Demand-Side Factors in Optimal Land Conservation Choice

The dominant paradigm of conservation-reserve planning in economics is to optimize the provision of physical conservation benefits (measured in units like species protected) given a budget constraint. Large-scale biology-based priority setting implies that the value we place on biodiversity and ecosystem function is not affected by human proximity to that natural capital. There is significant evidence, however, that human willingness to pay (WTP) for conservation declines with distance (e.g. Loomis 2000) – a phenomenon we refer to as “spatial value decay”. This paper begins a new strand of the conservation planning literature that takes demand-side factors – the location of people in the landscape and the degree to which their willingness to pay for an environmental amenity depends on proximity to that amenity – into account. We use theoretical models of linear abstract landscapes to explore the impact of demand-side factors on two facets of optimal conservation choices: siting of a single reserve when conservation value is greatest near a critical site in the landscape (optimal targeting), and siting of multiple reserves when fragmentation reduces physical conservation services produced (optimal agglomeration). Our results show how optimal conservation planning might differ from straight ecological prescriptions. While minimum fragmentation is often optimal, planners can usefully employ increased fragmentation to capture value when people’s preferences are not very highly localized. In a targeting problem, the ecologically critical site is often the right thing to protect, but optimal policy balances proximity to critical site with proximity to people. In some scenarios, the payoff to using a reserve design approach that considers demand-side factors is large. Finally, we find that spatial value decay reduces the maximum levels of welfare and environmental services that can be gained from any conservation-planning approach. When spatial value decay is present because people are simply unaware of environmental resources farther away from where they live, education campaigns might serve to increase social welfare and environmental services.