Spatial Targeting Strategies For Land Conservation

Purchasing development rights is a major mechanism for the protection of environmental quality and landscape amenities. This paper provides a targeting strategy for protecting multiple environmental benefits that takes into account land costs and probability of land use conversion. We compare two strategies. Subject to a budget constraint on parcel purchases, the standard strategy is to target parcels with the highest ratio of environmental benefits to land costs. The standard strategy selects parcels even if there is little probability that the parcel would otherwise be converted. Our new strategy targets parcels to minimize the benefit loss from land conversion, which weights parcel based on initial benefit endowment and expected probability of land use conversion. The empirical analysis focuses on targeting conservation easements in the exurban region of Sonoma County, CA, in which extensively-managed, developable parcels (i.e. pasture and forest areas) with environmental benefits are being converted to residential use and vineyards. Spatially-explicit modeling approaches are employed to estimate land values and likelihood of land use conversion, according to heterogeneous parcel site characteristics, for all developable parcels. Our results indicate that benefit-cost targeting is biased toward low cost parcels, since it ignores the variation in likelihood of future land use conversion. This inefficiency for benefit-cost targeting arises from the positive relationship that typically exists between likelihood of land use change and value of development rights. Hence, some parcels with poor land quality or remote accessibility to urban centers would have de facto conservation, and therefore do not warrant targeting of conservation funds, despite the low cost of protection. Our new targeting strategy balances the countervailing factors of land values and likelihood of land use conversion.