Group SPA #1-Large Warmwater River Assemblage. This community was dominated by larger, 

 warmwater river fisiies. including many of our natives, such as the sauger (Stizosledium canadanse), big 

 (Ictiobus cyprinellus) and smallmouth buffalo (Ictiobus bubalus) and the emerald shiner {Notropis 

 atherinoides), but also included fish species introduced to the Missouri and Yellowstone drainages: 

 smallmouth bass (Microplerus dolomieuX perch {Perca flavesceris), walleye {Slizosledium vitreum) 

 and northern pike i^Esox lucius). Warmwater generalists such as sunfish, bass and golden shiners are 

 also closely associated with this group in the Yellowstone drainages. As a general rule this assemblage is 

 found in larger, low gradient, glide-pool main branch streams (4* -6* order) with an average summer 

 temperature of 20-25°C. The 2 native ictalurid species, the stonecat {Noturus Jlavus) and the channel 

 catfish {Ictalurus punctatus), also cluster in this assemblage. This community can be found over a wide 

 range of low-elevation landscapes within all three ecoregions of the study area. 



Group SPA #2- Medium Warmwater River Assemblage. Most of the medium to large warmwater 

 river cyprinid species occur in this species assemblage (flathead chub, Platygobio gracilis; sand shiner, 

 Notropis stramineus; plains minnow, Hybognathus placitus: western silvery minnow, Hybognathus 

 argyritis\ as well as the shorthead redhorse {Moxostoma macrolepidotum), river carpsucker 

 {Carpiodes carpio), the exotic carp (Cyprinus carpio\ the introduced green sunfish {Lepomis 

 cyanelhis) and black bullhead (Ameiurus melas). This species assemblage occurs in most of the 

 Medium Prairie Rivers of Montana. The channel catfish & stonecat could co-occur within SPA 1 or 2 if 

 proper habitat requirements are met, such as deep, side channel pools and large structures for hiding 

 (large cobbles and woody debris). 



Group SPA #18-Brook Stickleback Assemblage. Includes the brook stickleback {Culaea 

 incomlans), brassy minnow {Hybognathus hankinsoni) and Iowa Darter (Etheostoma exile). This 

 species assemblage is found most commonly associated with small Northwestern Great Plains prairie 

 streams (AES C006 and D006) with relatively clear water, large pools and vegetative cover. 



Group SPA # 20-Core Prairie Stream Assemblage. Includes an assemblage of small native prairie 

 fish that form the core community for perennial prairie streams (AES code COOS in the Northwestern 

 Great Plains and C006 in the Northern Glaciated ecoregions. Included in this assemblage are the 

 longnose dace {Rhinichthys cataractae), lake chub {Couesius plumheus), fathead minnow (Piniephales 

 notatus) and the white sucker {Catostomus commersoni). The lake chub and fathead minnow 

 (Piniephales notatus) are species that occur in similar habitats of intermittent prairie stream systems 

 D005 and D006. although we found no lake chubs in any of the Slim Butte streams. As the small prairie 

 streams dominated by this core species assemblage proceed downstream and increase stream order and 

 linkages, they develop into the Medium Prairie River Community including the plains and western silvery 

 minnows (plains minnow is more tolerant of current, while the western silvery will be found in the 

 protected silted side channels out of the current), and the sand shiner (in slower pools of 8005 or larger 

 streams with gravelly/sandy bottoms), and the exotic carp and introduced black bullhead. 



Appendix E- 1 



