been documented in Montana. This type occurs in 

 small patches on the RNA in relatively broken 

 topography in north-facing coulee settings. Creeping 

 juniper Qurdperus horizcmtalis) is documented to occur 

 with bluebunch wheatgrass {Pseudoroegneria spicata) 

 and a number of other graminoids such as sun sedge 

 (Carex inops) and threadleaved sedge (Carex filifolia) . 

 Juniperus horizontalis is often associated with 

 intrinsically erosive sites and such may be the case 

 here. [Plot NHMTECCR97BH0004] 



This site is a significant representation of dissected 

 plains and the semi -open ravine systems on the 

 Missouri Breaks, with all the landforms and vegetation 

 typical of the Fox Hills Sandstone. It offers a larger 

 array of xeric ravine habitat and associated vegetation 

 than the Spring Creek RNA, and complements the 

 combination of the Missouri River Bottomlands RNA 

 and the Two Calf- Douglas-fir RNA as a Missouri 

 River Breaks landscape on Bearpaw Shale over 60 miles 



Pascopyrum smithii - Nasella viridula Herbaceous 



Vegetation 



[PASSMI-NASVIR] 



western wheatgrass - green needlegrass grassland 



This is a minor type, confined to swales and north- 

 facing slopes, usually on toe-slope positions. Both 

 dominants (also indicators of the type) are strongly 

 preferred forage by cattle and none of the sites had 

 green needlegrass (Nasella viridula) cover values even 

 approaching those registered on some sites (within the 

 region) where grazing has been less intensive. Needle- 

 and-thread {Stipa comata) , threadleaf sedge (Carex 

 filifolia) and blue grama {Bouteloua gracilis) are poorly 

 represented on these sites 



Note: With the incised drainages, considerable 

 topographic relief and some variety of parent materials 

 there are numerous habitats, including some badlands 

 topography, that was not adequately surveyed for 

 community types. 



SPECIES: 



Montana plant species of special concern were not 

 found. There are conmion species that might be 

 mistaken for rare species, including green milkweed 

 {Asclepias viridiflora) and linear-leaf four o'-clock 

 {Mirabilis linearis.) There are a few rare species that 

 were sought unsuccessfully on sandy habitat as found 

 on the south-facing slopes, including little Indian 

 breadroot {Psoralea enneandra) a species that blooms 

 early in the growing season, and nine-anther dalea 

 (Dalea enneandra) which blooms late in the growing 

 season. Review of twinpod {Physaria spp.) specimens 

 collected on-site and in herbaria are pending. The 

 widespread species, common twinpod (Phjsaria 

 didymocarpa) , has been documented from Garfield 

 County (Booth and Wright 1966). The regional 

 endemic species, double twinpod (Physaria brassicoides) , 

 has recently been documented from Carter County 

 (Vanderhorst et al 1998). 



OVERALL BIODIVERSITY SIGNIFICANCE: 



Though none of the plant associations are rare or 

 unusual at this location in the state, there is a high 

 vegetation and plant species diversity as supported by 

 the broken topography, sheltered north-facing slopes, 

 array of substrates, and seasonal water. As such, it 

 represent a typical Missouri River Breaks gradient. 



Wildlife values were not evaluated, though the RNA 

 with its diversity of habitats is presumed to complement 

 the overarching wildlife values of original game 

 preserve and national wildlife refuge establishment. 

 Overall values are enhanced by continuity with native 

 vegetation on all upland borders. 



LAND USE: 



This landscape has been grazed in the past and the 

 Rocky Mountain Juniper Qurdperus scopulonim) is likely 

 to have been cut for fencing. Grazing practices have 

 contributed to the infestation of armual brome grasses 

 like Bromus japonicus (Japanese brome) and B. tectomm 

 (cheatgrass) which is quite apparent in the western 

 portion of the RNA on the uplands. The area receives 

 at least light hunting use. 



MANAGEMENT COMMENTS: 

 There are almost no noxious weeds, except for Canada 

 thistle (Cirsium arvense) at a springhead. Yellow 

 sweetclover (Melilotus officinalis) is currently restricted to 

 shale slumps in lower ravine slopes, but has the 

 potential to occupy most of the terrain as judging by 

 results from other landscapes. The shores do not have 

 Tamarix chinensis (tamarisk) . Perhaps the most 

 abundant non-native species are the annual bromes, 

 mentioned previously. 



Fire and bison grazing were driving factors with which 

 this landscape evolved. Reintroducing fire as a 

 management tool is an option on the rolling uplands 

 provided that it was planned to favor the natives over 

 the annual brome populations. With continued fence 

 maintenance, this RNA provides a good rangeland 

 reference and ecological baseline. 



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