Our limited resources preclude customised management for the majority of species. Indeed, most species and their requirements may never be known to science. However, the management of several individual species simultaneously may make a substantial contribution to management of habitats, and the management of keystone species may be a particularly important part of such management (Section 3.1.4). Conservation focused on species may be applied in the wild habitat of the organism (‘in situ conservation’), or in captivity (‘ex situ conservation’), or both. This chapter examines conservation of individual species, and of groups of related species which can be treated together because they have similar requirements, threats, or appeal.

Local populations are being extirpated much faster than entire species, and whilst this is generally less irreversible than the loss of species, it makes each species more vulnerable. Prioritisation of populations for conservation may use methods similar to the prioritisation of species and habitats (Chapter 3), considering factors such as population size, position in a geographical unit, genetic distinctiveness, and the risk of parochialism (Section 3.1.2). Genetic markers (e.g. DNA sequences) can be used to identify the linkage, taxonomic distinctiveness, and hence phylogenetic importance of populations.

One form of customised management is to identify the way the local populations of a species are connected together by dispersal, and how these populations are created or lost. Sometimes a species occurs in several populations, and the most important aim is to conserve the whole population, rather than any local population.