Focal Species: A Multi-Species Umbrella for Nature Conservation. Especies Focales: Una Sombrilla Multiespecifica para Conservar la Naturaleza

Abstract

To prevent the further loss of species from landscapes used for productive enterprises such as agri- culture, forestry, and grazing, it is necessary to determine the composition, quantity, and configuration of landscape elements required to meet the needs of the species present. I present a multi-species approach for de- fining the attributes required to meet the needs of the biota in a landscape and the management regimes that should be applied. The approach builds on the concept of umbrella whose requirements are believed to encapsulate the needs of other species. It identifies a suite of focal species, each of which is used to define different spatial and compositional attributes that must be present in a landscape and their appropriate man- agement regimes. All species considered at risk are grouped according to the processes that threaten their per- sistence. These threats may include habitat loss, habitat fragmentation, weed invasion, and fire. Within each group, the species most sensitive to the threat is used to define the minimum acceptable level at which that threat can occur. For example, the area requirements of the species most limited by the availability of partic- ular habitats will define the minimum suitable area of those habitat types; the requirements of the most dis- persal-limited species will define the attributes of connecting vegetation; species reliant on critical resources will define essential compositional attributes; and species whose populations are limited by processes such as fire, predation, or weed invasion will define the levels at which these processes must be managed. For each rel- evant landscape parameter, the species with the most demanding requirements for that parameter is used to define its minimum acceptable value. Because the most demanding species are selected, a landscape designed and managed to meet their needs will encompass the requirements of all other species.