Biodiversity Indicators
SE Conservation Blueprint 2025 · SECAS
Biodiversity: what the land cover supports.
The Southeast Conservation Blueprint 2025 scores each acre of the watershed for ecological indicators based on habitat quality, species occurrence, and connectivity. Across Port Royal Sound, positive indicator values identify habitat associated with imperiled herpetofauna, estuarine fish, and beach birds, showing how biodiversity patterns connect with the watershed's land and water.
Imperiled amphibians & reptiles
69.9%
of watershed has positive indicator value
671,756 acres. Positive habitat for species including the eastern diamondback rattlesnake, gopher tortoise, striped newt, and several state-listed salamanders. The highest-scoring HUC12s are the interior headwater swamps and bottomland forests most distant from development.
| HUC12 | Coverage |
|---|---|
| Gillison Branch | 91.8% |
| Cooper River-Calibogue Sound | 91.5% |
| Beech Branch | 90.9% |
| Camp Branch-Coosawhatchie River | 89.0% |
| Harbor River-Trenchards Inlet | 88.7% |
Atlantic estuarine fish habitat
27.1%
of watershed has positive indicator value
260,240 acres. Habitat supporting species including striped bass, shortnose sturgeon, and American shad. Coverage concentrates in the estuarine zone, the tidal rivers, sounds, and adjacent marsh margins where juvenile fish use salt marsh as nursery habitat.
| HUC12 | Coverage |
|---|---|
| Harbor River-Trenchards Inlet | 86.2% |
| Broad River-Port Royal Sound | 84.0% |
| Cooper River-Calibogue Sound | 78.4% |
| Lower Beaufort River-Atlantic Intracoastal Waterway | 76.4% |
| Whale Branch | 75.7% |
South Atlantic beach birds
0.6%
of watershed has positive indicator value
5,618 acres. A small, concentrated footprint. Species including American oystercatcher, Wilson's plover, least tern, and piping plover depend on undisturbed beach and shell-hash habitat concentrated in Trenchards Inlet, the ACE Basin edge, and the outer barrier islands. Its limited mapped extent should not be read as a measure of conservation priority.
| HUC12 | Coverage |
|---|---|
| Harbor River-Trenchards Inlet | 6.9% |
| Broad Creek | 3.7% |
| Lower Beaufort River-Atlantic Intracoastal Waterway | 2.9% |
| Gaskins Banks-Atlantic Ocean | 2.0% |
| Calibogue Sound | 1.5% |
What the Blueprint indicators measure
Imperiled amphibians & reptiles Scores each acre based on species occurrence models, habitat suitability, and landscape connectivity. Forest cover, wetland condition, and connectivity to unfragmented natural land are its primary drivers.
Atlantic estuarine fish habitat Reflects the condition of the estuarine zone and its upstream connectivity. Intact salt marsh, low turbidity, and tidal exchange drive the indicator; those conditions depend on the land cover and wetland fabric upstream.
South Atlantic beach birds Scores undisturbed beach and wrack habitat along the Atlantic coast. Sensitive to human access, predator pressure, and storm overwash dynamics; in Port Royal Sound it is concentrated on outer barrier beaches with limited development exposure.