landcover mapping

In order to effectively plan and manage for retention of biological diversity on a regional or national scale, natural resource agencies need a method for characterizing and monitoring land cover and how it changes over time. The Gap Analysis Program of the USGS-BRD has been involved in mapping land cover in each of the 50 states—except Alaska—in order to serve that need.

In Alaska, the Gap Analysis Program will use two land cover maps being developed by LANDFIRE (http://www.landfire.gov/), a five-year, multi-partner project (wildland fire management programs of the National Forest Service and USDI) producing consistent and comprehensive maps and data describing vegetation, wildland fuel, and fire regimes across the United States.

The two statewide land cover maps are an existing vegetation map and an ecological systems map. The existing vegetation map represents the vegetation currently present at a given site using The Alaska Vegetation Classification (Viereck et al. 1992). The ecological systems map units are based on NatureServe’s Ecological Systems classification (http://www.natureserve.org/publications/usEcologicalsystems.jsp ), which is a nationally consistent set of mid-scale ecological units (Comer and others 2003). For Alaska, this classification also incorporates The Alaska Vegetation Classification (Viereck et al. 1992). Both classifications are being mapped using LandSat ETM+ satellite imagery at a 25 m pixel spatial resolution, which also contains an extra panchromatic band at 12.5 m resolution.

Comer, P., D. Faber-Langendoen, R. Evans, S. Gawler, C. Josse, G. Kittel, S. Menard, M. Pyne, M. Reid, K. Schulz, K. Snow, and J. Teague. 2003. Ecological Systems of the United States: A Working Classification of U.S. Terrestrial Systems. NatureServe, Arlington, VA. 75 p.

Viereck, L., Dryness, C., Batten A. and K. Wenzlick. 1992. The Alaska vegetation classification. General Technical Report PNW-GTR-286. Portland, Oregon. U.S. Forest Service, Pacific Northwest Research Station. 278 p.