Voluntary nonmonetary conservation approaches on private land: a review of constraints, risks, and benefits for raptor nest protection.

Biodiversity conservation on private land of the developed world faces several challenges. The costs of land are often high, and the attitudes of landowners towards conservation are variable. Scientists and practitioners need to scan for and adopt cost-effective solutions that allow for the long-term sustainability of conservation measures on private land. In this study, we focus on one of such possible solutions: Working with landowners to implement voluntary nonmonetary conservation. We restrict our focus to protection of raptor nests, but the ideas can be applied to other taxa as well. Through a literature review, we show that a voluntary nonmonetary approach for protecting raptor nests has been so far largely neglected and/or rarely reported in the scientific literature. However, results of a questionnaire sent to BirdLife partners across Europe indicate that this approach is more widely used than it appears from the literature. We show that voluntary nonmonetary approaches may represent useful tools to protect raptor nests on private land. We provide a workflow for implementation of such an approach in raptor nest protection, highlighting benefits, potential risks, and constraints in the application of the strategy. We suggest that a voluntary nonmonetary approach may have great potential for cost-effective conservation, but the risks it may entail should be carefully assessed in each case. There is an urgent need to consider and evaluate novel approaches, such as the one described here, which may constitute missed opportunities for cost-effective conservation.