FINDING ALL OPTIMAL-SOLUTIONS TO THE RESERVE SITE SELECTION PROBLEM -FORMULATION AND COMPUTATIONAL ANALYSIS

The problem of selecting nature reserves has received increased attent ion in the literature during the past decade, and a variety of approac hes have been promoted for selecting those sites to include in a reser ve network. One set of techniques employs heuristic algorithms and thu s provides possibly sub-optimal solutions. Another set of models and a ccompanying algorithms uses an integer programming formulation of the problem, resulting in an optimization problem known as the Maximal Cov ering Problem, or MCP. Solution of the MCP provides an optimal solutio n to the reserve site selection problem, and while Various algorithms can be employed for solving the MCP they all suffer from the disadvant age of providing a single optimal solution dictating the selection of areas for conservation. In order to provide complete information to de cision makers, the determination of all alternate optimal solutions is necessary. This paper explores two procedures for finding all such so lutions. We describe the formulation and motivation of each method. A computational analysis on a data set describing native terrestrial ver tebrates in the state of Oregon illustrates the effectiveness of each approach.