needle-and-thread {Stipa comata) , sand dropseed 

 (Sporobolus cryptandrus) and red threeawn (Aristida 

 longiseta) . Other short graminoids, not necessarily 

 associated with coarse-textured soils, can also dominate 

 these sites.The forb component is low in cover and 

 extremely heterogeneous, with high diversity (30 plus 

 species / plot-sized area) in some areas and scarcely one 

 third that in others. Almost ubiquitous within the type 

 are hairy golden-aster (Heterotheca villosa) , American 

 vetch (Vicia americana) , scarlet globemallow 

 (Sphaeralcea cocinea), scarlet gaura (Gaura coccinea), 

 silver-leaf scurf-pea (Psoralea argophylla) and woolly 

 groundsel (Senecio canus) . 



Other Vegetation Types: Where the woody draw opens 

 up and widens some distance above the reservoir, the 

 Artemisia cana I Fascopyrum smithii (silversage / western 

 wheatgrass) association is found contained within what 

 becomes a broad, shallow drainage. This community is 

 in relatively good range condition as indicated by the 

 high cover of Vascopryrum smithii and low cover of 

 Kentucky bluegrass (Poa pratensis) . Comparatively large 

 specimens of Artemisia tridentata ssp. wyomingensis 

 contribute to the high shrub cover. 



OVERALL BIODIVERSITY SIGNIFICANCE: 

 The boundaries were set to encompass the ravine, a 

 particularly well-developed landform with its full 

 complement of associated vegetation. The ravine itself 

 is an unusually mesic woodland in its composition for 

 the Northern Great Plains biome, though limited in 

 development and extent as is the case for most 

 Missouri Breaks ravines due to their narrowly-incised 

 settings of limited length. This gives it all the more 

 contrast and development in north-south ravine slope 

 vegetation as a corisequence. A segment of the 

 surrounding upland grassland features are 

 serendipitously included that are representative of a 

 prevailing Northwestern Unglaciated Plains landscapes 

 in excellent condition. Such grassland habitat extends 

 onto adjoining lands to provide landscape continuity, 

 though adjoining lands are not in as good a condition. 

 As such. Spring Creek RNA potentially affords a 

 rangeland reference area for land managers and ecology 

 researchers, and a striking fenceline contrast in range 

 condition between adjoining pastures. Wildlife values 

 were not evaluated. 



LAND USE: 



The site has been protected from livestock grazing to 

 keep the area in a natural state, presumably since 

 establishment in 1991. The current excellent condition 

 and paucity of exotic species suggests that it had been 



managed in good-excellent range condition prior to 

 establishment. 



MANAGEMENT COMMENTS: 

 No immediate management issues or concerns were 

 identified; there is a nearly complete absence of 

 noxious weeds and exotic species invasions with otdy 

 limited yellow sweetclover (Melilotus officinalis) along 

 the western bottoms. Vehicle access is limited, and 

 weeds were found along the corridor. 



Historically, fire and bison grazing were two major 

 driving forces in this landscape, responsible for 

 renewing the vigor of the grasses, stimulating forb 

 numbers, and keeping shrub density low. 

 Reintroduction of appropriately timed fire is a 

 management option to consider in stimulating grass 

 upland grass vigor and forb flowering, within the 

 wildlife management framework. 



The grassland had relatively low forb numbers and 

 litter accumulation. A policy excluding wildfire 

 suppression under discrete terms, if not a rotating 

 prescribed bum treatment, may warrant further 

 consideration. The corisideration of any treatment 

 must factor in yellow sweetclover life history and 



Two CalF'DouglaS'Fir Research 

 Natural Area 



environment: 



Two Calf- Douglas-fir Research Natural Area is a 160 

 acre block of Missouri Breaks that encompasses an 

 almost 500 feet vertical gradient of moderately to 

 highly dissected terrain developed in highly erodible 

 shales. It encompasses the upper slopes of Knox Ridge 

 and extends northward down to the Missouri River; 

 thus the mostly steep slopes have contrasting north- 

 and south-facing exposures. Barely reaching the 

 southern boundary, in the vicinity of an ephemeral 

 stream feeding Two Calf Creek, a wildfire has burned 

 the predominantly pine forest, leaving scattered 

 blackened snags. At the northern base of the ridge, the 

 ridge slope tapers into highly convoluted slump block 

 terrain with small-scale relief that is not revealed by 40 

 feet contour intervals. The climate is essentially 

 Continental (refer to the characteriiation of Mobridge 

 monitoring data, presented for Missouri River 

 Bottomlands RNA.) 



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