Mixed severity fire best for birds in Sierra Nevada

Like Goldilocks, birds prefer it just right when it comes to severity and time after wildfires, researchers found. Some like it hot. Some not so much. To accommodate a diversity of bird species, authors on a recent paper suggest managers in the Sierra Nevadas maintain a mix of fire severity.

In a study published in Ecosphere, researchers studied bird patterns in the Sierra Nevada following three wildfires beginning in 2000. “For the most part, the focus on fires has been on single species — basically black-backed woodpeckers,” said Ryan Burnett, the Sierra Nevada Director with Point Blue Conservation and second author on the study. The impact on these birds (Picoides arcticus) was important, but Burnett wanted to look at broader impacts to the avian community.

Examining national forest lands where several large wildfires burned, Burnett and his colleagues randomly selected locations and sampled habitat availability on the landscape. Then, they used point counts to detect which bird species were using the habitat after it burned as well as nearby unburned sites.

“The initial finding was that many species reach greatest density after fire, especially after high severity,” Burnett said. “It’s clearly very important habitat.”

But the team also found that different species had different preferences regarding fire. Some species liked it early and hot. Others liked areas that burned not so hot. Some liked both.

The Lazuli bunting (Passerina amoena) in particular surprised researchers. The species turned out to be one of the most abundant birds in areas that burned at high severity but were rare to absent in unburned forest. The black-backed woodpecker (Picoides arcticus) peaked two or three years after the fire but sharply declined 10 years later.

Burnett suggests managers find a way to have different severity fires on the landscape to support biodiversity of different species. “Having no fire to low severity, you aren’t going to achieve the objective of biodiversity,” he said. “Neither is having 90 percent high severity. We can find ways to manage fire on the landscape.”