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

Authors: David J. Syzdek

Year: 2013 (xlv)

Abstract

The Moapa Warm Springs in southern Nevada is a regional spring complex that is the headwaters of the Muddy River. These naturally-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 steadily increasing despite a wildfire in 2010 that burned over 600 acres of woodland near many of the streams that contain dace. 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. Moapa dace numbers are currently at a 19 year high and efforts continue to improve dace habitat, improve stream connectivity, and monitor for invasive species.