Protected areas cover about 15% of total land area worldwide, yet conservation outcomes still fall short of goals. As a result, the effectiveness of current conservation areas and the potential for conservation gains within protected areas is gaining attention. The predominant models in the reserve design literature implicitly assume costless and perfect enforcement and monitoring with no possibility of illegal harvest. However, especially in low- and middle-income country settings, which account for 70% of terrestrial protected areas, these assumptions often fail. Instead, attaining the expected conservation benefits may require ongoing management including monitoring and enforcing reserves, the cost of which may dwarf land acquisition costs. Failure to implement enforcement and monitoring programs may result in “paper parks” that provide limited benefits because of continuing harvest and land conversion activities. We relax the standard assumptions and develop a reserve site selection model that (1) accounts for the loss of conservation benefits from illegal harvest and (2) incorporates enforcement and monitoring costs into reserve design decisions.
Results/Conclusions
We demonstrate that ignoring management costs and threats to the production of benefits when selecting reserve sites can lead to far lower conservation benefits than expected. Additionally, there can be differences in the choice of reserve locations and sizes while considering these ongoing costs and threats. The optimal reserve network reflects the underlying distribution of ecosystem services, the distribution of enforcement costs across the landscape, and the likelihood of illegal harvest if reserves are implemented but not monitored. The impact of considering these costs and losses during reserve design leads to higher realized conservation benefits, with the magnitude of those conservation outcome differences depending on the underlying distribution of ecosystem service or conservation benefits and the underlying distribution of enforcement costs and people’s likelihood of illegal harvest in reserves. Specifically, we find that the gains of explicitly optimizing with management costs and threats are largest in settings with tight budget constraints for acquisition and enforcement and where species persistence within reserves is low without active management. A case study from the Neotropics illustrates the losses for realized biodiversity conservation value under business-as-usual models of conservation prioritization.