Mapping Expert Knowledge: Redesigning the Monarch Butterfly Biosphere Reserve

Expert consultation has been used to fill the information gaps that hamper conservation planning and nature reserve design. The use of expert knowledge in conservation planning is difficult, however, because it is subjective, biased, and value-laden. Decision theory provides a systematic and comprehensive means for addressing experts' subjective-and sometimes contradictory-judgments in the design of nature reserves. Thus, the experts can separate the objective criteria from the subjective components of decision making that place value on those criteria. When linked to a geographic information system (GIS), these techniques foster consensus among experts by allowing the exploration of alternative designs in an iterative way. We used such a decision-analysis approach to redesign the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico. We examined three reserve scenarios to identify the optimal overwintering habitats considering (1) an area equivalent to the previously defined boundaries of the core zone of the MBBR (4500 ha); (2) an area equivalent to the previously defined boundaries of the whole MBBR (16,000 ha); and (3) the maximum possible extent for a new core zone. This last scenario produced an area of 21,727 ha. These results were transferred to the GIS to create the respective nominal maps that were presented to the environmental authorities, who selected the third scenario for the core zone of the new MBBR. Our results allowed us to locate the prime overwintering habitats precisely and to delimit a core area for the reserve that would minimize the inclusion of forest stands valuable to local loggers.