A Multiscale Index of Landscape Intactness for the Western United States

Product Type: 

Data Release

Year: 

2016

Author(s): 

Carr, N.B., I.I.F. Leinwand, and D.J.A. Wood

Suggested Citation: 

Carr, N.B., I.I.F. Leinwand, and D.J.A. Wood. 2016. A Multiscale Index of Landscape Intactness for the Western United States. U.S. Geological Survey Data Release. https://dx.doi.org/10.5066/F75H7DCW.

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 Management’s (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 urban development, agriculture, energy and minerals, and transportation for 17 states. 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 data sets in this data release (Surface Disturbance Footprint from Development for the Western United States). We used a circular moving window to create a terrestrial development index for two scales of analysis, 2.5-kilometer (km) and 20-km, by calculating the percent of the surface disturbance footprint at each scale. The terrestrial development index at both the 2.5-km (Terrestrial Development Index for the Western United States: 2.5-km moving window) and 20-km (Terrestrial Development Index for the Western United States: 20-km moving window) were retained as separate raster data sets in this data release. The terrestrial development indexes at two analysis scales were ranked and combined to create the multiscale index of landscape intactness (retained as Landscape Intactness Index for the Western United States) in this data release. 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.