Enhancing agricultural landscapes to increase crop pest reduction by vertebrates.
A key challenge of the coming decades is increasing agricultural productivity while maintaining environments that optimize ecosystem service provisioning. Crop pests are a constant challenge for farmers. Recent investigations demonstrate that vertebrates consume numerous crop pests and that this consumption often reduces crop damage, a key ecosystem service. Pest-consuming vertebrates can be attracted to agricultural areas through several strategies that we refer to as landscape enhancements: (1) providing critical structures and materials like nest boxes and roosts, (2) managing habitat/landscape complexity, (3) reintroducing native species, and (4) reducing invasive species' impacts on target species. In addition to the potential for lower crop damage, attracting pest-consuming vertebrate to agricultural areas could: reduce use of pesticides, aid in the conservation of declining species, provide cultural ecosystem services like wildlife watching, and respond to consumer preferences regarding food production. Some of these benefits provide potential economic advantages to food producers. Our search of past research indicated that relatively few systematic studies have investigated vertebrate effects on crop pests and even fewer have studied how enhancements may increase trophic effects resulting in lower crop damage. Birds are the most studied vertebrate with regard to effects on crop pests, arthropods are the most studied pest group, and a plurality of studies have taken place in coffee and cacao. We lack information about key ecological and social questions related to enhancements including the contexts in which vertebrate predators are most likely to be attracted to enhancements and reduce crop pests, the potential economic benefits of enhancements, and how to marshal the human resources to install, maintain, and monitor enhancements. Addressing these questions will increase understanding of the interactions of vertebrate predators and their prey, the ways in which these interactions provide ecosystem services, and the roles of humans in protecting and encouraging these interactions.