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Where have all the flowers gone?

It's the desert's animals that bear brunt of record dry year

In the stark desert environment, a dry year is nothing new. As this weather season draws closer to becoming the driest on record for Southern California since 1877, seeds of native desert plants simply bide their time until the next big rain.

Sensitive species of animals in the desert and nearby mountains could bear the brunt of the dry weather, however, with less food and water available. Even some species that have adapted to cycles of drought could be harder hit because they are already under stress from human impacts. Reproduction levels in particular could be affected.

Anthony Chavez, a rangeland management specialist with the Bureau of Land Management in Barstow, called the conditions "horrible" but said such cycles are natural.

"The Mojave Desert has gone through hundreds of thousands of drought cycles like this," he said.

Drought cycles have become longer, however, according to wildlife biologist William Boarman.

Chavez said the dry season will affect animals "throughout the food chain or the food web." Small mammals such as squirrels and rabbits will reproduce less, which will mean less prey for hawks, owls and snakes, Chavez said. A lack of surface water could also mean animal deaths.

One species affected is the desert tortoise.

"There's practically no food for them," said Boarman, a desert tortoise expert who works near Fort Irwin. "I think I have personally seen six seedlings of any kind of annuals this year."

Tortoises have lived in the desert for 7,000 to 10,000 years and evolved to where they can store water for 1 1 /2 to two years, Boarman said.

"There is definitely evidence of tortoise mortality during periods of drought," Boarman said.

The tortoises also lay fewer eggs or sometimes none at all as a survival strategy in dry times, which would be hard on a population that needs to produce as many baby tortoises as possible. Already, Boarman has noticed that the tortoises are staying in their burrows more than normal for May, perhaps because they know that food and water are scarce. The threatened Mohave ground squirrel has also been observed coming above ground, said local biologist Tom Egan, but could also have lower rates of reproduction.

Effects of the dry season on reproduction will not be seen until later this year or next, particularly for bighorn sheep.

"There is a strong correlation between adequate rainfall and successful reproduction," said wildlife biologist Jeff Villepique of Fish and Game of the sheep. "When rainfall is very low, often the survival of the young is lower."

Bighor ns like to eat new growth on plants and grasses and in the San Gorgonio range of the San Bernardino National Forest, the habitat is "as poor as I've seen anywhere that I've worked," Villepique said.

While recent forest fires in the San Bernardino and San Gabriel mountains clear land and often create good foraging for the sheep, a lack of rain means fewer plants have sprouted.

One benefit of the record dry weather could be its effect on non-native grasses such as red brome, which are bad food for desert tortoises and often fuel forest fires.

Native annuals have adapted to keep their seed bank through dry spells, but non-natives are more likely to sprout with minimal rain and then die when it dries up, said Matt Brooks, a research botanist with the U.S. Geological Survey in Nevada.

"They can die before reproducing," he said.


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