THE ODONATA OF THE NORTHERN CORDILLERAN PEATLANDS OF NORTH AMERICA

Abstract

AbstractThe peatlands of the northern Cordillera of North America (consisting of the mountain ranges and intermontane lowlands and plateaus of British Columbia, Alberta, the Northwest Territories, the Yukon, and Alaska) support a distinctive Odonata fauna. Forty species in six families and 12 genera are typical of northwestern peatlands and another 12 species are occasional inhabitants of these environments. Of the 40 species, eight (20%) are peatland obligates and four (10%) almost always occur in such habitats. The remaining 28 (70%) are generalists and live in a wide range of aquatic habitats; nevertheless, they often are common inhabitants of, or are even dominant in, peatland environments. The fauna is dominated by the genera Aeshna Fabricius and Somatochlora Selys, with 11 and 10 species, respectively. It is also dominated by species restricted to Boreal regions (25 species, 62.5%), six (15%) of which have Holarctic distributions. The remainder of the fauna consists of eight species (20%) ranging transcontinentally in Transition Zone forests south of the Boreal Forest, five (12.5%) restricted to the Cordillera, and two (5%) with wide distributions in North America. Notes and maps summarize our knowledge of biogeographical information and previously unpublished records are listed. Significant southerly range extensions for species such as Coenagrion interrogatum (Hagen), Aeshna septentrionalis Burmeister, A. sitchensis Hagen, A. subarctica Walker, Somatochlora septentrionalis (Hagen), and Leucorrhinia patricia Walker are reported. Ecological and natural history data are outlined for each species. There do not appear to be any clear differences between the faunas of bogs and fens; dragonflies seem to respond to the habitat's form and structure rather than to its acidity or nutrient levels. Distinctive species associations result. A better understanding of the preferences of these dragonflies for different peatland microhabitats must await detailed research on oviposition behaviour and larval ecology.