CANADIAN WETLANDS - ENVIRONMENTAL GRADIENTS AND CLASSIFICATION

The Canadian Wetland Classification System is based on manifestations of ecological processes in natural wetland ecosystems. It is hierarchi cal in structure and designed to allow identification at the broadest levels (class, form, type) by non-experts in different disciplines. Th e various levels are based on broad physiognomy and hydrology (classes ); surface morphology (forms); and vegetation physiognomy (types). For more detailed studies, appropriate characterization and subdivisions can be applied. For ecological studies the wetlands can be further cha racterized by their chemical environment, each with distinctive indica tor species, acidity, alkalinity, and base cation content. For peatlan ds, both chemical and vegetational differences indicate that the prima ry division should be acidic, Sphagnum-dominated bogs and poor fens on one hand and circumneutral to alkaline, brown moss-dominated rich fen s on the other. Non peat-forming wetlands (marshes, swamps) lack the w ell developed bryophyte ground layer of the fens and bogs, and are sub ject to severe seasonal water level fluctuations. The Canadian Wetland Classification System has been successfully used in Arctic, Subarctic , Boreal and Temperate regions of Canada.