Indicator: Imperiled Aquatic Species

Aug 10, 2020
Open in Map

This indicator measures the number of aquatic species within each watershed that are listed as G1 (globally critically imperiled), G2 (globally imperiled), or threatened/endangered under the U.S. Endangered Species Act.

Reason for Selection

This indicator identifies areas with abundant rare and endemic aquatic species that would benefit from conservation actions. It captures patterns of rare and endemic species diversity not well-represented by other freshwater indicators.

Input Data

– Estimated Floodplain Map of the Conterminous U.S. from the EPA EnviroAtlas (see this factsheet for more information)

– [National Hydrography Dataset Plus Version 2] ( (NHD Plus Version 2)

– Aquatic imperiled species data for this indicator were provided by NatureServe and the Environmental Protection Agency (EPA) EnviroAtlas. This EnviroAtlas dataset includes analysis by NatureServe of species associated with aquatic habitat that are listed as G1 (globally critically imperiled), G2 (globally imperiled), or listed under the U.S. Endangered Species Act (ESA). The analysis results are for use and publication by both the LandScope America website and by EnviroAtlas. Results are provided for the total number of Aquatic Associated G1-G2/ESA species, the total number of Wetland Associated G1-G2/ESA species, the total number of Terrestrial Associated G1-G2/ESA species, and the total number of Unknown Habitat Association G1-G2/ESA species in each 12-digit hydrologic unit (HUC12). NatureServe is a non-profit organization dedicated to developing and providing information about the world’s plants, animals, and ecological communities. NatureServe works in partnership with 82 independent Natural Heritage programs and Conservation Data Centers that gather scientific information on rare species and ecosystems in the United States, Latin America, and Canada (the Natural Heritage Network). NatureServe is a leading source for biodiversity information that is essential for effective conservation action. This dataset was produced by NatureServe to support research and online mapping activities related to EnviroAtlas. EnviroAtlas allows the user to interact with an easy-to-use web-based mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Facts Sheet.

This indicator includes data for the following species: Broad River Stream Crayfish, Greensboro Burrowing Crayfish, Piedmont Blue Burrower, Lean Crayfish, Oconee Burrowing Crayfish, Chauga Crayfish, Sandhills Spiny Crayfish, Piedmont Prairie Burrowing Crayfish, Mimic Crayfish, Saluda Burrowing Crayfish, Newberry Burrowing Crayfish, Ochlockonee Crayfish, Santa Fe Cave Crayfish, Big Blue Springs Cave Crayfish, Woodville Karst Cave Crayfish, Pallid Cave Crayfish, Black Creek Crayfish, Florida Longbeak Crayfish, Spider Cave Crayfish, Gulf Sturgeon, Alabama Shad, Bluestripe Shiner, Altamaha Shiner, Thinlip Chub, Cape Fear Shiner, Carolina Redhorse, Robust Redhorse, Carolina Madtom, Orangefin, Broadtail Madtom, Stippled Studfish, Waccamaw Killifish, Waccamaw Silverside, Carolina Pygmy Sunfish, Bluebarred Pygmy Sunfish, Waccamaw Darter, Halloween Darter, Roanoke Logperch, Altamaha Arcmussel, Dwarf Wedgemussel, Carolina Elktoe, Apalachicola Floater, Delicate Spike, Pod Lance, Brother Spike, Brown Elliptio, Yellow Lance, St. Johns Elephantear, Inflated Spike, Altamaha Spinymussel, Tar River Spinymussel, Waccamaw Spike, Purple Bankclimber, Atlantic Pigtoe, Finelined Pocketbook, Waccamaw Fatmucket, Carolina Fatmucket, Carolina Heelsplitter, Ochlockonee Moccasinshell, Suwannee Moccasinshell, James Spinymussel, Oval Pigtoe, Tallapoosa Orb, Florida Mapleleaf, Savannah Lilliput, Peninsular Floater, Carolina Creekshell, Magnificent Ramshorn, Squaremouth Amnicola, Cobble Sprite, Suwannee Hydrobe, Slough Hydrobe, Creek Siltsnail, Green Cove Siltsnail, Ichetucknee Siltsnail, Ocmulgee Siltsnail, Emily’s Siltsnail, Halcyon Marstonia, Pumpkin Siltsnail, Reverse Pebblesnail, Flint Pebblesnail, Savannah Pebblesnail, Panhandle Pebblesnail, Flaxen Elimia, Pup Elimia, Slanted Elimia, Gem Elimia, Oak Elimia, and Timid Elimia.

Mapping Steps

1) We downloaded the watershed boundary dataset and the national metric tables in Esri FileGeodatabse format from the EPA EnviroAtlas and joined the tabular and spatial data.

2) We identified the field depicting total number of Aquatic Associated G1-G2 or ESA species in each HUC12.

3) We used the above field to convert the vector HUC12 layer to a raster with 30 m cell size using the ArcGIS Polygon to Raster tool with a cell assignment type of maximum combined area.

4) We clipped the resulting raster to the EPA Estimated Floodplain layer.

5) We reclassified the values depicting the total number of aquatic associated G1-G2 or ESA species in each HUC12.

6) We clipped the resulting raster to the extent of the NHD Plus catchments layer to remove values in the nearshore marine environment.

Final indicator values

4 = 4 or more aquatic imperiled (G1/G2) or threatened/endangered species observed (high)

3 = 3 aquatic imperiled (G1/G2) or threatened/endangered species observed

2 = 2 aquatic imperiled (G1/G2) or threatened/endangered species observed

1 = 1 aquatic imperiled (G1/G2) or threatened/endangered species observed

0 = No aquatic imperiled (G1/G2) or threatened/endangered species observed (low)

**Definitions **

Estimated Floodplain

The EPA Estimated Floodplain Map of the Conterminous U.S. displays “…areas estimated to be inundated by a 100-year flood, also known as the 1% annual chance flood. These data are based on the Federal Emergency Management Agency (FEMA) 100-year flood inundation maps with the goal of creating a seamless floodplain map at 30-meter resolution for the conterminous United States. This map identifies a given pixel’s membership in the 100-year floodplain and completes areas that FEMA has not yet mapped.”

Known Issues

– As this indicator is based on occurrence records, poorly surveyed areas may be scored too low. Therefore, this data does not imply absence of species.

– The data in this indicator was last updated in 2011. Subwatersheds with fewer than four imperiled aquatic species in 2011 that subsequently had new imperiled species discovered after 2011 would be scored too low.

–While this indicator generally includes the open water area of reservoirs, some open water portions of Kerr Lake are missing from the estimated floodplain dataset.

Disclaimer: Comparing with Older Indicator Versions

There are numerous problems with using South Atlantic indicators for change analysis. Please consult Blueprint staff if you would like to do this (email

Literature Cited

EPA EnviroAtlas. 2018. Estimated Floodplain Map of the Conterminous U.S.

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.

U.S. Environmental Protection Agency (USEPA) Office of Research & Development (ORD) - National Exposure Research Laboratory (NERL) and NatureServe. 2013. EnviroAtlas - NatureServe Analysis of Imperiled or Federally Listed Species by HUC-12 for the Conterminous United States.

U.S. Environmental Protection Agency (USEPA) and the U.S. Geological Survey (USGS). 2012. National Hydrography Dataset Plus. 2.10.

Data Provided By:
generated using ADIwg mdTranslator 2.17.1
Data Hosted by:
ScienceBase (USGS) View Record
Map Service URL:
Content date:
2020-08-15 04:00:00 (lastRevision Date), 2020-08-15 04:00:00 (Release Date), 2019-08-15 04:00:00 (Start Date), 2021-08-15 04:00:00 (End Date)
Rua Mordecai(Point of Contact), Amy Keister(Point of Contact), Hilary Morris(Point of Contact), U.S. Fish and Wildlife Service(Point of Contact), Southeast Conservation Adaptation Strategy (SECAS)(Point of Contact), 2020-08-15(lastRevision), 2020-08-15(Release), Indicator: Imperiled Aquatic Species,,
Contact Organization:
Southeast Conservation Adaptation Strategy (SECAS)
U.S. Fish and Wildlife Service
Contact Person(s):
Use Constraints:
otherRestrictions - limitation not listed; This work is licensed under a [Creative Commons Attribution 4.0 International License]( The blueprint data and maps provided are only intended for use as a reference tool for landscape-level conservation planning efforts.
Layer Type:
Currently Visible Layer:
All Layer Options:
Layers in this dataset are based on combinations of the following options. You may choose from these options to select a specific layer on the map page.
Spatial Resolution:
Other Information:
Time Period:
Layer Accuracy:
Attribute Accuracy:
FGDC Standard Metadata XML
Click here to see the full FGDC XML file that was created in Data Basin for this layer.
Original Metadata XML
Click here to see the full XML file that was originally uploaded with this layer.
[{"url": "", "title": "Download All Attached Files from ScienceBase"}, {"url": "", "title": "md_metadata.json"}, {"url": "", "title": "metadata.xml"}, {"url": "", "title": "Blueprint 2020 Data Download"}]

About the Uploader

South Atlantic Blueprint

The South Atlantic Conservation Blueprint is a living spatial plan to conserve natural and cultural resources for current and future generations in the face of future change. It spans parts of six states, from Virginia to Florida, including U.S. waters to 200 miles offshore. The Blueprint...