Valuing the tangible benefits that biodiversity provides to farmers may help incentivize conservation in farming landscapes. As insect pests destroy 8-15% of major food crops globally, much of our research focuses on how conserving biodiversity may help mitigate pest infestations. For example, we developed a system for quantifying the value of tropical forests to coffee production, via bird and bat predation on coffee’s most damaging insect pest, the coffee berry borer (Hypothenemus hampei) (Karp et al. 2013 Ecology Letters). In southern Costa Rica, we showed that birds halved borer infestations, preventing US$70-US$310/ha in coffee damage or ~US$10,000 for one small coffee plantation (Fig. 1). Bats, however, fed as intraguild predators and did not prevent coffee damage (Karp et al. 2014 Ecology). We also provided the first evidence that tropical forest increases pest control. After identifying borer-consuming birds with fecal DNA analyses (Karp et al. 2014 SpringerPlus), we showed that patches of forest near coffee farms increased the abundance of borer predators, pest control, and coffee yields. Small, unprotected forest patches provided the most value to farmers, underscoring the need to incorporate farmland forest into conservation planning.
Fig. 1: Excluding insectivorous birds from coffee plants doubled yield loss from coffee’s most damaging insect pest (Karp et al. 2013 Ecol. Lett.; Karp et al. 2014 SpringerPlus). Pictures depict bird exclusion treatments (top), the coffee berry borer beetle (bottom left), and a Yellow Warbler (bottom right), one of the species shown to consume berry borers.
Translating these results into practice requires generalizing findings and packaging them into practical tools for decision-makers. With Rebecca Chaplin-Kramer of the Natural Capital Project, Daniel formed an international working group of ecologists, social scientists, and conservation practitioners to (1) develop decision-support tools for considering pest control in land-use decisions, (2) demonstrate their efficacy with field data, and (3) identify conditions under which habitat would and would not be expected to increase pest control. Team members regularly met at the national Socio-Environmental Synthesis Center (SESYNC) to exchange ideas and data. The team compiled and standardized the most comprehensive global pest-control database of its kind, encompassing 132 studies across 6789 sites in 31 countries (Karp et al. 2018 PNAS). The subsequent analysis of this dataset (involving >150 co-authors) upended a burgeoning agro-ecological paradigm by suggesting that the effect of surrounding natural habitat on pests is context-dependent. That is, natural habitat bolstered pest populations as often as it depressed them.
This surprising finding has led to multiple collaborations focused on exploring mechanisms that underlie pest responses to natural habitat so as to improve farmer decision-making. First, some of the members of our SESYNC group are now working to develop analytical (rather than statistical) models for pest control. Second, with a recent grant from the USDA led by Rebecca Chaplin-Kramer, we are now working to transform these datasets into a living and growing database that can be broadly applied to both fundamental and applied questions in pest control research. Finally, postdoctoral scholar Daniel Paredes is exploring the effects of surrounding landscape context on pest regulation in European olive orchards (Paredes et al. 2019 J. Pest Sci.) and vineyards. Specifically, through our broader collaboration in the SECBIVIT project, funded by NSF and Biodiversa, Paredes is using “big data” to explore temporal dynamics in pest populations and pesticide sprays across landscape gradients in Spain. Initial results suggest landscape simplification causes pests to exceed established economic thresholds for pesticide spraying, leading to higher pesticide loads in more simplified landscapes.
- Maas, B., S. Heath, I. Grass, C. Cassano, A. Classen, D. Faria, P. Gras, K. Williams-Guillén, M. Johnson, D. S. Karp, V. Linden, A. Martínez-Salinas, J. Schmack, and Sara Kross (2019) Experimental field exclosure of birds and bats in agricultural systems – methodological insights, potential improvements, and cost-benefit trade-offs. Basic and Applied Ecology 35: 1-12.
- Chaplin-Kramer, R., M. O’Rourke, N. Schellhorm, W. Zhang, B. Robinson, C. Gratton, J.A. Rosenheim, T. Tscharntke, and D.S. Karp (2019) Measuring what matters: actionable information for conservation biocontrol in multifunctional landscapes. Frontiers in Sustainable Food Systems. 3: 60.
- Paredes, D., D.S. Karp, R. Chaplin Kramer, E. Benítez, and M. Campos (2019) Natural habitat increases the economic value of natural pest control in olive groves. Journal of Pest Science 92: 1111-1121.
- Dainese, M., et al. (2019) A global synthesis reveals biodiversity-mediated benefits for crop production. Science Advances 5: eaax0121.
- Karp, D.S., R. Chaplin Kramer, and 152 co-authors (2018) Crop pests and predators exhibit inconsistent responses to surrounding landscape composition. Proceedings of the National Academy of Sciences. 115: E7863-E7870
- Tscharntke, T., D.S. Karp, R. Chaplin-Kramer, P. Bátary, F. DeClerk, C. Gratton, L. Hunt, A. Ives, M. Jonsson, A. Larsen, E.A. Martin, A. Martínez-Salinas, T.D. Meehan, M. O’Rourke, K. Poveda, J.A. Rosenheim, A. Rusch, N. Schellhorn, T.C. Wanger, S. Wratten, and W. Zhang (2016) When natural habitat fails to enhance biological pest control- five hypotheses. Biological Conservation 204: 449-458
- Karp, D.S., R. Moses, S. Gennet, M. Jones, S. Joseph, L.K. M’Gonigle, L.C. Ponisio, W.E. Snyder, and C. Kremen. (2016) Farming practices for food safety threaten pest-control services to fresh produce. Journal of Applied Ecology 53:1402-1412
- Maas, B., D.S. Karp, J. S. Bumrungsri, K. Darras, C. Huang, C. Lindell, J. Maine, L. Mestre, N. Michel, E. Morrison, I. Perfecto, S. Philpott, C.H. Sekercioglu, R.M. Silva, T. Tscharntke, S. Van Bael, C.J. Whelan, K. Williams-Guillen (2016) Bird and bat predation services in tropical forests and agroforestry landscapes. Biological Reviews. 91: 1081-1101
- Karp, D.S., S. Judsen, E. Hadly, and G. Daily (2014) Molecular diagnosis of bird-mediated pest control across tropical countryside. SpringerPlus 3: 630
- Karp, D.S. and G. Daily (2014) Cascading effects of insectivorous birds and bats in tropical coffee plantations. Ecology 95: 1065-1074
- Karp, D.S., C.D. Mendenhall, R.F. Sandí, P.R. Ehrlich, E.A. Hadly, and G.C. Daily (2013) Forest bolsters bird abundance, pest control, and coffee yield. Ecology Letters 16: 1339-1347.
- Karp, D.S., H. Moeller, and L. Frishkoff (2013) Nonrandom extinction patterns can modulate pest-control service decline. Ecological Applications 23: 840-849.