From: ASSESSMENT OF SPECIES DIVERSITY IN THE MIXEDWOOD PLAINS ECOZONE

DRAGONFLIES AND DAMSELFLIES

P. M. Catling, R. Hutchinson and B. Ménard

7. MAJOR NEEDS WITH RESPECT TO BIODIVERSITY PROTECTION

While many dragonflies and damselflies can take advantage of a variety of ponds and streams, some are very specific in their habitat requirements. Within the Mixedwood Plains ecozone one of the significant habitats is the larger rivers with moderate current. Some larger rivers are more important than others. For example the lower Thames River, has four provincially rare damselflies including Argia sedula, A. tibialis, A. translata and Hetaerina titia as well as some rare dragonflies. The upper Ottawa River has Gomphus vastus, Stylurus spiniceps, Stylurus notatus and Ophiogomphus anomalus. The St. Lawrence river has Stylurus notatus (Fig. 1). The Ausable River and the Sydenham River also have populations of significant species. These large rivers are susceptible to pollution and other modifications, and the maintenance of water quality and appropriate natural levels and fluctuations will be essential to the survival of rare odonates as well as other rare aquatic insects, fish and molluscs. Changes in water table and surface flow associated with urbanization can adversely affect ponds and streams and impact rare species such as Enallagma traviatum westfalli. Certain aquatic habitats are very scarce in the ecozone such as bogs and fens, and these are the habitats of species that, although more common in the Mixedwood Shield ecozone, are rare in the Mixedwood Plains. Examples of this group include Nehalennia gracilis, Nannothemis bella and Somatochlora walshii. To protect Odonate biodiversity specifically and Canadian native biodiversity generally, it is essential that special aquatic habitats be identified and protected.

There is an urgent need for more data on importance of damselflies and dragonflies in maintaining wetland biodiversity. Improved identification aids need to be developed to allow greater participation in research, evaluation and monitoring. Few recent comprehensive monographs are available concerning the species of the Mixedwood Plains ecozone and identification and classification problems exist in the Lestes disjunctus - forcipatus group as well as in the genera Hetaerina and Argia (Donnelly 1996). Probably most important however, is the need for an increasingly strong commitment to protect natural environment and maintain environmental quality along with enlightened management practices. With regard to rehabilitation, a number of studies, including particularly those of Moore (1976, 1982, 1991a, 1991b), could pobably be advantageously adapted to the Canadian situation. The conservation of dragonflies in the Mixedwood Plains, and in North America generally (eg. Corbet 1993, Dunkle 1993) requires much more study.