A Multiscale Index of Landscape Intactness for the Western U.S.

Landscape intactness has been defined as a quantifiable estimate of naturalness measured on a gradient of anthropogenic influence. We developed a multiscale index of landscape intactness for the Bureau of Land Managements (BLM) landscape approach, which requires multiple scales of information to quantify the cumulative effects of land use. The multiscale index of landscape intactness represents a gradient of anthropogenic influence as represented by development levels at two analysis scales. To create the index, we first mapped the surface disturbance footprint of development, for the western U.S., by compiling and combining spatial data for transportation1, energy extraction and transport1,2, mineral extraction3, agriculture4, and urban5 development. All linear features and points were buffered to create a surface disturbance footprint. Buffered footprints and polygonal data were rasterized at 15-meter (m), aggregated to 30-m, and then combined with the existing 30-meter inputs for urban development and cultivated croplands. The footprint area was represented as a proportion of the cell and was summed using a raster calculator. To reduce processing time, the 30-m disturbance footprint was aggregated to 90-m. The 90-m resolution surface disturbance footprint is retained as a separate raster in this data release. We used a circular moving window to create a terrestrial development index for two scales of analysis, 2.5- and 20-kilometers (km), by calculating the percent of the surface disturbance footprint at each scale. The terrestrial development index at both the 2.5-km and 20-km were retained as separate rasters in this data release. The terrestrial development indexes at two analysis scales were ranked and combined to quantify landscape intactness level. To identify intact areas, we focused on terrestrial development index scores less than or equal to 3 percent, which represented relatively low levels of development on multiple-use lands managed by the BLM and other land management agencies. The multiscale index of landscape intactness was designed to be flexible, transparent, defensible, and applicable across multiple spatial scales, ecological boundaries, and jurisdictions. To foster transparency and facilitate interpretation, the multiscale index of landscape intactness data release retains four component data sets to enable users to interpret the multiscale index of landscape intactness: the surface disturbance footprint, the terrestrial development index summarized at two scales (2.5-km and 20-km circular moving windows), and the overall landscape intactness index. The multiscale index is a proposed core indicator to quantify landscape integrity for the BLM Assessment, Inventory, and Monitoring program and is intended to be used in conjunction with additional regional- or local-level information not available at national levels (such as invasive species occurrence) necessary to evaluate ecological integrity for the BLM landscape approach. 1 Roads, Railroads, and utility lines were mapped using Topologically Integrated Geographic Encoding and Referencing (TIGER) (https://www.census.gov/geo/maps-data/data/tiger.html) 2 Oil and gas wells were mapped using IHS Enerdeq Database (https://www.ihs.com/products/oil-gas-tools-enerdeq-browser.html); Solar energy was mapped using Surface area of solar arrays in the conterminous United States (https://www.sciencebase.gov/catalog/item/57a25271e4b006cb45553efa); Wind energy was mapped using Onshore industrial wind turbine locations for the U.S. http://energy.usgs.gov/OtherEnergy/WindEnergy.aspx#4312358-data); Oil and gas pipelines were mapped using the National Pipeline Mapping System (https://www.npms.phmsa.dot.gov/) 3 Surface mines and quarries were mapped using National Gap Analysis Program, Level 3 data (http://gapanalysis.usgs.gov/gaplandcover/data/download/) 4 Cultivated croplands were mapped using National Agriculture Statistical Service Cultivated Crop Layer (http://www.nass.usda.gov/research/Cropland/Release/index.htm) 5 Urban development was mapped using National Land Cover Dataset Impervious surface (Homer and others, 2015). References Carr, N.B., Leinwand, I.I.F. and Wood, D.J.A., In review. A multiscale index of landscape intactness for management of public lands in Carter, S.K., Carr, N.B., and Wood, eds, Developing multiscale tools and guidance for a landscape approach to resource management for the Bureau of Land Management. USGS Circular XXX 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.