Intact Habitat Cores (Southeast Blueprint Indicator)

Reason for Selection Large areas of intact natural habitat are favorable for conservation of numerous species, including reptiles and amphibians, birds, and large mammals. The Esri Green Infrastructure data covers the entire United States and has been used in other broad-scale conservation planning efforts, so using this existing data helps align the Blueprint with other conservation efforts and reduce duplication of effort. We chose to use “Core Size (acres)” as the metric for this indicator. Other evaluation attributes included in this index, such as the default “Core Score”, were less suitable because they were calculated using inputs that are duplicative of other indicators. Input Data * [2021 National Land Cover Database] (NLCD) * [Southeast Blueprint 2024 extent] * Esri’s [Intact Habitat Cores 2023,] accessed 2-16-2024: Core Size (Acres); to download, select “Open in ArcGIS Desktop” and make a local copy. According to Esri’s [data description for the 2023 intact habitat cores update]: “This layer represents modeled Intact Habitat Cores, or minimally disturbed natural areas at least 100 acres in size and greater than 200 meters wide. Esri created these data following a methodology outlined by the Green Infrastructure Center Inc. These data were generated using 2019 National Land Cover Data. Cores were derived from all “natural” landcover classes and excluded all “developed” and “agricultural” classes including crop, hay and pasture lands. The resulting cores were tested for size and width requirements (at least 100 acres in size and greater than 200 meters wide) and then converted into unique polygons.” Mapping Steps * Convert the Esri Intact Habitat Cores 2023 polygons to a 30 m raster using the values in the “Acres” field. We used the feature layer map service as the input in the Polygon to Raster function in the code. * Reclassify the above raster into 4 classes, seen in the final indicator values below. * Use NLCD to remove zero values in deep marine areas, which are outside the scope of this terrestrial indicator. Use a conditional statement to assign NoData to any area with a pixel value >0 in the NLCD. * As a final step, clip to the spatial extent of Southeast Blueprint 2024. Note: For more details on the mapping steps, code used to create this layer is available in the [Southeast Blueprint Data Download] under > 6_Code. Final indicator values Indicator values are assigned as follows: 3 = Large core (>10,000 acres) 2 = Medium core (>1,000-10,000 acres) 1 = Small core (>100–1,000 acres) 0 = Not a core Known Issues * The core analysis for this indicator is based on the 2019 NLCD, not the more recent 2021 NLCD. Esri has shared the scripts and input data used to create this layer, which may also help update this indicator in the future. * Even small dirt roads serve as hard boundaries for habitat cores. While this makes sense for some species, this indicator likely underestimates the effective size of the patch for some more mobile animals. * Waterbodies like reservoirs are also considered part of habitat cores, so this layer likely overestimates the effective size of the habitat core for most species. * Many intact habitat cores have a speckling of small altered areas inside of them. In some cases, like in areas of west TX with concentrated oil wells, there can be many alterations in a gridded pattern across the entire core. This indicator underestimates the cumulative impacts of interior alterations—especially when the small altered footprints are densely packed in a grid within a habitat core. Disclaimer: Comparing with Older Indicator Versions There are numerous problems with using Southeast Blueprint indicators for change analysis. Please consult Blueprint staff if you would like to do this (email [hilary_morris@fws.gov]). Literature Cited Esri Green Infrastructure Center. Data Description: Detailed Description and Methodology for Intact Habitat Cores. PDF. Last updated June 30, 2023. [[https://nation.maps.arcgis.com/home/item.html?id=047d9b05e0c842b1b126bc0767acfd5e]]. Esri Green Infrastructure Center, Inc. 2023. Intact Habitat Cores (2023). [[https://www.arcgis.com/home/item.html?id=b404b86a079a48049cb50272df23267a]].