|
The Mixedwood Plains Ecozone is the Canadian ecozone with the most southerly extent, covering all of southwestern Ontario, and parts of central and northeastern Ontario and southern Quebec along the Saint Lawrence River. It was originally dominated by temperate deciduous forest growing mostly on limestone covered by glacial till. It is the smallest ecozone in Canada, but it includes the country's most productive industrial and commercial region, and is home to nearly half of Canada's population, including its two largest cities, Toronto and Montreal. Hence, little of the original forest cover remains, making protection of the remaining forests a high conservation priority. This ecozone includes two regions described by J.S. Rowe in his classic ''Forest Regions of Canada'': the entire Deciduous Forest Region, and the southern portions of the Great Lakes-St. Lawrence Forest Region.〔Rowe. J.S. 1972. Forest Regions of Canada. Canadian Forest Service, Department of Fisheries and the Environment, Ottawa, Canada. 172 p. plus map. 〕 In the province of Ontario, the Ontario Ministry of Natural Resources maps this area as Site Regions 6E and 7E.〔Hills, G.A. 1961. The Ecological Basis for Land Use Planning. Ontario Department of Lands and Forests, Research Branch, Research Report No. 46, Toronto.〕 The United States uses a different terminiology; the corresponding Level I ecoregion of the United States Environmental Protection Agency system is the Eastern Temperate Forest ecoregion. To deal with the differences in names between Canada and the United States, the Commission for Environmental Cooperation has produced a continental atlas. In this atlas, the Mixed Wood Plains is a Level II Ecoregion 8.1, which includes the above areas within Canada, as well as adjoining parts of the United States.〔(【引用サイトリンク】 title=North American Environmental Atlas; Terrestrial Ecoregions )〕 ==Geography== The Mixedwood Plains stretch along the Quebec City-Windsor corridor. At its western end, it encompasses all of Southwestern Ontario, and is bounded by three Great Lakes and their connecting waterways. To its north is Lake Huron, and to the south Lake Erie. Further east, it has boundaries with Lake Ontario to the south and Lake Simcoe to the north, before continuing east along a narrow strip of the Saint Lawrence River coast toward Quebec. It covers approximately 9% of the total surface of Canada〔(【引用サイトリンク】url=http://www.canadiangeographic.ca/ATLAS/themes.aspx?id=mixedwood&sub=mixedwood_basics_introduction&lang=En )〕 and has a geographic area of 175,963 km².〔 Most of the ecozone is underlain by Paleozoic rock, mostly limestone, covered with various deposits of glacial till including moraines, drumlins and old glacial lake bottoms. The eastern areas were flooded by the Champlain Sea. One prominent rock feature is the Niagara Escarpment, which bifurcates the region from Niagara Falls to the northern tip of the Bruce Peninsula, then extends to Manitoulin Island. Another is the Frontenac Axis, an exposure of Canadian shield rocks that extends south to the St. Lawrence River near Kingston, creating the Thousand Islands. In south-central Ontario, the ecologically important and politically sensitive Oak Ridges Moraine is a major feature. 〔Eyles, N. Ontario Rocks: Three Billion Years of Environmental Change. Fitzhenry & Whiteside, Markham, Ontario. 339 p.〕 Owing to its southern location, it initially had a high natural biological diversity. For example, the Lake Erie Plains region has the highest tree diversity in Canada, with species such as tulip tree, cucumber tree, pawpaw, black gum, sassafrass and black oak.〔Rowe. J.S. 1972. Forest Regions of Canada. Canadian Forest Service, Department of Fisheries and the Environment, Ottawa,Canada. 172 p. plus map. p 89.〕 The chestnut also used to occur in this region before it was removed by chestnut blight. The area also has a high diversity of songbirds, reptiles and amphibians.〔Johnson, L. (ed.) 2007. The Natural Treasures of Carolinian Canada: Discovering the Rich Natural Diversity of Ontario's Southwestern Heartland. Lorimer/Carolinian Canada Coalition.〕 Some of the most fertile soil in Canada is located in this ecozone, in which the Holland Marsh has come to be known as ''"Ontario's vegetable basket"'', and the Niagara Peninsula is the most productive wine region in the country. This ecozone is subdivided into four ecoregions: St.Lawrence Lowlands 132, Frontenac Axis 133, Manitoulin-Lake Simcoe 134 and the Lake Erie Lowland 135.() The Lake Erie Lowland corresponds roughly to Site Region 7E,〔Hills, G.A. 1961. The Ecological Basis for Land Use Planning. Ontario Department of Lands and Forests, Research Branch, Research Report No. 46, Toronto.〕 and to the more general term "Carolinian Forest."〔Johnson, L. (ed.) 2007. The Natural Treasures of Carolinian Canada: Discovering the Rich Natural Diversity of Ontario's Southwestern Heartland. Lorimer/Carolinian Canada Coalition.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mixedwood Plains Ecozone (Canada)」の詳細全文を読む スポンサード リンク
|