BLM AK Roadless Core Areas

The areas depicted in this shapefile were derived for an analysis of potential conservation priority areas on Bureau of Land Management (BLM) lands, and across three BLM planning areas in Alaska, namely the Bering Sea/Western Interior, Central Yukon, and Eastern Interior planning areas. Steps used to derive these core areas are described below.

Due to data limitations for Alaska, certain input datasets have been substituted; therefore, this analysis of certain BLM lands in Alaska has not been wholly subject to peer review commensurate with the below-referenced study.  For a detailed account of the general methodology used, see the peer-reviewed article by Dickson et al. 2014.

Specifying the analysis extent
Ownership data were obtained from the AK state spatial data management system (http://sdms.ak.blm.gov/sdms/).
Areas included in the analysis extent were located outside of existing special designations, including national monuments, wilderness areas, and wilderness study areas (WSAs). We excluded WSAs because they are provisionally protected until their designation is changed through legislative action by the U.S. Congress. We used land management designations in the U.S. Protected Areas Database and a geographic information system (GIS; ArcGIS v10.1, Esri, Redlands, CA) to identify and remove the aforementioned lands from our analysis extent.

Because we were interested in identifying candidate areas that could meet the criteria for the highest level of protection, i.e., wilderness designation, we also required lands in the analysis extent to be contiguous areas > 20.2 km2 (or 5,000 ac, by convention the minimum size for wilderness designation in the U.S.) after removal of areas otherwise occupied by roads, railroads, and electric power transmission lines. We used roads data obtained from the AK State Geo-spatial Data Clearing House (2006) to buffer (5 m per side) and remove all linear road features from the analysis extent. Additionally, we removed railroads and powerlines, also using a 5-m buffer. Contiguous areas < 20.2 km2 were removed from consideration in our analysis extent.

We defined our analysis extent using readily available data on current road networks. Nevertheless, our results likely reflect errors in these data that would be difficult to quantify over extensive portions of AK, so we urge data users to scrutinize areas we assumed to be ‘roadless.’ Users should also be mindful of high value areas within BLMs jurisdiction where errors of commission (i.e., the presence of a road is falsely indicated by the roads data) could have resulted in these areas being excluded from our analysis.

All results were derived within three BLM planning areas in Alaska, namely the Bering Sea/Western Interior, Central Yukon, and Eastern Interior planning areas.

Full metadata can be viewed upon download in the file named 'metadata1_original.xml'

Dickson, B.G., L.J. Zachmann, and C.M. Albano. 2014. Systematic identification of potential conservation priority areas on roadless Bureau of Land Management lands in the western United States. Biological Conservation, 178:117-127.