The Jefferson County sites have substrates developed from late Quaternary 

 alluvium (Kuenzi and Fields 1971). The particular landscape segments that 

 have the wetland inclusions which provide habitat for Spiranthes diluvialis 

 are mapped as the Neen or Villy soil series among the seven western 

 occurrences (Beaverhead, Jefferson and Madison counties) and as the 

 Fairway-Threeriver-Rivra complex or the Saypo series among the three 

 eastern occurrences in Gallatin County. Note: The soil series of actual 

 wetland microhabitats has not been determined, and the following discussion 

 pertains to the terrain surrounding meandered wetlands. 



Neen soils are fine silty mixed frigid Aquic Calciorthids, Villy soils are fine 

 silty mixed (calcareous) fiigid Typic Fluvaquents, and Fairway soils are fine, 

 laomy mixed Fluvaquentic Haploborolls. They are classified as wetland soils. 

 The meandered wetlands are just inclusions that are not mapped separately. 

 The distribution of at least the first these two of the soils series corresponds 

 with the distribution of alluvial fans laced by meandered wetlands (Boast and 

 Shelito 1989). It appears that soils mapping can be used with efficiency and 

 possibly accuracy exceeding that of aerial photointerpretation for pinpointing 

 areas with the microhabitat features that signify potential habitat. These first 

 two soil series make up small fractions of the land area in Madison County 

 (totaling 1.2 % and 0.3%, respectively) and are surrounded by other soil 

 series that represent aridisols and mollisols. 



The soil series that make up the landscapes surroimding the Spiranthes 

 diluvialis habitat are all characterized in soil classifications as high in calcium 

 carbonate and "salt-affected" within the rooting zone. They are also all 

 classified as "subirrigated" range sites. 



Soil temperature was measured at the five sites (1 cm. Depth) at places where 

 soil samples were collected in August. These were compared to air 

 temperature readings to investigate the groundwater source. Soil temperatures 

 ranged from 15.0 -20.8 degrees Celsius; not appreciably different from the 

 mean August air temperatures. It is inferred that deep water sources would 

 have constantly cold water temperatures (unless connected to thermal 

 features). The moderate soil temperature readings, presence of very coarse 

 unconsolidated alluvial cobble underlying the soil profiles, and likelihood of 

 accompanying impervious lenses in alluvial deposits supports the idea that 

 the groundwater draws from shallow rather than deep aquifers. 



6. Dependence of this taxon on natural disturbance: This species has been 

 characterized as a colonizer of early successional riparian habitat; persisting 

 in those areas where successional conditions are perpetuated or competition is 

 constrained in some way (U.S. Fish and Wildlife Service 1995b.) In 

 keeping with this riverine habitat model of scouring and deposition, the 



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