DOI: 10.5066/f7c24vq0
title: Biophysical assessment for indemnity selection of federal lands in Colorado

description: Information on the biophysical features of federal lands identified as suitable for transfer to the State of Colorado was requested by the Bureau of Land Management (BLM). This information is intended for use in conducting an environmental assessment prior to transfer of ownership (conveyance) to the State. The Enabling Act of 1864 provided for the conveyance of federal lands to the State for the support of schools. If designated lands were unavailable for transfer at the time of statehood, the Act provided for the transfer of alternative federal lands in compensation, using a process referred to as "school-land indemnity selection." To initiate indemnity selection, the Colorado State Board of Land Commissioners filed a selective application "to obtain public land and mineral estate in lieu of lands to which the State did not receive" at the time of statehood. To address this legal obligation, 339 parcels of federal lands (organized into 89 Indemnity Units) currently under management by the BLM have been identified as suitable for transfer to the State. The Indemnity Units encompass 23,130 acres of both surface and mineral estate, as well as 6,150 acres of only mineral estate. The specific parcels of federal lands to be conveyed to the State will be finalized after an environmental analysis and other evaluations are completed. For each of the 89 Indemnify Units, we summarized information on land cover, soil salinity, and spatial patterns of land use (development), as well as documented occurrences or potential habitat for species of management concern (federally threatened or endangered species, Colorado BLM sensitive species, U.S. Fish and Wildlife Service Birds of Conservation Concern, and Colorado Parks and Wildlife big game species). Datasets from a companion data release (Carr and others, 2018a) were used to summarize land cover types, soil salinity, and development. For all 179 species or subspecies of management concern in Colorado identified by the BLM, we compiled information on occurrences, habitat (seasonal, specialized, or potential general), and overall ranges. The compiled information was used to determine which species could potentially occur on an Indemnity Unit, based on documented occurrences or habitat within the unit. A total of 72 species had the potential for occurrence on at least one Indemnity Unit. This data release "Biophysical features for indemnity selection in Colorado" is organized into five datasets summarizing information for each of the 89 Indemnity Units: two geospatial datasets and three comma-separated value (CSV) text files. Indemnity Unit Locations provides the location and perimeters of Indemnity Units. Soil salinity using electrical conductance is a raster dataset of soil map units attributed with estimated soil salinity for each Indemnity Unit. The three CSV files summarize information by Indemnity Unit; Land cover types summarizes the area of land cover types; Terrestrial development provides the surface disturbance footprint from development, summarized at three analysis scales; Potential species of management concern lists the 72 species of management concern with potential for occurrence on each Indemnity Units. The SupplementalMethods.pdf included with this data release provides the scientific names, conservation status, and data sources for all 179 species evaluated, as well as methodological details for the analysis of the species of management concern. A companion data release (Carr and others, 2018), describes the methodology for creating the datasets used in the analysis of land cover, soil salinity, and terrestrial development. The 89 Indemnity Units are widely distributed across the State and generally are representative of BLM lands or Colorado overall. Shrublands and steppe, and grasslands, are the most abundant land cover classes in Indemnity Units. Several Indemnity Units with open water border a reservoir. Mountain forests are common on many of the higher elevation Indemnity Units. Only two of the Indemnity Units have the potential for moderate salinity levels. Development levels on the Indemnity Units and surrounding areas is slightly higher than all lands managed by the BLM in Colorado, but similar to development levels for the entire State. Of the 179 species or subspecies of management concern evaluated, there were 72 species that had documented occurrences or habitat within at least one Indemnity Unit; six species listed as federally threatened and endangered, 35 Colorado BLM sensitive species, 24 species listed as Birds of Conservation Concern, and seven Colorado big game species. Additional information is provided in a companion report (Carr and others, 2018b). Carr, N.B., Burris, L.E., and Manier, D.J., 2018a, Broad-scale assessment of biophysical features in Colorado: U.S. Geological Survey data release, https://doi.org/10.5066/F7GT5MGV. Carr, N.B., Burris, L.E., and Manier, D.J., 2018b, Biophysical assessment for indemnity selection of Federal lands in Colorado: U.S. Geological Survey Open-File Report 2018-1167, 51 p., https://doi.org/10.3133/ofr20181167.