|Scientific Name:||Etheostoma cragini|
|Species Authority:||Gilbert, 1885|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
Listed as Near Threatened because the species nearly qualifies for Vulnerable status; area of occupancy is less than 2000 sq km and may be less than 500 sq km, number of locations is at least 12 (one location is defined as one watershed as defined by USFWS 2011), population size varies and may or may not exceed 10,000, and distribution and abundance apparently are undergoing a slow decline.
|Range Description:||The range includes the Great Plains region of southeastern Colorado, southwestern and southcentral Kansas, and northwestern Oklahoma, and the Spring, Neosho (Grand), and Illinois river drainages of the Ozark Plateau region in southwestern Missouri, southeastern Kansas, northeastern Oklahoma, and northwestern Arkansas. Localized populations occur in the Arkansas River drainage in southeastern Colorado (upstream to El Paso County) (Miller 1984), southern Kansas (mostly south-central Kansas south of the "big bend" of the Arkansas River; Cross and Collins 1995), northern Oklahoma (mainly in the Grand River system in the northeast and the Cimarron River and tributaries in the northwest; Pigg and Gibbs 1994, Miller and Robison 2004), southwestern Missouri (Pflieger 1997), and northwestern Arkansas (Hargrave and Johnson 2003). Populations in Colorado are now isolated from the nearest populations in Kansas and Oklahoma, but it is likely that the distribution was continuous prior to Euro-American settlement. The largest remaining populations appear to be in southwestern Missouri, where the species occurs in the Spring River system; it occupies almost the entire lengths of the Spring River, Shoal Creek, and Center Creek and becomes progressively more abundant toward the headwaters (Pflieger 1997).
Populations are currently disjunct from each other on a watershed scale due to anthropogenic effects, resulting in gaps of unsuitable habitat limiting or preventing dispersal (USFWS 2011). Unsuitable habitat types include long reaches of large mainstem rivers, long reaches of streams with no flow, long reaches of streams with no suitable habitat, and drainages segmented by dams and their resulting reservoirs (USFWS 2011).
|Range Map:||Click here to open the map viewer and explore range.|
This species is represented by at least 12 metapopulations in five states. It has been found in approximately 164 localities (USFWS 2011).
Pflieger (1997) mapped a few dozen localities in Missouri. Surveys in 1990-1991 in Missouri obtained 430 specimens at 32 of 61 sampled localities (see Pflieger 1997).
Surveys in 1994–1997 in south-central Kansas and adjacent Oklahoma recorded this species from 67 of the 108 localities that were sampled within the general historical range of the species; the species was found at 26 (67%) of 39 historic localities and at 41 previously unrecorded collection sites (Eberle and Stark 2000).
This species was recently found in three locations in Arkansas, one of which was represented by only one individual; between 1979 and 2001, it was found at 9 locations (Hargrave and Johnson 2003).
Total adult population size is unknown but may exceed 10,000. Subpopulations vary from 10s to low 1,000s. Historically this fish apparently was never very common.
In a 1997 survey in Arkansas, two populations of E. cragini had an estimated population size of 546 and 79 individuals; a third site was represented by only one captured individual (Hargrave and Johnson 2003). In Missouri, surveys in 1990–1991 yielded 430 specimens; this species was third in abundance among 13 species of darters in the collections (Pflieger 1997).
Overall, the species still occupies all major watershed units where it was present at the time it was originally designated a candidate species in 1991. However, there has been some range contraction identified in the Chikaskia and Medicine Lodge basins. Populations within three watershed units have shown recent declines and/or elevated levels of threat. In the western portion of the Cimarron basin in northwestern Oklahoma and southwestern Kansas, several tributaries have dried and lost isolated occurrences of the Arkansas darter. This contraction of range within the Cimarron basin is expected to continue. In the Rattlesnake Creek watershed in central Kansas, the last identified collection of the species was in 1997; however, additional sampling is needed. In the Illinois River watershed in northwestern Arkansas, several robust populations continue to exist. However, urban/suburban development is rapidly occurring that could severely impact the species in this watershed. Source: USFWS (2011).
The range in Arkansas has diminished since 1983; in general, large populations (population size greater than 500) persisted but small populations (population size less than 100) did not (Hargrave and Johnson 2003). The distribution has also declined in the western portion of the range on the High Plains (Miller 1984, Pigg and Gibbs 1994, Eberle and Stark 2000).
Based on surveys conducted in 1994–1997, the Arkansas darter still occurred throughout most of its historical range in south-central Kansas and adjacent Oklahoma; the species was also collected within what had been a large gap in the distribution in the upper Salt Fork Arkansas River Basin (Eberle and Stark 2000). The overall condition of Arkansas darter populations in south-central Kansas appeared to be reasonably stable (Eberle and Stark 2000).
Distribution and abundance appear to be stable in Missouri, where the largest remaining populations of the species may occur (Pflieger 1997).
Current range-wide trend (past 10 years) is uncertain, but distribution and abundance likely are slowly declining (see USFWS 2011).
Recent sampling of 15 historical sites in Colorado produced collections of E. cragini in 14 sites; overall, the species appears to be relatively stable within Colorado, though populations in the Arkansas river floodplain have persisted and even thrived, while those in the more upland portions of the species' range, which were formerly considered the most robust, have held steady or perhaps lost ground (Crockett 2010).
|Habitat and Ecology:||Preferred habitat is spring-fed headwaters and creeks with cool, clear, shallow water, slow current, and herbaceous aquatic vegetation such as growths of watercress or other aquatic plants; often in pools with sand, fine gravel, or organic detritus substrate; sometimes in turbid water away from springs (Lee et al. 1980, Cross and Collins 1995, Hargrave and Johnson 2003, Miller and Robison 2004, Page and Burr 2011). Eggs are laid in gravel bottoms.|
USFWS (2011) reported the following:
"Populations are impacted by decreased water quantity in western portions of its range, including the Cimarron basin of northwestern Oklahoma and southwestern Kansas; Arkansas River tributaries in eastern Colorado; and the upstream portion of the Rattlesnake Creek basin. Stream dewatering and decreased flows have occurred due to groundwater pumping in some of these areas. In this portion of the species' range the intensity and overall threat level are considered moderate to high. In the remainder of the middle Arkansas drainage (Chikaskia, Ninnescah, Salt Fork Arkansas, Medicine Lodge, and eastern Cimarron basins), the possibility of future expanded irrigation for agricultural production and increased ethanol processing could increase water quantity impacts. Here, the intensity and overall threat is believed low to moderate, but could increase if higher levels of pumping occur. Precipitation patterns and drought cycles also exacerbate the threat of decreased flows and dewatering. Water quality degradation also impacts the species in portions of its range.
"Water quality degradation occurs from a variety of sources, including: chemical and sediment runoff from urban, rural, and agricultural sources; localized intensive livestock grazing and small feeding operations; application of animal wastes as fertilizer to cropland; salt water intrusion into groundwater due to heavy exploitation; and infrequent accidental spills from large CAFOs. However, these threats are believed to occur mainly on a localized level resulting in low to moderate intensity and overall threat.
"Urban/suburban development and its associated impacts are a significant and immediate threat to the north-western Arkansas populations and are likely to increase in significance in the southwestern Missouri and northeastern Oklahoma areas. However, threats from urban/suburban development and road and bridge construction are considered low in intensity and overall threat to populations in the middle and upper Arkansas basins.
"Invasions by exotic plants that can alter Arkansas darter habitat and water quantity (primary salt cedar, tamarisk spp.) occur in varying densities throughout the middle and upper Arkansas basins. This threat generally increases from east to west, as precipitation levels and their resulting scouring flows decrease. Throughout these areas, threat levels are considered moderate to high in both intensity and overall threat. The species' habitat in the Neosho basin areas is not presently threatened by salt cedar invasion.
"Threats to the Arkansas darter from population fragmentation and drought primarily result from its present discontinuous distribution. This isolation results mainly from anthropogenic changes to the landscape (i.e., dams, long reaches of dewatered stream channels, etc.). As future periodic droughts occur, in combination with the landscape changes and other threats, isolated spring-fed habitats are more likely to dry, eliminating localized populations. Since the species now mainly occurs in small, isolated areas in much of its range, the intensity and overall threat of isolation and protracted drought to the Arkansas darter is considered moderate to high. Climate change may exacerbate this threat by increasing the intensity and scale of spring and stream dewatering."
In Arkansas, it is possibly affected detrimentally by gravel mining (e.g., at Galey Hollow) and livestock, which may have altered habitats through changes in substrate composition and vegetative cover (Hargrave and Johnson 2003), but these fishes have been collected in turbid streams away from nearby spring sources (Matthews and McDaniel 1981, Pigg et al. 1984), suggesting some degree of tolerance for suboptimal conditions (Hargrave and Johnson 2003). In Missouri, the species "seems to be relatively secure," but anticipated increases in confined livestock production, industrialization, and urbanization may threaten it in the future (Pflieger 1997).
Cross and Collins (1995) reported that although irrigation and drought have dried much of the habitat in the western part of Kansas this darter "has somehow managed to sustain itself by finding new habitats at other sites in streams overlying the Ogallala and Great Bend aquifers as flows decline due to receding water tables." In south-central Kansas, the area of greatest concern is in the Ninnescah River Basin, where large-scale groundwater declines are possible, and the species may be vulnerable to extirpation or near extirpation, as is the situation in western Kansas (Eberle and Stark 2000).
Water quality factors limiting populations need to be investigated.
Population trend at sites affected by dewatering should be documented. Better information is needed on status in Oklahoma. Populations at protected sites should be monitored.
Further lowering of water table by ground water pumping in Kansas and Colorado should be prevented. Streams connecting spring habitats are potential corridors for dispersal and recolonization, so maintenance of both main-stream and spring habitats is important (Hargrave and Johnson 2003).
|Citation:||NatureServe 2014. Etheostoma cragini. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 29 July 2015.|
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