Collateral benefits from public and private conservation lands: a comparison of ecosystem service capacities

Protected areas remain the most commonly used tool for in situ conservation; however growth in the USA's system of public lands has stagnated while private land conservation continues to expand. Easements can provide a range of ecosystem services (ESs), but it is unknown whether conservation easements maintain ES capacities equivalent to public protected areas. Evaluation of the capacity of seven ESs on federal and state protected areas and conservation easements in the USA using spatially-explicit ES models and publicly available data indicated that ES capacities in easements were equal to or greater than capacities within state or federal protected areas for six of seven services and, when bundled together, conservation easements protected greater focal ES capacity than other conservation areas. Economic incentive programmes and regulatory mechanisms may be used to stimulate capacity improvements for surface water regulation, riparian filtration, erosion control, and carbon storage on conservation easements, and landscape-level conservation efforts should (1) continue to protect natural and uninhabited areas that provide ecosystem and biological diversity, (2) expand private conservation efforts close to human population centres, and (3) limit future development to areas with high regulating service capacity that can sustain new population growth.