 

ISSUE PRIMER
DETAILED REPORT
- - - - INTERNATIONAL
- - - - NORTH AMERICA
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Northern Great Lakes National Parks and Protected Areas
The vast Great Lakes region of the United States plays host to a patchwork of human development and natural habitat. Large cities, including Chicago, Detroit, and Cleveland, nestle on the shores of the lakes, and pollution of all sorts has afflicted some local areas for more than a century. Despite the years of heavy human use in many parts of the region, the Great Lakes still harbor many important wildlife areas, and in the north, significant tracts of wilderness. The roadless Isle Royale National Park is the largest island in the world's largest freshwater lake C Lake Superior. Of the 700 or so plants found on the island, 22 are relics from the last ice age, more commonly found in the tundra of Alaska or arctic Canada, and are restricted to the cool, moist habitats at the eastern end of Isle Royale. These species would be especially vulnerable to changes in climate that are expected to make the area warmer and drier.
Slightly west of Lake Superior, running along the Canadian border, lies Voyageurs National Park, a vast area of glacial lakes, islands and subarctic pine, spruce, aspen, and white birch forest. A new WWF analysis of protected area sensitivity to climate change in the U.S. puts this park at the top of the list of National Parks likely to experience major changes in vegetation as a result of global warming (see Appendix 1). Previous computer modeling exercises have also identified this region as sensitive to change. The IPCC predicts that as much as 40% of the world's boreal forest (like that in Voyageurs National Park) could eventually be lost as a result of climate change (Houghton et al. 1996). More detailed analysis for the Boundary Water Canoe Area, a designated wilderness within the Lake Superior National Forest, shows how rapid and dramatic these changes could be. Scientists Daniel Botkin and Robert Nisbet predict that diverse white birch, balsam fir, and quaking aspen forests could all start to decline and be replaced by sugar maple forest by 2010, and the white cedar bogs would most likely be replaced by shrubby, treeless habitat (Botkin and Nesbit 1992). However, the most critical factor in determining successional patterns in these northern hardwood-conifer forests is the interplay of wind and fire. Alterations in the disturbance regime will ultimately determine how the forests change (Peterson in litt.). In some cases, natural succession in northern forests may be accelerated by global warming. For example, research has shown that warmer and drier growing conditions in the late 1980s may have hastened the decline of mature paper birch forest in northern Michigan due to infestation with the insect pest, bronze birch borer (Jones et al. 1993). Loss of boreal forest at the southern edge of its distribution and invasion by northern hardwoods would result in lower biodiversity and less overall forest biomass. Similar changes are likely to be seen throughought the boreal zones of the world, and may represent one of the most alarming global impacts of climate change.
An example of how changes in forest composition might affect wildlife can be seen from predictions about the fate of the endangered Kirtland's warbler in a small nature reserve at Grayling, on Michigan's northern peninsula between lakes Huron and Michigan. The warbler depends on a few remaining areas of jack pine growing on "Grayling" soils. Models predict that these jack pine stands are likely to be replaced by white pine and red maple, and then, eventually, by a treeless plain. With none of its highly specialized habitat available in alternative nearby areas, the Kirtland's warbler would face extinction (Botkin and Nesbit 1992). The first impacts of global warming may already be identifiable in this region. Biologist Terry Root has recorded that many migratory birds are arriving up to 21 days earlier than they were 35 years ago, possibly because spring is arriving earlier at northern latitudes. Farther south, at Indiana Dunes National Lakeshore, plant species that are restricted to this narrow band at the lower end of Lake Michigan may become locally extinct as climate tends to drive the climatic zone northward C into the lake. Species at risk here include white pine and Canada bunchberry (Ken Cole pers. com.).
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