Ecological RegionsEssential Knowledge for Naturalists
What is an Ecoregion?Ecological Regions, or ecoregions, are geographic areas that exhibit similarity in the attributes of plant and animal communities present there. the ecoregion of a particular area develops over time in response to a great number of factors. Geology plays a primary role, as do Weather and Climate, soils, glacial history, elevation, and hydrological conditions. What makes the concept of an ecoregion useful to naturalists is the predictive power of knowing what types of natural communities may be found in each ecoregion.
If you know where you are, you can guess with reasonable certainty what types of plants and animals you may find. Likewise, if you can observe the plant communities and wildlife around you, you may get a good idea of what portion of the world you are in. Now, you may never be struck with amnesia or being secretly kidnapped to a different region in your sleep, but there are more practical reasons for understanding ecoregions as well.
For example, if you know you are in the eastern temperate forest ecoregion, but around you are fields, and no forests, that tells you something about the disturbance history of the area. Knowing the disturbance history can give you clues to what stage of natural succession the area is in.
This in turn tells you whether the area will contain pioneer species, or species more adapted to an older ecological stage. Knowing all of this may help you to identify the plants or animals you see. Certain birds, for example might be found only in old growth woods, whereas a similar appearing bird may be found in less mature woodlands. Knowing the stage of succession can help you rule out one of the possibilities. Think for a moment what other information you could have access to just by knowing what ecological region you are in.
The North American Continent is divided by scientists into 15 major ecological regions, according to the Commission for Environmental Cooperation, which has posted a useful map of the ecoregions of North America on its web site.
The eastern third of the United States falls mainly in the Eastern Temperate Forest region, with portions of the Northeast falling into the Northern Forests ecological region, and the tip of Florida falling into the tropical humid forest ecoregion.
The Eastern Temperate Forests Ecoregion covers the U.S. from the Gulf of Mexico to the Great Lakes. From the east coast, west to eastern Texas, this ecoregion covers a vast area that was historically vegetated with broadleaved trees and conifers. Of course, this vast area is not uniform, and the climate could hardly be considered similar in east Texas and northeast Ohio.
From the broad level of Eastern Temperate Forests, the ecoregion can be broken down further. Across the U.S., our ecoregions can be broken down into over 50 categories at the next hierarchical level down. In Ohio, which is completely in the Eastern Temperate Forest Ecoregion, there are five "level II" ecoregions. These are:
Eastern Corn Belt PlainsThis ecoregion was once home to broad plains. Endless seas of grasses once grew here, with Oak forests growing along the river corridors. Some sand dune communities can still be found here, along with areas of wet prairies and swamp forests.
Huron/Lake Erie Lake PlainsThe Huron/Lake Erie Lake Plains Ecoregion is nearly flat, and encompasses the bottom of a larger precursor to Lake Erie, Lake Maumee. Much of the region was once called the Great Black Swamp. It was impenetrable, and inhibited westward, travel, expansion, and agriculture. Thus, as humans often do, we drained the Great Black Swamp. The original vegetation was that of wetland complexes. Elms, swamp white oaks, green ash, cottonwood. Today, remnants of the swamp remain, but most of the area is in agricultural use. The Maumee River, locates in this ecoregion, contributes approximately 25% of all the sedimentation and pollution to Lake Erie.
This ecoregion also is the location of the "Oak Openings". These openings are highly diverse plant communities of mixed oak forests and Oak savannas that formed on sand dunes.
Erie/Ontario Drift and Lake PlainNortheast Ohio, from the Pennsylvania State Line to roughly Erie County, lies in this ecological region. Some scientists divide the Erie/Ontario Drift and Lake Plains ecoregion into a lake plain region, and the Unglaciated Allegheny Plateau. For our purposes, the distinction need not be made. The entire ecological region was glaciated multiple times, with the last glacier retreating 10,000-12,000 years ago. This relatively young landscape is not nearly as hilly as its neighbor to the south, the unglaciated Western Allegheny Plateau.
The historical vegetation of the region differed depending on soil conditions. In wetter areas, where soils with high clay content predominate, the forests were often beech-maple, with bottomland forests of swamp white oak, elms, sycamore and cottonwood common as well. On well-drained sites, mixed oak forests dominated this portion of Ohio. Moister sites were places where mixed mesophytic forests grew historically.
Because of the glacial history of the region, unique ecosystems such as sand barrens, bogs, fens, and kettle-hole lakes dot the northeast Ohio landscape. The extreme northern portion of the ecoregion lies along Lake Erie, and has a much longer growing season than most of Ohio because of the moderating effects of the Lake. Additionally, as the northernmost portion of Ohio, this area is home to more "northern" species than the rest of the state. Because of these factors, the plant and animal diversity of northeastern Ohio is exceptional.