
Ecoregions of Pennsylvania
What are ecoregions?
Ecoregions reflect broad ecological patterns occurring on the landscape. In general, each ecoregion has a distinctive composition and pattern of plant and animal species distribution. Abiotic factors, such as climate, landform, soil, and hydrology are important in the development of ecosystems, and thus help define ecoregions. Within an individual ecoregion, the ecological relationships between species and their physical environment are essentially similar.
Why use ecoregions?
Using ecoregions as a framework for assessing the distribution and status of species and ecosystems makes biological sense, compared to using politically derived lines like county, state or national boundaries. Ecoregions also provide an ecological basis for partitioning the state into subunits for conservation planning purposes.
Ecoregions in Pennsylvania
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Central Appalachian Forest Ecoregion
The Central Appalachian Forest ecoregion includes the Blue Ridge Mountains from Virginia to southern Pennsylvania, the historic Great Valley, and the dramatic ridges and valleys of the Allegheny Mountains that stretch south to north.
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North Atlantic Coast Ecoregion
The North Atlantic Coast Ecoregion (NAC) consists of parts of nine states (DE, PA, NJ, NY, CT, RI, MA, NH, ME) and their near shore marine waters. The land and freshwater component of the ecoregion encompasses 12.7 million acres in a narrow band from the southwestern shore of Delaware Bay north to Pemaquid Point in Maine.
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High Allegheny Plateau Ecoregion
The High Allegheny Plateau extends over 16.9 million acres, north from the Great Lakes Plains of Lake Ontario to the Ridge and Valley region of the Central Appalachians to the south, and from the Lake Erie Plain in the west to the Hudson River Valley in the east.
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Western Allegheny Plateau Ecoregion
Encompassing some 26 million acres across the plateau of the Allegheny Mountains, the Western Allegheny Plateau ecoregion is, like its neighbor the High Allegheny Plateau, divided into northern areas that were gouged by glaciers and the southern plateau that lay beyond.
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Lower New England-Northern Piedmont
Stretching from southern Maine and New Hampshire through western Massachusetts and Connecticut, Vermont, and eastern New York, the Lower New England-Northern Piedmont includes, all told, portions of 12 states -- and the District of Columbia.