Buena Vista Audubon explores impact of Southern California wildfires
photo by David S. Roberts
Recent wildfires in San Diego County have had a profound impact on area bird populations, according to an expert from the San Diego Natural History Museum who in April spoke before the Buena Vista Audubon Society.
Phil Unitt, curator of the museum’s Department of Birds and Mammals, described in detail the devastating fires struck San Diego County in 2002, 2003, and 2007 seasons, burning over 700 square miles in 2002 and 2003. He spoke about how he and other naturalists in the area set out to conduct a survey of how birds were faring post-fires in the recovering landscape. Over the course of five years, bird populations were assessed through periodic counts, with sometimes surprising results.
Unitt reported that certain birds have adapted well to the new environment, even preferring the burned areas. However, the Mockingbird, Mourning Dove, Rock Wren, and above all the Lazuli Bunting’s numbers have dropped off considerably after the fires.
The Black-chinned Sparrow increased spectacularly – by three years after the fire becoming perhaps the most abundant bird. Other species, like the Bushtit and Wrentit, increased after being decimated by the fire, though after five years their population is still far from pre-fire levels.
Species recovery depends partly on the type of terrain, vegetation, and climate of the area burned, according to Unitt. In chaparral, birds that adapted well after the fires were roughly equal to the number of species that reacted poorly. But in the forest, where the recovery of conifers is almost nil, fewer species have been able to adapt. California Thrashers, for instance, along with Hutton’s Vireo, are both recovering very slowly, or, in the case of the Hutton’s vireo, possibly not at all.
Unitt said that the future threat posed by wildfire depends more on climate than anything else.
“As catastrophic as the fires seem, I believe the more insidious threat to our wildlife is the trend to a dryer climate,” he said. “If the fires are contained within historic rainfall patterns, their effect is likely to be made up sooner or later. But if the fires are a symptom of a shift toward a dryer climate, they may have marked a quantum shift toward reduced numbers and reduced ranges of many species.”
