From: ASSESSMENT OF SPECIES DIVERSITY IN THE MIXEDWOOD PLAINS ECOZONE

DRAGONFLIES AND DAMSELFLIES

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

6. INFORMATION GAPS

Although knowledge of the Odonata of the Mixedwood Plains of Canada is fairly complete, there is still much to learn in terms of biology and systematics and there are still probably at least 5-10 species that have yet to be discovered in the ecozone. As recently as 1996 two species, Gomphaeshna furcillata and Progomphus obscurus were newly discovered in the Ontario portion of the ecozone (Burke 1996). There are at least 4 species of damselflies which are potential additions to the Canadian portion of the Mixedwood Plains that occur in adjacent portions of the ecozone in Michigan and Ohio. These are Archilestes grandis (Rambur), Enallagma divagans Selys, Ischnura kellicotti Williamson and Ischnura perparva McLachlan in Selys (Catling 1998). Among the dragonflies, Cordulegaster erronea, a more southern species of small spring-fed woodland streams about 1 foot wide (Barlow 1995, Glotzhober & Riggs 1996) is also a potential addition. The globally rare Somatochlora hineana is also a potential addition. Arigomphus submedianus, Gomphus lineatifrons and Stylurus laurae occur in nearby portions of southeastern Michigan and thus may also occur in the extreme southwestern portion of Canada's Mixedwood Plains. Ophiogomphus howei is also a possible addition (Tennessen 1993), as is Zoreana bilineata (Carle 1983). The recently described Lanthus vernalis (Carle 1980) occurs in Orleans Co., Vermont, adjacent to the Quebec border.

Knowledge of distribution of certain species of specific habitats, and of inconspicuous species, remains incomplete. There has never been a comprehensive inventory of a big river in the ecozone, despite the fact that big rivers appear to be a specialized habitat of a number of rare species. It seems likely that Stylurus amnicola, which has been reported from the Ottawa River in Quebec also occurs on the Ontario side, but in this and a few other cases occurrence in Ontario has yet to be proven. Ophiogomphus mainensis is also to be expected in the Ontario portion of the Mixedwood Plains. The ecoregion 133 is a rather small area for which there are fewer records than for the other three much more extensive ecoregions. . With a more complete knowledge of distribution and ecology some species of Odonata could serve as useful bioindicators, but differential effects of environmental stress are poorly documented at present. Several taxonomic problems require study and others are likely to be revealed as more material is incorporated into collections. Not only is extensive field study required, but some of the recently produced keys (see above) have yet to be applied to material in collections representing the Mixedwood Plains.