Idaholanx fresti

This limpet is only known to occur in four springs isolated from one another in a very small area of occupancy with imminent threats.

Restricted to four coldwater springs on the Snake River in Idaho (USFWS, 2006).

It is currently known to only exist in four coldwater spring complexes along 10 river km of the middle Snake River: Thousand Springs, Box Canyon Springs, Banbury Springs, and Briggs Springs (USFWS, 2006).

From USFWS (2006):
The foremost threat is habitat modification as much of the spring water at Thousand Springs that originally cascaded down the basalt cliffs is now diverted into a concrete flume for hydroelectric power (plant created 1912) so today the snail only exists at one section of the North Channel near Minnie Milner Springs. Discharge in Box Canyon is currently the lowest it has been in 50 years as much of the water (86%) is diverted upstream of the snail colony into a flume for delivery to a commercial aquaculture facility. At Banbury Springs, the entire stream is captured into Morgan Lake (where the snail cannot live) and the snail is found only in the lower riffle complex in one of five spring outflows that enter Morgan Lake. Up until 1998, the Lake was used for recreational activity (canoeing and swimming), and although this has been discontinued, it still occurs illegally. At Briggs Springs, the snail occurs upstream of the uppermost diversion (for commercial fish production at a fish hatchery) as well as just downstream of this diversion in a diversion canal 50 m from this location (note none at confluence with Snake River). This water diversion limits potential habitat for the species. Poor groundwater quality is an anthropogenic factor which likely impacts this species and limits its geographic distribution. Springflow diversions and irrigation return flows are believed to degrade water quality and are detrimental to the snail due to the resulting flow reduction, increased water temperature, decreased dissolved oxygen, elevated nutrient concentrations, and the accumulation of pollutants and sediments. USGS records show that the average spring outflows in the Hagerman reach of the Snake River have declined over the past 50 years and these declines have been observed at locations occupied by snail [e.g., Box Canyon and Briggs Springs]. In part, these declines are due to groundwater pumping of the Snake River Plain aquifer for agricultural and urban use, as well as a gradual replacement of flood irrigation practices with the use of center-pivot sprinkler systems, which contribute to little or no aquifer recharge. Groundwater pumping continues today and the potential exists for severe aquifer depletion in the future with continuing and new demands from water users such as municipalities and irrigators. Although water temperature may not be a major issue of concern in the four coldwater spring complexes where it resides, anthropogenic activities in the springs such as impoundments and/or diversions can alter natural thermal characteristics of water bodies including reducing capacity to hold oxygen as water temperatures change from human activities. Excessive nutrients is a potential threat and the main sources of excessive nutrient and sediment loads are agriculture in the form of crop production, cattle grazing, confined animal feeding operations, aquaculture facilities, and municipal wastewater treatment facilities. Approximately 80 aquaculture facilities are located in the Hagerman Valley, of which at least 3 utilize or divert coldwater spring and tributary flows where the snail resides. The return of diverted irrigation water to the coldwater springs and tributaries plays a major role in degrading water quality; especially via increased sediment. Industrial wastes (including nuclear waste which was buried nearby until 1984) in groundwater are also a potential threat. Invasive species may affect the continued existence of the snail; and New Zealand mudsnail (Potomopyrgus antipodarum) occurs with all four populations but in very low densities.