From: ASSESSMENT OF SPECIES DIVERSITY IN THE MIXEDWOOD PLAINS ECOZONE

DRAGONFLIES AND DAMSELFLIES

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

5. ZONAL BOUNDARIES AND SUBREGIONS

Dragonflies that do not breed in most of the ecozone evidently stray into it from the north (Aeshna sitchensis, A. subarctica) and south (Tramea spp.) and perhaps also from the west (S. corruptum), and are counted as part of the total diversity, but only about 10 species fall into this category. The best documented case of this kind is probably Pantala flavescens arrives from the south and is able to complete a generation, but evidently not to overwinter (Trottier 1967, Hutchinson 1977).

Several boreal species are known only from the bogs and acid lakes in ecoregion 132 (near the northern limit of the ecozone) including Aeshna sitchensis, A. subarctica, and Somatochlora cingulata. Although these species are actually characteristic of areas to the north and barely enter the ecozone, they are nevertheless present. Ophiogomphus colubrinus is a species of the Canadian Shield that spills over into the Mixedwood Plains. Ophiogomphus anomalus, O rapinsulensis and Stylurus amnicola (Stohr 1918) are associated with large rivers that drain the Canadian Shield country, but are actually within the Mixedwood Plains.

A number of other species in the ecozone have been reported from parts of the ecozone that may be considered as small islands of another ecozone. The occurrences of Lanthus parvulus and Calopteryx amata in the Covey Hill area of the eastern townships of Quebec for example might be considered as a disjunction of the Appalachians ecoregion of the Atlantic Maritime ecozone. Ophiogomphus carolus is also evidently more representative of the Appalachian region. Likewise Lestes eurinus and Williamsonia fletcheri in a few bogs, may represent occurrences that are far more typical of areas within the southern portion of the Algonquin-Lake Nipissing ecoregion of the Boreal Shield ecozone.