b. Self-sustaining breeding populations: None. 



c. Stored seed: None. The value of saving orchid seeds in a seedbank 

 without the fungal symbiont has been debated by mycologists (Zettler 

 1997). 



11. Evidence of threats to survival. 



A. Present or threatened destruction, modification, or curtailment of habitat or 

 range: Alteration of river flow regimes does not directly threaten the species in the 

 same way or magnitude as the riverside occurrences in much of the rest of its range 

 where charmelization and impoundment are major threats (U.S. Fish and Wildlife 

 Service 1992). Yet the Montana occurrences may still fit within the pattern of 

 imperilment shared by many Western species of declining under altered surface 

 waters (Flather et al. 1994). Its highly restricted microhabitats are linked to shallow, 

 stable groundwater in temporarily inimdated emergent wetlands. These may be 

 affected at some level by small water diversions, ditches, and irrigation discharges 

 which are widespread. 



The soils are marginally suited to crop production, v^ndbreaks, and homestead 

 development. Nevertheless, its habitat is being cultivated, often with use of 

 irrigation, altered by neighboring water diversions or inflows, and affected by 

 valleybottom developments including roads systems and buildings. There is not the 

 threat of urbanization as identified for Colorado occurrences (U.S. Fish and Wildlife 

 Service 1992), except for one occurrence that lies directly outside of city limits 

 where development could occur. The spread of noxious weeds that often 

 accompanies developments is a more pervasive, if not more severe threat for 

 Montana occurrences. 



Noxious weeds including leafy spurge (Euphorbia esula), spotted knapweed 

 (Centaurea maculosa) and Russian knapweed (Centaurea repens) are the most 

 pervasive immediate threats. They are threats as competitors, and in the 

 indiscriminate spraying of herbicides to treat them. Fortimately, noxious weed 

 invasion is absent or at early stages in the Spiranthes diluvialis habitat of the ten 

 occurrences, though a couple have severe weed infestation problems nearby. The 

 invasion of knapweeds is concentrated mainly along roads and irrigation canals. The 

 invasion of leafy spurge is most serious along water courses, but it is also spreading 

 in a patchy, more difficult to predict pattern that may reflect the influence of v^ldlife 

 vectors like whitetail deer and mourning doves that are common in the bottomlands. 

 The indiscriminate treatments of noxious weeds and rangeland pests with herbicides 

 and pesticides also pose a potential threat. 



B. Overutilization for commercial, sporting, scientific, or educational purposes: 



Collecting of this species is regulated under authority of the Endangered Species Act 



44 



