Choosing the appropriate scale of reserves for conservation

Over the past ten years the scientific basis for reserve selection and design have rapidly developed. This period has also been characterized by a shift in emphasis toward large spatial and organizational scales of conservation efforts. I discuss the evidence in support of this shift toward larger scale conservation by contrasting the success of fine-filter (genes, populations, species) conservation and coarse-filter (communities, habitats, ecosystems, landscapes) conservation. Conservation at both organizational scales has been successful and merits continued support, although fine-filter conservation is more straightforward. Ecological theory suggests that conservation at large scales is preferred. Despite this preference, both fine- and coarse-filter conservation objectives have been met by small reserves. In many landscapes there are no opportunities for the conservation of native species diversity that encompass a large spatial scale. Thus, reserve selection at any organizational scale may include conservation at a variety of spatial scales. A variety of methods have been suggested that integrate across scales of conservation. Some, such as umbrella, flagship, and indicator species, remain very problematic. Reserve selection algorithms and gap analyses, in contrast, offer promising opportunities to increase the efficiency of conservation at all scales.