from the park website:
The Moapa Valley National Wildlife Refuge was established September 10, 1979, to secure habitat for the endangered Moapa dace, a small fish commonly found throughout the headwaters of the Muddy River system. In the last decade, dace populations have declined due to habitat destruction and modification.
Competition with introduced species such as the mosquitofish and shortfin molly have also added to the dace's decline. The Moapa White River springfish, however, compatibly coexists with the dace.
The refuge is located on 117 acres in northeastern Clark County and is approximately 60 miles north of Las Vegas, Nevada. Dace habitat on the refuge consists of stream channels supported by six thermal springs emerging near the center of the refuge.
Due to its small size, fragile habitats, and on-going restoration work, the wildlife refuge is only open Saturday and Sunday, 9 a.m. to 3 p.m., from Labor Day through Memorial Day. The wildlife refuge is closed from Memorial Day until Labor Day.
The Moapa Valley National Wildlife Refuge (MVNWR) is a protected wildlife refuge administered by the U.S. Fish and Wildlife Service, located in the Warm Springs Natural Area in the Moapa Valley of Clark County, Nevada. The refuge is east of Death Valley and 60 miles (97 km) northwest of Las Vegas, Nevada.
The 106-acre (43 ha) refuge was created as part of the larger Desert National Wildlife Refuge Complex, on September 10, 1979. The Desert National Wildlife Refuge complex also includes the Ash Meadows National Wildlife Refuge, the Desert National Wildlife Refuge, the Pahranagat National Wildlife Refuge, and the Amargosa Pupfish Station.
Moapa dace fishThe refuge was established to provide and protect the habitat of the endangered species of Moapa dace of which about 1,900 exist in the Muddy River area. The habitat on the refuge consists of stream channels feeding the Muddy River including six hot springs emerging near the center of the refuge.
Since the 1990s the dace have been in decline mainly due to habitat destruction and modification. Nearby groundwater pumping has decreased stream discharge and streamflows and decreased dace habitat. Competition with introduced species such as the mosquitofish and shortfin molly have also added to the dace's decline.
In August, 2005 the National Wildlife Refuge Association and again in September, 2005 the Defenders of Wildlife listed the Refuge as one of the 10 most endangered refuges in the United States.
One of the areas of the MVNWR, now called the “Plummer Unit,” was a public, family-owned recreational park. A former general manager of the Aladdin Hotel in Las Vegas, Bob Plummer, purchased a 100-acre (40 ha) parcel of land with an oasis of California Fan Palms (Washingtonia filifera) and natural hot springs. It became known as "Desert Oasis Warm Springs." During the 1970s and 80's he converted the property into a spa, resort and retreat enjoyed for over several decades by Las Vegas area families, with fond memories at the "Jewel in the Desert". By 1990 the resort changed from an open-to-the-public venue into a private time-share spa.
The Desert Oasis Warm Springs Resort continued to operate until a wildfire swept through the area in 1994. After the fire, the resort remained unused until 1997 when the property was purchased by Del Webb Inc., turned over to the Fish and Wildlife Service, and incorporated as part of the Moapa Valley National Wildlife Refuge.