Conservation efforts for the Endangered Moapa dace, Moapa coriacea at the Warm Springs Natural Area, Clark County, Nevada

Authors: David Syzdek

Year: 2016 (xlviii)

Abstract

The Moapa Warm Springs in southern Nevada is a regional spring complex that form the headwaters of the Muddy River. These thermal springs and associated streams are habitat for an endemic suite of thermophilic aquatic species that includes the federally endangered Moapa dace (Moapa coriacea).Currently, the Southern Nevada Water Authority (SNWA) and stakeholders are undertaking recovery actions for the Moapa dace and its habitat. These include construction of fish barriers, reduction in or removal of non-native and invasive species, riparian and aquatic habitat restoration, and development of an ecological model for the Moapa dace. To facilitate recovery of the dace and other native species, SNWA purchased the 1,218-acre Warm Springs Ranch in September 2007 and designated it the Warm Springs Natural Area for conservation and environmental stewardship purposes. In 2008, Moapa dace numbers suddenly declined to a record low of 459 individuals. Working with the US Fish and Wildlife Service (USFWS), Nevada Department of Wildlife (NDOW), and the US Geological Survey, SNWA is conducting stream restoration work and intensive habitat improvements to reverse the population’s decline. Following the February 2008 nadir, dace numbers have been generally increasing. NDOW and SNWA have subsequently treated the Upper Muddy River with rotenone to control the invasive and predatory blue tilapia (Oreochromis aureus). Furthermore, stream restoration and clearing of dense stands of invasive tamarisk (Tamarix spp.) and fan palms (Washingtonia filifera), is facilitating the re-establishment of native riparian vegetation, providing prevention of future wildfires, and continued improvement in Moapa dace numbers. In 2015, a removable fish barrier was opened which allows this fish access to its entire historical range. Moapa dace numbers are currently stable and work continues to improve dace habitat, improve stream connectivity, and to monitor for invasive species.