-- The Nature Conservancy’s (TNC) Resilient Land Project
-- TNC's Secured Lands Database (External Eastern Division 2014)
Mapping Steps
1) Individual ecosystem integrity scores (Zonation outputs) for the inland ecosystems (beach and dune, estuarine marsh, forested wetland, freshwater marsh, maritime forest, pine and prairie, upland hardwood) were mosaiced together into one raster. Areas in the highest scoring 10% of the inland South Atlantic LCC area (based on ecosystem integrity scores) were identified as potential hubs.
2) Outside of the South Atlantic LCC geography, we used local connectedness from TNC’s Resilient Land Project. Areas ≥ 1 standard deviation above average were identified as potential hubs.
3) We selected polygons from TNC's Secured Lands Database (External Eastern Division 2014) that were in GAP Status 1 - Permanent Protection for Biodiversity, 2 - Permanent Protection to Maintain a Primarily Natural State, 3 - Permanently Secured for Multiple Uses, or 9 - Unknown GAP status.
4) Since military-owned lands are often protected for training or defense rather than conservation, we removed any polygons that listed the Fee Owner as U.S. Department of the Army, U.S. Department of Defense, U.S. Air Force, or U.S. Department of the Navy.
5) We converted this polygon layer to a raster with a cell size of 200 m using a maximum combined area cell assignment. This allowed us to match the data from step 2, and also helped identify large patches of secured lands that are near one another, but separated by a narrow linear feature like a river or road. It also allowed us to combine tracts that are contiguous but differ in ownership.
6) We combined potential hubs from the ecosystem integrity scores (step 1), TNC Resilience Project (step 2), and Secured Lands (step 5).
7) Contiguous patches greater than 2,000 ha (5,000 acres) in size were kept as hubs. We identified these patches using the ArcGIS Spatial Analyst-Region Group function (8-neighbor). This size threshold from Hoctor et. al (2000) is also used by the neighboring LCC to the south for connectivity purposes.
8) The raster patches were converted to polygons.
9) All polygons either within the South Atlantic LCC geography or within 26.1 km of the South Atlantic LCC boundary were used as inland hubs in the Linkage Mapper analysis. The distance of 26.1 km is based on dispersal distances of subadult black bears (White et al. 2000), a species that disperses from within the LCC into all other adjacent LCCs.
Inland Corridors
This is the corridor raster used in the inland portion of the South Atlantic area in Blueprint 2.2.
Input Data
-- Blueprint 2.2 ecosystem integrity scores (from Zonation) for all inland ecosystems (beach and dune, estuarine marsh, forested wetland, freshwater marsh, maritime forest, pine and prairie, upland hardwood)
-- TNC's Resilient Land Project
-- Blueprint 2.2 Inland Hubs (created above)
-- National Land Cover Database 2011 (NLCD 2011)
Mapping Steps
1) All inland ecosystem integrity scores (beach and dune, estuarine marsh, forested wetland, freshwater marsh, maritime forest, pine and prairie, upland hardwood) were mosaiced to form a new raster.
2) We used the local connectedness layers from TNC’s Resilient Land Project to fill in a buffer area around the South Atlantic LCC geography. This allowed corridors to connect from inside the South Atlantic geography into the neighboring landscapes.
3) To create a single resistance layer, we rescaled and inverted the inland ecosystem integrity scores (within the LCC boundaries) and the local connectedness metric (outside the LCC boundaries) to ensure they used the same scale and that high values represented high resistance.
4) As a final step in creating the resistance layer, we defined the NLCD 2011 classes "Developed, medium intensity" and "Developed, high intensity" as the highest possible resistance. This discourages corridors from routing through dense urban areas.
5) We performed a Linkage Mapper corridor analysis using the following settings as pictured below (open image in new tab to see the entire image):
4) Linkage Mapper outputs a corridor raster with a continuous surface. We used the ArcGIS-Slice function to identify the top 35% of the corridor surface by area. This result is the "marine corridor" layer you see in this map service. Marine corridor pixels not already covered by highest, high or medium priority pixels were incorporated into Blueprint 2.2 as the corridor class. We chose a 35% cutoff because it resulted in a corridor area of approximately 5% of the South Atlantic marine environment (not already covered by highest, high, or medium priority pixels).
Full Connectivity Analysis
Literature Cited
Anderson, M.G., A. Barnett, M. Clark, C. Ferree, A. Olivero Sheldon, and J., Prince., 2014. Resilient Sites for Terrestrial Conservation in the Southeast Region. The Nature Conservancy, Eastern Conservation Science. 127 pp.
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.
Krueck, N. C., Legrand, C., Ahmadia, G. N., Estradivari, E., Green, A., Jones, G. P., Riginos, C., Treml, E. A. and Mumby, P. J. 2017. Reserve Sizes Needed to Protect Coral Reef Fishes. Conservation Letters. Accepted Author Manuscript. doi:10.1111/conl.12415
McRae, B. and Kavanagh, D. Linkage Mapper User Guide: Version 1.0. 2014. <http://www.circuitscape.org/linkagemapper>.
Moilanen, A., Pouzols, F. M, Meller, L., Veach, V., Arponen, A., Leppänen, J. Kujala, H. Zonation Version 4 User Manual: Spatial conservation planning methods and software. <http://cbig.it.helsinki.fi/files/zonation/zonation_manual_v4_0.pdf>.
The Nature Conservancy. 2014. Secured Lands dataset. The Nature Conservancy, Eastern Conservation Science. Boston, MA. <https://www.conservationgateway.org/ConservationByGeography/NorthAmerica/UnitedStates/edc/reportsdata/terrestrial/secured/Pages/default.aspx>.
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