Big Horn Fishing Access Site 



This site occupies bottomlands along the Big Horn River. 

 Although it is in the vicinity of Big Horn Canyon and the 

 Pryor Mountains, areas known for their many endemic and other 

 rare plant species, the site has low potential for hosting 

 MPSSC. The native vegetation, most notably sagebrush 

 grasslands {Artemesia cana/Bouteloua gracilis ?) , has been 

 mostly replaced by weedy hayfields. Cultivated species in 

 these fields include Agropyron cristatum (crested wheat) , 

 Bromus inermis (smooth brome) , Medicago sativa (alfalfa) , and 

 Melilotus officinale (sweet clover) . Weedy adventive taxa 

 include Cirsium arvense (Canada thistle) , Bromus tectorum 

 (downy brome) , Lactuca serriola (prickly lettuce) , and 

 Sisymbrium altissimum (tumble mustard) . The understories of 

 the floodplain woodlands are either mowed or weedy. 

 Floodplain thickets along the river are dominated by a mixture 

 of woody natives (Salix spp. , Eleagnus commutatus and Rhus 

 trilobata) and exotics (Eleagnus angustifolia and Tamarisk 

 chinensis) . A small swampy area is dominated by Typha 

 latifolia (cattails) . It was thought that this wetland might 

 be potential habitat for Eupatorium maculatum or other 

 sensitive species, but none were found. 



As with many of the lowland fishing access sites, native 

 plant taxa, especially in the open and understory habitats, 

 have been almost entirely replaced by adventives. Precluding 

 expensive and perhaps impossible efforts to reestablish the 

 native communities, the best alternative at many of these 

 sites may be to manage the open areas as mowed turf or 

 hayfields. Weed control at these sites, provided it is aimed 

 at introduced weedy taxa, is not likely to have adverse impact 

 on MPSSC or the native flora in general. 



Bluewater Springs Trout Hatchery 



Located along Bluewater Creek in the foothills of the 

 Pryor Mountains, this site hosts several native plant 

 communities, along with aggressive weeds and at least one 

 MPSSC, Eupatorium maculatum. For this reason it is strongly 

 recommended that further sensitive plant surveys be conducted 

 before weed control measures are taken and that weed 

 management plans be designed which minimize impacts on species 

 of concern and native communities. 



The species of concern, commonly called Joe Pye Weed, is 

 found in the wetland thickets around Big Bluewater Spring and 

 along the creek (Figure 1) . Woody dominants in these thickets 

 include Betula occidentalis (water birch) , Salix drummondiana 

 and other Salix spp. (willows) , Ribes spp. (currants) , Cornus 

 stolonifera (dogwood) , Eleagnus angustifolia (Russian olive) , 

 and Tamarisk chinensis (salt cedar) . Herbaceous associates 

 include Solidago canadensis , Scirpus acutus , and Thalictrum 

 dasycarpum. Introduced weeds directly associated with the 

 species of concern are Cirsium arvense (Canada thistle) , 



