Assessing habitat suitability at multiple scales: A landscape-level approach

The distribution and abundance of many plants and animals are influenced by the spatial arrangement of suitable habitats across landscapes. We derived habitat maps from a digital land cover map of the ∼ 178,000 km 2 Chesapeake Bay Watershed by using a spatial filtering algorithm. The regional amounts and patterns of habitats were different for species which occur in ‘woody’, ‘herbaceous’, and ‘woody-edge’ habitats. Habitat for finer-scale species (∼ 5 ha home ranges) was twice as abundant and more evenly distributed than habitat for coarser-scale species (∼ 410 ha home ranges) in a 11,000 km 2 sub-region. Potential impacts of land cover changes on habitats in different parts of the region were assessed by the frequency distributions of habitat suitability for smaller (∼ 3000 km 2) embedded watersheds. The methods described in this paper can be applied to several scales of digital land cover data, and used to derive multiple-scale habitat suitabilities for a number of species or guilds.