COSSARO Candidate Species at Risk Evaluation Form. for

Transcription

1 COSSARO Candidate Species at Risk Evaluation Form for Eastern Mole (Scalopus aquaticus) Committee on the Status of Species at Risk in Ontario (COSSARO) Assessed February 2011 by COSSARO as Special Concern February 2011 Final

2 PART 1 COSSARO Candidate Species at Risk Evaluation Form Feb Eastern mole (Scalopus aquaticus) Current Designations: GRANK G5 (1996) NRANK Canada N2 (20 Jan 2000) COSEWIC Special Concern (November 2010) SARA Special Concern (Schedule 1) General Status Canada Sensitive (2005) ESA 2007 Special Concern SRANK S2 General Status Ontario Sensitive (2005) Distribution and Status Outside Ontario: Outside Canada, the Eastern Mole occurs in most eastern and central states of the USA, and into northern Mexico. In Canada, this species is restricted to a small area near Point Pelee National Park in southwestern Ontario (COSEWIC 2010). Native Status yes. Taxonomic Distinctness yes. ELIGIBILITY CRITERIA Designatable Units All individuals in Canada belong to a single subspecies, and there is no additional information to suggest that there should be more than one designatable unit. Recent Arrival no Non-resident no PRIORITY-SETTING CRITERIA 1

3 PRIMARY CRITERIA (rarity and declines) 1. Global Rank Not in any category. The global status of Eastern Mole was last assessed in 1996 as secure (G5; NatureServe 2011). 2. Global Decline Not in any category. There is no evidence to suggest any global range loss or population declines outside of natural fluctuations, and global status of this species was suggested to be stable by IUCN Red List evaluators (Matson et al. 2008). 3. Northeastern North America Ranks Not in any category. Eastern Mole occurs in 19 NE North American jurisdictions and has been ranked in 16 (84%). It is ranked S1, S2, SH or SX only in Ontario (6%), where its status is S2. (Table 1; NatureServe 2011). 4. Northeastern North America Decline Not in any category. Although population densities, and therefore trend data, are unknown in most parts of its range, Eastern Moles are considered to be a common species in the U.S.A. (COSEWIC 2010, Wilson & Ruff 1999). 5. Ontario Occurrences Threatened. Eastern moles are restricted to three municipalities in Essex County (Town of Essex, Town of Kingsville, and the Municipality of Leamington) and the western portion of Romney Township in the Municipality of Chatham-Kent. According to NHIC, there are only 20 extant element occurrences in Ontario for this species (NHIC 2011). 6. Ontario Decline Not in any category. Although some regular surveys of Eastern Moles have taken place in Ontario, the reliability of this effort as a means of monitoring population trends is questionable. This is due both to the survey techniques that are used for this species, which rely on mole sign (tunnels and pushups), and to the low statistical power of the effort. Forty-eight prospective locations were searched for mole signs in 1997 as part of field work for the 1998 status report (Waldron 1998, Waldron et al. 2000). In 2008, Ritchie and Nocera (2010) resurveyed 46 of these sites using a similar level of search effort. Additionally, six sites in Point Pelee National Park that contained moles were surveyed annually for mole sign between 1985 and There was a 26% decline in occupied sites between two surveys in 1997 and 2008, although this trend was not significant. Regular surveys in Point Pelee National Park suggested no declines between 1985 and The number of surface tunnels and push-ups may be a poor indicator of population size because of the ephemeral nature of moles, and the variable length and complexity of mole tunnels (Gorman and Stone 1990). Relative occurrence 2

4 of mole sign may ultimately depend on habitat structure and soil moisture. This means that the ephemeral nature of this animal, combined with the lack of habitat decline, make it unlikely that a true population trend has been detected (COSEWIC 2010). 7. Ontario s Conservation Responsibility Not in any category. Less than 1% of the global range of Eastern Mole occurs in Ontario (COSEWIC 2010). SECONDARY CRITERIA (threats and vulnerability) 1. Population Sustainability Insufficient information. The lack of reliable population estimates precludes an evaluation of population sustainability. 2. Lack of Regulatory Protection for Exploited Wild Populations Not in any category. Although this species receives no regulatory protection, it is not subject to any known targeted exploitation in Ontario. Thirty-three percent of the suitable habitat (compared with Waldron 1998, who erroneously reported 66%) occurs within Point Pelee National Park, which is managed and protected under the National Parks Act. In the US, moles often are considered to be horticultural pests and are persecuted because their activities disfigure lawns and gardens, but the extent to which this is an issue in Ontario is unknown. 3. Direct Threats Special Concern. Lands with suitable soils for Eastern Moles have been extensively modified or covered by intensive agriculture and residential development, with only a small percentage remaining that contains sufficient vegetative cover to provide suitable habitat. Habitat patches frequently are small and surrounded by unsuitable habitat. Eastern Moles may have limited ability to move large distances across inhospitable habitat, resulting in isolation of populations in proximity to forest patches (COSEWIC 2010). 4. Specialized Life History or Habitat-use Characteristics Special Concern. The range of the Eastern Mole in Canada appears to be limited by suitable soil types and shade; moles require soil that is sufficiently soft to allow tunnel construction. Approximately 929 ha of potential habitat are estimated to occur in Canada (COSEWIC 2010). COSSARO CRITERIA MET (primary/secondary) ENDANGERED 0/0 THREATENED 1/0 SPECIAL CONCERN 0/2 3

5 SUMMARY Eastern Mole (Scalopus aquaticus) is of Special Concern in Ontario because of its limited distribution and uncertain status in the face of potential habitat threats. This species is widely-distributed in most eastern and central states of the USA, and northern Mexico. In Canada it is restricted to ca ha near Point Pelee National Park in southern Ontario. This mole requires soft soils and has a fragmented distribution in Ontario. There is, however, a lack of adequate monitoring effort or quantification of threats that together underline the uncertainty of its conservation status. Although there is some evidence of a decline in distribution, the survey data do not have enough power to draw any conclusions. The range of the Eastern Mole in Canada appears to be limited by availability of suitable soil types which have been extensively modified or covered by intensive agriculture and residential development. Information Sources COSEWIC Update COSEWIC status report on Eastern Mole (Scalopus aquaticus) in Canada. Committee on the Status of Endangered Wildlife in Canada, 2- month Interim Status Report. Ottawa. viii + 29 pp. [Two-month interim report] Gorman, M.L., and R.D. Stone The Natural History of Moles. Cornell University Press. Ithaca, New York, USA. Matson, J., N. Woodman, I. Castro-Arellano, & P.C. de Grammont Scalopus aquaticus. In: IUCN IUCN Red List of Threatened Species. Version < Downloaded on 28 January NatureServe NatureServe Explorer: an Online Encyclopedia of Life. [ Accessed January Ritchie, L.E., and J.J. Nocera Assessing the distribution of Eastern Moles (Scalopus aquaticus) in Canada in relation to loam soils and forest cover. American Midland Naturalist 164: Waldron, G. E Update COSEWIC status report on the Eastern Mole Scalopus aquaticus in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. in COSEWIC Update COSEWIC status report on Eastern Mole (Scalopus aquaticus). Committee on the Status of Endangered Wildlife in Canada, Ottawa. 2-Month Interim Status Report. Viii + 29 pp. Waldron, G., L. Rodger, G. Mouland, and D. Lebedyk Range, habitat, and population size of the Eastern Mole, Scalopus aquaticus, in Canada. Canadian Field- Naturalist 114: Wilson, D. E. and S. Ruff The Smithsonian Book of North American Mammals. 4

6 Smithsonian Institution Press, Washington, DC, USA. 5

7 Table 1 NORTHEASTERN NORTH AMERICA RANK, STATUS AND DECLINE CT DE IL IN IA KY LB MA MB MD ME MI MN NB NF NH NJ NS NY OH ON PA PE QC RI VA VT WI WV S4 SNR SNR S2 SNR S3 Occurs as a native species in 19 of 29 northeastern jurisdictions Srank or equivalent information available for 16 of 19 jurisdictions = 85% S1, S2, SH, or SX in 1 of 16 = <1% 6

8 PART 2 Ontario Evaluation Using COSEWIC Criteria Regional (Ontario) COSEWIC Criteria Assessment Criterion A Decline in Total Number of Mature Individuals No (N/A). There has been a statistically non-significant decline of 26% reported in occupied sites outside of Point Pelee N.P. between 1997 and 2008, but the difficulty and inconsistency of detection of this species makes trend assessment unreliable. There has been no significant change within Point Pelee N.P. (COSEWIC 2010). Criterion B Small Distribution Range and Decline or Fluctuation No (N/A). The Extent of Occurrence has been calculated as 546 km 2 which meets the level for Endangered status under this criterion, but none of the subcriteria are met (number of locations, evidence of severe fragmentation, evidence of continuing decline, and evidence of extreme fluctuations). Criterion C Small and Declining Number of Mature Individuals No (N/A). No population estimates exist. Surveys are conducted on the basis of mole evidence (tunnels, etc.), but there is no clear relationship between this form of evidence and numbers of animals at a site. Also, the evidence regarding declines is equivocal, given the difficulty and inconsistency in detection. Criterion D Very Small or Restricted Total Population No (N/A). No population estimates exist. Vulnerability of the population to human or stochastic events in a very short time is not supported by evidence. Criterion E Quantitative Analysis No (N/A). No Population Viability Analysis has been conducted. Rescue Effect No. The Eastern Mole is not highly mobile. Although the species appears to be relatively common in adjacent jurisdictions, its ability to cross the river or lake between those jurisdictions and Ontario has a low probability. 7