Conservation of wildlife. A bio-economic model of a wildlife reserve under the pressure of habitat destruction and harvesting outside the reserve

摘要

Biodiversity is today threatened by many factors of which destruction and reduction ofhabitats are considered most important for terrestrial species. One way to counteract thesethreats is to establish reserves with restrictions on land-use and exploitation. However, veryfew reserves can be considered islands, wildlife species roam over large expanses, often viasome density dependent dispersal process. As a consequence, habitat destruction, andexploitation, taking place outside will influence the species abundance inside theconservation area. The paper presents a theoretical model for analysing this type ofmanagement problem. The model presented allows for both the common symmetric dispersalas well as what is called asymmetric dispersal between reserve and outside area. The mainfinding is that habitat destruction outside may not necessarily have negative impact upon thespecies abundance in the reserve. As a consequence, economic forces working in thedirection of reducing the surrounding habitat have unclear effects on the species abundancewithin the protected area. We also find that harvesting outside the reserve may have quitemodest effect on the species abundance in the reserve. This underlines the attractiveness ofreserves from a conservation viewpoint.