Results 



The Slim Buttes region of northwest South Dakota 

 is an excellent example of untilled, intact 

 Northwestern Great Plains or Northern Great 

 Plains Steppe. The extent of some of these intact 

 prairies and quality of the landscape rivals or 

 exceeds landscapes that I have personally seen in 

 Northwestern Great Plains reference sites of 

 southeast Montana. One of the most impressive 

 areas includes the landscape of the South Fork of 

 the Grand River watershed, which exhibited high 

 integrity at the landscape level and at the local 

 stream-reach scale. We identified fish and 

 macroinvertebrate communities with high 

 ecological integrity within 5 Prairie Aquatic 

 Ecological Systems (AES) during this study: 

 Medium Prairie River (AES B005), Northwestern 

 Great Plains Prairie (AES COOS) and Intermittent 

 Prairie Streams (AES code D005), Intermittent 

 Fishless Prairie Stream (AES code E005) and the 

 Northwestern Great Plains Perennial Spring (AES 

 code S005) (Table 4). 



Habitat Evaluations 



Overall, 11 of 1 8 sites had good to excellent habitat 

 quality ranked by at least one of the assessment 



methods (Table 5). Highest site habitat scores 

 using both the EPA RBP (200 max. score) and 

 BLM (24 max. score) habitat assessment methods 

 were measured in the South Fork Grand River 

 basin. South Fork Grand River Sites # 1 & #2 had 

 reference site conditions for a Great Plains Prairie 

 Stream with EPA RBP scores of 188 and 189, 

 respectively (Table 5). Most stream sites visited in 

 the Grand River basin had higher than average 

 landscape integrity measured at the local reach- 

 scale. All sites in the Little Missouri River basin 

 ranked high for a Medium-Large Prairie River. The 

 North Fork Moreau River site #2 had the highest 

 integrity of sites visited in the Moreau basin. Sites 

 in the South Fork Moreau River scored lowest in 

 habitat integrity. South Fork Moreau site #3 near 

 Hoover showed moderate integrity but the water 

 quality parameters show impairment. The water 

 quality parameters conductivity and turbidity both 

 increased at the downstream reaches of a stream 

 series. Two conductivity values that would exceed 

 DEQ impairment standards in Montana were 

 recorded at the South Fork Moreau River #3 and 

 the Crooked Creek sites (>3,000y4s). 



Table 4. Aquatic Ecological System types, biological community groups (SPA) associated with the defined 

 aquatic ecological communities and occurrences in the Slim Buttes Study Area. 



'^See Appendix E for Fish Species Assemblages 



* See Appendix C & D for Macroinvertebrate species groups 



**Nuniber of sites visited with data collected 



9 



