The Dragonflies
(Insecta: Odonata)
of the Columbia Basin, British Columbia:
Field Surveys, Collections Development and Public Education
Recommendation for Future Inventory, Research
and Monitoring
Until the 1998/99 Living Landscapes
project, dragonfly inventory in the Columbia Basin was sparse and
sporadic. Even the more systematic inventories undertaken in these
two field seasons has not covered the whole region, and there is
still much to learn. For example, a comprehensive inventory in 1997
in the Okanagan Basin (the best collected area in the British Columbia
Interior) greatly increased our knowledge of the abundance and distribution
of many species (Cannings et al. 1998). For example, the
known range of Coenagrion interrogatum was extended from
Heckman Pass, Tweedsmuir Park (west-central Interior) south to the
Okanagan Highlands four localities for the species were discovered
in the Okanagan. The species was recently found in Kootenay National
Park (Rocky Mountains) in 1999 -- the result of this Living Landscapes
project inventory. It is clear that the distribution of this species
in the southern Interior remains poorly known. In the Okanagan inventory
the number of localities for some uncommon lowland species was also
increased significantly: for example, Argia vivida localities
increased from three to eight and Argia emma from five to
sixteen.
Several species are known from adjacent areas and
may occur within the Columbia Basin. Tramea lacerata Hagen,
Pantala hymenaea (Say), and P. flavescens (Fabricius),
all well known for their wide-ranging flights, are recorded from
central Washington State (Paulson 1997, 1999); the first two have
been recorded as wanderers on the south coast of British Columbia
(Cannings 1988, 1997). Aeshna septentrionalis Burmeister,
Somatochlora hudsonica (Selys), S. septentrionalis (Hagen)
and Leucorrhinia patricia Walker are northern species that
probably occur around mountain lakes, ponds and peatlands in the
Columbia Basin. A. Septentrionalis is known from Boom Creek,
Alberta, only a few hundred metres from the British Columbia border.
Enallagma clausum Morse, E. hageni (Walsh), Stylurus
olivaceus (Selys), Epitheca canis MacLachlan and Erithemis
collocata (Hagen) live in the southern Interior of British Columbia
and may occur in the Columbia Basin.
Increased inventory efforts would especially improve
our knowledge of the species that may range widely in the region,
but are known from few localities. Examples include Lestes forcipatus,
Aeshna tuberculifera, Cordulegaster dorsalis, Somatochlora cingulata
and S. forcipata.
No studies examining the effects of human activity
in the environment (e.g. siltation and elevated temperatures in
streams in logged areas or the effect of dams on dragonfly populations)
have been undertaken in the Columbia Basin, and no long-term monitoring
studies are in place that could detect changes in species composition
and abundance of dragonfly populations. Although this study has
increased our knowledge of the habitat requirements of a number
of the species, our understanding of the needs of most species is
rudimentary -- and more ecological studies would be enormously beneficial.
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