Species-area relationships and marine conservation

The species-area relationship (SPAR) was the central paradigm for the emerging science of reserve design in the 1970s and early 1980s. The apparent consistency of the SPAR for natural areas suggested that it could be used to predict the number of species that would be maintained within the isolated confines of a nature reserve. This proposed use of the SPAR led to heated debates about how best to partition space among reserves. However, by the end of the 1990s, the SPAR was no longer a central issue in. reserve design. There was too much uncertainty about the underlying causes of the SPAR to trust that it would hold for reserves. The SPAR was also inappropriate for the design of single-species reserves and thus did not answer the traditional needs of wildlife managers. Ecologists subsequently focused their reserve-design efforts on the management of individual populations to reduce the probability of extinction and the loss of,,genetic variation. Nevertheless, because the SPAR does not require detailed knowledge of the requirements of individual species, it is still used to estimate local species richness and to predict the effects of habitat loss and fragmentation on biodiversity. These applications of the SPAR may be especially useful in the design of marine reserves, which often differ in purpose from conventional terrestrial reserves and may require fundamentally different approaches.