Scientific Name: Stylurus olivaceus
Taxonomy Group: Arthropods
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: May 2011
COSEWIC Status: Endangered
COSEWIC Status Criteria: B2ab(iii)
COSEWIC Reason for Designation:
This highly rare, stream-dwelling dragonfly with striking blue eyes is known from only 5 locations within three separate regions of British Columbia. It is restricted to small areas along warm lowland rivers, and infrequently lakes, where continuing decline in the quality of habitat is occurring. Threats include loss and disturbance of habitat due to human activity, such as beach recreation, impacts of invasive species of fish, invasive aquatic plants, and pollution by pesticides and fertilizing nutrients.
COSEWIC History of Status Designation: Designated Endangered in May 2011.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2017-02-03
Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.
The Olive Clubtail is a dragonfly in the clubtail family. Adults are 56-60 mm long, have widely separated eyes and the tip of the abdomen, especially in males, is swollen; the wings are clear. The thorax is grey-green with broad, brown shoulder stripes and the black abdomen bears a yellow mark on the top of each segment and has yellow on the sides. The elongate larvae are distinguished by vestigial burrowing hooks on the tibiae (middle of front legs). All larval records of the Olive Clubtail in Canada are of exuviae (singular “exuvia”), the cast exoskeletons of the final larval stage, left on the shore after adult emergence. The Olive Clubtail is the only representative of the genus Stylurus in British Columbia. Few odonates (damselflies and dragonflies) in British Columbia develop in streams; this species may prove to be a good indicator of stream ecosystem health for warm, mesotrophic lowland rivers – a scarce habitat in the province. [Updated by COSEWIC- May. 2011]
Distribution and Population
The Olive Clubtail lives in scattered populations across western North America from south-central British Columbia south through the interior of Washington and Oregon, Idaho, Utah, Nevada, and California. There are five locations in three separate regions in British Columbia and Canada – South Thompson River, Christina Creek and the Okanagan Valley (including three locations). Based on substantial search effort, it is a rare species throughout its Canadian range. Populations in British Columbia are not known well enough to provide good size estimates. The data set used in this report consists of 31 specimens and 26 sight records; each record may relate to more than one individual. Specimens total 18 adults and 69 larval exuviae. Speculative estimates for the whole Canadian population are: Christina Creek –
Larvae burrow in the bottom of mud- or sand-bottomed rivers or streams, rarely along lakeshores. The rivers can be as large as the lower Columbia River below Portland, Oregon and the streams may be as small as the 10 m-wide Christina Creek. Because the habitat requirements of the larvae are imprecisely known, it is difficult to determine whether there has been a decline in quality and quantity of habitat. Most of the Canadian length of the Okanagan River was channeled in the 1950s; presumably this has reduced both quantity and quality of habitat. The South Thompson River is relatively natural, except for agricultural, transportation and housing developments along some stretches. Christina Creek remains mostly in a natural state. [Updated by COSEWIC- May. 2011]
The larvae of Olive Clubtails are aquatic predators, living for about two years in the bottom sediments of streams or lakes until emerging as adults. They eat bottom-dwelling invertebrates. Adults, like other dragonflies, consume a great variety of small, flying insects. In British Columbia, adults fly from mid-July to mid-October. Males fly over open water, as opposed to along the shore. Females lay eggs on the water surface. Adults rest in riparian perennials, shrubs and trees; sometimes they perch on the ground. [Updated by COSEWIC- May. 2011]
Much of the Olive Clubtail’s habitat in the south Okanagan has been altered by river channeling. Urban, residential, transportation and marina developments; pollution from power boats; and disturbance at popular swimming beaches all have potential impact on larval survival. Introduced fish have altered the ecology of the Okanagan and Christina watersheds and are major predators of odonate larvae. Both watersheds have also been invaded by Eurasian Milfoil, an aggressive aquatic weed that changes aquatic environments. Pollutants may come from land development, agricultural practices, storm water runoff, sewage systems, forestry and range activities, and other sources. Pesticides are a potential problem in the South Okanagan, as the Okanagan River flows through many orchard and vineyard lands. Eutrophication resulting from agricultural runoff and sewage is a worry in the Okanagan and along the Thompson River, although major nutrient from sewage have been reduced dramatically through tertiary treatment of sewage, which was implemented in all major centres in the 1980s.[Updated by COSEWIC- May. 2011]
The Olive Clubtail is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
Provincial and Territorial Protection
Status of Recovery Planning
Recovery Strategies :
Name Recovery Strategy for the Olive Clubtail (Stylurus olivaceus) in Canada
Status First posting on SAR registry
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
8 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Consultation Documents (1 record(s) found.)
- Related Information (1 record(s) found.)
COSEWIC Status Reports
Response Statement - Olive Clubtail (2011-12-08)This highly rare, stream-dwelling dragonfly with striking blue eyes is known from only 5 locations within three separate regions of British Columbia. It is restricted to small areas along warm lowland rivers, and infrequently lakes, where continuing decline in the quality of habitat is occurring. Threats include loss and disturbance of habitat due to human activity, such as beach recreation, impacts of invasive species of fish, invasive aquatic plants, and pollution by pesticides and fertilizing nutrients.
COSEWIC Annual Reports
COSEWIC Annual Report - 2010 - 2011 (2011-09-09)Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.