An Ecohydraulic Model to Identify and Monitor Moapa Dace Habitat

Abstract

Moapa dace (Moapa coriacea) is a critically endangered thermophilic minnow native to the Muddy River ecosystem in southeastern Nevada, USA. Restricted to temperatures between 26.0 and 32.0°C, these fish are constrained to the upper two km of the Muddy River and several small tributaries fed by warm springs. Habitat alterations, nonnative species invasion, and water withdrawals during the 20th century resulted in a drastic decline in the dace population and in 1979 the Moapa Valley National Wildlife Refuge (Refuge) was created to protect them. The goal of our study was to determine the potential effects of reduced surface flows that might result from groundwater pumping or water diversions on Moapa dace habitat inside the Refuge. We accomplished our goal in several steps. First, we conducted snorkel surveys to determine the locations of Moapa dace on three warm-spring tributaries of the Muddy River. Second, we conducted hydraulic simulations over a range of flows with a two-dimensional hydrodynamic model. Third, we developed a set of Moapa dace habitat models with logistic regression and a geographic information system. Fourth, we estimated Moapa dace habitat over a range of flows (plus or minus 30% of base flow). Our spatially explicit habitat models achieved classification accuracies between 85% and 91%, depending on the snorkel survey and creek. Water depth was the most significant covariate in our models, followed by substrate, Froude number, velocity, and water temperature. Hydraulic simulations showed 2–11% gains in dace habitat when flows were increased by 30%, and 8–32% losses when flows were reduced by 30%. To ensure the health and survival of Moapa dace and the Muddy River ecosystem, groundwater and surface-water withdrawals and diversions need to be carefully monitored, while fully implementing a proactive conservation strategy.

Use of Underwater Videography to Quantify Conditions Utilized by Endangered Moapa Dace While Spawning

“…Study site.-Moapa Dace spawning behavior was filmed in the furthest upstream reach of Plummer Stream, located in the Moapa Valley National Wildlife Refuge (Figure 1). This approximately 120-m, spring-fed section of stream is a northeasterly flowing tributary of the Muddy River, with a median width of roughly 1 m, stable base flow of 0.11-0.14 m 3 /s, and maximum depth of approximately 0.5-0.6 m (Hatten et al 2013; U.S. Geological Survey [USGS], unpublished data). It is situated in the Mojave Desert approximately 70 km northeast of Las Vegas, Nevada, at about 540 m above sea level.…”

“…; Hatten et al. ). Understanding the factors affecting their behavior and survival at various life stages is important for their conservation, and a life stage of particular interest for those managing rare species is the spawning period.…”

“…Many rare fishes are declining, threatened, endangered, or on the verge of extinction (Minckley and Deacon 1991;Scoppettone et al 1998;Hatten et al 2013). Understanding the factors affecting their behavior and survival at various life stages is important for their conservation, and a life stage of particular interest for those managing rare species is the spawning period.…”

Effects of Dam Removal on Tule Fall Chinook salmon Spawning Habitat in the White Salmon River, Washington

“…We created substrate maps of the project area in 2011 and 2012 with a composite of methods, utilizing GIS technology, Real-time Kinetic (RTK) GPS, underwater videography, still imagery and sketch maps (Warrick et al, 2008;Hatten et al, 2013). In 2011, the water was too deep to wade in most locations, so an underwater-video camera system was utilized with two lasers spaced 10-cm apart to determine substrate size in each video frame: RTK-GPS position Figure 1.…”

Influence of discharge on fish habitat suitability curves in mountain watercourses in IFIM methodology

“…At present, these specialists believe that the success or failure of any restoration project will depend on ongoing stream monitoring. Therefore, the aim of current research is to quantify the design characteristics of suitable habitats for river restoration (Döll and Zhang, 2010;Hatten et al, 2013;Pastuchová et al, 2010).…”