HABITAT: Throughout its range, Visher's buckwheat is restricted to sparsely vegetated, highly 

 erodable sedimentary outcrops with badlands topography. In North and South Dakota, the species 

 has been found on at least three geologic formations, the Hell Creek formation, where it is most 

 abundant, a phase of the Pierre formation, and a formation in the White River group (Ode 1987, 

 Vanderpool 1993). The Carter County, Montana population is in badlands of the Hell Creek 

 Formation. At the Carter County site, all plants in the population were confined to dense clay 

 alluvial outwash flats at the bottoms of eroded shale mounds, but elsewhere the species also occupies 

 mid- and upper-slope positions in badlands. Ode (1987) characterized the growing substrates of 

 Ehogonum visheh in South Dakota as heavy clay textured entisols, sodium affected, and nutrient 

 poor, with low organic matter, low infiltration rates, and high shrink-swell potential. Few plants are 

 adapted to these harsh conditions, and vegetation is sparse. The soils at the Montana site were 

 derived from eroding bentonite and were vesicular silt. 



The habitat of the Montana population was sparsely vegetated, with over 90% exposed bare ground. 

 Commonly associated plant species at the Montana site, included: shadscale {Atriplex confer tifolia), 

 Wyoming big sage {Artemisia tridentata ssp. wyomingensis), leafy musineon {Musineon 

 divaricatum), white prairie onion {Allium textile), thick-spiked wheatgrass {Elymus lanceolatus), 

 bottlebrush squirreltail {Sitanion hystrix), winterfat {Kraschnekovia lanata), desert evening-primrose 

 {Oenothera cespitosa), and Gardner's saltsage {Atriplex gardneri). 



SPECIES BIOLOGY: The Montana population was discovered in early June, exceedingly early in 

 the flowering stage. A complete survey was conducted in mid- July when most plants were in full 

 flower. A total of about 1,000 plants were estimated in 4 subpopulations covering a total of about 40 

 acres across less than 1 mile of badlands front. The population is centered around and straddles the 

 Powderville Road. This population number is relatively high while site acreage is relatively low 

 compared to average size estimates of South Dakota populations (Ode 1987). High plant densities 

 may reflect favorable growing conditions during the relatively cool, wet growing season of 1997. 

 Populations of annuals often undergo major fluctuations in response to climate, and may remain 

 dormant as seedbanks in unfavorable years. 



OTHER COMMENTS: The Montana population of Eriogonum visheri lies within rangeland 

 grazed by cattle and horses. Much of it is situated near the upper end of a pasture fenceline, so its 

 distance from water may limit the levels of use. The associated vegetation is relatively sparse for 

 attracting livestock to the immediate area of the population. Though most plants were in positions at 

 the base of slopes readily accessible to livestock, no browsed or trampled plants were observed. 

 Elsewhere in its range, its outwash habitat may be trampled with early-season livestock use, 

 affecting its suitability for species' seed germination. 



Ode (1987) identified invasion of habitat by exotic weeds, summer cypress {Kochia scoparium) and 

 Russian thistle {Salsola iberica, as a primary potential threat to populations in South Dakota. Neither 

 of these was observed at the Montana population site, but cheatgrass {Bromus tectorum), Japanese 

 brome (Bromus japonicus), and yellow sweetclover {Melilotus officinalis) are locally abundant 

 weeds that may have potential for invading the population area. This regionally endemic species is 

 recommended for addition to the ELM watch list in Montana, consistent with its recognition 

 elsewhere in its range, because land management actions affect weed populafions. 



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