Drought Stresses Nevada Wildlife: Impact on Wild Horses and Ecosystems

Stressed and hungry, Nevada's wild horses wander a parched landscape in an increasingly difficult search for food. The state's fish are running out of water and in some places, are doomed to die. In Reno, snakes are crawling closer to homes as the little animals upon which they prey cluster closer to urban areas that offer the resources they need to survive. Deer numbers are down and this summer could offer a particularly busy time when it comes to problems with bears and people at Lake Tahoe.

It's drought and when it comes to wildlife, it's trouble.

"It's stressing the animals and it's stressing the habitat itself," David Catalano, a supervisory biologist with the Nevada Department of Wildlife, said of a drought now three years in duration.

Lack of a snowpack after a dismal winter caused streams and creeks that normally flow into July or later instead go dry in March or April, Catalano said. Rabbits and squirrels, mice and chipmunks — all are responding. Many congregate in human neighborhoods where water, grass and insects are readily available.

"They've got a mini ecosystem that is flourishing so all these little critters are drawn there," Catalano said. "Now they are all competing a lot more for shelter and for foraging."

Predators follow, including hawks and snakes, with Catalano reporting a significant increase in calls regarding snakes on people's property since the drought began two years ago.

Drought is affecting Nevada's mule deer herd, which declined from an estimated 112,000 animals when dry conditions arrived in 2012 to about 108,000 this year, said Cody Schroeder, mule deer specialist with the Department of Wildlife. The Truckee-Loyalton herd, which wanders the mountains west of Reno along the Nevada-California border, dropped from an estimated 1,750 to 1,700.

With so little moisture, the grasses and flowering plants deer depend upon for summer forage are increasingly scarce. Lack of water also hurts the sagebrush and bitterbrush they eat in winter.

The end result — the deer are slowly wasting, with the youngest the most vulnerable. Continuing drought make it "much less likely" fawns born this summer will survive through next winter, Schroeder said.

And, in an irony of sorts, should a big drought-busting winter come next year — and few disputed that one is needed — it could prove particularly disastrous for Nevada's deer herd, resulting in a significant die-off of weakened fawns and adults alike.

"The worst combination of weather events is a drought followed by a heavy winter. That can push them over the edge," Schroeder said.

The U.S. Bureau of Land Management is closely monitoring the estimated 25,000-plus wild horses wandering across the state's federally owned range. Spring rains helped generate forage that have horses in OK shape so far, but what's to come later in the summer is unknown, said Alan Shepherd, wild horse and burro program lead for BLM Nevada.

"Right now the horses are in fair condition. They haven't started the progression downward yet in body condition," Shepherd said. "In the next couple months it will probably be more noticeable that the horses are being impacted by the temperatures and the dry conditions."

The BLM could choose to haul water to those herds most affected or gather them in roundups, but drought could make the later course particularly problematic.

"We just hope it doesn't hit us so hard the animals are in a real dire condition because that makes gathers all the more difficult," Shepherd said.

Fish need water and in Nevada this summer; water is lacking. Kim Tiscale, supervisory fisheries biologist for the Nevada Department of Wildlife, is confident adequate flows will continue to protect the trout and other fish living in the Truckee River.

That might not be the case in the Carson and Walker rivers, which lack the same upstream storage that exists on the Truckee. They could go dry, or mostly so.

"We could lose those fisheries," Tisdale said. "It's a possibility. We're hoping not."

Lahontan and Rye Patch reservoirs are down, way down. Tisdale is hopeful those fisheries will survive the summer, but he acknowledges a stretch of very hot weather could rob the lakes of dissolved oxygen with lethal results.

A die-off appears all but certain at Wildhorse and Willow Creek reservoirs in Elko County. In mid-May and for the second year in a row, the state lifted limits of fish allowed caught in the two reservoirs in an attempt to empty them of fish before conditions become unsurvivable.

The department started stocking the Truckee River and urban ponds around Northern Nevada in March, the earliest time in 20 years since the last major drought forced similar actions in 1994.

"This is as bad as it was at the end of that seven-year drought," Tisdale said. "It's the same across the board. It's low water conditions everywhere."

At Lake Tahoe and across the Carson Range, hungry bears are on the move and, due to the drought, aren't finding the berries and other natural food sources upon which they normally depend.

That could set the stage for problems similar to what occurred in 2007, when drought conditions combined with a spring freeze to kill vegetation sought by black bears and resulted in an unprecedented surge of bear problems as the animals raided Dumpsters and broke into homes in search of food. More than 1,500 bear complaints were recorded.

"We certainly could, by the time fall rolls around, see something like that again," said Carl Lackey, state bear biologist. "I hope not, but it could be as bad. It's already been a busy spring, and I don't anticipate it getting any better. We're probably going to get buried."

Drought and Nevada Wildlife

• Mice, squirrels and other little critters: Increasingly are clustering in urban areas where water and food is available.
• Snakes, coyotes and other predators: Follow their prey into neighborhoods and are seen increasingly more frequently.
• Wild horses: Appear OK for now but are lacking forage and water.
• Mule deer: Numbers are down. A big winter after drought could be disastrous.
• Black bears: With the drought killing natural vegetation, bears will likely turn to trash and other human food sources. This summer could be a big problem.