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Recovery Strategy for Hotwater Physa
Habitat and Actions
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 andCharagrowth, 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 Activity||Outcome/Rationale||Timeline|
|Develop assessment methodology||· Standard survey protocol specifically to determine population abundance. Methodology needs to be repeatable and with minimal disturbance to the snails and habitat.||2006 – 2007|
|Distribution surveys||· Surveys 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 elements|
· Define 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.
· 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.
|2007 – 2011|
1.7 Actions already completed or underway
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
- 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.
- 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.
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.
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