A reliance on agricultural land values in conservation planning alters the spatial distribution of priorities and overestimates the acquisition costs of protected areas

Abstract

A common focus for conservation planning is to identify locations for siting potential protected areas, something that requires estimates for the costs of setting up these areas and benefits for biodiversity of doing so. When cost data are not available over relevant scales, conservation planners commonly rely on proxy data that they hope will estimate conservation costs. Here, we assessed how accurately agricultural land values, a commonly used proxy for cost data in conservation planning, estimate the actual acquisition costs of protected areas, focusing on a case study from the central and southern Appalachians. We compared plans based on cost estimates derived from different sources and that involved different levels of spatial aggregation to understand how a reliance on these estimates would impact conservation planning. We found that the average agricultural land value in a county did not accurately predict the acquisition costs of protected areas in that county. This lack of accuracy was a result of choosing agricultural land values as a proxy for acquisition costs, and not spatial averaging. A reliance on agricultural land values risks diverting limited funds for establishing protected areas away from parcels that offer the greatest return-on-investment. It would also lead a conservation organization to overestimate the budget needed to protect a given number of species. Our findings highlight the importance of incorporating data on how much protected areas actually cost in future conservation planning studies.