Voluntary, permanent land protection reduces forest loss and development in a rural-urban landscape

Voluntary, permanent land protection is a key conservation process in many countries. Concerns with the effectiveness of such decentralized processes exist due to the potential for (1) selection bias, that is, the protection of parcels whose land cover would have been conserved in the absence of protection, and (2) local spillover effects, that is, protection increasing the likelihood that adjacent parcels lose land cover due to additional conversion. We examine the validity of both concerns using a quasi-experimental approach and a dataset of 220,187 parcels and 26 years of protection and land-cover change in Massachusetts. We find that land acquisitions and conservation restrictions implemented by state, local, and nongovernmental actors reduced forest loss and conversion to developed uses without increasing either type of land-cover change on adjacent parcels. Our results suggest that voluntary, permanent land protection can make significant contributions in protecting land cover in landscapes dominated by private ownership.