An ecosystem services cost-benefit analysis for NGO-led private land conservation

NGO-led private land conservation (PLC) must often prioritize among sites, yet comparable evidence on costs and ecosystem service (ES) benefits is scarce because primary valuation is expensive. We present a protocol that combines structured interviews with site managers (to identify services, compile costs and revenues, and define counterfactual land-use trajectories) with ES benefit transfer from the Ecosystem Services Valuation Database (ESVD), discounted to present values over 100 years. We apply the protocol to five sites supported through the This is My Earth (TiME) initiative. Under a baseline scenario (4.3% discount rate; mean transfer values; linear area scaling), total discounted ES values were 42,372–2,475,450 thousand Intl$ (2020), versus costs of 128–5,236 thousand Intl$ (2020), producing positive net values for all sites. Ranking sites by added value shows El Silencio (Colombia) highest, followed by Serra Bonita (Brazil) , Jardines Angel del Sol (Peru), Pampa del Burro (Peru), and El Toro (Peru). Added value was highest where managers expected little natural habitat to persist without conservation. Sensitivity analyses showed that area-scaling assumptions dominate uncertainty, far more than discounting or alternative summaries of transfer values. Site ranking remained stable across all sensitivity analyses except those involving strongly diminishing returns with increasing area, which produced modest reordering, suggesting that the method can produce stable ranking for prioritization. With some refinements, the workflow can support faster, more defensible funding decisions, and improve transparency and comparability for NGOs and donors. These results highlight private land conservation’s strong societal benefits, supporting continued investment in biodiversity.