Ecological degradation is both ubiquitous and relentless. Human activities have left a footprint even in the most remote locations. Some species benefit from certain forms of degradation whereas many others are expected to decline to extinction under current or increasing land-use intensity (Vitousek et al. 1997; Norris and Pain 2002). While the optimal allocation of conservation efforts and funding at the global scale is being debated (Myers et al. 2000; Balmford et al. 2002; O'Connor et al. 2003; Lamoreux et al. 2006), target setting at the landscape scale should be viewed as equally important because, for many taxa, this is the scale over which most human activities take place and management regulations are applied. A landscape can be defined as a mosaic of habitat types whose extent reflects the perspective of target species or taxa (Wiens et al. 2002). However, it should be noted that this organism-centered perspective of the landscape must interact with human perception and action. Forest managers perceive the landscape as that of the “forest” or “forest management unit”, which may cover hundreds of square kilometers.

The landscapes we tend to envision when considering human activities such as timber harvesting or agriculture may match those perceived by many birds and mammals, but not those over which the dynamics of most species (e.g. plants and insects) take place. With the exception of some mega-projects, most human activities tend to alter relatively small patches (e.g. a forest stand or a field).