Degree of Threat: Very high - high
Comments: Pyrgulopsis sp. 8 population (Columbia River population): From Bowler (2004): Throughout their ranges, populations of the Jackson Lake, Harney Lake, and Columbia springsnails have declined for a number of reasons (Frest and Johannes 1995a, Hershler 1994, 1998). Habitat loss, degradation, and/or modification has been identified as a primary factor causing declines, and remains a prominent threat to the species throughout their ranges (Hershler 1994, 1998, Frest and Johannes 1995a, Sada and Vinyard 2002). Domestic livestock grazing, water pollution, spring development, dams and diversions, groundwater withdrawal, stream and lake modification, and recreational developments and activities have all negatively impacted the habitat of one or more of the three species throughout all or a significant portion of their ranges and continue to pose threats to the species (Burch 1989, Fleischner 1994, Hershler 1994, 1998, 1999, Frest and Johannes 1993b, 1995, 1996, Winter et al. 1998, Belsky et al. 1999, Hovingh 1999, Berkamp 2000, Frest 2002a, 2002b, Sada and Vinyard 2002, Bartolino and Cunningham 2003, Hershler and Liu 2004). The species also remain threatened by a host of other factors, including, but not limited to, herbicide and pesticide application, competition with and/or predation by nonnative species (e.g., New Zealand mudsnail (Potamopyrgus antipodarum), nonnative crayfish), population isolation and fragmentation, and climate change (Brown 1978, Brooke 1991, 1993, Frest and Johannes 1995a, EPA 1997, 1998a, 1998b, 1998c, Hershler 1998, McCarty 2001, Richards et al. 2001, Hershler and Liu 2004).
Pyrgulopsis hendersoni population (Oregon closed basin population): From Bowler (2004): Throughout their ranges, populations of the Jackson Lake, Harney Lake, and Columbia springsnails have declined for a number of reasons (Frest and Johannes 1995a, Hershler 1994, 1998). Habitat loss, degradation, and/or modification has been identified as a primary factor causing declines, and remains a prominent threat to the species throughout their ranges (Hershler 1994, 1998, Frest and Johannes 1995a, Sada and Vinyard 2002). Domestic livestock grazing, water pollution, spring development, dams and diversions, groundwater withdrawal, stream and lake modification, and recreational developments and activities have all negatively impacted the habitat of one or more of the three species throughout all or a significant portion of their ranges and continue to pose threats to the species (Burch 1989, Fleischner 1994, Hershler 1994, 1998, 1999, Frest and Johannes 1993b, 1995, 1996, Winter et al. 1998, Belsky et al. 1999, Hovingh 1999, Berkamp 2000, Frest 2002a, 2002b, Sada and Vinyard 2002, Bartolino and Cunningham 2003, Hershler and Liu 2004). The species also remain threatened by a host of other factors, including, but not limited to, herbicide and pesticide application, competition with and/or predation by nonnative species (e.g., New Zealand mudsnail (Potamopyrgus antipodarum), nonnative crayfish), population isolation and fragmentation, and climate change (Brown 1978, Brooke 1991, 1993, Frest and Johannes 1995a, EPA 1997, 1998a, 1998b, 1998c, Hershler 1998, McCarty 2001, Richards et al. 2001, Hershler and Liu 2004).