Western Canada and Central Alaska are part of one of the largest forested regions in the world. A particularly important and distinctive portion, hereafter referred to as the Western Boreal Forest (WBF) is at the heart of this ecosystem and covers >3 million km2. In addition to vast timber reserves, this region encompasses thousands of km2 of lakes and wetlands providing critical breeding, staging and molting habitats for North American waterfowl and waterbirds.
The eight ecozones that comprise the WBF contain a mosaic of wetland complexes, meandering river valley flood plains and some of the largest inland river deltas in the world. Spruce, pine and fir dominate much of the uplands along with mixed-wood forests of aspen, birch and poplar. Forest fire historically has been the dominant rejuvenating force influencing upland and wetland vegetation structure. Beavers also influence wetland abundance and function.
The WBF annually supports breeding populations of 12-14 million ducks (Table 1). Scaup, mallard, American wigeon, green-winged teal and scoters each have breeding populations between 1 and 4 million birds. Boreal lakes, fens and bogs also are primary breeding areas for common loons, sandhill cranes and red-necked grebes. Several species of shorebirds, including greater and lesser yellowlegs, short-billed dowitchers, spotted and solitary sandpipers and Wilson's phalaropes, use boreal wetlands for breeding. At least two bird species of special interest, the trumpeter swan and whooping crane depend almost exclusively upon boreal wetlands for breeding. Riparian and wetland habitats also are important for nesting and foraging for many passerine species.
The permanent water provided by boreal wetlands and lakes is important to millions of molting waterfowl from the parklands and prairies to the south. During spring and fall migration, northern-breeding waterfowl also congregate on these lakes.
Boreal wetlands have been considered stable and largely undisturbed because of their remoteness, and thus management of boreal wetlands has been viewed as expensive and unnecessary. This situation is changing. The WBF, though vast and difficult to access, is undergoing rapid transformation from undisturbed wilderness to a resource-rich, commercially exploited region. Wetlands systems are being impacted by forest cover removal, climate change and extensive linear developments (e.g., roads, seismic lines). Five environmental pressures predominate: