This community was found on steep, south-facing 

 slopes eroded from acid shales that heat up under direct 

 exposure to the sun. Both of the community co- 

 dominants, long-leaved sagewort (Artemisia longifolia) 

 and few-flowered wild buckwheat (Eriogonum 

 paucifloum) are highly associated with soils derived from 

 acid shales (in Montana the Bearpaw, Colorado and 

 Clagget Shales) and bentonite. These shales are 

 intrinsically highly erosive, with sheet, rill and gully 

 erosion evident on site. Plant establishment is further 

 hindered by low pH values (< 5) and low values for 

 moisture available to vegetation. Thus, these sites are 

 very stressful for vegetation and support a suite of 

 uniquely adapted species, which individually, or in the 

 aggregate, seldom exceed 10% canopy cover (the value 

 defining the break between sparse/not sparse in the 

 NVCS) . We have placed the inventoried stand into 

 this association using the key of DeVelice et al. (1995); 

 the congruence between our plot and their description 

 of this type, regarding both envirorunent and 

 vegetation, is close. Several species present are 

 generally associated with sandy soils such as soapweed 

 yucca (Yucca glauca) , indian ricegrass (Oryzopsis 

 hymenoides) , and prairie sandreed (Calamovilfa 

 longifolia). They are found on these clay shales because 

 the weathering process produces a substrate of 

 predominantly sand-sized platy shards rather than the 

 clay-sized particles that are the ultimate product of 

 shale decomposition. Forbs typical of disturbed sites 

 occur in trace amounts. 



Other vegetation: In the northern portion of the RNA, 

 where the ridge slope tapers into highly convoluted 

 slump block terrain, there is a fragmented and 

 repeating pattern in plant communities within a short 

 distance, with most of the communities occupying only 

 a few square meters. Some of the communities noted 

 but not formally sampled were Pinus ponderosa / Carex 

 mops and a Pinus ponderosa -dominated type that had 

 virtually no undergrowth due to the highly erosive 

 nature of the substrate. These types were not sampled 

 because the surface was so rolling and convoluted that 

 there was no portion extensive enough to 

 accommodate a plot sample. 



Other Vegetation Types: Small patches of the following 

 types were noted; Chrysothamnus nauseosus - Eriogonum 

 pauciflorum (a variation of ARTLON - ERIPAU), 

 PASSMl; SARVER - ATRGAR and ARTTSW / 

 PASSMl. 



OVERALL BIODIVERSITY SIGNIFICANCE: 

 This is significant as the only RNA that contains the 

 uncommon to rare PSEMEN / ORYMIC Forest. It 



encompasses an interesting contrast of vegetation for a 

 small area; juxtaposed with the north slope PSEMEN / 

 ORYMIC c.t. is ARTLON / ORYHYM occurring on 

 the steep south slopes. As such, this RNA captures an 

 unusual slice of the Great Plains biome. 



Two Calf-Douglas-fir RNA is contiguous with and 

 provides access to the Missouri River Bottoms RNA 

 below. >X^le the latter does not provide additional 

 PSEMEN/ORYMIC habitat, the two together represent 

 an outstanding example of the Missouri Breaks gradient 

 and complement one another. 



The relatively dense canopy of the PSEMEN / 

 ORYMIC and other forested types of northerly slopes 

 constitute important thermal and hiding cover for large 

 native ungulates. The palatable shrubs of these slopes, 

 including serviceberry (Ameianc/iier drdfolia) and 

 chokecherry (Prunws virginiana) have been reduced to 

 stubs only inches high presumably due to intensive 

 wildlife browsing. 



The skewed orientations of otherwise straight tree 

 trunks ("drunk forest") raised questions about the 

 history of slumping. The massive slope wasting 

 phenomena currently under intact vegetation signifies 

 an interesting subject for research into "natural" 

 stability/ir\stability of this landscape. 



LAND USE: 



The general area has been grazed in the past but local 

 conditions are unfavorable for such use. It may have 

 been subject to selective removal of suitable trunks of 

 Junipenis scopulorum cut for fencing, and trunks of 

 Pseudotsuga menziesii cut for fuel and building material 

 from the perimeter of the stand where access and 

 removal were practical. 



MANAGEMENT COMMENTS: 

 This 160 acre patch is too small to encompass the 

 disturbance regimes (wildfire, wildlife browsing and 

 grazing) affecting the Missouri Breaks landscape. If a 

 wildfire were to bum the northern slope, it would 

 probably crown-out and be stand replacing for most of 

 the forested landscape, setting back the forested 

 landscape to an early serai stage. Tree seedling 

 establishment in such an environment is very sporadic, 

 and it takes many years for an established forest to 

 produce a mature stand in this dry enviroment. Given 

 the rarity of the type and relative lack of its protection 

 in Montana, it would be prudent to either add more 

 area of this association to the current RNA or find 

 additional examples of high quality PSEMEN / 

 ORYMIC that could be placed in RNA status. Note: 



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