Species Spotlight: Olive Clubtail Dragonfly
Common name: Olive Clubtail
Latin name: Stylurus olivaceus
Status under the Species at Risk Public Registry (SARA): The Olive Clubtail was designated as Endangered. 2011 COSEWIC assessment: Endangered.
Range: There are several scattered populations of the Olive Clubtail throughout western North America. Their range contains parts of the United States, including Washington and Oregon, Idaho, Utah, Nevada and California. Their dispersal in Canada is confined to five locations in British Columbia: South Thompson River, Christina Creek and the Okanagan Valley, which contains three locations.
Size: Adults of this dragonfly species in the clubtail family can grow between 56 and 60 millimetres in length.
Population estimate: There is a total population estimation of 2,500–90,000 individuals between the five British Columbia locations: less than 500 at Christina Creek, between 1,000 and 50,000 in the Okanagan Valley, and between 1,000 and 50,000 at South Thompson River. More comprehensive studies are required to minimize the ranges of these estimates and make them more accurate.
- The female Olive Clubtail will lay their eggs on the water’s surface of streams and rivers (rarely do they choose lakeshores to lay eggs). Once hatched, Olive Clubtail larvae burrow into mud along the water where they will remain for two years until they emerge as adults.
- Olive Clubtail larvae are aquatic predators throughout their two-year development cycle. Their diet consists of a variety of bottom-dwelling invertebrates, whereas adults consume various small, flying insects.
- In British Columbia, the flying season of adult Olive Clubtails is from mid-July to October. Males will fly over open waters, whereas females will fly along the shores.
- Adult Olive Clubtails will perch on riparian perennials (i.e., plants that grow along the water’s edge), trees and shrubs. They are also known to perch on the ground.
Though small, this dragonfly species is definitely mighty. As there are few odonates (i.e., damselflies and dragonflies) in British Columbia that develop in streams, this rarely sighted arthropod may in fact be a good indicator of the habitat quality of warm lowland rivers, a habitat that is scarce in the region. As such, maintaining the populations of the Olive Clubtail will have numerous benefits for the entire ecosystem.
Although little is still known about the habitat requirements of Olive Clubtail larvae, there are a few known threats to the species. As the Olive Clubtail lives along rivers and streams, much of its habitat in the South Okanagan Valley has been changed due to river channeling. Other forms of development including urban, residential, transportation and marinas, continue to alter the shorelines of water courses. Disturbances along the shoreline associated with recreation and swimming may also impact larval survival as they require sand and mud to mature. Agricultural runoff, as well as pollutants from land development, storm water runoff, and pesticides, may also pose problems for the species.
What Is Being Done:
The Olive Clubtail has protection under the Species at Risk Act. Currently, the provincial Riparian Areas Regulation under the British Columbia Fisheries Act helps manage the development in riparian zones and may perhaps have a positive impact on the Olive Clubtail habitat, especially along the shores of Christina Creek and the South Thompson River where the shoreline remains intact in some places.
What You Can Do:
Farmers in the Okanagan Valley can educate themselves on pesticide-free farming techniques to help curb the pesticide runoff into the Olive Clubtail’s habitat. In addition, consumers can promote these techniques by being choosy about natural farming methods.
We should also all be aware and conscious of shorelines that the Olive Clubtail calls home. Minimizing disturbances to these areas will help promote a natural shoreline for the Clubtails’ habitat. And those interested can contact BC Nature to get involved with their conservation efforts, and to stay up to date on ways to help.
- Committee on the Status of Endangered Wildlife in Canada (COSEWIC)
- Species at Risk Public Registry (SARA)
This profile was written by Brydie Brown and edited by Karolina Lada.