|Scientific Name:||Etheostoma nianguae|
|Species Authority:||Gilbert & Meek, 1887|
|Red List Category & Criteria:||Vulnerable B1ab(ii,iii,v)+2ab(ii,iii,v) ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
This species is listed as Vulnerable because its extent of occurrence is less than 20,000 sq km, area of occupancy is less than 500 sq km, the species occurs in 8 locations, and habitat quality (and probably the species' distribution and abundance) are subject to continuing declines.
|Range Description:||This darter is rare and localized in north-flowing tributaries of the Osage River, Missouri River basin, Missouri (Figg 1993, Pflieger 1997, Page and Burr 2011): Maries River and Little Maries Creek (Osage County); Big Tavern Creek, Barren Fork, Brushy Fork, and Little Tavern Creek (Miller County); Niangua River and Greasy Creek (Dallas County); Little Niangua River (apparently the most secure population), Starks Creek, Thomas Creek, and Cahoochie Creek (Camden, Hickory, and Dallas counties); Pomme de Terre River (Benton, Green, and Webster counties); Brush Creek and Panther Creek (Cedar and St. Clair counties) (possibly extirpated); Bear Creek; and the North Dry Sac River (Polk County). Formerly the species was more widespread and abundant within these river systems.|
Native:United States (Missouri)
|Range Map:||Click here to open the map viewer and explore range.|
Eight of the 10 known populations are extant (Mattingly and Galat 2002).
This species is rare and localized (Pflieger 1997); total population was estimated at less than 1,000 in 1969.
Stream miles of occupied habitat declined from 142 miles in the 1970s to not more than 115 miles in the 1990s, and fish densities appeared to decline in most populations. Figg and Bessken (1995) commented that survey results suggest "a continuing decline in populations."
Pflieger (1997) stated that most populations seem to be declining or have disappeared.
|Habitat and Ecology:||
Habitat includes rocky pools and runs of clear creeks and small to medium rivers (Page and Burr 2011); this darter avoids headwater creeks and large Ozark rivers. Most of the year it occurs in shallow pools and runs having slight currents and gravel or rock substrates (Lee et al. 1980). It may favour "stream reaches with relatively intact banks and riparian corridors, and less agricultural development" (Figg and Bessken 1995). Spawning occurs on swift gravel riffles; eggs are laid while the female is buried in gravel.
In the Little Niangua River, darters were found disproportionately in reaches (1) located in the mid- to lower sections of the stream (elevations of 230-250 m), (2) with riffles spaced 40–80 m apart or with gradients of 2–4 m per km, and (3) with relatively uneroded banks; within occupied reaches, darters were commonly in microhabitats 20-40 cm deep with substrate particles averaging 3–5 cm in diameter (Mattingly and Galat 2002).
See Mattingly and Galat (1998, 2002) for further information.
|Use and Trade:||This species is not utilized.|
|Major Threat(s):||Construction of Truman Reservoir fragmented populations. Highway and bridge construction, stream channelization, removal of woody riparian vegetation, overgrazing, livestock production, and agriculture have degraded habitat quality, largely through increased siltation and sedimentation. Predatory fishes (rock and spotted bass) introduced into reservoirs could reduce darter populations if the non-native species invade tributary streams. In-stream gravel mining was an on-going threat in the early 1990s (Figg 1993).|
Mattingly and Galat (2002) provided models that can be used to guide conservation and recovery efforts by ranking sites based on their relative suitability for Etheostoma nianguae. Sites near or downstream from gravel mining areas may be less than optimal as preserves.
Recovery goal is establishment or discovery of additional populations to bring the total to twelve. See Mattingly and Galat (1998).
The relationship between environment and reproductive biology needs further study. Further surveys are needed to document current distribution and abundance. The entire basin should be protected through acquisition easement or registry. See Figg (1991, 1993) for brief summaries of steps taken to facilitate recovery. Recovery plan was completed and approved in 1989. See also Mattingly and Galat (1998).
|Citation:||NatureServe 2013. Etheostoma nianguae. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 31 July 2015.|
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