High: 100% natural habitat surrounding rivers and streams by catchment
Low: 0% natural habitat surrounding rivers and streams by catchment
Defining the Spatial Extent of Ecosystems
Freshwater aquatic indicators were applied to all parts of the South Atlantic LCC geography not classified as marine or estuarine, so no refined extent was needed.
Active River Area:
SEACAP developed an Active River Area layer (final SEACAP report, page 21):
"The Active River Area (ARA) is a 'spatially explicit framework for modeling rivers and their dynamic interaction with the land through which they flow' (Smith et al. 2008). Key features of the ARA include the meander belt, riparian wetlands, floodplains, terraces, material contribution areas. The ARA is different from, but was calibrated to and compared against, the FEMA 100‐year floodplain. SEACAP used the ARA as a unit within which various landcover metrics, such as forest cover and impervious surface, were summarized. For the SEACAP area, we delineated the ARA for each of the seven size classes described in Section 2.1.3, using a seamless mosaic of 10m DEM data from the National Elevation Dataset (Gesch 2007; Gesch et al. 2002) as well as stream polylines, waterbody polygons, and stream area polygons from the NHDPlus v2 dataset. We selected and resampled wetflat landforms from a 30m landform model developed for the Southeastern United States (Anderson et al. 2014) to identify ARA components that occurred on wetflats and where longer-term storage of water is expected to occur. In addition, we obtained 100-yr floodplain polygons from the FEMA National Flood Hazard Layer (NFHL) in spring 2013 and used this data to inform cost distance threshold selection in the ARA delineation. Any FEMA 100-yr floodplain areas that were not captured by the ARA delineation were gridded at 10m resolution and merged underneath the ARA components in the final product. The final 10m ARA was resampled to 30m for use in the SEACAP metric calculations due to the resolution of other key input datasets (i.e., landcover). 22 The methods used to calculate all metrics was automated and documented via ArcGIS Model Builder models and custom Python scripts. Contact the authors for more information on the methods used to calculate metrics."
-- Does not account for accumulated impacts of upstream riparian buffers. Buffers at the headwaters are treated the same as those downstream.
-- Does not account for variation in buffer quality within the Active River Area at a scale below the catchment. This means that within the Active River Area, loss of natural habitat adjacent to the river is treated the same as loss farther away.
Disclaimer: Comparing with Older Indicator Versions
While this indicator has changed since the version of riparian buffers used in Blueprint 2.0, this only reflects differences in the way it was calculated and should not be compared to measure change over time.
The South Atlantic ecosystem indicators serve as the South Atlantic LCC's metrics of success and drive the identification of priority areas for shared action in the Conservation Blueprint. To learn more about the indicators and how they are being used, please visit the indicator page. Check out the Blueprint page for more information on the development of the Blueprint, a living spatial plan to conserve our natural and cultural resources.
Homer, C.G., Dewitz, J.A., Yang, L., Jin, S., Danielson, P., Xian, G., Coulston, J., Herold, N.D., Wickham, J.D., and Megown, K., 2015, Completion of the 2011 National Land Cover Database for the conterminous United States-Representing a decade of land cover change information. Photogrammetric Engineering and Remote Sensing, v. 81, no. 5, p. 345-354.
Martin, E. H, Hoenke, K., Granstaff, E., Barnett, A., Kauffman, J., Robinson, S. and Apse, C.D. 2014. SEACAP: Southeast Aquatic Connectivity Assessment Project: Assessing the ecological impact of dams on Southeastern rivers. The Nature Conservancy, Eastern Division Conservation Science , Southeast Aquatic Resources Partnership. <maps.tnc.org/seacap>
Naiman, Robert J., and Henri Decamps. “The Ecology of Interfaces: Riparian Zones.” Annual Review of Ecology and Systematics 28 (1997): 621–58.
U.S. Environmental Protection Agency (USEPA) and the U.S. Geological Survey (USGS). 2012. National Hydrography Dataset Plus. 2.10. <http://www.horizon-systems.com/nhdplus/>
The South Atlantic LCC encompasses and ecologically diverse 89 million acres across portions of six states, from southern Virginia to northern Florida. The geography also includes the marine environment within the federal Exclusive Economic Zone The South Atlantic region is a place ...