Site accessibility and prioritization of nature reserves

Nature reserves not only protect habitat-stressed species but also provide recreation and welfare services to people. Therefore, site accessibility matters in reserve design. This study incorporates public accessibility, determined by urban populations and distances between urban areas and reserve sites, as an additional factor in conservation reserve design besides species representation and economic characteristics of individual sites. An optimization approach is introduced to determine a reserve network with maximum accessibility while satisfying specified representation targets under financial constraints. The paper also presents an empirical application of this approach to endangered/threatened birds in Illinois, USA, and analyzes the tradeoffs between ecological, economic, and social objectives of biological conservation. The results show that: i) the conventional minimal representation approach would result in a small reserve network, but this network would have poor accessibility; ii) public accessibility can be improved significantly by selecting alternative sites with the same amount of conservation budget; iii) further improvement in accessibility can be achieved by enlarging the network, but in this particular case the gains would be insignificant after the first few additional sites; and iv) a regionally integrated conservation plan, as opposed to decentralized conservation efforts, is beneficial for both species protection and social welfare.