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Recovery Strategy for Hotwater Physa (final)


Executive Summary

Hotwater Physa, Physella wrighti, is an aquatic snail known globally from one location at Liard River Hotsprings Provincial Park, a small hotsprings complex located in north-central British Columbia (BC). The snail was first collected in 1973 and scientifically described in 1985 (Te and Clarke 1985). Liard River Hotsprings Provincial Park is a unique system of thermal springs that provide consistently warm lotic and lentic habitat for several populations of locally endemic animals and plants. The warm shallow marsh and aquatic environments do not freeze and allow vegetation to thrive throughout the year.

Biologically, this species has likely persisted in the Liard River Hotsprings complex since the retreat of the glaciers (Remigio et al. 2001). However, the species has an isolated and localized occurrence and its distribution is limited to the Liard River hotsprings complex, which makes it vulnerable to the risk of extinction due to anthropogenic or catastrophic events.

The threats to Hotwater Physa are from potential changes to the hotsprings habitat resulting from recreational activities within the park. Future interest may arise outside the park for oil and gas exploration, or renew for hydroelectric development, in which case further assessment of the threat to the source of the geothermal water outside the park will be required.

The recovery goal for Hotwater Physa is to maintain and protect the population(s) of Hotwater Physa within its natural geographic range and within its current variation of abundance at Liard River Hotsprings. As such, recovery is considered biologically and technically feasible.

The short-term objectives on which the Hotwater Physa's recovery will be monitored over the next 5 years are 1) to observe that the species' current distribution within the Alpha and Beta pools and streams is maintained, and to refine the understanding of the current distribution to better quantify this objective by 2011; and 2) to observe that the species' current relative abundance is maintained, and to develop methodology that increases survey precision by 2011.

Given the endemism of Hotwater Physa to this unique and localized stretch of habitat and the continued known persistence of this species below the weir since its initial recording in 1973, critical habitat is expected to be largely located within the park boundaries. However, additional work must be completed to determine the factors that define critical habitat for this species.

In addition to a schedule of studies to identify critical habitat, the strategies that are recommended to address threats and effect recovery of Hotwater Physa are: population monitoring; protection through the Liard River Hotsprings Park Master Plan and minimizing impacts from recreational use within the park; threat monitoring; filling knowledge gaps to support recovery; and education to minimize impacts from recreational users within the park. An action plan, which provides the specific details for recovery implementation, will be completed by 2011. Currently, a single-species approach to recovery has been adopted, however, an ecosystem-based approach may eventually be warranted to include the entire hotsprings area.