowpack that prevented access to the lake's islets, and gull breeding seasons.
Biologists will now wait to see if the decline in the gull breeding population will be reversed.