To maximize opportunities for colonization and reduce the probability of extinction, Diamond recommended large, compact, closely spaced, connected reserves. However, species with limited ability to disperse and requirements for specific habitats found in small, dispersed patches may need several small reserves, and corridors may facilitate the spread of introduced species, diseases, or fire. Preserves in ecotones are likely to be valuable for organisms with low mobility as the climate changes. A coarse-filter approach to protection prioritizes ecosystems that contain high biodiversity, such as biological hotspots. In gap analysis, the distributions of selected taxa are compared to the locations of protected areas to identify priority areas for additional protection. Reserves may have a variety of levels of protection. Some conservation biologists advocate using the absence of human influence as the benchmark for strictly protected reserves. Restoration should conserve key processes, structures, and interactions such as fire in native prairie. Restoration should also address both abiotic and biotic elements of an ecosystem. Advocates of rewilding support the restoration of animals, especially megafauna, to their former ranges through reintroductions .