Options for the conservation of large and medium-sized mammals in the Cape Floristic Region hotspot, South Africa

Abstract

We assessed options for conserving the large- and medium-sized mammals indigenous to the Cape Floristic Region, South Africa, using systematic conservation planning, the first such attempt for an entire ecoregion. The potential distributions and abundances of the 41 extant species for the entire region prior to anthropogenic transformation of habitats were estimated. This was particularly useful as it obviated any reliance on records of occurrence for conservation planning. Areas that had not been transformed through agriculture or other developments were considered available for conservation. The fragments of untransformed habitat were identified as being large enough to support communities at least 25 individuals of the smallest herbivore species. Smaller fragments were not considered suitable for mammal conservation. Transformation and fragmentation had significant impacts on potential populations, and this was asymmetrical across species, being higher for lowland than montane species. The existing reserve system was estimated to effectively conserve only half the mammal species, using the criteria applied here. Two conservation goals were compared; first, either conserving only CFR endemics and threatened species; and second, conserving all the mammals (with some exceptions for marginally occurring species). Options for protected area systems were assessed using C-Plan, a decision support system designed for systematic conservation planning. The irreplaceability of the planning units varied only slightly under the two goals, and the more inclusive goal was used to develop a proposed reserve network in which targets for all the species were achieved. The CFR endemics and threatened species effectively function as umbrella species for the remaining mammals. This study demonstrates that the incorporation into systematic conservation plans of conservation targets adequate for the persistence of populations comprising communities across entire ecoregions is feasible. © 2003 Elsevier Science Ltd. All rights reserved.