Role of complementary and competitive relationships among multiple objectives in conservation investment decisions

A growing body of literature suggests a need to incorporate both complementary and competitive relationships among multiple objectives into conservation investment decisions. To do this, we hypothesize that spatial budget allocations and overall benefits for payment for ecosystem services (PES) are influenced by the complexity of complementary and competitive relationships among multiple objectives of PES, i.e., maximizing forest-dependent biodiversity (or “biodiversity”), forest-based carbon storage (or “carbon”), and economic impact triggered by PES. To verify the hypothesis, we apply the multi-objective optimization framework to 231 counties in eight states of the Central and Southern Appalachian Region of the United States. We find 1) narrower spatial budget allocations with inclusion of the objective of maximizing economic impact, which has competitive relationships with the existing complementary biodiversity and carbon objectives, and 2) the foregone overall benefits from the existing complementary objectives increase with further increases in the competitive economic-impact objective. These findings imply that conservation agencies involved in PES planning should be cautious about the negative consequences on distributional equity found in 1) above, and the increasing sacrifice in the existing complementary objectives found in 2) above, when considering introduction of a new economic objective that has a competitive relationship with the existing ecological objectives.