Biotic and Abiotic Factors Influencing the Distribution of the Huachuca Springsnail (Pyrgulopsis thompsoni)

Abstract

The Huachuca springsnail (Pyrgulopsis thompsoni) is a species of concern inhabiting springs of the Huachuca Mountains in southeastern Arizona, USA. We documented springsnail distribution and examined the major abiotic and biotic factors influencing springsnail abundance at eight spring channels before and after the onset of seasonal summer rains in 2003. Of the abiotic factors examined (total dissolved solids, pH, distance from spring source, spring channel, water temperature, and dissolved oxygen), only spring channel and total dissolved solids were strongly associated with springsnail abundance. However, correlation of total dissolved solids with pH, temperature, dissolved 02, and distance downstream necessitated hrther exploration of these explanatory variables. We found that sampling locations with P. thompsoni were characterized by cooler, more oxygenated, and less-occluded water conditions relative to sampling locations without springsnails. Springsnail abundance was positively associated with abundance of caddisfly larvae (Helicopsyche sp.) but not significantly associated with abundance of a co-occurring snail (Physa sp.). The most important outcomes of this study were the documentation of major factors associated with springsnail abundance, and recovery of springsnails at greater distances downstream than previously documented.

A New Springsnail (Hydrobiidae:Pyrgulopsis) from the Lower Colorado River Basin, Northwestern Arizona

“…Note that this lineage is composed of several re cently discovered populations that were assigned to P. thompsoni bereft of taxonomic study (Tsai et al 2007) and was also detected at a low frequency in a sample from the type locality of this species (Peterson Ranch Springs; Pyrgulopsis hualapaiensis is endemic to a spring complex that is a culturally sensitive site for the Hualapai Tribe. This aquatic habitat has been altered by trenching to focus flow and construction of a concrete spring box on the side of a heavily used road (BIA 6/Diamond Creek Road).…”

Associations between Aquatic Habitat Variables andPyrgulopsis trivialisPresence/Absence

“…Or maybe our sample sizes were too small to detect important associations. Nevertheless, the distribution of hydrobiids is often linked to environmental conditions provided by spring water (Hershler 1984and 1998, O'Brien and Blinn 1999, Mladenka and Minshall2001, Malcom et al 2005, Martinez and Thome 2006, Tsai et al 2007.…”

“…This may suggest these two snail species are similarly influenced by habitat, though how they interact is not known. Tsai et al (2007) found that Pyrgulopsis thompsoni may compete with a Physa sp. in habitats where they are .…”

“…Due to the rarity and vulnerability of these snails, scientists and resource managers have recognized the need to conserve springsnails and their habitats. Recently published studies of hydrobiid habitats have focused on parameters such as substrate, aquatic vegetation, temperature, dissolved carbon dioxide, dissolved oxygen, conductivity, pH, water depth, and total dissolved solids (O'Brien and Blinn 1999, Mladenka and Minshall 2001, Malcom et al 2005, Martinez and Thome 2006, Tsai et al 2007). …”

Current Population Status of a Locally Endemic Springsnail (Hydrobiidae:Pyrgulopsis bedfordensis) in Montana

“…The Bedford springsnail is restricted to approximately 2 km of this spring creek and has no possibility of expansion upstream or downstream into suitable habitat. Other springsnail conspecifics are restricted to much smaller distances from the spring source (5-300 m) due to changing abiotic factors (Mladenka and Minshall 2001, Malcom et al 2005, Tsai et al 2007. During summer 2012, the private pond that is fed by the spring was drained and subsequently dried out, likely killing any springsnails inhabiting this habitat (DMS personal observation).…”