Humans compete with wildlife for Tahoe habitat
Editor’s note: This is the fourth installment in the Tahoe Daily Tribune’s examination of the Tahoe Regional Planning Agency’s five-year evaluation of Lake Tahoe’s environment. Today, a look at the basin’s wildlife.
The animals that are native to the Tahoe Basin lost much of their favorite habitat when pioneers settled the area 140 years ago.
From 1860 to 1890, loggers leveled much of the basin’s old-growth forest to supply the gold and silver mines of the Comstock Lode with timber and fuel. Gone was the favorite habitat of such forest denizens as the bald eagle, pine marten, osprey and spotted owl.
Later, settlers built residences in some of the basin’s most valuable habitat, including its meadows and stream valleys. More than 4,000 acres of the basin’s most productive habitat was lost before strict land-use regulations halted development in stream zones.
Today, the basin’s wildlife face added competition from year-round human recreation, according to a five-year evaluation of the Lake Tahoe environment by the Tahoe Regional Planning Agency.
“Lake Tahoe is becoming more and more a year-round resort,” said Colleen Shade, a TRPA assistant planner who manages the agency’s wildlife and fisheries programs. “There is less and less of a shoulder season. It’s good for the basin’s economy, but it definitely has its consequences for wildlife.”
Such activities as cross-country skiing, mountain biking and the use of personal watercraft may be forcing some animals deeper into the forest. While the number of ospreys nesting in the basin has increased over the past five years, for instance, the fish-hunting birds have abandoned some shoreline nests and moved farther from the lake, Shade said.
“Even if you provide perfect habitat, it still may not be utilized,” she said. “Do you have human intrusion? Is it occurring when eggs are ready to hatch?”
About 250 species of animals make their home in the Tahoe Basin at different times of the year. In its monitoring of the basin’s wildlife, the TRPA has focused on preserving and restoring favored habitats rather than conducting an annual census of wildlife populations.
The strategy stems partly from a 1982 agency study of the basin’s habitat, which found that animals and birds were abundant in certain locations. More than 200 species were discovered in stream zones, 140 in mixed-conifer forests and about 110 in Jeffrey pine forests – far more than in any of the basin’s other habitats.
While the TRPA has set a goal of restoring 1,100 acres of disturbed wetlands, by 1996 just 321 acres had been restored at a cost of $17.6 million.
In the agency’s 1996 Evaluation, it recommends adding old-growth forest as another habitat that deserves special protection.
While progress toward expanding desirable habitat has lagged, the TRPA reported greater success in tracking populations of certain species, including the goshawk and bald eagle. Since 1991, the number of osprey nests has apparently increased from nine to 13, although nesting birds may be retreating inland because of increased boating on Lake Tahoe.
The number of overwintering bald eagles has remained stable, according to the report, and the first nesting pair in the basin since 1972 was sighted last year.
For other species, human encroachment in their preferred habitats could signal a future crisis. Waterfowl habitat, for instance, has been protected, but increased human activity in wetlands could disrupt their breeding.
“The whole Taylor Marsh area is supposed to be closed until March because of the nesting season,” Shade said. “But people have been observed cross-country skiing there, even though it’s prohibited.”
Similarly, the winter habitat for mule deer on the eastern slopes of the Carson Range has experienced greater competition from human development in recent years, a trend that could limit the basin’s deer population.
The 1996 evaluation calls for a study of the impact on wildlife from such sources as off-road vehicles and personal watercraft. It also recommends a study of the conditions that affect wildlife populations.
“We don’t know what the carrying capacity for wildlife is in the basin,” said Shade. “Is the fauna at capacity or is it short of capacity? Is the wildlife being pushed out because of human intrusion? We have a lot of questions that still must be answered.”
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