The major threat to the Amargosa Canyon speckled dace is the potential dewatering of its unique habitats, the Amargosa River and tributaries, combined with interactions with invasive species (Table 1).
Agriculture, rural residential development, urbanization. These three categories of threat are lumped together because together they result in by water withdrawals from both distant and near points on the aquifer that feeds the Amargosa River. The Amargosa Aquifer supplies the springs of Ash Meadows, Nevada, and the Amargosa River to which they are tributary (Riggs and Deacon 2002). It receives much of its recharge flow from areas on the northern and northeastern slopes of the nearby Spring Mountains but, along with springs on the eastern side of Death Valley, is partially dependent on regional groundwater movement through large, ancient aquifers that extend into western Utah and central Nevada (Dettinger et al.1995, Deacon et al. 2007). In order to slake the ever-thirsty city of Las Vegas, the Southern Nevada Water Authority (SNWA) proposed to mine large quantities of this water from several different valleys which lie within the Ash Meadows groundwater basin (Breen 2004, Southern Nevada Water Authority 2004, Vogel 2004). At the present time, farming operations and human settlements in the Amargosa region are withdrawing increasing amounts of water from the aquifer and groundwater pumping from the regional aquifer already is producing declines in water stored in the aquifer, noticeable as in the decline of the water level of the closely-monitored Devils Hole, Nevada (habitat of the endangered Devil's Hole pupfish, Cyprinodon diabolis) (Riggs and Deacon 2002, Bedinger and Harrill 2006). If the Amargosa region water withdrawals continue to increase and if Las Vegas proceeds with its planned withdrawals, it is highly likely that the Amargosa River will have its flows greatly reduced or even disappear completely during dry years. Already, diversions of springs and outflows on private land in the Tecopa area have reduced local flows in the river and local pupfish populations as well. With an increasing human population in Tecopa and the upper Amargosa Valley, demand for water and protection from floods is increasing. The latter can result in channelization of sections of the river.
Although most land in the Amargosa Canyon is owned by The Nature Conservancy or the Bureau of Land Management, critical habitat for the dace includes a large tract of privately owned land, China Ranch. This ranch contains the headwater area of Willow Creek. Diversion of water from the creek or other alterations affecting water quality could cause dace populations to decline further.
Grazing. While water is diverted from the stream directly for cattle and pumped to grow alfalfa, there are enough cows scattered through the dace region to affect streambanks and riparian vegetation, at least locally. Cows tend to concentrate around water to their effects can be disproportionate to their actual numbers.
Recreation. The deserts of California receive high recreational use, especially from people coming from the urban areas of the southern California. Much of this recreation is focused on vehicular use, both off-road and on the hundreds of old mining and other roads that lace the landscape. Such use is hard to regulate, much less keep track of, so even though rules are in place banning use of off-road vehicles from sensitive areas, destruction of riparian and streambed habitat by recreational users still happens. This is always a threat to the Amargosa River and its watershed.
Alien species. A more immediate threat to the dace is the presence of alien fish species in the quiet-water habitat it prefers. In particular, western mosquitofish may be reducing its numbers through competition and predation. The presence of large numbers of mosquitofish, which are omnivorous like the dace, indicates they are consuming resources otherwise available to the dace. Because much of its habitat is on public land, additional introductions of undesirable species that may affect dace populations are possible.