Metropolitan natural area protection to maximize public access and species representation

In response to widespread urban development, local governments in metropolitan areas in the United States acquire and protect privately-owned open space. We addressed the planner's problem of allocating a fixed budget for open space protection among eligible natural areas with the twin objectives of maximizing public access and species representation. Both objectives were incorporated into a discrete, 0-1 integer optimization model and applied to a problem with 68 sites, 61 species, and 34 towns in the Chicago metropolitan area. Increasing required species representation reduced the maximum number of towns with access to reserves, and the tradeoff between species representation and site accessibility increased as the budget was reduced. The definition of site accessibility affected optimal reserve design. A town had access if a specified number of reserves was located within a specified distance from the town. Increasing the distance standard resulted in more, smaller sites protected in a uniform spatial pattern. Increasing the minimum number of sites required to be within a distance standard caused the selection of clusters of sites near a few towns. The study adds a new dimension to reserve site selection models by including site accessibility as a goal. Published by Elsevier Science Ltd.