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Sandhills Ecology

The Sandhills are an inland habitat type, characterized by rolling hills capped by deep coarse sands. They are wedged between the Coastal Plain and Piedmont regions of North and South Carolina and Georgia.

Scientists believe the Sandhills were formed by ancient oceans that rose and then receded in response to melting and freezing of polar ice caps. Beaches formed wherever the water met the land. Each time a beach formed, dune lines were left behind when the ocean receded.

Because the Sandhills contain dry, nutrient-poor soil, this habitat contains only plants adapted to such harsh conditions. Turkey oak and longleaf pine trees are typical Sandhills tree species. The root systems of these two species allow them to extract water from various soil depths. These trees are also well adapted to the frequent, lightning-induced fires that strike the Sandhills. Longleaf pines have a thick, fire-resistant bark, and turkey oaks that are burned above ground will resprout because the fire does not damage their root systems.

The longleaf pine is the dominant tree species in this system and is essential to its integrity, but the floral and faunal diversity of the system lies in its understory. In fact, the longleaf pine–wiregrass forest may well be the most diverse North American ecosystem north of the tropics, containing rare plants and animals not found anywhere else. The understory throughout the longleaf range contains from 150 to 300 species of groundcover plants per acre, more breeding birds than any other southeastern forest type, about 60 percent of the amphibian and reptile species found in the Southeast—many of which are endemic to the longleaf forest—and at least 122 endangered or threatened plant species.

The biodiversity of the Sandhills depends on a combination of relatively high rainfall, very porous, sandy soils and an active cycle of wildfires that creates a mosaic of longleaf pine community types. Longleaf pine forests, though once covering over 90 million acres of the Southeastern United States, are now greatly diminished and fragmented by human development. The history and current status of human activities in the Sandhills has greatly reduced the intact longleaf pine habitat in the Sandhills with much of this remnant within the boundaries of the Fort Bragg military installation. Fort Bragg, government agencies and other organizations are seeking to manage and protect this habitat not only for the endangered red-cockaded woodpecker and native biota, but also for military training purposes. However, the Sandhills is currently experiencing a surge in population growth, a trend that is expected to continue in the near future.

Longleaf Pine and the role of Fire

Longleaf pine ecosystems once occupied over 90 million acres in the South. Today less than three million acres remain, with many of the remaining acres in an unhealthy state, due partially to the exclusion of fire. The longleaf ecosystem figured prominently in the cultural and economic development of the South. Today, these forests and landscapes represent significant components of the region's ecological diversity and offer new economic opportunities for many private landowners they also provide essential habitat for many rare animals and plants. The continuing loss of longleaf forests has prompted increasing concern among conservation and natural resource organizations. Restoration efforts are now underway on National Forests and other public lands in the Southeast.

Interruption of natural fire regimes in the Southeast has resulted in alteration of native plant abundance to a degree that threatens long-term longleaf pine ecosystem sustainability. The decline of longleaf pine, native grasses and forbs and increase in competing trees and shrubs, forming high-density midstory fuel ladders, are the direct results of decreased fire frequencies. These altered ecosystems have become increasingly vulnerable to destruction by catastrophic fire, which may also directly threaten human life and property, and invasion by noxious weeds and undesirable woody plants.

Restoring periodic fire as a disturbance agent is fundamental to the ecological restoration and maintenance of longleaf pine ecosystems. Fire returns nutrients to the nutrient-poor sandhill soils and temporarily creates more open space that allows new species to become established. Research has shown an increase in both the number of plant species and the number of individual plants. Scientists say such increases mean there is a potential for increase in the number of animal species that inhabit Sandhills.