Date: 8/21/08
Contact: C. Douglas Nielsen
Phone: (702) 486-5127, ext. 3500

AMPHIBIANS IN THE DESERT

Few people have heard of the Amargosa Toad and even fewer have seen one. Yet every night throughout the summer the Amargosa Toad can be found along the Amargosa River near the town of Beatty about 120 miles north of Las Vegas. It is only here, in the Oasis Valley, along a 10-mile stretch of the Amargosa River and some adjacent upland springs that the toad is found.

Brian Hobbs, a native fish biologist with the Nevada Department of Wildlife (NDOW), is one of the few who have seen the Amargosa Toad. Recently he and several teams of biologists and volunteers from NDOW, the US Fish and Wildlife Service, Bureau of Land Management and several other organizations spent a week searching for and capturing Amargosa Toads. Each night from 8:30 to midnight the toad catchers collected data that will help NDOW and the other agencies to better understand the toad, its current status and the environment in which it lives.

Data is obtained from the toads by screening them with a devise that picks up a signal from a PIT tag placed in their body. If the toad does not have a tag and is larger than 50mm (2 inches) one is inserted through the skin of the animal usually near its shoulder. The toad’s length is measured and recorded along with its gender, location and proximity to water. “We’ve tagged 9711 toads with a few captured this year that were originally captured in 1998 making them at least 12 years old,” Hobbs explained.

While Hobbs and company had trouble finding toads on cool and windy nights, their counts were successful nonetheless. “The population is holding steady, even doing slightly better than it was 10 years ago when we started the surveys,” Hobbs said.

These surveys are conducted because populations of frogs, toads, newts and salamanders are declining worldwide. The majority of the problems creating this situation are human-caused. Habitat loss is one of the top factors, and is due in part to the draining and alteration of wetlands. Other factors include pesticide use and the spread of invasive species like bullfrogs and crayfish. Non-human factors of climate fluctuation and disease also play a part.

Hobbs and the other biologists are hoping the Amargosa toad won’t end up like the now extinct Vegas Valley leopard frog. Loss of spring related habitat to ongoing construction in the valley played a significant role to that frog’s extinction. Biologists also believe that the American bullfrog squeezed the leopard frog out. If frogs, toads and other amphibians continue to decline in Nevada and worldwide, it will affect the delicate ecology of the wetland areas where they live. These animals are in the middle of the food web, which means that they consume a large number of invertebrates (insects), but also are a food source for snakes, birds, and other animals.

“There is no one thing causing declines in amphibians and usually there are several things acting at the same time on the same population,” Hobbs said. “It is also important to note that amphibians are very resilient and populations can recover once the threats are removed or at least decreased to some extent.”

The Nevada Department of Wildlife (NDOW) protects, restores and manages fish and wildlife, promotes fishing, hunting, and boating safety. NDOW’s wildlife and habitat conservation efforts are primarily funded by sportsmen’s license and conservation fees and a federal surcharge on hunting and fishing gear. Support wildlife and habitat conservation in Nevada by purchasing a hunting, fishing, or combination license. For more information, visit www.ndow.org.