Laura’s clubtail evaluation
This document describes the Committee on the Status of Species at Risk in Ontario’s evaluation of Laura’s clubtail. This evaluation determines whether the species will receive protection under the Endangered Species Act.
Photo by Linda Gilbert
Assessed June 2010 by COSSARO as Endangered
Part 1: COSSARO candidate species at risk evaluation form – June 2010
Laura’s Clubtail (Stylurus laurae)
Current designations:
GRANK – G4 (January 1999)
NRANK Canada – N1
COSEWIC -- Endangered (April 2010)
SARA – Not Listed
General Status Canada – May be at Risk
ESA 2007 – Not listed
SRANK – S1
General Status Ontario – May be at Risk
Distribution and status outside Ontario:
Range includes Ontario and 17 states in the US extending from the Florida Panhandle to east Texas, north to Michigan and southern Ontario. Most common in the south central US east of the Appalachians.
Eligibility criteria
Native status
Yes. Recently discovered in Ontario, but not known to be invasive and almost certainly native.
Taxonomic distinctness
Yes. First described in 1932 and universally recognized as a full species.
Designatable units. The two streams constituting the Ontario range are within 23 km of each other and represent a single designatable unit.
Priority-setting criteria
Recent Arrival
No. Discovered in Ontario in 1999, but probably present for > 25 years.
Non-resident
No.
Primary criteria (rarity and declines)
-
Global rank
Not in any category. G4.
-
Global decline
Not in any category. Global population is stable (unchanged or within +/- 10% fluctuation in population, range, area occupied, and/or number or condition of occurrences) (NatureServe 2010).
-
Northeastern North America ranks
Endangered. Occurs as a native species in 7 of 29 northeastern jurisdictions. Srank or equivalent information available for 7 of 7 jurisdictions = (100%). S1, S2, SH, or SX in 7 of 7 = (100%).
-
Northeastern North America decline
Not in any category. Probably similar to global population: stable (unchanged or within +/- 10% fluctuation in population, range, area occupied, and/or number or condition of occurrences) (NatureServe 2010).
-
Ontario occurrences
Endangered. Four occurrences (NHIC 2010) and two "locations" (COSEWIC 2010) on Big Creek and Big Otter Creek.
-
Ontario decline
Insufficient Information. Ontario population is recently discovered and no numerical estimates prior to 2008 or long term population trend data are available.
-
Ontario’s conservation responsibility
Not in any category. Ontario has far less than 10% of the global range (global extent of occurrence = 1.5 million km². Ontario extent of occurrence = 256 km²).
Secondary criteria (threats and vulnerability)
-
Population sustainability
Insufficient Information. No Population Viability Analyses have been conducted for the species in Ontario or elsewhere.
-
Lack of regulatory protection for exploited wild populations
Not in any category. May be occasional taken by collectors, but unlikely to threaten populations. Proposed Endangered federally by COSEWIC in April 2010.
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Direct threats
Threatened. Aquatic habitat degradation through pollution, water removal for irrigation, and invasive species (especially Round Goby) are threats to all Ontario occurrences. Nitrate and phosphorus concentrations in both watersheds consistently exceed water quality objectives. Water removal for irrigation significantly reduces stream flow during dry summers. Round Goby has invaded the streams since about 2004 and is potentially a significant predator on larvae.
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Specialized life history or habitat-use characteristics
Threatened. Larvae inhabit small to medium unpolluted sandy streams in the Carolinian Zone in southern Ontario. This habitat is restricted to a few streams in the Norfolk Sand Plain.
COSSARO criteria met (primary/secondary)
- Endangered – [2/0]
- Threatened – [0/2]
- Special concern – [0/0]
Recommended status: Endangered
Summary
Laura’s Clubtail is a medium sized dragonfly inhabiting clean, sandy streams in eastern North America from Ontario, south to Florida and Texas. Its Ontario range includes sections of Big Creek and Big Otter Creek on the north shore of Lake Erie. The larvae burrow in the silt and sand in the stream bed for two years or more. The adults emerge in July or early August and disperse to the surrounding forest until they return to the stream to breed. Laura’s Clubtail was discovered in Ontario in 1999 and population trends are unknown. Threats include aquatic habitat degradation through pollution, water removal for irrigation, and the invasive Round Goby. Given its small population size, limited distribution, and declines in habitat quality, this species is classified as Endangered in Ontario.
Information sources
COSEWIC. 2010. COSEWIC 2-month interim updated status report on Laura’s Clubtail (Stylurus laurae) in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa, Ontario. iv + 33 p.
Howell, D., Iowa Natural Areas Inventory, Department of Natural Resources. pers comm. 2009. Email correspondence to A. Harris. January 2009. Natural Heritage (NHIC) 2010. Website. Accessed May 2010
NatureServe. 2010. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available. (Accessed: May 28, 2010).
Appendix 1: Northeastern North America rank, status and decline
Region | Rank | Source |
---|---|---|
CT | not present | |
DE | not present | |
IL | not present | |
IN | S1 | |
IA | SNR |
No verified records (D. Howell pers. comm. 2009) |
KY | S2 | |
LB | not present | |
MA | not present | |
MB | not present | |
MD | S2 | |
ME | not present | |
MI | S1S2 | |
MN | not present | |
NB | not present | |
NF | not present | |
NH | not present | |
NJ | not present | |
NS | not present | |
NY | not present | |
OH | S2 | |
ON | S1 | |
PA | not present | |
PE | not present | |
QC | not present | |
RI | not present | |
VA | S2 | |
VT | not present | |
WI | not present | |
WV | not present |
Occurs as a native species in 7 of 29 northeastern jurisdictions SRANK or equivalent information available for 7 of 7 jurisdictions = (100%) S1, S2, SH, or SX in 7 of 7 = (100%)
Part 2: Ontario evaluation using COSEWIC criteria
Regional (Ontario) COSEWIC criteria assessment
Criterion A – declining population
N/A. There are no accurate population data
Criterion B – small distribution and decline or fluctuation
Endangered. B1ab(iii)+2ab(iii) The maximum area of occupancy encompasses 22 km² (using a 1 km x 1 km grid) or 60 km² (using a 2 km x 2 km grid) and extent of occurrence is 256 km². Less than 5 locations, and there is observed, inferred and projected decline of habitat.
Criterion C – small population size and decline
N/A. There are no accurate population data
Criterion D – very small or restricted
Threatened. D2. Meets Threatened D2 as there are less than 5 locations and the populations are subject to rapid loss due to pollution or water withdrawal.
Criterion E – quantitative analysis
N/A. Not undertaken.
Rescue effect
No. Unlikely since the nearest population is 120 km across Lake Erie and there is little suitable intervening habitat. Adults are non-migratory.