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San Diego’s Fragile Ecosystems Threatened By Predicted Jump In Wildfires

More fires could make large sections of San Diego County uninhabitable

Credit: Wikimedia Commons

Above: Trees that were burned in the 2003 Cedar Fire blanket the lower slopes of Cuyamaca.

San Diego has experienced a surge in wildfires during the last decade, and researchers warn that may be a prelude to many more such events in the future.


Climate Change And Disruptions To Global Fire Activity

Climate Change And Disruptions To Global Fire Activity

Future disruptions to fire activity will threaten ecosystems and human well-being throughout the world.

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San Diego has experienced a surge in wildfires during the last decade, and researchers warn that may be a prelude to many more such events in the future.

Using satellite-based fire records and 16 different climate-change models, researchers from UC Berkeley and around the world found that climate change will make wildfires in the West, like those now raging in parts of Colorado, California and New Mexico, more frequent in the coming decades.

California is projected to see a jump in the frequency of wildfires, primarily because of rising temperature trends, the report warns. Researchers say increased fire activity will not only affect people’s livelihoods, but also add stress to native plants and animals that are already struggling to adapt to habitat loss.

San Diego’s wildfires in 2003 and 2007 have already caused "catastrophic changes" to the region’s sensitive ecosystems and crippled native species, according to Philip Unitt, researcher and curator with the Natural History Museum’s Department of Birds and Mammals.

One of the most radical changes was the coniferous forest that formerly blanketed the Cuyamaca Mountains. The dominant tree was the Jeffrey Pine, until the 280,000-acre Cedar Fire swept through in 2003, said Unitt. “The recovery of the Jeffrey Pine in those areas has been almost nil,” he said.

The bird species that depended on the pine tree for their way of living, like the Pygmy Nuthatch that probed into clusters of pine needles for small insects, no longer have a habitat, he said.

“That’s one of the starkest examples that we see,” said Unitt.

Another bird species that has fared poorly in the defoliated forest is the Western Tanager.

“When the fire burned through, the Western Tanager had already left and gone to its winter range in Mexico. So then they came back in the spring and, ‘oops my forest burned.’ "

Unitt said the birds built their stick nests atop the canopy of the forest, but were exposed to predators and direct sunlight.

“So what we saw with the Western Tanagers was they came back in surprising numbers the first summer after the fire, but the second summer, the numbers dropped dramatically.”

Certain species have capitalized on the burned areas and the regrowth of thick chaparral that followed, like the Black-chinned Sparrow. “There were basically none of them before,” explained Unitt. “So we see all of these changes of species that take advantage of different habitats.”

Unitt said the coniferous forest won’t come back in our lifetime. “And it’s likely the climate that allowed the coniferous forest to grow in the first place doesn’t exist anymore,” he warned.

Low temperatures during winter months in the mountains have increased an average of 3 degrees since 1960, said Unitt.

“The winters are so warm that the bark beetles aren’t killed off in the winter, and pine trees are susceptible to attack by those,” said Unitt. “And of course we see large areas all over the Western United States of pine forests dying off from the beetle infestation even if they aren’t burned.”

If uncontrollable fires rage through San Diego County every few years, large sections of San Diego County could become uninhabitable. “It’s a very real threat to all of us,” said Unitt.

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