A. Pervasive disturbances: The most common disturbances based on total stream length in a given region.
Top five overall most pervasive disturbances to all stream reaches, regardless of stream size and across all spatial scales (ranked highest first):
- Total excessive (anthropogenic or man caused) sediment yield
- Impervious surface cover
- Road crossing density
- Population density
- Pasture and hay land use
Top three most pervasive disturbances to creeks (<100 km 2 watersheds) across all spatial scales :
- Total excessive sediment yield
- Impervious (hard) surface cover
- Road crossing density
Top three most pervasive disturbances to rivers (>100 km 2 watersheds) across all spatial scales:
- Upstream dam density
- Pasture and hay land use
- Impervious surface cover
Top five most pervasive disturbances to creeks, specific to spatial scale:
- Excessive sediment yield in network catchments
- Road crossing density in network catchments
- Impervious surface cover in network catchments
- Crop land use in local buffers
- Downstream dam density in network catchments
Top five most pervasive disturbances to rivers, specific to spatial scale:
- Upstream dam density in network catchments
- Pasture and hay land use in network catchments
- Pasture and hay land use in network buffers
- Impervious surface cover in network catchments
- High intensity urban land use in network catchments
In the Eastern Gulf of Mexico state group, 64.4% of streams are classified as low or very low risk of habitat degradation.
B. Most severe disturbances (a subset of pervasive disturbances): Disturbances associated with stream reaches in a given region that were scored as having high or very high risk of habitat degradation (red and orange color groups).
Top five overall most severe disturbances to all stream reaches, regardless of stream size and across all spatial scales (ranked highest first):
- Crop land use
- Pasture and hay land use
- Upstream dam density
- Total excessive sediment yield
- Low intensity urban land use
Top three most severe disturbances to creeks (<100 km 2 watersheds) across all spatial scales:
- Crop land use
- Pasture and hay land use
- Total excessive sediment yield.
Top three most severe disturbances to rivers (>100 km 2 watersheds) across all spatial scales:
- Upstream dam density
- Pasture and hay land use
- Crop land use
