Ad Hoc Reservations: Forward or Backward Steps in Developing Representative Reserve Systems?

A major reason for land reservation has been the relative lack of value of selected sites for major commercial land uses or for human habitation. Other important reasons include scenery, recreation, tourist potential, the influence of lobby groups, and historical protection for uses such as hunting or water supply. There are two main disadvantages of such ad hoc approaches to reserve planning. One is the bias in the content of regional reserve systems, leaving some species, communities, or ecosystems without protection, often the ones most in need of strict reservation. The second is that ad hoc reservations can make the goal of representing regional biodiversity more expensive, reducing the likelihood of protecting many elements of biodiversity. Ad hoc approaches to reservation persist despite clearly stated representation goals, improving data bases, and systematic techniques for reserve selection. The main causes need to be understood and addressed if the potential value of reservation for protecting biodiversity is to be realized.