Ecological theory and political realities
The theory of island biogeography states that the biodiversity on any given island is proportional to the rate of immigration of new species to that island divided by the rate of extinction on that island. This chapter shows that extinction at a local level is a perfectly normal process, one that can be seen, albeit using subtle clues, on many islands and in many fragments. The prevailing wisdom amongst many conservationists is that the political agenda is uniquely determined by the need to protect remaining natural habitats, which is to focus on the islands in the landscape. Successful protection strategies require societal change, it seems clear that the sharing versus sparing debate reflects profoundly different historical traditions, philosophical positions, and political loyalties. Land-sparing advocates assume a degree of consensus and/or exercise of sheer political power that is unrealistic in the extreme.