{{Short description|Ecosystem in south-eastern Canada}} {{About|the Canadian ecozone|the CEC Ecozone in North America|Mixed Wood Plains Ecozone (CEC)}} {{Infobox ecoregion |name = Mixedwood Plains |image = Kelso Conservation Area- Escarpment - Milton Heights-Ontario (2).jpg |image_size = 300px |image_alt = |caption = A representative stand of [[deciduous forest]] typical of this ecoregion |map = Mixedwood Plains Ecozone (Environment Canada) 2012.png |map_size = |map_alt = |map_caption = |biome = |animals = |bird_species = |mammal_species = |border1 = [[Atlantic Maritime Ecozone|Atlantic Maritime]] |border2 = [[Boreal Shield Ecozone (CEC)|Boreal Shield]] |area = 168,204 |country = [[Canada]] |state1 = [[Ontario]] |state2 = [[Quebec]] |region_type = Provinces |elevation = |coordinates = |geology = |seas = |rivers = |climate = [[Warm-summer humid continental|Humid continental]] ([[Hot-summer humid continental|hot summer]] in some areas) |soil = |conservation = |global200 = |habitat_loss = |habitat_loss_ref = |protected = |protected_ref = |embedded = }} The '''Mixedwood Plains Ecozone''' is the [[Ecozones of Canada|Canadian ecozone]] with the most southern 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,<ref name=smallest>{{cite web|title=Urban Corridor|url=http://www.ec.gc.ca/soer-ree/English/vignettes/Terrestrial/mp/default.cfm|work=Mixedwood Plains Ecozone|publisher=[[Environment Canada]]|accessdate=January 19, 2012|archiveurl=https://web.archive.org/web/20040622111910/http://www.ec.gc.ca/soer-ree/English/vignettes/Terrestrial/mp/default.cfm|archivedate=June 22, 2004}}</ref> and is home to nearly half of Canada's population, including its two largest cities, [[Toronto]], Ontario and [[Montreal]], Quebec.<ref name=SfS>{{cite web|title=Canada's Ecozones|url=http://www.spaceforspecies.ca/resources/ecozone/canada/|publisher=Space for Species|accessdate=January 19, 2012|archiveurl=https://web.archive.org/web/20071216223337/http://www.spaceforspecies.ca/resources/ecozone/canada/|archivedate=December 16, 2007}}</ref><ref name="bernhardt">{{Cite web | url = http://canadianbiodiversity.mcgill.ca/english/ecozones/mixedwoodplains/mixedwoodplains.htm | title = Mixedwood Plains | work = Canada's Ecozones, Canadian Biodiversity project | last = Bernhardt | first = Torsten | publisher = [[McGill University]], Redpath Museum | accessdate = 2008-02-02 }}</ref> 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.<ref>Rowe. J.S. 1972. Forest Regions of Canada. Canadian Forest Service, Department of Fisheries and the Environment, Ottawa, Ontario, Canada. 172 p. plus map.</ref> In the province of Ontario, the Ontario Ministry of Natural Resources maps this area as Site Regions 6E and 7E.<ref name="Hills, G.A 1961">Hills, G.A. 1961. The Ecological Basis for Land Use Planning. Ontario Department of Lands and Forests, Research Branch, Research Report No. 46, Toronto.</ref>

The United States uses a different terminology; the corresponding Level I ecoregion of the United States [[United States Environmental Protection Agency|Environmental Protection Agency]] system is the [[List of ecoregions in the United States (EPA)#Eastern Temperate Forest|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 [[Mixedwood Plains Ecozone (CEC)|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.<ref>{{cite web| url=http://www.cec.org/atlas/| title=North American Environmental Atlas; Terrestrial Ecoregions| accessdate=June 26, 2012| url-status=dead| archiveurl=https://archive.today/20120724143053/http://www.cec.org/atlas/| archivedate=July 24, 2012}}</ref>

==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 [[waterway]]s. 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<ref>{{cite web|title=Mixedwood Plains|url=http://www.canadiangeographic.ca/ATLAS/themes.aspx?id=mixedwood&sub=mixedwood_basics_introduction&lang=En|publisher=[[Canadian Geographic]]|accessdate=January 19, 2012}}</ref> and has a geographic area of 175,963&nbsp;km<sup>2</sup>.<ref name="smallest" />

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 [[Thousand Islands – Frontenac Arch|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.<ref>Eyles, N. Ontario Rocks: Three Billion Years of Environmental Change. Fitzhenry & Whiteside, Markham, Ontario. 339 p.</ref> [[File:Wilsonia citrina (Belize).jpg|thumb|200px|right|The hooded warbler nests in the southern forests of the mixedwood plains ecozone.]] 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.<ref>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.</ref> American chestnut was common in this region before the arrival of [[chestnut blight]], though it is now very rare. The area also has a high diversity of songbirds, reptiles and amphibians.<ref name="Johnson, L. 2007">Johnson, L. (ed.) 2007. The Natural Treasures of Carolinian Canada: Discovering the Rich Natural Diversity of Ontario's Southwestern Heartland. Lorimer/Carolinian Canada Coalition.</ref>

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, [[Thousand Islands – Frontenac Arch|Frontenac Axis]] 133, [[Manitoulin-Lake Simcoe]] 134 and the [[Lake Erie Lowland]] 135.[http://ecozones.ca/english/zone/MixedwoodPlains/ecoregions.html] The Lake Erie Lowland corresponds roughly to Site Region 7E,<ref name="Hills, G.A 1961"/> and to the more general term "Carolinian Forest."<ref name="Johnson, L. 2007"/>

===Ecoprovinces=== This ecozone can be further subdivided into two ecoprovinces:<ref>{{Cite web|last=Secretariat|first=Treasury Board of Canada|title=National Ecological Framework for Canada - Open Government Portal|url=https://open.canada.ca/data/en/dataset/3ef8e8a9-8d05-4fea-a8bf-7f5023d2b6e1|access-date=2020-11-07|website=open.canada.ca}}</ref> *[[Great Lakes-St. Lawrence Lowlands]] *[[Huron-Erie Plains]]

==Climate== The climate of the Mixedwood Plains is characterized by warm to hot summers and cool winters. The Great Lakes and Saint Lawrence River have a significant [[Continentality|moderating effect]] in this ecozone, which is in a major North American storm belt. [[Warm front|Warm air fronts]] from the [[Gulf of Mexico]] and US south- and mid-west often collide with cold polar [[air mass]]es, providing abundant [[Precipitation (meteorology)|precipitation]] in some areas.<ref name="SfS" /> Annually, the region receives between 720 and 1,000&nbsp;mm of precipitation. Most areas receive close to 150&nbsp;cm of snowfall but snowbelt areas can receive well over 300&nbsp;cm during a typical winter.<ref name=landforms>{{cite web|title=Landforms and Climate of the Mixedwood Plains Ecozone|url=http://www.ec.gc.ca/soer-ree/English/vignettes/Terrestrial/mp/land.cfm|work=Mixedwood Plains Ecozone|publisher=[[Environment Canada]]|accessdate=January 19, 2012|archiveurl=https://web.archive.org/web/20070125161828/http://www.ec.gc.ca/soer-ree/English/vignettes/Terrestrial/mp/land.cfm|archivedate=January 25, 2007}}</ref>

Summers average about 23&nbsp;°C in July in the southwestern end of the zone, to 18&nbsp;°C in the higher part of the north. Winters are much milder in the southwest along the Lake Erie shore, with a mean January temperature of -3&nbsp;°C, whereas mean lows are -12&nbsp;°C in the northeast. Some lakeshore areas have over 200 frost-free days per year.<ref name="landforms" />

Because of the relatively mild climate for Canada, the region has become an important and productive [[agriculture|agricultural]] area. Agriculture has been the primary cause of [[deforestation]] in the ecozone;<ref name="SfS" /> it was once covered entirely by forests. The resultant loss of natural [[habitat]] has caused a decline in the populations of many native species, and now over half of the [[List of Wildlife Species at Risk|Species at Risk]] in Canada are found in this zone.<ref name="SfS" />

==Ecology== ===Forests=== [[File:Forest-peterborough-Ontario.jpg|thumb|200px|right|A representative stand of deciduous forest near Peterborough with white trilliums in flower.]] [[File:Liriodendron tulipifera flower.jpg|thumb|200px|right|The tulip tree grows in the southern forests of the mixedwood plains ecozone.]] The forests are a part of the [[temperate deciduous forest]] that extends from Florida north to eastern Canada.<ref>Braun, E. L. 1950. Deciduous Forests of Eastern North America. New York: Hafner.</ref> The mixed plains ecozone has the highest plant diversity in Canada, with the Lake Erie lowland having trees species that occur nowhere else in Canada. Within Canada, these forest types are often referred to as the 'Carolinian zone' owing to the many southern plants and animals that reach their northern limits here. Clearing for agriculture and urbanization have reduced natural forest cover to less than ten percent. An overview of the flora and fauna of this distinctive region is available in ''The Natural Treasures of Carolinian Canada''.<ref name="Johnson, L. 2007"/> A few of the many examples of southern species found here include the hooded warbler, king rail, prothonotary warbler, blue-gray gnatcatcher, American badger, opossum, and eastern spiny softshell turtle. Past work has identified 38 critical natural areas, and an initiative known as The Big Picture aims to restore natural corridors as part of a natural heritage system. Some of the critical core areas in this region include Point Pelee, Long Point, Rondeau Park, Skunk's Misery, Backus Woods and Willoughby Marsh.

===Wetlands=== [[File:LongPointLakeErieOntario23.jpg|thumb|200px|right|Long Point extends into Lake Erie. It supports a rich flora and fauna typical of the Lake Erie Lowland.]] There is a rich diversity of wetlands in this ecozone owing to the presence of the Great Lakes and two major rivers, the Ottawa River and the St. Lawrence River. The wetlands on the Great Lakes are influenced by the slope of the shoreline, the type of substrate, exposure to waves, and the natural water level changes that characterize these lakes.<ref>Keddy, P.A. 2010. [https://www.amazon.com/Wetland-Ecology-Conservation-Paul-Keddy/dp/0521739675 Wetland Ecology: Principles and Conservation] (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Chapter 2.</ref> Some nationally significant wetlands include [[Point Pelee National Park]] and [[Long Point, Ontario|Long Point]], both on Lake Erie, and [[Presqu'ile Provincial Park]] on [[Lake Ontario]]. The wetlands of the St. Lawrence and [[Ottawa River]] have a diverse array of vegetation types as well, although these have been damaged by the construction of power dams and locks for shipping.<ref>Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Chapter 2.</ref> Vast numbers of waterbirds use these wetlands during migration, and they provide important habitat for fish.<ref>Maynard, L., and Wilcox, D.A., 1997, Coastal wetlands of the Great Lakes—State of the Lakes Ecosystem Conference 1996 background paper: Environment Canada and U.S. Environmental Protection Agency, EPA 905–R–97–015b, 99 p.</ref>

==Human population== The Mixedwood Plains is the most populated ecozone in Canada, with about half of the country's total population.<ref name=bernhardt/> Of the top 25 most populous cities in Canada, 13 are found in this ecozone, including the two largest, [[Toronto]] with 6.1 million inhabitants and [[Montreal]] with 4.2 million inhabitants, as well as the country's capital city, [[Ottawa]].

==Conservation== Human settlement has had a major impact on this ecoregion. A majority of the forested land has been cleared for agriculture, and a majority of the wetlands have been drained or filled. Hence, the remaining forests and wetlands are important for conservation of wild species, and for the ecological services provided to humans by forests and wetlands.

===Protected areas=== A number of [[protected area]]s have been established to protect representative and/or significant portions of this ecozone. Those designated by the federal government include [[Bruce Peninsula National Park]], [[Point Pelee National Park]], and [[Thousand Islands National Park]]. Those designated by provincial governments include [[Presqu'ile Provincial Park]].<ref name=protected>{{cite web|title=Mixedwood Plains Ecozone|url=http://www.pc.gc.ca/apprendre-learn/prof/itm2-crp-trc/htm/ecozone_e.asp#no10|work=Teacher Resource Centre: Terrestrial Ecozones of Canada|publisher=Parks Canada|accessdate=January 19, 2012}}</ref>

About 1.51% of the ecozone is protected,<ref name=ecoprotect>{{cite web|title=Total area protected by ecozones, 2010|url=http://www.ec.gc.ca/indicateurs-indicators/default.asp?lang=en&n=8390800A-1#pa4|work=Protected Areas Data|publisher=Environment Canada|accessdate=January 19, 2012}}</ref> the smallest percentage amongst the terrestrial ecozones in Canada.

==References== {{Reflist}}

==External links== *{{Commons category-inline|Mixedwood Plains}}

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[[Category:Ecozones of Canada]] [[Category:Ecozones and ecoregions of Ontario]] [[Category:Ecozones and ecoregions of Quebec]]