USA — Unnaturally frequent wildfires may wipe out reptiles and amphibians that live in complex shrub lands, shrinking the biological diversity of burned areas, a study in San Diego County concluded.
The study, released this week to the media and published in the Journal of Herpetology, looked at 55 plots of land that burned during the 2003 wildfires, which torched nearly 380,000 acres in San Diego County.
U.S. Geological Survey researchers looked at 38 types of lizards, snakes and salamanders, comparing their populations before the fires to their numbers afterward. These animals serve as indicators of a “healthy, diverse system,” and as food sources for birds and larger reptiles said Carlton Rochester, the lead author of the study and a biologist with the survey.
Researchers published the first two years of results in the article, showing that more-frequent blazes exceed the animals’ abilities to rebound from a wildfire.
“As we get those fires coming more frequently, these shrub lands don’t have time to recover,” Rochester said. “As the fires impact the vegetation, the animals that live in those areas are impacted.”
While a handful of species appeared to thrive in the hot, dry grasslands that replaced the burned chaparral and coastal sage scrub, others diminished after the blazes, or even disappeared.
Whiptail lizards and side-blotched lizards prefer open, sunny habitat, which allows them “to get their body temperatures up and run around like crazy,” Rochester said.
Two species of whiptails and the common side-blotched lizard more than tripled in chaparral areas after the fire, and also increased in coastal sage scrub habitat, the study showed. However, Rochester said, animals like these are “generalists” that don’t require specific habitat to survive. Other animals that need more specialized conditions fared poorly after the fires, he said.
“Some species need moist habitats, and need the leaf litter that collects under shrubs,” he said. “When that burns off, the soil holds less moisture.The sun is beating directly on the soil, temperatures get higher …. Salamanders don’t do well with that and retreat underground.”
The study found that the garden slender salamander disappeared from chaparral habitat that burned in the fires, and dwindled in coastal sage scrub areas. The salamander species Ensatina vanished from both habitat types after the fire, results showed. Several species of frogs and toads also disappeared or diminished, the study found.
“For some species, we don’t know what happened,” Rochester said. “The yellow-bellied racer (snake) disappeared after the fire. We don’t know what change accounts for that.”
Rochester said the findings could provide an argument for protecting sensitive ecological areas during wildfires. However, fire authorities said they’re limited in how they can tackle fires in such areas, and often lack the personnel to address environmental concerns during wildfires.
“The environmental issues are a factor, but only after lives and property,” said Sid Morel, fire marshal for the North County Fire Protection District, which serves Fallbrook, Bonsall and Rainbow.
“There’s very specific things we are able to do or not able to do (in sensitive areas), such as using bulldozers to make fire breaks, or using fire retardant from airplanes,” said Gary Lane, division chief of operations for the district. “And for us to commit resources where no human life or property is there, I dont know that we would ever have the resources to make that happen.”
Rochester said, however, that San Diego County’s wide range of reptiles and amphibians are threatened by human changes to the fire cycle, and deserve consideration in fire-fighting efforts.
“There’s already talk that humans are causing mass extinctions, and these animals that have been here for millions of years could get wiped out by us,” he said.