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Recovery Strategy for Hotwater Physa (final)


1. Background

Hotwater Physa, Physella wrighti, is a freshwater snail globally endemic to Liard River Hotsprings located in Liard River Hotsprings Provincial Park, BC (Figure 1). The snail was first collected in 1973 and taxonomically described in 1985 (Te and Clarke 1985). Over 80 hotsprings are known throughout BC, and there have been few recent surveys of the invertebrate fauna at these hotsprings (e.g. Lee and Ackerman 1998; Salter 2001 and 2003; Remigio et al. 2001; Wethington and Guralnick 2004).

Figure 1. Global location of Hotwater Physa (Salter 2003)

Figure 1. Map of British Columbia with the global location of Hotwater Physa in the Liard River Hotsprings.

1.1 Species Assessment Information

The Status Report and Assessment Summary for Hotwater Physa is available from the Committee on the Status for Endangered Wildlife in Canada (COSEWIC) Secretariat.

Common name: Hotwater Physa

Scientific name: Physella wrighti

COSEWICStatus: Endangered April 1998.

SARAStatus: Endangered June 2003.

Last Examination and Change: May 2000. No change.

Canadian Occurrence: British Columbia (BC).

Reason for designation: Small endemic population with narrow ecological requirements occurring in an extremely restricted area subject to threats resulting from human use of hot springs pools. Probability of extinction is high.

Status history: Last assessment based on existing status report.

1.2 Description

Hotwater Physa, Physella wrighti (Te and Clarke 1985), is a freshwater snail classified in the gastropod family Physidae (generally referred to as physids) (Pulmonata: Physidae). Hotwater Physa has a very small blackish/grey shell ranging from 3.25 – 9.1 mm. The shell is sinistrally (i.e., opening to the left) coiled with an ear-shaped aperture, an outer lip callus along its rim, a curved perimeter and a narrow elongate-ovate shape (Figure 2) (Lee and Ackerman 1998).

Figure 2a. Hotwater Physa, Physella wrighti

Illustration by Trent Hoover, used with permission.

figure2a

Figure 2b and c. Hotwater Physa on emergent vegetation.

Photos by Mike Rowe, used with permission.

Figure 2b. Hotwater Physa on emergent vegetation. Photo: Mike Rowe, used with permission.    Figure 2c. Hotwater Physa on emergent vegetation. Photo: Mike Rowe, used with permission.

The Hotwater Physa is currently acknowledged by the American Fisheries Society as a unique species. Te and Clarke (1985) used morphological, anatomical, cladistic and phenetic analyses to describe the species and concluded that "P. wrighti is certainly a primitive species not closely related to any other species in northwestern North American and it is virtually impossible that it could have evolved as such a distinct species since the end of the Pleistocene", and suggested that Hotwater Physamay have been at its type locality for 100,000 years.

Molecular systematic relationships have been completed between P. wrighti and Physella johnsoni, an endemic snail to Banff Hotsprings, Alberta. P. johnsoni is listed as Endangered by COSEWIC. The relationship between both P. wrighti and P. johnsoni has been examined to determine the origins of these two species and their inter-specific relationships. Remigio et al.'s (2001) molecular data supports continued recognition of Hotwater Physa as an endemic species but suggests the species probably arose from a population isolated during the most recent glacial retreat. Further, both species are endemic to their respective locations and that P. wrighti was likely the source ancestral population from which P. johnsoni was derived (Remigio et al. 2001).

More recently, molecular evidence has been used to assess species age and relationships and this has yielded contradictory results. Wethington (2002) found fault with Remigio et al.'s (2001) study design, and concluded from molecular data of physid hotspring endemics that there is not a monophyletic hot spring physid group and that members of the closely related Physa gyrina species group includes the putative Hotwater Physa. This group can invade or survive introduction to hot water environments and can develop distinctive shells in as few as five generations (Wethington and Guralnick 2004) and so are not distinct species but habituated populations. Taylor (2003) also regards Hotwater Physa to be a synonym of P. gyrina. An authoritative decision will probably not be available until the American Fisheries Society updates the mollusc species list that currently includes Hotwater Physa as a distinct species (Turgeon et al. 1998).

Physids are very common throughout North America and are very difficult to identify, it is possible that other species may occur within Liard River Hotsprings Provincial Park. Additional Physella species endemic to hotsprings complexes in BC and western Canada have yet to be fully studied. A snail of the family Physidae is present in Deer River hotspring, which is approximately 50 km from Liard River Hotsprings Provincial Park. Initial examinations by biologists determined this snail to be Physella virginia, but a genetic comparison of its relationship to P.wrightihas not been completed.

1.3 Populations and distribution

The Hotwater Physa is known globally from one location at Liard River Hotsprings complex in the Liard River Hotsprings Provincial Park, BC. The snail was initially reported from one breeding population along a 34 metre stretch of Alpha Stream, at the outlet of Alpha Pool (Figure 3) (Lee and Ackerman 1998). This outlet is also the type locality for the species (Te and Clarke 1985; Lee and Ackerman 1998).

The snail has since been observed to occupy additional habitats within the hotsprings complex, including Alpha and Beta Pools and the entire length of Alpha Stream (Figure 3) (Salter 2001, 2003). The area with the highest recorded density is downstream from the weir that impounds water flowing from Alpha Pool, specifically in a section from two metres below the weir at the head of the stream to 34 metres downstream (Salter, 2003). In 1997, the highest concentrations of snails were observed approximately 20 metres downstream from the weir (Lee and Ackerman 1998). Alpha Pool and Beta Pool have distinct sources and the two outflows do not connect. In previous surveys (Lee and Ackerman 1998) there was no observation of snails in Beta Pool. The recent population expansion in to Beta Pool may be due to previous populations being overlooked or to recent passive dispersal by park users or wildlife.

Researchers believe the distribution of the Hotwater Physa within Liard River Hotsprings complex varies spatially and temporally and the species likely occupies additional areas within the hotsprings complex (Salter, pers. comm.). It is unlikely that new occurrences found within the Liard River Hotsprings complex are another species, although there is a remote possibility that specimens of P. gyrina are indirectly or unknowingly brought into Liard River Hotsprings Provincial Park through wildlife or transfer by people. P. wrighti from P. gyrina can not be distinguished by the human eye. Currently, the only visual means of distinguishing these two species is through dissections by a trained individual.

The population trend has not been measured or tracked for Hotwater Physa. Some population estimates of Hotwater Physa in upper Alpha Stream have been calculated. On October 1, 1997, the conservative population estimate within Alpha Stream was 979 – 1735 individuals (Lee and Ackerman 1998). In August 2000 and January 2001 the population in Alpha Stream was estimated at 5185-7000 individuals (Salter 2001, 2003). There has been no evidence of a decline in the population (Salter, pers. comm.). It is possible the snails congregate based on a combination of temperature, abiotic factors and biological cycles. As population estimates and species range both have increased over time, this population appears to be stable or expanding. However, it is premature to calculate population estimates based on one or two-day sampling efforts taken years apart.

The distribution of the Hotwater Physa within the Liard River hotsprings complex has not been thoroughly studied. Salter (2003) noted larger numbers of snails in the cooler perimeter of Alpha Pool, Alpha Stream and Beta Pool. The temperature in Alpha Pool and Beta Pool has been recorded daily by data loggers since July 2004 (Rowe, pers. comm.). Alpha Pool was artificially created through the installation of a dam and a weir. The dam backs up water directly from the hotwater vent (source) and creates a pool < 1.5 metre depth at a temperature varying between 40° - 44.5° Celsius, with temperatures > 45° Celsius at the source in July 2004 (Rowe, pers. comm.). A weir installed approximately 5 metres below the dam also captures the flow of a small cool water creek reducing the water temperature in this secondary pool to 38° Celsius in July 2004. This mixed source water tumbles over the weir to form Alpha Stream. This mixing of two water sources has affected the temperature distribution at the micro-habitat level in the area immediately downstream of the weir, but it is not certain how this may have influenced Hotwater Physa distribution.

It is not known if snails congregate based on food sources alone, or more likely a combination of temperature, abiotic factors and biological cycles. The cyclical nature of Hotwater Physa populations is unstudied. Researchers believe this population has remained stable since its first recording in 1973 (Lee, pers. comm., Salter pers. comm.), although this statement is an educated guess and some of the threats (Section 1.5) have since increased.

Figure 3. Liard River Hotsprings Provincial Park showing the sites within the hotsprings complex where Hotwater Physa is found (A, B & F) and where search efforts were made but no snails were found (C – E)(Salter 2003).

Figure 3. Liard River Hotsprings Provincial Park showing the sites within the hotsprings complex where Hotwater Physa is found (A, B & F) and where search efforts were made but no snails were found (C – E)(Salter 2003).

1.4 Needs of Hotwater Physa

1.4.1 Biological needs

Physids are generally considered to be detritivores and/or bacterial feeders (Brown 1991) and the habitat in which Hotwater Physa is found suggest that this is true for this species. There have been no in-depth species-specific studies conducted on Hotwater Physa, although P. wrighti kept in captivity lived and reproduced on a diet of mixed brewer's yeast and fish food (Lee and Ackerman 1998).

The snails in Liard River Hotsprings Provincial Park are found most densely on Chara vulgaris. C. vulgaris (or Chara) is an algae which grows at the shallow edges of hotwater springs on rocks, submerged branches, introduced garbage and other submerged materials in the aquatic habitat (Salter pers. comm.) including rotting paper birch (Betula papyrifera) leaves (Lee and Ackerman 1998). This green algae (Class Charophyceae (Stoneworts)) and the outer cell layers are impregnated with calcium carbonate (Scagel et al. 1965) giving the plant a very crisp texture. Chara grows floating near the surface and forms dense mats attached at various intervals along the streamsides. When the spring water (high in calcium) cools, the calcium precipitates out onto the surface of the Chara and results in significant calcification of the plant, particularly those plants floating along the edges of the stream. Calcification of these plants and other surfaces eventually forms tufa, which is a crumbly and porous 'rock'. The snails are probably not feeding directly on any of these substrates but are grazing on the aufwuch, which is the organic material that comes to encrust submerged substrates.

There is no known information regarding species-specific reproduction of Hotwater Physa. The Physid family, in general, replace generations annually, thus an individual snail will likely live approximately one year. These snails are oviparous hermaphrodites that breed once; the young overwinter, mature into adults, lay eggs in the spring, and die after eggs are laid. However, these observations are from temperate areas and it is likely that physids living at constant warm temperature may lay eggs continuously until senescence. Reproduction of P. wrighti has only been observed in captive specimens. In a heated aquarium with water from the hotspring, P. wrightilaid "clear crescent-shaped gelatinous egg masses containing 6 to 18 eggs laid above the water line in a temperature of approximately 25° Celsius with hatching after nine days (Lee and Ackerman 1998).

Physids are pulmonate snails, which use a richly vascularized pulmonary cavity in the mantle to extract oxygen from air or water. Some physids rely on aerial respiration and are somewhat amphibious (Brown et al. 1998) whereas others fill the pulmonary cavity with water and use it as a derived gill (Russel-Hunter 1978). The relative reliance of the Hotwater Physa on aerial or dissolved oxygen is unknown but the snails are usually found on substrates near a water/air interface (Figures 2a and 2b) as these substrates offer secure anchoring surfaces, allow grazing on organic material, and allow access to the air/water interface for oxygen acquisition.

1.4.2 Biologically limiting factors

  1. Small and spatially isolated population: Globally, the Hotwater Physa is endemic only to the Liard River Hotsprings complex. At least until the taxonomic uncertainty is clarified, the Hotwater Physais a unique species and as such there is no possibility of a rescue effect from outside of this hotsprings complex. The population densities at sites within the Liard River Hotsprings complex vary, and the connectivity between these sites is limited.
  2. Small occupied area of population: Concentrated subpopulations of the snail within the Liard River Hotsprings complex occupy small areas on substrates at the edges of Alpha Pool, Alpha Stream and Beta Pool. Dispersal and occupancy of sites are likely due to temperature and substrate availability at depths where these pulmonate snails can access air and food.
  3. Habitat specificity: Hotwater Physa is associated with hotwater springs; which may also be in demand from development and human use. This species is restricted to its type locality, which makes it particularly susceptible to habitat disturbance. Changes to temperature and flow regime would undoubtedly affect reproductive success.
  4. Interspecific competition: Competition between Hotwater Physa and lymaeid and planorbid snails in other parts of the thermal spring ecosystem could be a limiting factor. However, the habitats of the physid and lymnaeid snails are distinct in cooler water habitats and appear not to overlap (Salter, 2003).
  5. Quality and quantity of food supply: Food supply is likely to be a limiting factor on a given population. Direct and indirect effects on food sources may be limiting to Hotwater Physa, including changes to riparian vegetation and habitat adjacent to the streamside.

1.4.3 Habitat needs

The specific habitat needs of Hotwater Physa and the dependent relationship the snails have on their hotsprings habitat has not been studied. However, there are conclusions that can be drawn from knowledge of physids in general, and observations of Hotwater Physa in situ. The continued health of both the riparian and instream habitats are undoubtedly of vital importance to the survival of this species.

Aquatic Habitat

Aquatic habitat factors thought to affect the habitat needs of Hotwater Physa are listed below.

  1. Water temperature: The geothermally heated water emerges from Alpha Pool at approximately 38° Celsius year round. The water will naturally cool as it flows away from the emergence point and is further cooled by purposeful mixing within the pool. The water temperature undoubtedly influences many aspects of the life history of Hotwater Physa.
  2. Water flow: At the site of the highest concentration of Hotwater Physa, in Alpha Stream,water enters over the weir at a rate of 80 – 81 litres/second (annual average)(Peepre 1990). While the initial observations of the Hotwater Physa'srestriction to Alpha Stream could have been correlated to habitat requirements found only in the flowing water, subsequent observation of the snails within the pools negates this relationship.
  3. Mineral composition and the content of dissolved substances in the water: The mineral composition of the water affects the amount of tufa formation and the surface area upon which bacterial and algal growth occurs.
  4. Chara, coarse woody debris and other substrates in the stream: Hotwater Physa has been observed grazing on Chara, coarse woody debris and various other substrates. These substrates provide the surface area for the growth of algae and bacteria upon which the snail feeds, as well as an anchor in the water current of Alpha Stream. The abundance and distribution of these objects within the hotsprings habitat is likely important to the species.
  5. Stream dynamics: The width, length and the depth of water throughout the hotsprings is variable, and it is not known if the snails will inhabit areas according to the stream dimensions. The stream will likely not become ice-covered, although the greatest temperature variation will occur in the winter months and will largely be in the pools and eddies. Research on the factors that influence the distribution of the Hotwater Physa within the hotsprings complex are included under the schedule of studies (Section 1.6.1).
  6. Oxygen Requirements: The respiratory requirements of Hotwater Physa were previously described. Distribution throughout the hotsprings is probably influenced by the availability of suitable substrates at suitable depth for oxygen acquisition.
Riparian Habitat

The habitat needs of the snail are both terrestrial and aquatic, and the quality of riparian habitat is as much a component to the health of the ecosystem as the water quality itself. Riparian habitat factors thought to affect the habitat needs of Hotwater Physa are categorized below.

  1. Streambank stability: Streambank stability and changes to this stability can affect Hotwater Physa habitat. Snails are known to congregate on Chara, which float in eddies as well as attach to the water bank edges. Soil compaction, disturbance and the removal of vegetation increases soil surface erosion into the hotsprings. In the first 60 metre section of Alpha Stream below the weir, there is a well defined, calcified channel with little sedimentation. However in the next 140 metres, the stream widens and slows due to an accumulation of sediment (presumably from Alpha Pool). This change may contribute to the habitat unsuitability for Hotwater Physa further downstream.
  2. Riparian vegetation and shade:  The dependence of Hotwater Physa on allochthonous inputs, such as leaves, is unknown, but the snails have been observed grazing on the aufwuch on paper birch leaves within Alpha Stream (Lee & Ackerman 1998). The riparian vegetation also affects the amount of light reaching stream edges, which may influence the density and distribution of Chara, which appears to be a preferred substrate for Hotwater Physa.
  3. Ambient air temperatures: Outside air temperature will have an influence on the aquatic environment, although the effect on the temperature of the hotsprings is unknown.

1.5 Threats

Most threats to Hotwater Physa are a result of potential changes to the hotsprings habitat as a result of human activities, whether from recreational activities occurring within the park or the potential for industrial activities that could affect the source water entering the hotsprings complex. The threat from human activities is of particular concern given the biological factors that limit the species (Section 1.4.2).

  1. Change to the flow regime as a result of human activities.
    • Weir maintenance. The natural flow of water from Alpha Stream to Alpha Pool has been changed due to the installation of the dam and weir prior to knowledge of the endemic snail. The mixed hot and cool water now exits through a narrow spillway in the top of the weir into the habitat colonized by Hotwater Physa. Failure of the dam or the weir could result in a large surge of water flowing down the stream, and this flash flooding could physically move snails into unsuitable habitat and significantly alter existing Hotwater Physa habitat. Alternately, a decrease in the flow of water during dam or weir maintenance activities could expose snails to drying and also result in altered water temperature in the area below the weir as the hot and the cold water sources would not be pre-mixed. Routine maintenance and repair of the dam and weir are conducted to maintain the integrity of Alpha Pool and Stream, and maintains Hotwater Physa habitat.
    • Recreational activities. Blockages, erosion or alterations to the weir or pool banks from recreational users may alter the flow of the stream. While these destructive activities are prohibited, park visitors have, for example, been known to block the outflow to the lower Alpha Pool. Temperature loggers in Alpha Stream during the September 2005 Labour Day weekend showed that water levels fell below the height of the temperature logger (Rowe, pers. comm.).
    • Drilling activities for oil and gas exploration.Although there is currently no specific application, drilling activities for oil and gas exploration could potentially affect the geothermally heated water from its source outside of the park boundaries to where it surfaces within the park. In the event an interest arises in oil and gas exploration in this area, a more detailed risk assessment will be required to determine specific high risk areas and to develop mitigation strategies.
    • Hydroelectric development. There were historic hydroelectric evaluations in the Liard River in the early 1990's and at least one site was identified outside the park boundaries on the Liard River. This proposal, titled Devil's Gorge Project, would flood the Liard Hotsprings and most of the adjacent campground as it would raise the water elevation to greater than 420m. This flooding would also allow aquatic species to access the hotsprings marsh that is located on a bench above the Liard River and currently are not connected through waterways (Hill, pers. comm.). In the event there is a renewed interest in this or other projects in future, further assessment of the risk to Hotwater Physa and their habitat will be required.

  2. Introduction of deleterious substances: It is estimated that Liard River Hotsprings Provincial Park currently receives over 40,000 bathers to the springs each year (Rowe, pers. comm.). While bathers are asked to shower before entering the hotsprings and are prohibited from using soaps and shampoos while bathing, the introduction of insect repellents sunblock, shampoos, soaps, and bath oils is still possible. Water contamination likely has cumulative and possibly detrimental effects directly to the snails or their habitat.

  3. Physical habitat destruction or alteration: The boardwalks and trail structure established within the park discourages people from creating new trails to the stream edges. However, trampling and/or direct disturbance of the riparian areas and/or the Chara floating plant mats is possible from people walking within the aquatic habitats and downstream of Alpha Pool or Beta Pool, or from the stream edges through the riparian areas. Natural events, such as windthrow resulting in falling trees and changes to the riparian or channel structure, could also result in changes to the aquatic habitat that could be detrimental.

  4. Introduced species: The introduction of exotic plants or animals into the hotsprings could pose a threat to Hotwater Physa. In the past two years, there have been two known introductions of turtles into the hotsprings (Hansen, pers. comm.; Elliott, pers. comm.), although these animals were found and removed. Evidence from other hotsprings shows a high potential for devastating ecological effects from the introduction of exotic species with a tolerance for warm water. For example, the introduction of a mosquito fish (Gambusia affinis) into Banff Hotsprings for mosquito control resulted in the extinction of a subspecies of the Banff longnose dace (Rhinichthys cataractae smithi) in 1987 (Environment Canada 2006).

  5. Collecting: Periodic inventory studies that involve work within the hotsprings complex require both a fish collection permit under the Wildlife Act (BC) and a Park Use Permit under the Parks Act (BC) as well as a permit under the Species at Risk Act (Canada) all of which ensure collections are conducted to standards that minimize harm. Illegal collection by park visitors has the potential to impact the Hotwater Physa population, although currently it is not likely a significant factor.

1.6 Critical Habitat

Hotwater Physa were initially reported from a 34 metre stretch of Alpha Stream at the outlet of Alpha Pool (Lee and Ackerman 1998). This is also the type locality for the species (Te and Clarke 1985). Hotwater Physa are maintained by the specific conditions in this section of the stream, including the amount of tufa formation and Chara growth, and the surface area upon which bacterial and algal growth occurs (food). The geothermally heated water emerging from Alpha Pool does not vary significantly in temperature, emerging at approximately 38oC year round, and water enters Alpha Stream from Alpha Pool through a man-made weir at a rate of 80 – 81 litres/second (Peepre 1990). Given the endemism of Hotwater Physa to this unique and very localized stretch of habitat and the continued known persistence of the species below the weir since its initial recording in 1973, the critical habitat is expected to be largely located within the park boundaries.

Additional work must be completed to identify if additional Hotwater Physa habitat may be present within or outside of the park boundaries. A schedule of studies to identify critical habitat is outlined below (Section 1.6.1). These activities are not exhaustive and may lead to the discovery of further knowledge gaps that will need to be addressed. Until Critical Habitat can be defined, the areas listed in the currently occupied habitat (Section 1.3) are considered the most important areas in need of conservation.

1.6.1 Schedule of studies to identify critical habitat

Further information is required before locations within the hotsprings complex may be considered critical habitat for Hotwater Physa. The following schedule of studies (Table 1) lists the activities recommended over the next 5 years to identify critical habitat.

Table 1. Schedule of studies recommended to identify critical habitat for Hotwater Physa.
Description of ActivityOutcome/RationaleTimeline
Develop assessment methodologyStandard survey protocol specifically to determine population abundance. Methodology needs to be repeatable and with minimal disturbance to the snails and habitat.2006–2007
Distribution surveysSurveys within the hotsprings aquatic habitat, to document habitat use patterns, abundance and population structure.2006–2011
Determine if there are additional viable populations/subpopulations of snails.2006–2011
Delineate parameters of habitat use and relate to population fluctuations. These factors will help define the components of the aquatic habitat that are critical to the snail.2006–2011
Identify critical habitat elementsDefine the abiotic (including water temperature and flow, and tufa formation) and biotic (including Chara and aufwich occurrence) factors and compare to snail distribution as determined from surveys.2007–2011
Determine the influence that stream dimensions, dynamics, pools and eddies and coarse woody debris and other substrates may have on the distribution of the snail
Identify elements considered to be critical to the snail's survival.

1.7 Actions already completed or underway

1.7.1 Protection

Hotwater Physa and their occupied habitat are contained within the Liard River Hotsprings Provincial Park, although the source of the geothermally heated water extends outside the park boundaries. Under the Park Act (BC) the disturbance or destruction of habitat within parks is prohibited except for the development of recreational services. Hotwater Physa has been incorporated into management activities in the Liard River Hotsprings Park Master Plan, although it has been a number of years since the plan has been updated (Elliott, pers. comm.). Since the last update, there have been a series of improvements in monitoring of recreational activities, including having parks staff present at the main publicly used sites, as well as considerable signage to park users. Bathers must shower (to clean off potentially deleterious substances such as sunblock and insect repellent) before entering the hotsprings, and park users must stay on marked trails and boardwalks and not block the weirs, alter stream flow, damage park facilities or riparian vegetation. There is currently little signage specific to the snails, however, as there is concern that signs may inadvertently encourage recreational users to search for the snail and take specimens from the park.

The Fisheries Act (Canada) prohibits works which may result in harmful alteration, disruption or destruction of fish habitat (Section 35) and prohibits the release of deleterious substances, such as contaminants, into fish-bearing waters (Section 36). The Fisheries Act applies to all fish habitat, therefore, it will provide protection of the source water from development inside and outside the park.

Hotwater Physa are protected under SARA from killing, harming, harassing, capturing or taking and from the destruction of their critical habitat once identified. Exceptions may be made under SARA to permit activities that benefit the species or are required to enhance its chances of survival in the wild. Such activities would include dam and weir maintenance that is required to maintain the integrity of Alpha Pool and Alpha Stream. SARA (Section 73) requires that such activities do not jeopardize survival or recovery of the species and are conducted in a manner that minimizes harm.

1.7.2 Population Monitoring

Revised Status Report on the Hotwater Physa in Canada is in preparation by Jacquie Lee, independent malacologist, for COSEWIC. Fieldwork is occurring in summer 2006.

1.8 Knowledge Gaps

Threats

  • The effects of changes to the aquatic and riparian habitats on Hotwater Physa.
  • Changes to water quality – it is unknown to what level the introduction of substances by bathers, including shampoos, soaps, sunblock, bath oils, and urine, and natural elements of the water, including mineral content, pH, temperature shifts, sediment disturbances, organic debris and changes to streamside structure alter the water quality and how this may affect Hotwater Physa.
  • The source of the geothermally heated water has been identified as being outside the park and the route that it takes before emerging within the park is unknown. Drilling into the source water at any point may markedly affect the flow of hot water within the Park. Mitigating the risks from drilling activities will require additional assessment and the development of new standards and guidelines.
  • Effects of introduced species.

Critical habitat

  • Spatial and temporal distribution of the snail within the hotsprings complex and the ability of the snail to disperse between areas. Subpopulations of the snail within the Liard River Hotsprings complex occupy small areas and are known to congregate spatially and temporally at certain sites (Alpha Pool, Alpha Stream and Beta Pool). It is unknown what factors limit the dispersal and occupancy of sites, in-between sites, or elsewhere within the hotsprings complex.
  • Habitat specificity, abiotic and biotic needs.

1.9 Importance to people

The Hotwater Physa is endemic to Liard River Hotsprings and, like so many endemic species, it therefore holds distinctive adaptations of special scientific and conservation interest (Scudder 1989). The species is not known to have any commercial value.

First Nations

There is no evidence of its use by First Nations or other people of BC. However, both the Fort Nelson First Nation and the Kaska Nation include Liard River Hotsprings within their traditional territories. The Kaska Nation is represented by five member bands located in northern BC. The Fort Nelson First Nation is part of the Treaty 8 Tribal Association.

Recreational users of Liard River Hotsprings

It is estimated that Liard River Hotsprings Provincial Park receives over 40,000 bathers to the hotsprings each year (Rowe, pers. comm.) and is a popular stop-over for visitors traveling the Alaska highway.

1.9.1 Anticipated conflicts or challenges

In the short-term, priority recovery activities will involve inventory and continued protection within the park, and there are few anticipated conflicts with these activities. Protection of habitat at known sites and management of this hotsprings habitat will likely require minimal changes to current practices however conflicts with recreational use of these areas is possible.  Identifying the underground route of the geothermally heated water from source to the hotsprings represents a significant challenge.  Mitigative measures to ensure that oil and gas or geothermal exploration do not impact on the hot water source has the potential for conflict. A potential long-term challenge will be to garner public support and research interest in this group of animals as there are currently few active researchers for these snails.