Banff Springs Snail (Physella johnsoni): COSEWIC status appraisal summary 2018

Official title: COSEWIC Status Appraisal Summary on the Banff Springs Snail (Physella johnsoni) in Canada 2018

Committee on the Status of Endangered Wildlife in Canada (COSEWIC)
Endangered 2018

COSEWIC assessment summary

Assessment summary – April 2018

Common name: Banff Springs Snail

Scientific name: Physella johnsoni

Status: Endangered

Reason for designation: This is a Canadian endemic species with a distribution entirely within the upper reaches of fewer than five separate clusters of thermal springs in Banff National Park, Alberta. These short-lived animals undergo extreme natural annual fluctuations in numbers. This snail is a habitat specialist requiring a steady supply of warm thermal-spring water containing a high concentration of dissolved minerals and a complex microbial community that provides food and habitat. All thermal springs historically or currently occupied by this species have been impacted by human activities. Habitat disturbances continue but the effects of climate change (increased frequency of springs drying and storms with more rain) also are important threats to this species’ survival.

Occurrence: Alberta

Status history: Designated Threatened in April 1997. Status re-examined and designated Endangered in May 2000, April 2008, and April 2018.

COSEWIC status appraisal summary

Banff Springs Snail

Physe des fontaines de Banff

Physella johnsoni

Range of occurrence in Canada: Alberta

Status history

COSEWIC: Designated Threatened in April 1997. Status re-examined and designated Endangered in May 2000, April 2008, and April 2018.

Evidence (indicate as applicable)

Values for EOO and IAO are still well below thresholds and subpopulations still undergo fluctuations in number of individuals of up to two orders of magnitude. Continuing decline in area, extent and quality of habitat is applicable because of the various threats, including thermal spring drying. COSEWIC’s interpretation of “severe fragmentation” has changed since the previous assessment and is probably no longer applicable.

Wildlife species

Change in eligibility, taxonomy or designatable units:

No

Explanation

Shell morphology, allozymes, and mtDNA suggest significant differentiation between Physella johnsoni and its apparent sister species, Physella gyrina (Tadpole Snail), a ubiquitous freshwater snail found throughout much of North America (COSEWIC 2008); however, not all authorities agree. Additional genetic analysis using DNA microsatellites was suggested to further investigate the relatedness within Physidae. But, if P. johnsoni was synonymized with P. gyrina, the Banff Springs Snail population could then be considered as a Designatable Unit (COSEWIC 2008), meeting many of the criteria for evolutionary significance and discreteness.

Three undergraduate research projects have been completed since COSEWIC (2008) and used microsatellites (Muise 2012 but no report produced; Pink 2013; and Petterson 2014). In 2012 Muise (no report produced) characterized several dozen markers but only a few were found to be variable and potentially useful. The specific Physella subpopulations from which the pedal mucus was originally collected are uncertain but included some from the Cave and Basin and Middle Springs areas (see COSEWIC 2008 for explanations of subpopulation structure and Range).

Pink (2013) tested three loci using mucus from P. johnsoni collected from the Basin Spring Pool (n=26 individual snail samples) and Lower Middle Spring (n=29). Only three individual snails from the Basin and six from Lower Middle showed alleles on the produced electropherogram. While there was allelic polymorphism both between and within subpopulations at 2 loci, there was no allelic polymorphism at the third locus. A between population Fst value of 0.4724 was found at one locus but Fst values of 0.000 were found at the other two loci. The total Fst value between the two subpopulations was 0.2793. Fst values derived from small sample sizes are suggested to be unreliable (Pink 2013). The presence of allelic polymorphism suggested there was some genetic variation within subpopulations (Pink 2013). In addition, the presence of a high fixation index between subpopulations suggests there was no gene flow between them, although sample sizes were small (Pink 2013). Increased sample sizes including additional loci would likely result in a lower Fst value (Pink 2013).

Pettersen (2014) used the same samples collected by Pink (2013). Four primers successfully amplified microsatellite DNA, two of which were polymorphic (Phjo 5561 and Phjo 301) and yielded an Fst value of 0.43172. While this suggested a considerable degree of genetic differentiation between the Basin and Lower Middle subpopulations (Pettersen 2014), the Structure Harvester statistical program suggested there was a single population. Pettersen (2014) suggested these results were unreliable because that program needs a minimum of seven polymorphic loci to accurately determine the presence of one or two populations. Both these contradictory conclusions of Pettersen (2014) as well as the conclusion of Pink (2013) are based on limited quantities of DNA and genetic markers.

Range

Change in Extent of Occurrence (EOO):

No

Change in Index of Area of Occupancy (IAO) :

No

Change in number of known or inferred current locations^{Footnote 1} :

No

Significant new survey information

Yes

Explanation

The range map in COSEWIC (2008; reproduced here as Figure 1) is still accurate and reflects the current range of P. johnsoni.

The Extent of Occurrence (EOO) has not physically changed from COSEWIC (2008). But because an Index of Area of Occupancy (IAO) based on 2 km x 2 km grid squares was not calculated for the previous assessment, EOO has been increased to match the IAO based on the 2 km x 2 km grid as per IUCN and COSEWIC convention.

All historically occupied thermal springs have continued to be monitored since May 2007 (the end date for the previous status report; COSEWIC 2008) once every four weeks (quad-weekly) using the same personnel and protocol established in January 1996 although the intensity of monitoring changed beginning with the winter of 2016 to 2017 (see Population Information). COSEWIC (2008) summarizes the methodology.

Since the previous status report (COSEWIC 2008), unidentified physid snails have been observed in three other localities. However, these localities would fit within the previously determined EOO and IAO if these snails prove to be P. johnsoni and would be included in the previously determined number of locations (see COSEWIC 2008 and attached Technical Summary for discussion on number of locations).

Physid snails were first observed in West Cave, a spring in the Middle Springs area, beginning in October 2009 and have been present since. This spring has been visited and monitored since January 1996 and flows to within 7 metres of the Upper Middle Springs. It was never considered a historically occupied site because of its habitat characteristics, i.e., cooler and seasonal temperature profile and visually different microbial community in contrast to other springs (Lepitzki 2007, 2013, 2014, 2015, 2016). It was not even mentioned in COSEWIC (2008) and bottom sediments were never examined for physid shells. It is uncertain if the physids occupying this spring are P. johnsoni. Although snails in this subpopulation have been counted, it is not included in the overall population counts (see Population Information). The maximum number counted is 520 (13 February 2016; Lepitzki unpubl. data for Parks Canada). It is also uncertain if they or those from Gord’s Pool (next paragraph) were used by Muise to initially characterize microsatellites.

Beginning in October 2010, unidentified physids were observed at Gord’s Pool, another cooler spring in the Middle Springs area (Lepitzki 2013, 2014, 2015, 2016). This spring was previously considered to be a historical locality for P. johnsoni because physid shells, “most likely P. johnsoni”, were found in the bottom sediments of the outflow stream (COSEWIC 2008). This spring only began to be regularly visited and monitored in 2001 and was not occupied by snails until October 2010. This spring is typically cooler than the other monitored springs occupied by P. johnsoni and has an anomalous seasonal temperature and drying pattern (Lepitzki 2007, 2013, 2014, 2015, 2016; also see below). Due to time constraints, complete population counts (see Population Information) never occurred.

Thermal water ceased flowing at Gord’s Pool from October 2012 to May 2013 and then again from November 2013 to May 2014 (Lepitzki 2013, 2014, 2015, 2016) similar to the winters of 2005 to 2006 and 2006 to 2007 (COSEWIC 2008). This physid subpopulation was extirpated because of this drying event. No live physids were observed after the water began flowing in May 2014 until they were observed beginning in September 2015 (Lepitzki 2016). Dead snails were salvaged in October 2012 but DNA was too degraded for use.

As part of the Cave and Basin (C&B) redevelopment project (Highwood 2010), during which the Cave and Basin National Historic Site closed to the public from July 2010 until May 2013, a thermal water touch feature was installed. This allows visitors to legally touch thermal spring water during the summer operating season. Because it uses thermal water from an additional source that was not designated Critical Habitat (Lepitzki and Pacas 2007, amended 2010) and the water then drained into the sanitary sewer, it has no impact on P. johnsoni or its designated Critical Habitat. No physids were observed in the original water source expected to be used for this touch feature: thermal water seepage collected in a chase; however, another source (from a concrete cistern in the basement of the C&B building) which also results from thermal water seepage, was ultimately used. This source was not examined for aquatic life before it began to be used for the touch feature. Beginning in June 2013, shortly after the site was reopened to the public and the touch feature was operational, a few unidentified live physids (maximum 31 removed per week) and physid shells began to be observed in the touch feature (Lepitzki 2014). The concrete cistern source was examined and physids were observed. A change in the configuration of the pump supplying water to the touch feature resulted in physids (six shells) only being observed in October of the following year. While both live and dead amphipods were observed in the touch feature during the summer of 2015, no physids were seen in 2015 (Lepitzki 2016). Physids again were observed in the touch feature beginning in July 2016 with the maximum number (n=8) being observed in October (Lepitzki unpubl. data). One dead physid was observed in the touch feature in September 2017 which was then drained for the season two weeks later.

The identity of these physids also is uncertain. When physids were first observed in the touch feature in June 2013, it was recommended that some be collected and genetically analyzed (Lepitzki 2014). This did not occur and they are not part of the current SNPs (single nucleotide polymorphisms) study. They could be a remnant subpopulation of P. johnsoni that has been isolated from natural subpopulations because the public swimming pools used thermal spring water from the Cave and Basin springs before the 1995 redevelopment. All piping infrastructure was in the basement of the building; physid shells have been observed and photographed in an old valve that used to be stored in the basement (Lepitzki pers. obs.).

Population information

Change in number of mature individuals:

Yes

Change in population trend:

Yes

Change in severity of population fragmentation:

No

Change in trend in area and/or quality of habitat:

Yes

Significant new survey information:

Yes

Explanation

Snail subpopulation counts occurred continuously from January 1996 through September 2016 using the same methodology, frequency, and personnel as summarized in COSEWIC (2008), and resumed from April through September 2017 (Figure 2). Snails are not counted during the winter but all sites are visited every four weeks. Snail subpopulations have continued to exhibit a seasonal pattern with population peaks during the winter (when thermal water is warmest) and lows during the summer (when thermal water is recovering from its spring time minimum). Since May 2007, the end-date for the previous assessment (COSEWIC 2008), new subpopulation minima were observed at three springs: Kidney, Cave, Lower C&B (Table 1).

Thermal water ceased flowing at Kidney Spring for 8 to 12 weeks sometime between 18 February and 14 March 2011, but resumed flowing by 13 May a year after very low flow rates were recorded in late-winter 2009 to 2010 (Lepitzki 2012; Figure 3). This was the second known instance of this thermal spring drying (COSEWIC 2008). The 2011 drying event was predicted based on temperature and surface flow patterns recorded at Kidney and adjacent springs (Lepitzki 2011). Parks Canada decided not to intervene or try to salvage and maintain snails ex situ (Parks Canada 2011).

During this drying event, no live snails were observed for four quad-weekly surveys: from 18 March through 10 June 2011 (Figure 2; Table 1). However, six live snails were observed on the 8 July 2011 survey (Figure 2), and this subpopulation survived the drying event.

While all subpopulations fluctuate annually, annual minima and peaks do not occur simultaneously among the seven subpopulations (Figure 2). Combining subpopulation counts makes the overall population fluctuation more evident; however, the pattern and magnitude of the overall population fluctuation is highly dependent on the pattern occurring in the subpopulations that contribute most to the global population. During certain years and certain times of the year, more snails are found at the re-established Upper Middle Springs subpopulation than at all others combined, perhaps because of the amount of available habitat (see Table 1 in COSEWIC 2008 – while more sq. m. of habitat is available in the Cave, much is not high quality i.e., warm, flowing water habitat with abundant microbial community). Similarly, the long-term overall global population trend, which appears to be declining since 2005, is dependent on what is occurring at the Upper Middle Springs subpopulation (Figure 2).

The annual population minima over the last 10 (or 11) years for the original five subpopulations and for all seven subpopulations combined declined non-significantly by 21.4% and 14.1% respectively (Figure 4; Table 2). Trends for these groups of springs are shown separately because the re-establishments more than doubled the number of snails, obscuring the trend for the original five natural subpopulations (see also Summary and Additional Considerations). The seven subpopulations combined include the Upper Middle Spring and Kidney Spring subpopulations, re-established in November 2002 and November 2003, respectively (COSEWIC 2008). Annual minimum counts were below 10,000 for six of the past 10 years (2007 to 2016) for all springs combined (Figure 4). While it is uncertain if the Upper Middle Springs subpopulation reached its low in 2017 after counts ceased in September (Figure 2), there were only 8506 snails counted in all seven springs combined in early June 2017 suggesting the minimum in 2017 also was below 10,000. Annual maxima declined significantly by 36.9% and 26.5% for both groups. Because population peaks could occur before or after 1 January, annual maxima may not coincide with population peaks between the annual population lows. The declining 10-year trends for the population peaks, 29.1% and 9.6%, for the original five and all seven, respectively, are statistically significant (Figure 4; Table 2). These declines in the two groups reflect the trends in the Basin and Upper Middle springs subpopulations, the two subpopulations with the largest number of snails.

The previous 10-year population trends for annual minima and maxima for both the original five and all seven subpopulations combined were all positive and, with the exception of the minima for the original five, statistically significant (COSEWIC 2008).

Threats

Change in nature and/or severity of threats:

Yes

Explanation

Threats, including limiting factors, were scored as having a high, medium, or low impact for each thermal spring in COSEWIC (2008; modified from Lepitzki and Pacas 2007, amended 2010). All these threats and limiting factors are still applicable and have now been arranged into the IUCN / COSEWIC threats assessment categories (see Technical Summary).

Flow stoppages, most likely caused by changes in precipitation patterns as a result of climate change, is still the most serious, plausible threat to the species (see COSEWIC 2008 for an explanation of how the springs operate along the Sulphur Mountain Thrust Fault). As suggested in COSEWIC (2008), what was once a rare occurrence, a thermal spring drying, has now become the norm. An update to the drying pattern of the thermal springs in Banff since 31 December 2006 (the end date for COSEWIC 2008) is provided (Figure 3). The Upper Hot has ceased flowing for 16 of the past 22 years of monitoring, with only a trickle observed flowing on 10 February 2018, while Kidney Spring has dried twice (2002 and 2011). The two late-winter drying events at Kidney were preceded by the Upper Hot drying the previous fall (Figure 3) suggesting that temperature and flow patterns can be used to predict drying events.

The drying pattern at Gord’s Pool Spring (Figure 3) is also indicative of the amount and timing of precipitation and therefore water in the underground thermal spring system along the Sulphur Mountain Thrust Fault. For some unknown reason, when there is more water in the Sulphur Mountain thermal spring system, Gord’s Spring dries, as occurred during the years 2005 to 2007 and 2012 to 2014 with 2005, 2012, and 2013 being exceptionally wet with heavier rains in early spring, during the summer, or the fall. The June 2013 floods in southern Alberta were caused by heavy rainfall and rapidly melting alpine snow (Pomeroy et al. 2016). However, when Gord’s dries, the Upper Hot does not (Figure3). During these exceptionally wet years, water temperatures in the springs reach atypical low minima and do not quickly recover after their spring-time temperature lows (Figure 5). Coincidental with the abnormally wet years, lower than typical water temperature minima, and slow water temperature recovery, snail subpopulations are also lower than typical (Figure 6). The conclusion from these simultaneous patterns is that too much water at the wrong time of year is also a threat to this species.

Observations on habitat disturbance and human intrusion into legally closed areas occur at the same frequency as do snail population and water physicochemistry monitoring (Lepitzki 2012, 2013, 2014, 2015, 2016). The prevalence of habitat disturbance has been zero (there have been none at Kidney and, Lower Middle) or very low (one incident at Upper Middle in 2012) since 2009 at springs within the full closures. Installation of audio alarms, triggered by entering the closures, cameras, and silent alarms have all contributed.

Because of various protection actions and the multi-year closure (due to the redevelopment), the interpretation of the prevalence of habitat disturbance at the Cave and Basin National Historic Site is complicated. A few conclusions (Lepitzki 2012, 2013, 2014, 2015, 2016) can be made:

Habitat disturbance and snail mortality caused by humans continue to occur. The prevalence of disturbance varies throughout the year but increases during the summer when visitor numbers increase and snail subpopulations are at their lowest. The snails continue to survive.

Invasive species were not considered to be a threat in COSEWIC (2008) or in Lepitzki and Pacas (2007, amended 2010). Mosquitofish (Gambusia affinis), introduced to the Cave and Basin National Historic Site in the 1920s, as well as other exotic fish were discussed as a threat of unknown impact to the recently assessed Vivid Dancer (Argia vivida) (COSEWIC 2015). A feral population of Goldfish (presumably Carassius auratus) has occupied a human-constructed pool in the Middle Springs area (devoid of physids) since at least 1996 and is self-sustaining. Two Goldfish were observed in an outflow stream at the Cave and Basin National Historic Site on 16 May 2016 and were promptly removed by Parks Canada. These two Goldfish were within delineated Critical Habitat (Map 4h in Lepitzki and Pacas 2007, amended 2010). Because the distribution of the various exotic fishes does not typically overlap the highest densities of Banff Spring Snail, the effects of the invasive fishes on the snail would be negligible.

Tracks of a Raccoon (Procyon lotor) were observed (Lepitzki pers. obs.) on a boardwalk within delineated Critical Habitat at the Cave and Basin National Historic Site (Map 4h in Lepitzki and Pacas 2007, amended 2010) on 4 December 2017. It was live-trapped at the site four days later and destroyed because Banff is outside its natural range (Ellis 2017) and it had been at the site for about two weeks; it had first been observed in Banff at the end of August (Ellis 2017).

Protection

Change in effective protection:

No

Explanation

The species is listed as Endangered under SARA since it was enacted in 2003, and is also protected under the National Parks Act. Nonetheless, habitat disturbances and snail mortality continue to be observed (see Threats). Actions such as cleaning valves and dropping water levels at the Cave and Basin National Historic Site are permitted activities under SARA and have the potential to kill snails and disturb Critical Habitat. The ~4 cm drop in the water level in the Basin Spring Pool in mid-December 2016 (Lepitzki unpubl. data) due to a plumbing repair probably resulted in the freezing and death of numerous egg capsules and may have contributed to the low snail numbers in this spring, with only the subpopulation count for this spring being lower in 1996 (Figure 2; Table 1). The water level did not revert back to its previous level for at least eight weeks (Lepitzki unpubl. data) and egg capsules are typically laid at the air-water interface (COSEWIC 2008). The first successful prosecution for destruction of Critical Habitat under SARA was the result of illegal swimming in delineated Critical Habitat (Lepitzki and Pacas 2007, amended 2010) in the Cave Spring pool while the site was open to the public (Derowitz 2015). However, all subpopulations continue to survive.

Rescue Effect

Change in evidence of rescue effect:

No

Explanation

Rescue is not applicable for a Canadian endemic species.

Quantitative Analysis

Change in estimated probability of extirpation:

No

Explanation

No additional population viability analyses or updates to the previous modelling exercises have occurred since those summarized in COSEWIC (2008).

Summary and Additional Considerations [e.g., recovery efforts]

The first SARA Recovery Strategy and Action Plan for any wildlife species in Canada (Lepitzki and Pacas 2007, amended 2010), was approved in 2007 and underwent minor modifications (corrections for Critical Habitat coordinates) in 2010. A report on the implementation of the Recovery Strategy and Action Plan was recently completed (Parks Canada Agency 2017a). A final multi-species action plan for five terrestrial, aquatic, and aerial species, including Banff Springs Snail was posted 12 December 2017 (Parks Canada Agency 2017b). One of the stated recovery measures is to use the results of an M.Sc. project that began in 2016 “to better inform both emergency response options and considerations for repeated reintroduction in response to extirpation of current populations as a result of thermal water failure (natural drying events)”. This project will target SNPs instead of microsatellites. Questions to be addressed include the relationship between P. johnsoni and P. gyrina; characterize P. johnsoni sub-population structure; and test hypotheses for local adaptation to thermal spring habitats.This directive is based on the conclusions from the February 2011 Recovery Team meeting: re-establishment of extirpated subpopulations is the preferred option; the two re-established populations would be allowed to become extirpated if they dried; but the original five subpopulations would be salvaged / protected (Parks Canada 2011). As such, the separate examination of the population trends for the original five subpopulations is warranted.

The species’ public profile has risen over the past 20 plus years of research and it is considered a Native Biodiversity, Species at Risk indicator (Parks Canada 2016); however, interest now appears to be lagging and there is a new directive for increased visitation to Canada’s National Parks (Parks Canada 2010). Targets were to increase visitation to Banff National Park 2% annually for the first five years of the plan and to increase visitation to the Cave and Basin National Historic Site to 300,000 per year from the previous ~100,000 (Parks Canada 2006 in COSEWIC 2008) by 2013 to 2014 (Parks Canada 2010). Visitation to Banff National Park in 2014 to 2015 increased by 10.4% for a total of 3.6 million visitors; in 2015 to 2016, there was a further 7.6% increase in visitor numbers (Parks Canada 2016). Since reopening, visitation has steadily increased month after month at the Cave and Basin National Historic Site with paid visits up by 55% compared to 2014/2015 as of 1 January 2016 (Parks Canada 2016). A further increase in visitor numbers was expected in 2017 because entrance fees for national parks and historic sites were waived.

Acknowledgements and authorities contacted

Jurisdictions (Parks Canada Agency, Fisheries and Oceans Canada, Alberta, Canadian Wildlife Service, Canadian Museum of Nature, ATK SC co-chairs, Banff National Park Aquatics Specialist and Resource Conservation Manager) were contacted via email (21 January 2016) outlining the SSC’s recommendation for the 10-year reassessment to proceed using a Status Appraisal Summary with a request for additional information. No new information was received.

Information sources

COSEWIC. 2008. COSEWIC assessment and update status report on the Banff Springs Snail Physella johnsoni in Canada. Committee on the Status of Endangered Wildlife in Canada. vii + 54 pp. (Species at Risk Public Registry)

COSEWIC. 2015. COSEWIC assessment and status report on the Vivid Dancer Argia vivida in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. ix + 53 pp. (Species at Risk Public Registry).

Derowitz, C. 2015. Man who swam in endangered snail pool because ‘God” told him to gets $4,500 in fines. Website: [accessed 31 October 2016].

Ellis, C. 2017. Banff raccoon caught and killed. Website: [accessed 7 February 2018].

Highwood Environmental Management Ltd. 2010. CEAA screening environmental assessment for Cave and Basin Renewal Project. August. VII + xi + 316 pp.

Lepitzki, D.A.W. 2007. Ten-plus-year data summary for the Banff Springs Snail. Prepared for Heritage Resource Conservation (Aquatics), Banff National Park. 22 October. 134 pp.

Lepitzki, D.A.W. 2011. Research and monitoring activities: 1 January 2010 through 14 February 2011. Prepared for and presented at the Banff Springs Snail Recovery Team Meeting, 28 February. 23 pp.

Lepitzki, D.A.W. 2012. Research and monitoring activities: 15 February 2011 through 27 February 2012. Prepared for and presented at the Banff Springs Snail Recovery Team Meeting, 1 March. 27 pp.

Lepitzki, D.A.W. 2013. Research and monitoring activities: 27 February 2012 through 31 January 2013. Prepared for and presented at the Banff Springs Snail Recovery Team Meeting, 4 February. 48 pp.

Lepitzki, D.A.W. 2014. Research and monitoring activities: 1 February 2013 through 31 March 2014. Prepared for and presented at the Banff Springs Snail Recovery Team Meeting, 8 April. 7 April. 49 pp.

Lepitzki, D.A.W. 2015. Research and monitoring activities: 1 April 2014 through 27 March 2015. Prepared for Heritage Resource Conservation (Aquatics), Banff National Park in lieu of 2015 Banff Springs Snail Recovery Team Meeting. 27 March. 49 pp.

Lepitzki, D.A.W. 2016. Research and monitoring activities: 27 March 2015 through 15 February 2016. Prepared for and presented at the Banff Springs Snail Recovery Team Meeting, 24 February. 20 February. 47 pp.

Lepitzki, D.A.W., and C. Pacas. 2007 (amended 2010). Recovery strategy and action plan for the Banff Springs Snail (Physella johnsoni) in Canada. Species at Risk Act Recovery Strategy Series. Parks Canada Agency, Ottawa. February. 61 pp. (Species at risk public registry) (amendment 18 Nov 2010, vii + 63 pp.)

Parks Canada. 2010. Banff National Park of Canada management plan. 190 pp.

Parks Canada. 2011. Banff Spring Snail recovery team meeting: February 28, 2011. Unpublished meeting minutes. 8 pp.

Parks Canada. 2016. Banff National Park. Progress report on park management plan implementation for the period of April 1, 2014 – February 1, 2016. Website: [accessed 6 February 2018].

Parks Canada Agency. 2017a. Report on the implementation of the Recovery Strategy and Action Plan for the Banff Springs Snail (Physella johnsoni) in Canada( 2007 to 2017). 11 December. 4 pp. Website: [accessed 7 February 2018].

Parks Canada Agency. 2017b. Multi-species action plan for Banff National Park of Canada [Final]. Species at Risk Action Plan Series. Parks Canada Agency. Ottawa. 12 December. iv + 27 pp.

Pettersen, N. 2014. An analysis of population genetic structure of the Banff Spring Snail (Physella johnsoni). Unpublished Ecology 530 thesis prepared for Dr. Sean Rogers, University of Calgary, Calgary, Alberta. 26 pp.

Pink, N. 2013. Population genomics of the Banff Springs Snail (Physella johnsoni). Unpublished undergraduate research report prepared for Dr. Sean Rogers, University of Calgary, Calgary Alberta. 15 pp.

Pomeroy, J.W., R.E. Stewart, and P.H. Whiflied. 2016. The 2013 flood event in the South Saskatchewan and Elk River basins: causes, assessment and damages. Canadian Water Resources Journal 41:105-117.

Writer of SAS

Dwayne A.W. Lepitzki, Ph.D., is the sole non-Parks Canada Agency member of the Recovery Team. He has been the Principal Investigator for the Banff Springs Snail research and recovery program on annual contract with Parks Canada since the fall of 1995.

^a Minima occurred within the first four weeks of subpopulations being established.

^b df = 1,9 not as indicated

Technical summary

Scientific name: Physella johnsoni

English name: Banff Springs Snail

French name: Physe des fontaines de Banff

Range of occurrence in Canada: Alberta

Demographic information

Generation time (usually average age of parents in the population; indicate if another method of estimating generation time indicated in the IUCN guidelines(2011) is being used):

<1 yr

Is there an [observed, inferred, or projected] continuing decline in number of mature individuals?

Yes, observed decline since 2005

Estimated percent of continuing decline in total number of mature individuals within [5 years or 2 generations]:

Unknown

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last [10 years, or 3 generations]:

Observed decline over the past 10 (or 11) years: non-significant declines of 21.4% (5 original subpopulations combined, 11 years) and 14.1% (all 7 subpopulations, including 2 re-established, combined, 10 years) in population minima but significant declines of 29.1% and 9.6% in population peaks.

[Projected or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations]:

Unknown

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over any [10 years, or 3 generations] period, over a time period including both the past and the future:

Unknown

Are the causes of the decline a) clearly reversible and b) understood and c) ceased?

a. no, if climate change
b. no
c. no

Are there extreme fluctuations in number of mature individuals?

Yes

Extent and occupancy information

Estimated extent of occurrence (EOO) Actual EOO calculated (COSEWIC 2008) = 0.177 km²:

8 km²

Index of area of occupancy (IAO) (Always report 2x2 grid value):

8 km²
Maximum two 2 km x 2 km grid squares

Is the population “severely fragmented” i.e., is >50% of its total area of occupancy in habitat patches that are (a) smaller than would be required to support a viable population, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?:

a. no
b. yes

Number of “locations”^* (use plausible range to reflect uncertainty if appropriate):

Seven subpopulations are found in three clusters: Kidney, Middle Springs (Upper Middle and Lower Middle), and Cave and Basin (Cave, Basin, Upper C&B, Lower C&B); however, all are found along a single thrust fault which is the geologic structure that creates the string of thermal springs

Is there an [observed, inferred, or projected] decline in extent of occurrence?

No

Is there an [observed, inferred, or projected] decline in index of area of occupancy?

No

Is there an [observed, inferred, or projected] decline in number of subpopulations?

Observed: Yes but known subpopulation (Kidney) survived drying event (see below re: extreme fluctuations in number of subpopulations)

Is there an [observed, inferred, or projected] decline in number of “locations”*?

No

Is there an [observed, inferred, or projected] decline in [area, extent and/or quality] of habitat?

Yes, observed and projected decline in area, extent and quality of habitat due to a variety of continuing threats

Are there extreme fluctuations in number of subpopulations?

No
Population counts at one re-established population were 0 for four consecutive 4-week counts when no thermal water flowed on the surface in 2011 but the population survived.
Physid snails, which could be this species, appeared in two additional thermal springs in the Middle Springs area in 2009 and 2010. When one of these springs dried, no live snails were observed for two years after thermal water flow resumed. However, live physids were once again observed at this spring beginning in 2015.

Are there extreme fluctuations in number of “locations”?

No

Are there extreme fluctuations in extent of occurrence?

No

Are there extreme fluctuations in index of area of occupancy?

No

^* See Definitions and Abbreviations on COSEWIC website and International Union for Conservation of Nature (IUCN) (Feb 2014) for more information on this term.

Quantitative analysis

Is the probability of extinction in the wild at least [20% within 20 years or 5 generations, or 10% within 100 years]?: 0% (all five original subpopulations combined) (COSEWIC 2008); Population Viability Analyses have not been updated

Threats (actual or imminent, to populations or habitats, from highest impact to least)

Was a threats calculator completed for this species? No

Using information in COSEWIC (2008; derived from Lepitzki and Pacas 2007, amended 2010), the following IUCN threat categories would be applicable:

1. Climate Change: habitat shifting and alteration; droughts; storms and flooding
2. Human intrusions and disturbance (recreational activities, work and other activities)
3. Natural system modifications (dams and water management/use; other ecosystem modifications)
4. Invasive and other problematic species and genes (invasive non-native/alien species)
5. Pollution (household sewage and urban waste water)

What additional limiting factors are relevant? Limited habitat.  Population fluctuations leading to genetic bottlenecks.

Rescue effect (immigration from outside Canada)

Status of outside population(s) most likely to provide immigrants to Canada.

Not applicable – endemic

Is immigration known or possible?

Not applicable

Would immigrants be adapted to survive in Canada?

Not applicable

Is there sufficient habitat for immigrants in Canada?

Not applicable

Are conditions deteriorating in Canada?⁺

Not applicable

Are conditions for the source population deteriorating?⁺

Not applicable

Is the Canadian population considered to be a sink?⁺

Not applicable

Is rescue from outside populations likely?

Not applicable

⁺ See Table 3 (Guidelines for modifying status assessment based on rescue effect).

Data-sensitive species

Is this a data sensitive species? No, information on the exact sites of occupancy are well publicized and the public can see the snails at the Cave and Basin National Historic Site.

Status history

COSEWIC: Designated Threatened in April 1997. Status re-examined and designated Endangered in May 2000, April 2008, and April 2018.

Status and reasons for designation

Status: Endangered

Alpha-numeric codes: B1ab(iii)c(iv)+2ab(iii) c(iv)

Reasons for designation: This is a Canadian endemic species with a distribution entirely within the upper reaches of fewer than five separate clusters of thermal springs in Banff National Park, Alberta. These short-lived animals undergo extreme natural annual fluctuations in numbers. This snail is a habitat specialist requiring a steady supply of warm thermal-spring water containing a high concentration of dissolved minerals and a complex microbial community that provides food and habitat. All thermal springs historically or currently occupied by this species have been impacted by human activities. Habitat disturbances continue but the effects of climate change (increased frequency of springs drying and storms with more rain) also are important threats to this species’ survival.

Applicability of criteria

Criterion A (Decline in Total Number of Mature Individuals): Does not meet criteria. The most recent 10-year rates of decline exceed thresholds.

Criterion B (Small Distribution Range and Decline or Fluctuation): Meets Endangered, B1ab(iii)c(iv)+2ab(iii)c(iv), with both EOO and IAO well below thresholds (< 5000 km² and 500 km², respectively). The species occupies fewer than 5 locations (a), where area, extent, and quality of habitat continues to decline (b(iii)) due to a variety of threats; subpopulations undergo extreme fluctuations (c(iv)).

Criterion C (Small and Declining Number of Mature Individuals): Not applicable. Numbers exceed thresholds. Not applicable. May meet Threatened, C2b. The minimum total number of mature individuals has dropped below the threshold (< 10,000) for 6 of the 10 years since 2007 and there is a continuing decline observed in numbers of mature individuals with subpopulations undergoing asynchronous extreme fluctuation (b).

Criterion D (Very Small or Restricted Population): D1 is not applicable as the number of mature individuals exceeds the threshold. Meets criteria for Threatened, D2. There are both fewer than 5 locations and the IAO is below the threshold (20 km²), and the species is prone to stochastic events that could within a very short time result in it becoming critically endangered.

Criterion E (Quantitative Analysis): Not applicable. Updated analyses since COSEWIC (2008) have not been done.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2018)

Wildlife species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special concern (SC)
(Note: Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.)

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at risk (NAR)
(Note: Formerly described as “Not In Any Category”, or “No Designation Required.”)

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data deficient (DD)
(Note: Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” [insufficient scientific information on which to base a designation] prior to 1994. Definition of the [DD] category revised in 2006.)

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.