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<br />SIGNIFICANT NATURAL HERITAGE AREAS OF ORANGE COUNTY
<br />Orange County is located near the eastern edge of the North Carolina Piedmont, within the popular and rapidly
<br />developing Research Triangle region of North Carolina. Typical landscape features of the county include gently rolling
<br />hills, broad, upland ridges, and low energy streams with narrow floodplains. The two most common natural communities
<br />are Mesic Mixed Hardwood Forest and Dry- Mesic Oak- Hickory Forest, types of eastern deciduous forest.
<br />The natural communities of Orange County are strongly associated with the variety of topographic, geologic, soil, and
<br />hydrologic conditions found throughout the county. Geologically, much of the county's 396 square miles is within the
<br />Carolina Slate Belt, which is composed of diverse, generally metamorphosed volcanic rocks. Two geographic features in
<br />Orange County stand out against the background of typical Piedmont formations. The southeastern most corner dips into
<br />the Triassic Basin, which is a low- elevation area of sedimentary, easily eroded rock. Orange County's lowest elevation,
<br />240 feet, occurs in an area of Piedmont Swamp Forest along the western margin of the Triassic Basin. Many of the
<br />animals found here are normally distributed in the Coastal Plain.
<br />The other important geographic feature is the monadnocks, which are hills capped with rock that is more resistant to
<br />erosion than the surrounding terrain. The highest elevation in Orange County is the monadnock summit of Occoneechee
<br />Mountain, at 860 feet high. Monadnocks are rare in the outer Piedmont, and their flora and fauna often show distinctly
<br />montane affinities. The group of monadnocks nearest to Orange County is in the Uwharrie range, and their summits have
<br />a similar montane biota. Orange County monadnocks are smaller in area. While the habitat on Occoneechee Mountain is
<br />the most unique and important, Orange County has a significant cluster of these isolated hills, including Blackwood,
<br />Bald, Pickards, McCauley, Crawford, and Mitchells "mountains." Other higher elevation areas occur along Morgan
<br />Creek, New Hope Creek, and the Eno River, where steep slopes have been cut by water action, but these rarely exceed
<br />150 feet in relief. Many of the most unique natural areas of the county, such as rhododendron communities, pine — oak
<br />bluffs, and all of the dry, rocky slopes are restricted to these steep, stream -cut slopes.
<br />Though a small area, Orange County has an unusually high degree of diversity in its aquatic species, due to the presence
<br />of three different river basins (Cape Fear, Neuse, and Roanoke) within its limits. Orange County contains the headwaters
<br />of numerous streams that flow into these rivers. New Hope Creek, Morgan Creek, Cane Creek, and Back Creek flow into
<br />the Cape Fear River system via the Haw River, which forms the county's southwestern corner. In the north, the Eno
<br />River and Little River (North and South forks) flow eastward into the Neuse River. South Hyco Creek and Lynch Creek,
<br />in Cedar Grove Township, flow north into the Roanoke River system, which soon enters Virginia. The Neuse River
<br />waterdog (Necturus lewisi) is probably the most restricted animal that occurs within Orange County. It is found only
<br />within the Neuse and Tar River systems of North Carolina and reaches it westernmost limit in the Eno River within
<br />Orange County.
<br />There are no natural lakes in Orange County. Small examples of marshy terrain are found in some of the larger semi-
<br />permanent beaver ponds, and around the margins of University Lake and several other long - established reservoirs.
<br />Humans have generally altered seeps and springs, except in situations directly within floodplains, where these important
<br />amphibian- breeding habitats have been allowed to persist.
<br />The natural area inventory conducted in Orange County during 2001 -2002 identified 53 significant natural heritage areas,
<br />including 3 sites of national significance, 10 sites of state significance, 8 sites of regional significance, and 32 sites of
<br />county significance. Of the three nationally - significant sites, two are entirely within North Carolina Public Waters and
<br />one is privately- owned; of the ten state - significant sites, one is entirely within North Carolina Public Waters, two are
<br />privately- owned, one is partially in private conservation, one is publicly - owned, two are partially publicly -owned and in
<br />private conservation, one is entirely publicly -owned or within private conservation, and two are partially within a state
<br />park. Of the eight regionally - significant sites, three are privately - owned, two are partially publicly- owned, one is
<br />partially within a state park, two are partially in private conservation.
<br />Frequently, sites occur in clusters with strong geographical connections and ecological relationships. Such clusters of
<br />sites are designated as "macrosites ". The natural heritage areas of national, state, and regional significance in Orange
<br />County are summarized below, and are grouped according to their occurrences within macrosites. Isolated sites (those
<br />not in a macrosite) are placed in a stand -alone group.
<br />Funding for this project was provided by the North Carolina Natural Heritage Trust fund and Orange County, North
<br />Carolina. The inventory was updated by Bruce Sorrie and Rich Shaw and published by the North Carolina Natural
<br />Heritage Program.
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