Biodiversity and extinction

Introduction extract: Species-level conservation activities tend to be focused on those species that are highly threatened with global or regional extinction in the near future. This is broadly logical, if one of the principal goals is to retain as great a proportion of the composition of original species assemblages as possible, within the severe constraints of available conservation resources. In the main, those species which have a high likelihood of rapidly becoming regionally or globally extinct also have small total population sizes and/or restricted geographic ranges within the appropriate region or worldwide (Gaston, 1994; 2003). That is, the importance of each individual organism to the persistence of the species is on average high, and/or there is limited spatial spreading of risk, increasing the vulnerability of the species to quite localized threats.