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Recovery strategy and action plan for the Banff springs snail (Physella johnsoni) in Canada
- 1.1 Species assessment information from COSEWIC
- 1.2 Description
- 1.3 Populations and distribution
- 1.4 Needs of the Banff springs snail
- 1.5 Threats
- 1.6 Actions already completed or underway
- 1.7 Knowledge gaps
The recovery program for the Banff springs snail is administered by the Banff National Park of Canada (BNP). The Cave and Basin National Historic Site of Canada (C&BNHS) is located within BNP and as such, it is subject to the Canada National Parks Act and its Regulations, but as a national historic site, it is also managed to preserve commemorative integrityFootnote 2 in accordance with the Management Plan of the site and its Commemorative Integrity Statement.
1.1 Species assessment information from COSEWIC
Common Name: Banff springs snail
Scientific Name: Physella johnsoni (Clench 1926)
Last Examination and Change: May 2000
Canadian Occurrence: Alberta
Reason for designation: Highly specialized species with extremely limited distribution subject to human disturbance and extreme fluctuations in population size.
Status History: Designated Threatened in April 1997. Status re-examined and designated Endangered in May 2000. Last assessment based on an existing status report.
The Banff springs snail is a small, globe-shaped snail with a short spire about the size of a kernel of unpopped corn. The maximum published shell length is 8.8 mm (Clarke 1973) although living animals with shells up to 11 mm in length have been observed. It is a member of the Family Physidae and therefore has a shell coiling to the left. Technical descriptions and illustrations are given by Clench (1926) and Clarke (1973). Recent systematic studies have confirmed that the Banff springs snail is a unique species based on morphological, allozyme, and mitochondrial DNA analyses (Hebert 1997; Lepitzki 1998; Remigio and Hebert 1998; Remigio et al. 2001).
1.3 Populations and distribution
The Banff springs snail is endemic to Canada, and has been documented from only 11 thermal springs in BNP (Figures figure1 and figure2, Table 1). It is ranked G1 globally and S1 in Alberta, the only province where it occurs (NatureServe 2006). The snail continues to exist naturally in five springs (Lower Middle, Cave, Basin, Upper Cave and Basin (C&B) and Lower C&B). It has been recently re-established into two springs (Upper Middle and Kidney), and both of these populations continue to persist. Three populations (Upper Hot spring, Gord’s spring, and Banff springs hotel site) are extirpated. It is questionable if the species ever existed at the Vermilion Cool springs (Lepitzki et al. 2002a). Four populations inhabit springs and outflow streams at the C&BNHS that are highly regulated by pipes, drains, and artificially maintained pools (Table 1). All populations can be considered individually because there is little opportunity for natural genetic mixing among the thermal springs (Lepitzki 2002a).
Figure 1. Distribution of the Banff springs snail
Description of Figure 1
Map showing the distribution of the Banff springs snail in Canada.
Figure 2. Location of Banff springs snail sites within Banff National Park
1 is the Upper Hot spring. 2 is the Kidney spring. 3 is Gord’s spring. 4 is the Upper Middle spring. 5 is the Lower Middle spring. 6, 7, 8, and 9 are the Basin, Cave, Lower, and Upper spring of the Cave and Basin National Historic Site. 10 is the Vermilion Cool springs. 11 is the Banff springs hotel site. I, II, and III are the three Vermilion lakes
Description of Figure 2
Map showing the location of Banff springs snail sites. It is also showing thermal springs, roads, CPR railway and the town of Banff.
As of the end of December 2005, the total global population was estimated to be nearly 34 000 snails (Figure 3). The snail’s population fluctuates annually by over two orders of magnitude. Populations generally fluctuate seasonally, increasing during the fall and decreasing during the late winter and early spring. The cause of this seasonal pattern is unclear.
There are no historic population levels recorded for the Banff springs snail at any spring, so long-term trends cannot be determined. The overall population trend for the past ten years (1996 through 2005) is significantly increasing if yearly minima, maxima, and mean population estimates are examined, but only if the two re-established populations are added to the original five springs (Lepitzki unpubl. data). Within each individual spring, the only discernible 10-year trend is found at the Basin Spring, whose yearly minima and mean population estimates have also significantly increased (Table 1, Lepitzki unpubl. data).
Population modeling using data from 1996 through 2002 has calculated the probability of extinction for five populations over 40 years (Tischendorf 2003). Results suggest that, when all five original populations are combined, there is no extinction risk within 40 years. However, some populations are more vulnerable than others. After 40 years, extirpation probabilities were less than 5% for the Basin and Upper C&B populations; 20% for the Cave population, nearly 30% for the Lower C&B population, and between 25 and 30% for the Lower Middle spring population (Tischendorf 2003). Uncertainty about several aspects of snail life history means that these figures should be cautiously interpreted (Tischendorf 2003).
|Spring||Site StatusFootnote a||Population (10 year)||Comments|
|Status||Mean||Max.||Min.||Trend (10 year)|
|Upper Hot||R, O||Extirpated||-||-||-||Currently no suitable habitat|
|Kidney||N, C||Re-established||1 542||8 852||8||Annual fluctuations||Re-established in Nov. 2003|
|Upper Middle||N, C||Re-established||5 068||16 247||16||Annual fluctuations||Re-established in Nov. 2002|
|Lower Middle||N, C||Extant||748||4 221||30||Annual fluctuations (indiscernible)|
|Gord’s||N, C||Extirpated||-||-||-||Snail shells only, spring dried fall of 2005|
|Cave||R, O||Extant||1 877||5 657||474||Annual fluctuations (indiscernible)||C&BNHS. Origin pool and outflow streams regulated|
|Basin||R, O||Extant||2 893||10 242||162||Annual fluctuations (significant increase)||C&BNHS. Origin pool and outflow streams regulated|
|Upper C&B||R, O||Extant||1 280||2 858||147||Annual fluctuations (indiscernible)||C&BNHS. Outflow stream regulated|
|Lower C&B||R, O||Extant||1 728||4 619||43||Annual fluctuations (indiscernible)||C&BNHS. Outflow stream regulated|
|Vermilion Cool||R, O||Occupied by Physella gyrina||-||-||-||Possibly erroneous historical record, spring may not have been occupied by Banff springs snail|
|Banff springs hotel||-||Extirpated||-||-||-||Site no longer exists, most likely resulted from water piped from Kidney and Upper Hot springs|
- Footnote A
Site status refers to whether the site is Regulated (R) by a complex pipe and drain system, or Natural (N), i.e. largely undisturbed and not controlled through artificial means and whether the site is Open (O) to the public or Closed (C), i.e. access is restricted to authorized personnel only.
Figure 3. Total number of Banff springs snails counted in population surveys from January 1996 to April 2006
Description of Figure 3
Line chart showing the total number of Banff springs snails counted in population surveys from January 1996 to April 2006 and population re-establishements for Kidney spring and Upper Middle spring.
1.4 Needs of the Banff springs snail
1.4.1 Biological and habitat needs
The Banff springs snail is highly specialized and has an extremely restricted micro-distribution within each spring. For example, more than 90% of the Cave Spring population is located in the origin pool, where the spring surfaces. Similarly, most snails in the Kidney, Lower Middle, Upper, and Lower C&B springs are found within 10 to 20 metres of the origin pool. Causes of the specialized micro-distribution are unknown. High snail numbers are correlated with higher water temperature, lower pH and dissolved oxygen, and higher hydrogen sulphide levels (Lepitzki 2002b). Declining hydrogen sulphide along outflow streams may limit sulphide-oxidizing bacteria, such as Thiothrix, and cause other changes in the microbial community upon which the snail grazes. Green algae such as Chara, another species of snail (Helisoma anceps anceps), and introduced mosquito fish (Gambusia affinis) appear to become more abundant as Banff springs snail numbers drop along outflow streams (pers. obs., Lepitzki). The Banff Springs Snail appears to be dependent on constantly flowing springs to maintain these conditions, as the species has been extirpated at four springs where flow stoppage has been recorded.
The natural function of the springs depends on the flow of warm, gas- and mineral- laden waters that are modified by a subterranean bacterial community (Lepitzki unpubl. data, Parks Canada 2003). Upon surfacing, interactions with the environment, and microbial, riparian, aquatic, and terrestrial communities result in abiotic and biotic gradients along the outflow streams. A summary of water physicochemistry parameters (water flow, temperature, pH, dissolved oxygen, conductivity, and sulphide) found at the ten existing springs where the snail has been recorded is located in Table 2.
Presumably, the Banff springs snail, like other physids, grazes on plant matter or Aufwuchs (a microscopic coating of plants and animals). Snails have been observed ingesting white-filamentous bacteria (pers. obs., Lepitzki). The diets of other physids (P. gyrina, P. integra) include dead and decaying vegetation and living algae, water molds, diatoms, filamentous algae, green and blue algae, rotifers, crustaceans, pieces of arthropods, small amounts of vascular plant tissue and sand grains (Dewitt 1955; Clampitt 1970). It is likely that the diet of the Banff Springs Snail is similar, although studies have not confirmed this. Microbial mats, consisting of bacteria, algae, sticks, and vascular plant leaves, are frequently the substrate to which snails are attached, and serve a structural habitat function as well.
|Thermal spring||Water physicochemistry (spring origin)|
|Upper Hot||545Footnote b|
|Kidney||55Footnote c or 91Footnote b|
|Upper Middle||228Footnote b 250-1240Footnote f||34.1-37.3||6.93-7.29||0.08-1.80||1148-1402||0.134-5.599|
|Lower Middle||62-120Footnote f||34.1-37.3||6.92-7.42||0.15-2.51||1145-1411||0-5.599|
|Gord’s||To Be Determined||4.8-35.2||6.94-7.78||0.10-6.75||1149-1517||0.013-4.060|
|Upper C&B||64Footnote d||29.7-34.4||6.69-7.38||0.03-11.55||1033-1347||0-5.011|
|Lower C&B||486Footnote d||30.2-35.3||6.84-7.74||0-4.67||1030-1330||0-2.865|
|Vermilion Cool||228Footnote b or 750Footnote e||17.1-21.4||7.00-7.70||0-2.20||543-718||0-1.771|
|Banff springs hotel||-||-||-||-||-||-|
- Footnote A
Instantaneous flow rates:
- Footnote B
- Footnote C
Grasby and Lepitzki, unpubl. data;
- Footnote D
Van Everdingen and Banner 1982;
- Footnote E
Van Everdingen 1972 and seasonal range
- Footnote F
Hayashi 2004, Schmidt 2005.
The snail is most likely hermaphroditic, or capable of self- or cross-fertilization, as are other physids (Clarke 1973; Dillon 2000). Reproduction likely occurs year-round, as reproduction in other physids is triggered by a minimum temperature (Dewitt 1955, 1967; Sankurathri and Holmes 1976). Egg capsules are normally found at or slightly above the water’s surface, attached to a hard substrate such as the concrete pool wall, floating microbial mat, sticks, and live snail shells, suggesting that atmospheric oxygen may be required for development (Lepitzki, 1998, 1999, 2000a). Recently, systematic and detailed basic resource inventories (Parks Canada 1992) were undertaken for some of the thermal spring ecosystems in BNP (Rice 2002; Wallis 2002; Hebben 2003; Krieger 2003; Lepitzki and Lepitzki 2003; Londry 2004; Yurkov 2004). Results indicate that the thermal springs contain high numbers of rare species in a number of taxonomic groups.
1.4.2 Ecological role
Just as large carnivores such as grizzly bears are used to indicate the ecological integrity of large ecosystems, the health of the thermal spring ecosystems on Sulphur Mountain may be indicated by the Banff Springs Snail. The extinction of the species would be a loss of biodiversity and the thermal spring ecosystems could shift due to the loss of this important grazer (Hebert 1997). Blooms of algae and bacteria could result and organisms potentially dependent on the infusion of snail excrement and shell material may suffer irrevocable harm (Lepitzki et al. 2002a).
The Banff Springs snail may also provide a food source for some waterfowl, shorebirds and garter snakes (see below). Other roles it serves in the hot springs ecosystem are not well understood.
1.4.3 Limiting factors
The greatest natural limiting factors of the Banff Springs Snail are its limited habitat availability and large population fluctuations, leading to isolated and extremely low populations found in some springs at certain times of the year. The snail is a habitat specialist that is dependent on some of Banff’s thermal springs, and it has been extirpated from four thermal springs where water flow stoppages have recently been recorded.
Predation may also occur at some springs. Predation is suspected by mallards (Anas platyrhynchos), blue-winged teal (Anas discors) (Dirschl 1969; Swanson et al. 1974; Taylor 1978), common snipe (Gallinago gallinago), robins (Turdus migratorius), varied thrushes (Ixoreus naevius), and garter snakes (Thamnophis elegans) (Russell and Bauer 1993). All of these species have been observed at the thermal springs (Lepitzki unpubl. data) but predation has not been confirmed.
Competition for food by soldier fly larvae (Stratiomyidae), which have a diet very similar to freshwater snails (Pennak 1978; Clifford 1981), may also occur in the thermal springs on Sulphur Mountain (Lepitzki 1997a,b).
1.5.1 Threat classification
Please refer to Table 3.
|Threat||Type||Status*||Upper Hot||Kidney||Upper Middle||Lower Middle||Gord’s||Cave||Basin||Upper C&B||Lower C&B||Vermilion Cool|
|Thermal water flow - stoppages||N||C||H||H||H||H||H||H||H||H||H||-|
|Flow – reductions/fluctuations||N||C||H||H||M||L||M||L||L||L||L||-|
|Flow – reductions/fluctuations||FO||C||H||-||-||-||-||H||H||L||M||-|
|Thermal water flow -redirections||N||C||L||L||L||L||L||L||L||L||L||-|
|Thermal water flow -redirections||FO||C||H||-||-||-||-||H||H||L||M||-|
|Limited or low quality habitat||N/FO||P||M||M||M||M||M||M||M||M||M||-|
|Soaking and Swimming||Hu||C||M||M||M||L||L||M||M||M||L||-|
|Pop’n lows & genetic inbreeding||N||P||UNK||M||L||M||UNK||L||L||M||M||-|
|Trampling / local disturbance||Hu||C||M/L||L||L||L||L||M/L||M/L||M/L||L||M|
|Others (collecting, predation, competition, twitch-ups)||Hu/N||P||L||L||L||L||L||L||L||L||L||-|
Threats listed in order of certainty and severity (vertically) and among springs (horizontally). Type refers to whether it is naturally (N) occurring, caused by facility operations (FO), or humans (Hu). Status refers to whether the threat is Confirmed (C - there is evidence that the threat results in mortality or decreased reproductive success, etc.) or Potential (P - could be very likely but there is no evidence that it causes harm, often because confirmation studies have not yet occurred). The severity of the threat to the species or habitat is also indicated as high (H), medium (M), or low (L). Threats at the Upper Hot and Gord’s Springs are anticipated if the species was re-established. A dash (-) indicates that the particular threat does not occur at that thermal spring, UNK indicates unknown.
1.5.2 Description of threats
Threats are described below in order of certainty and severity.
Thermal water flow stoppages, reductions, and redirections
Thermal water flow stoppages are a threat with localized but severe consequences. Periodically, some of the thermal springs on Sulphur Mountain stop flowing. While it is normal for flow rates to decrease as underground reservoirs are depleted of water during late winter and early spring (Van Everdingen 1970, 1972; Grasby and Lepitzki 2002), there is evidence that flow stoppages are increasing. The only historically recorded instance of any Sulphur Mountain thermal spring drying is the Upper Hot Spring in 1923 (Elworthy 1926; Warren 1927). However, the Upper Hot Spring has ceased flowing every winter from 1998 through to 2005 (Lepitzki 1999, 2000a, 2002b, unpubl. data; Grasby and Lepitzki 2002). Flow stoppages have also been recently documented from Kidney Spring (Grasby and Lepitzki 2002; Lepitzki 2003), Upper Middle spring (Lepitzki 1997b), and Gord’s spring (Lepitzki unpubl. data).
The effects of thermal spring flow cessations on the Banff Springs Snail are detrimental, as populations of the Banff Springs Snail have been extirpated from the four thermal springs where water flow stoppages have been recorded. These flow stoppages could threaten re-establishment success at Kidney and Upper Middle springs, and potential re-establishment efforts at the Upper Hot and Gord’s springs. Coupled with already low population levels, thermal spring drying would result in the depletion or local extirpation of snail populations. Below normal precipitation may be the cause for the recent reduced flows (Grasby and Lepitzki 2002) and continued flow anomalies may be expected due to climate change (Scott and Suffling 2000).
Natural, seasonal reductions in water flow rates could also threaten snail populations, however, as the magnitude of seasonal flow fluctuations is not equal among all springs (Table 2), the severity of the threat also varies (Table 3). The threat of flow re-direction is small because natural re-directions typically occur downstream of areas containing high snail numbers. Re-directions may occur due to tufa mound build-up, debris deposition, or erosion.
Thermal water flow stoppages, reductions and redirections can also result from facility operations at regulated springs (Tables table1 and table3). The prioritized diverting of water to the bathing facility and re-directing chlorinated, used pool water into the outflow stream significantly reduces potential snail habitat for re-establishment at the Upper Hot spring. Without the periodic cleaning and flushing of drains, valves, and pipes at the C&BNHS, they become clogged with microbial mat and other debris that cause flooding and damage cultural resources. Changes in water levels in the Basin and Cave pools require the manipulation of valves. It is suspected that adult snails can cope with gradual decreases or increases in water levels (pers. obs., Lepitzki) but drastic drops (up to 50 cm in less than 15 minutes) have stranded many snails. This necessitates washing snails into the water before they desiccate or freeze. Snail eggs have only been found at the water’s surface, possibly as a consequence of very low levels of dissolved O2 (Lepitzki 1999, 2000a, 2002b) and the presumed requirement of oxygen for development. Water level changes in the Basin and Cave pools could result in the termination of snail embryo development by asphyxiation or desiccation for those eggs attached to the pool walls (Lepitzki 2000a).
Valves and pipes also control the amounts of water in the various outlet streams at the C&BNHS. These valves and pipes periodically become clogged with microbial and other debris, redirecting water flow. This has resulted in the loss and lowering of outflow stream snail populations.
Limited or low quality habitat
Due to its extremely limited distribution and habitat requirements, some populations of the Banff springs snail may be very susceptible to extirpation. In general, additional populations would reduce the probability for species’ extinction. Similarly, increasing snail numbers within individual populations would reduce the probability for population extirpation. Some built structures (outlet streams) and operations at the Upper Hot and C&BNHS may limit the quality of habitat thereby limiting the number of snails occupying or potentially occupying the habitat. For example, the rapid discharge of water through piping into steep terrain at some of the outflow streams at the C&BNHS diminishes the habitat’s capacity to support snails.
Soaking and swimming
Soaking and swimming are documented threats with localized but occasionally severe consequences. Entering and exiting pools can crush snails and disrupt the floating microbial mat causing both the mat and snails to become stranded above the water line. Dislodged microbial mats clog pipes, affecting water drainage in regulated pools. Swimming can alter water clarity and water levels. Chemicals such as suntan oil, deodorants and insect repellents could impact snails and their habitat. Significant alterations in water physicochemistry have been detected following swimming events, as have significant changes in snail microdistribution (Lepitzki 1998, 1999). Others (Kroeger 1988; Lee and Ackerman 1999) have speculated that the addition of toxic substances (e.g. soap, shampoo, oil) by bathers may threaten hot springs flora and fauna. Confirming chemical toxicity to the Banff springs snail and its habitat could be challenging.
Swimming and soaking are not permitted at any of the springs where the Banff springs snail is found, and are prevented by surveillance, fencing and signage. Despite these efforts, some illegal swimming and soaking continue. Effects can be severe. Snails died during two 2005 incidents when pipes draining the Basin Pool became clogged with debris and the pool flooded, stranding thousands of snails in freezing temperatures.
Population lows & genetic inbreeding
Although snail populations fluctuate naturally, extremely low population numbers in some years may increase the risk that some populations are extirpated. Monitoring has revealed that all populations fluctuate seasonally, although the causes are unknown. Demographic models indicate that the entire population shows no risk of extinction due to demographic factors alone (Tischendorf 2003). However, this modeling is based upon a limited understanding of certain demographic parameters. Low seasonal populations should still be considered a potential threat, especially in those springs where extremely low numbers have been documented (Tables table1 and table3).
A consequence of seasonally low populations is genetic inbreeding. The extent to which genetic inbreeding constitutes a threat to the Banff springs snail is not known. Hebert (1997) found very limited polymorphism, although this was not unexpected given that the snails are probably hermaphrodites and that other in-breeders have also shown impoverished levels of allozyme variation. Perhaps the only opportunity for genetic mixing occurs among the four populations at the Cave and Basin thermal spring complex during years of abnormally high spring run-off. Unless snails are transported by humans or birds, (Roscoe 1955; Rees 1965; Malone 1965a,b, 1966; Dundee et al. 1967; Boag 1986) there appears to be little opportunity for genetic mixing among the Kidney and Middle spring populations and those at the Cave and Basin complex. Because this is likely a natural situation, genetic inbreeding is considered a potential but unconfirmed threat.
Trampling and other local disturbance
Trampling and other disturbance (e.g. littering, substrate movement or removal, dam construction) likely have a variable impact on Banff springs snail populations that is related to site visitation rates. Some effects have been observed at all springs. Trampling of fragile riparian habitat occurs when people or dogs walk along outflow streams or at the edges of thermal spring origin pools. While the boardwalks and barrier fencing at the C&BNHS prevent much damage, footprints are found along the outlet streams, or adjacent to origin pools. Removal or movements of substrates including the microbial mat, rocks, and sticks, the preferred micro-habitat of the snail, have been observed at all sites. Crushed, frozen and desiccated adult snails have been documented adhering to moved substrates. The tossing of garbage, coins, snow balls, ice chunks, rocks, and logs have been detected (Lepitzki et al. 2002a). The addition of coins containing copper may be particularly damaging as copper sulphate was used as a molluscicide (Swales 1935). Even the removal of garbage from the thermal springs by well-meaning visitors could result in the death of snails and eggs if the garbage is not first examined carefully for the small snails and cryptic eggs.
The dipping of feet or hands is a potential threat to the Banff springs snail, although its effects on the thermal spring environment are unknown. Like swimming, it may lead to the crushing of snails and the addition of toxic substances, but this is difficult to document. Limb-dipping is widespread and occurs with regularity, especially at the C&BNHS (Lepitzki 2000b; Thomlinson 2005). A study involving the observation of visitor behaviour in 1999 and 2000 determined that on average, 73% of visitors to the Cave spring dipped their hands in the water (Lepitzki 2000b). Substantially fewer individuals did so at the other thermal springs (12%, 6%, and 8%, Basin, Upper, and Lower springs, respectively), possibly because kneeling is required to reach the water. Since nearly 165 000 people visited the Cave and Basin springs during 1998/99, over 120 450 people could have dipped their limbs into the Cave spring water. Thomlinson’s (2005) social science study re-affirmed limb dipping within the Cave and Basin springs and suggested that many of the individuals who limb dipped were unaware that this activity was not allowed. With limb-dipping occurring at all sites, it should be considered a potential widespread threat, and its effects on snail populations confirmed.
Threats due to environmental stochasticity (e.g. disease, storms, flood) have not been studied and are virtually impossible to quantify but could have severe, local effects. In general, evidence indicates that stochastic impacts may increase as population size decreases (Lande 1993). The Banff springs snail may be very susceptible to catastrophic population loss, even through a single unpredictable chance event. Although only a potential threat, the fact that no other populations exist globally to recolonize sites magnifies its severity. Tischendorf (2003) commented that the main reason for increased probability of extinction over time in the Banff springs snail population modeling was due to propagation of stochastic events.
Predation and competition are natural threats with which the species has evolved. However, they could result in extirpation of a population when combined with other threats, especially when snail populations are at their lowest. Similarly, trees adjacent to outflow streams form another natural mortality factor. During heavy, wet snowfalls branches become laden with snow and bend into the stream. Bacteria and snails colonize the immersed branches. When the snow anchor melts, the branch and its accompanying bacteria and snails rise out of the water, and freeze. Over 40 and 60 of these “quick-frozen” snails have been found in two separate incidents along the Lower Middle and Basin spring outflow streams (Lepitzki 1998). It is possible that public awareness may result in illegal shell collection and may require enhanced enforcement.
1.6 Actions already completed or underway
BNP has undertaken many recovery and management actions to date, many of which are outlined in the Resource Management Plan (Lepitzki et al. 2002a).
Direct habitat protection measures have reduced impacts and will continue. The Sulphur Mountain Wildlife Corridor (containing two inhabited thermal springs – Upper and Lower Middle) has been established, permanently closed to unauthorized persons and enforced through regular patrols and electronic surveillance. Closure and fencing of the re-establishment site at Kidney spring has occurred. Swimming has ceased at the C&BNHS pools. Starting in 1997, illegal swimming at the Basin spring pool has been reduced through signage, fencing, installation of a security system, and the apprehension and conviction of several individuals. Frequency of intrusions has further declined with additional signage and audio alarms. Restrictive signage was first placed at the C&BNHS springs in 1997, and has been augmented in subsequent years.
Because the C&BNHS is also a national historic site and an integral part of the history of Canada’s National Park system, eliminating public access for the purposes of snail protection is not an option. However, The Commemorative Integrity Statement (Parks Canada 1998) for the Historic Site recognizes that protection of snail habitat enhances and supports heritage values at the site.
Changes in management practices have also occurred. Janitorial and technical trades staff have modified some activities that previously impacted the snail and its habitat. For example, the use of chemical de-icers along the Basin spring pool boardwalk has stopped since at least 1999. A preliminary resource reconnaissance following the Natural Resources Management Planning Process (Parks Canada 1992) has occurred for some sections of some thermal springs.
A Research and Recovery Program was initiated in 1996. Population monitoring and measurement of physicochemical parameters have been completed regularly since the program began. A captive breeding program in aquaria was initiated in 1997 and decommissioned in 2006 (Lepitzki et al. 2002a; Lepitzki 2004). The captive breeding program has led to information on the successful rearing of snails, examination of various reproductive parameters, and the ability to maintain snails in tap water (as may occur if a thermal spring naturally dried).
Based on direction given in several assessments and discussion papers (Lepitzki et al. 2002a; Lepitzki and Pacas 2001, 2002, 2003), snail populations have been re-established at the Upper Middle and Kidney springs. Fifty snails were translocated from Lower Middle spring to re-establish the Upper Middle spring population in November 2002. Fifty snails (25 from Lower Middle and 25 from Upper Middle) were subsequently translocated to Kidney spring in November 2003. Following initial population drops, both populations increased and have undergone annual fluctuations similar to those observed at the other thermal springs. Both re-establishments appear to be successful.
Since 1997, communications strategies have directed actions aimed at key target groups to reduce disturbance to the snail and its habitat. Interpretive programs have undertaken public education about the Banff springs snail. Interpretive displays now introduce the public to the snail and efforts toward recovery. Information on the snail has been added to brochures and other Park publications. Other initiatives including posters, public and scientific presentations, press releases, fact sheets, magazine articles, and articles in local, regional, national, and international media, continue to raise public awareness of this species.
1.7 Knowledge gaps
The Recovery Team identified the following areas where more information is required.
- Analyze ten years of population and distribution data
- An evaluation of the population data in order to determine the level of monitoring surveys required to detect population trends
- Continue to study the diet and ecological role of the Banff springs snail
- Refine knowledge of demographic parameters (e.g. fecundity, longevity, etc.) in order to enhance population viability analyses with increased confidence.
- Improve knowledge of thresholds of tolerance to physicochemical parameters
- Confirm the extent to which limb-dipping, thermal flow stoppages, and genetic inbreeding threaten the Banff springs snail
- Confirm that operational, protection and communications actions result in a reduction in human impacts to the snail and its habitat
- Confirm public awareness of the snail, habitat and threats to its survival
Detailed actions that will help to fill knowledge gaps are identified in Table 4.
- Footnote 2
Parks Canada is committed to protecting “ecological integrity” in National Parks and ensuring “commemorative integrity” at National Historic Sites. Protecting these takes precedence in acquiring, managing, and administering heritage places and programs. The integrity of natural and cultural heritage is maintained by striving to ensure that management decisions affecting these special places are made on both sound cultural resource management and ecosystem-based management practices. Commemorative integrity means protect, present and manage cultural resources.
- Date Modified: