Like no other place on earth: Ash Meadows, a Biological Oasis.[ILLUSTRATION OMITTED]
Located in the middle of nowhere, according to most of our visitors, is Ash Meadows National Wildlife Refuge. An area just over 23,000 acres (9,300 hectares), it supports at least 26 species of plants and animals that cannot be found anywhere else on earth. In fact, the Ash Meadows ecosystem supports the highest concentration of endemic species in the continental United States. The refuge contains the largest oasis of springs within the Mojave Desert, which is the driest region in North America, and it was also one of the first sites in the nation to be designated as a Wetland of International Importance. Never heard of Ash Meadows? We know. Few people have, and you won't find it using your GPS.
As you leave the glitz and glamour of Las Vegas, the Nevada landscape becomes a dry, vast, and sparsely populated desert. This is not a place where you would ever expect to see rare flowers, hundreds of species of birds, and fish that swim in Caribbean-blue spring pools. Most tourists drive on past by the refuge entrance signs toward a more famous place, the nearby Death Valley National Park.
Prior to 1960, five endemic fishes were known to exist within the Ash Meadows ecosystem. Around that time, their unusual habitats began to be altered extensively by farming, mining, water diversion, artificial dams and channels, extensive removal of native vegetation, and the introduction of non-native aquatic species. These impacts are blamed for the extinction of the Ash Meadows poolfish (Empetrichthys merriami).
Receiving only a few inches of rain each year, the Ash Meadows ecosystem is supported by an aquifer of "fossil" water left behind from the Pleistocene epoch, a time when the region was wetter and crossed by interconnected lakes and rivers. One of its most famous surviving residents is the Devils Hole pupfish (Cyprinodon diabolis), which exists only in a single water-filled cavern, Devils Hole. This small fish was already endangered when corporate farming in the Ash Meadows area began to grow to massive proportions in 1967. Large-scale farming in such a dry area requires intensive pumping of ground water for irrigation. As the aquifer was depleted, the water needed to support the Devils Hole pupfish began to decline. After a 1971 federal court injunction against over-pumping the aquifer, the U.S. Supreme Court guaranteed sufficient water levels for the Devils Hole pupfish permanently in a landmark 1976 ruling. But the decision applied only to the Devils Hole pupfish, since at the time it was the only Ash Meadows species listed as endangered. The ecosystem's other unique animals and plants went unprotected.
In the late 1970s, the landowner, Cappaert Enterprises, determined it no longer had enough water to continue large-scale farming, so it decided to sell the land. In 1980, a private company purchased the property with the intent to subdivide it into 34,000 residential lots. When development began, important habitats suffered further degradation and the aquifer was again threatened, along with the species that depended on it.
In 1982, the U.S. Fish and Wildlife Service published a temporary emergency rule listing two endemic fishes, the Ash Meadows Amargosa pupfish (Cyprinodon nevadensis mionectes) and the Ash Meadows speckled dace (Rhinichthys osculus nevadensis), as endangered species. This halted additional habitat damage for 240 days, allowing time to determine if final Endangered Species Act (ESA) protection was warranted. In 1983, both fish species received final ESA protection and The Nature Conservancy negotiated a purchase of the property. The following year, the Service purchased the land from the Conservancy to create Ash Meadows National Wildlife Refuge. A recovery plan for the area was developed in 1990 to restore habitats and recover the listed species, which by then included four endangered fishes, seven threatened and endangered plants, and a threatened aquatic insect, the Ash Meadows naucorid (Ambrysus amargosus).
Restoration and Recovery
Back in the 1930s, Ash Meadows speckled dace inhabited at least 13 springs in the area, but by 2009 only two viable populations remained. The Ash Meadows Amargosa pupfish and the Warm Springs pupfish (Cyprinodon nevadensis pectoralis) survived in most of their historic habitat but faced lingering threats. Even today, new threats have emerged from pumping and aquifer drawdown in the basin outside the boundary of Ash Meadows NWR.
All of the pupfish species, which reach about the size of your thumb, live for only one to three years. The males, a silvery- iridescent blue, can be seen darting among the algae. This behavior was originally mistaken for the kind of playfulness shown by puppies, hence the name pupfish. In reality, the males are guarding their small territories. But even this display of bravado is no match for invasive species such as western mosquitofish (Gambusia affinis), red swamp crayfish (Procambarus clarkii), and sailfin molly (Poecilia latipinna), which have became established in most springs and compete for the same resources needed by native species. Eradicating invasive species is challenging. Chemical treatments can be lethal to native invertebrates, and physical removal methods, such as netting, are time consuming with usually marginal success. A new plan for restoring the unique creatures of Ash Meadows was needed, so in 1995 biologists began working on an innovative strategy.
Because it is unlikely that invasive species can be eradicated from the ecosystem, the new management approach is to remove as many nonnative fish as possible using traditional methods, such as trapping, while restoring habitats to conditions that favor native fish over non-natives. Focusing on the most numerous invasive species, sailfin molly and mosquitofish, biologists began extensive research on historical habitats, restoration processes, and fish behavior. Among the habitat characteristics they studied were water depth, velocity, and temperature at various sites in the system. The findings guided managers in choosing the designs for habitat restoration.
For example, if invasive species flourish in slower, cooler water, habitat improvements include measures to restore outflows that retain warmer temperatures with flow rates conducive to native species. The success of this strategy was validated in 2003, when the percentage of native species finally surpassed, by a large margin, the invasive species.
In 1997, habitat restoration began at Kings Pool Spring, an area severely affected by the former farming activities. Before the project, Ash Meadows Amargosa pupfish comprised only 23 percent of the spring's fish population, but they rose to 91 percent after the restoration. The entire process took 4 years. Since 2008, 10 populations of invasive aquatic species (e.g., red swamp crayfish) have been eradicated from six spring systems in Ash Meadows.
Today, Tomorrow, and Beyond
Reestablishing a healthy ecosystem and historic populations of native species is challenging, but refuge managers have achieved substantial success. In 2010, four miles (6.5 kilometers) of the Fairbanks Spring outflow were rehabilitated to promote the restoration of Carson Slough, which was the largest wetland in southern Nevada before it was drained and mined for its peat. The habitat once again supports the endemic Fairbanks springsnail (Pyrgulopsis fairbankensis), the Ash Meadows Amargosa pupfish, and the previously extirpated Ash Meadows speckled dace. Speckled dace disappeared from the Fairbanks Spring system in the 1950s but were reintroduced in 2010. Post-project monitoring reveals that all three species are well established and reproducing.
The successful reestablishment of speckled dace into the Fairbanks system would not have been possible without numerous volunteers and partners. Funding was obtained by the Desert Fish Habitat Partnership, a group representing state and federal resource agencies, tribes, conservation organizations, and other interests. Habitat restoration continues at Ash Meadows NWR. There are plans to reintroduce Ash Meadows speckled dace into other spring systems the fish once occupied.
The desert fish of Ash Meadows are not the only native species benefitting from habitat restoration; many trees and other plants are beginning to flourish. The area also is frequented by a wide diversity of migratory birds. At least 239 bird species have been recorded in Ash Meadows, in addition to 27 mammals, more than 20 reptiles, five amphibians, and more than 330 flowers and shrubs.
Given the high rate of endemism in the Ash Meadows area, it is not surprising that species may still be discovered. In 2009, we learned of two new species of bees that may be unique to Ash Meadows. One can only imagine the fate of these and other unusual creatures if conservation efforts to protect endangered species had not been successful.
For detailed information on habitat restoration as a means to control non-native species, refer to an article by Scoppettone, et al., "Habitat Restoration as a Means of Controlling Non-Native Fish in a Mojave Desert Oasis," published in the June 2005 edition of Restoration Ecology (Vol. 13, No. 2, pp. 247-256).
Cyndi Souza, a visitor services specialist at Ash Meadows NWR, can be reached at firstname.lastname@example.org or 775-372-5435. Darrick Weissenfluh, a fish biologist at Ash Meadows NWR, can be reached at 775-372-5435 or email@example.com.