Members of the Audubon Society say they visited the area in the Sepulveda Basin during the Christmas bird count, the Los Angeles Times reported. What had been a lush piece of river bottom, land used as a pit stop by migratory birds, had become a piece of dirt.
The Corps, which says much of the vegetation in the area was not native to Southern California, said the plan is to replace it with native grasses. The area, part of the Los Angeles River Basin, was planted in the 1980s.
Ellen Zunino, a botanist who participated in the 1980s work, said she did not see any signs the Corps was planning to restore the area.
"I'm heartbroken. I was so proud of our work," she told the Times. "I don't see any of the usual signs of preparation for a job like this, such as marked trees or colored flags. It seems haphazard and mean-spirited, almost as though someone was taking revenge on the habitat."
A 1930s flood control project put the Los Angeles River into a concrete channel, with a few spots like the Sepulveda Basin left open. The Corps said the native-grass plan is aimed at making the basin safer and removing cover that shielded illicit activities.