Natural Communities

Tue, 11/08/2011 - 07:41 -- cadoughe

Natural communities generally occur in continuously varying patterns. Most of the environmental factors that determine communities vary over continuous gradients. We can best decipher the tremendous complexity of natural communities by categorizing them according to their ecology.

Natural communities are valuable elements of natural diversity for a variety of reasons. They are generally regarded as coarse filters for diversity of organisms. By protecting examples of all the natural community types, the majority of species can be protected without laborious individual attention. Like species, communities have an intrinsic value as natural systems, as well as aesthetic value to human beings. These thirteen communities represent some of the most common communities as well as those considered of high visual interest across the landscape.

Community Types

Community types

Spruce-Fir

Generally found above 5,500 feet (though locally lower in suitable sites) and extending to the tops of all but the highest peaks.

Beech Gap

High elevations, within the range of spruce-fir forests. Primarily in south-facing gaps, but may occur on exposed ridgetops in areas lacking spruce and fir or adjacent to grassy balds.

Grassy Bald

Slopes, ridgetops, and domes of high mountains, usually on gentle slopes.

Heath Bald

Extremely exposed high elevation sites: peaks, sharp ridges, and steep slopes.

Northern Hardwood

Medium to fairly high elevation coves, flats, and slopes, particularly on north-facing slopes.

High Elevation Red Oak

Found on dry to moderately moist slopes and ridgetops at mid to high elevations (around 3,500- 5,500 feet).

Pine-Oak/Heath

Exposed sharp ridges, knobs, low elevation peaks, and steep south slopes.

Montane Oak-Hickory

Dry to moderately moist slopes and partly sheltered ridgetops at moderate to fairly high elevations (about 2,500-5,000 feet).

Hemlock

Slightly less moisture than cove forest sites, including open valley flats, slopes above cove forests, sheltered low ridges, narrow ravines, and open north-facing slopes at fairly high elevations.

Acidic Cove

Sheltered low and moderate elevation sites, primarily narrow, rocky gorges, steep ravines, and low gentle ridges within coves.

Rich Cove

Sheltered, moderately moist, low to moderate elevation sites, primarily broad coves and lower slopes.

Short Leaf Pine-Oak

Found at low elevations, generally below 2,300 feet.

Montane Alluvial

Stream and river floodplains at low elevations, generally below 2,300 feet.

Community Inventory

What is biodiversity?

Biological diversity, or biodiversity, describes the variety and abundance of all life forms in a given place - plants, animals, and other living organisms such as fungi, lichens, and mosses. Biological diversity also describes the processes, functions, and structures that sustain that variety and allow it to adapt to changing circumstances. Moreover, it encompasses the complexity of gene pools, species, communities, and ecosystems at spatial scales from local to regional to global.

Is biodiversity important in Western North Carolina?

The temperate ecosystems of the Blue Ridge Mountains are exceptionally diverse. Ancient geological events followed by climatic reversals and weathering formed the mountains that today feature the highest peaks in the eastern United States. In the moist, deep-soiled, densely-forested valleys, the daily range of temperature, wind, and humidity remains relatively constant. On the thin-soiled and exposed ridges, balds, and mountain tops, the daily range of climate conditions is much wider. This variability in elevation, aspect, climate, geology, and soils accounts for the occurrence of hundreds of plants and animals that exist at the edge of their natural range.

The geographic isolation of high-altitude species in the Blue Ridge Mountains has allowed some to evolve into unique species of their own, adding further to the biological diversity of these mountains. Examples are the Blue Ridge goldenrod and the spreading avens.

Secure Habitats

Acidic Cove Forest G5

Red maples, tulip poplars, rhododendron, sweet birch, and eastern hemlock are the dominant species in this forest. The presence of thick rhododendron and hemlock indicates that the soil is acidic. Fewer types of plants and trees can tolerate this acidic soil.

Example: White Water River Gorge

Montane Oak-Hickory Forest G5

This forest receives less rainfall even though it is at a moderate elevation. The dryer soil supports white oak, red oak, chestnut oak, pignut hickory, and mockernut hickory, plus a variety of small trees such as dogwood and sourwood. A diverse understory of shrubs and herbs is present, but not as diverse as in a Rich Cove forest.

Example: The Black Mountains

Rich Cove Forest G4

The rich, moist soils of the Rich Cove Forest support a wide range of trees and plants. Sugar maple, sweet buckeye, basswood, and Carolina silverbell are only a few of the types of trees growing in this forest. Spring wildflowers are well known in the lush, diverse herb layer present in the type. Mosses and rotting logs make the damp forest floor suitable for salamanders.

Example: Joyce Kilmer Memorial Forest

Threatened Habitats

Red Spruce-Fraser Fir Forest G2

This rare and extremely endangered community type only exists above 5,500 feet. More than a mile above sea level, the high rainfall, fog, and low temperatures make the climate similar to Maine and Canada.

Logging and fires in the 1910’s and 1920’s radically changed these communities, with some sites no longer supporting spruce-fir forests.

Threats: Balsam wooly adelgid, air pollution

Example: Mt. Mitchell

Grassy Bald G2

The origin of these treeless mountain tops is unknown. Grassy Balds are gentle slopes, ridgetops, and domes of high mountains where grasses, sedges, and herbs dominate with patches of shrubs and some small trees.

Threats: Woody plant invasion

Example: Roan Mountain

Montane Alluvial Forest G2*

Sycamore, tulip poplar, sweet birch, and hemlock are found at low to mid elevation. Subject to occasional flooding, water scrubs away perennials and leaves behind many seeds from annuals. For this reason, fewer large trees survive and more dense shrubs and small plants are found here.

Threats: Development

Example: French Broad River