Agriculture faces a set of major interrelated challenges in the 21st century: it must achieve global food security, meet high quality and safety demands, reverse degradation of ecological life-support systems, and respond to an ongoing biodiversity crisis. While agricultural systems can be managed to yield diverse benefits, only recently have we begun to acknowledge and identify the multiple ecological tradeoffs associated with alternative management decisions. These tradeoffs suggest that optimal conservation strategies in agricultural lands may differ radically depending on the objective. For example, preventing agricultural expansion with nature reserves may stave off extinctions through protecting severely threatened species, while incentivizing farmers to plant hedgerows may benefit people through bolstering pest-eating or pollinating species. Win-win interventions that satisfy multiple objectives are alluring, but can also be elusive.

To achieve better outcomes, we developed and implemented a practical typology of nature conservation framed around six common conservation objectives (Karp et al. 2015 PNAS a,b). Using an intensively studied bird community in southern Costa Rica as a model system, we applied the typology in the context of biodiversity’s most pervasive threat: habitat conversion. Despite several observed tradeoffs, our approach identified strategies for achieving multiple conservation objectives simultaneously; for example, by maintaining forest patches within agricultural systems.

In California, concern that wildlife spread foodborne diseases has created strong pressure on growers to prevent wildlife from accessing their farms (See video below). Despite increasing recognition that agro-ecosystems should be managed to yield diverse, multifunctional benefits, growers are now forced to engage in practices that narrowly address perceived food-safety risks. The socio-ecological consequences may be severe (Karp et al. 2015 Bioscience). For example, our work has demonstrated that removing non-crop habitat to prevent wildlife from entering farm fields reduces pest-control services to agriculture without mitigating food-safety risks (Karp et al. 2015 PNAS, Karp et al. 2016 Journal of Applied Ecology).

Looking forward, we seek to develop better strategies for co-managing food safety, biodiversity, ecosystem service, and yield outcomes. For example, through a grant from the USDA, we are quantifying the services (e.g., pest regulation) and disservices (e.g., foodborne disease propagation, intraguild predation, and crop losses) associated with birds that frequent strawberry fields and test how alternative practices affect both beneficial and problematic species.  Our objectives are to (1) analyze DNA content in bird fecal samples to identify pest, disease vector, and beneficial species, (2) quantify how farming practices affect birds’ net economic impact on yields, and (3) explore how farmers’ attitudes towards birds influence their practices. To date, we have collected >1000 fecal, blood, and feather samples across ~60 species; conducted a bird exclusion experiment across 15 farms; surveyed birds, nest density, strawberry damage, and fecal contamination across 20 farms; and administered 52 farmer surveys. Our fecal analyses are already identifying species that consume pests, consume pest predators, consume strawberries, and/or vector foodborne diseases (e.g., Salmonella). Overall, the net effects of birds appear to be neutral (Gonthier et al. 2019 J. Appl. Ecol.), as pest consumption balances strawberry consumption. Yet these neutral effects mask complex bird community shifts between diversified farms and large monocultures, with cascading implications for services and disservices (Olimpi et al 2020 Ecol. Appl.).

Finally, through NSF’s Coupled Human Natural Systems program, we are also working with colleagues at UC Berkeley to understand how diversified farming practices affect biodiversity, ecosystem services, and farmer livelihoods.  Ultimately, by combining ecological, economic, sociological, and psychological approaches as well as by disseminating findings in workshops and with decision-support tools, our intent is to change practices and potentially reframe grower attitudes towards wildlife and conservation.

Video: The Nature Conservancy’s media team produced a video showcasing our research into the cascading socio-ecological consequences of food-safety management in California’s Central Coast.

Publications

  1.  Garcia, K., E.M. Olimpi, D.S. Karp, and D.J. Gonthier (2020) The good the bad and the risky: can birds be incorporated as biological control agents into integrated pest management programs. Journal of Integrated Pest Management 11: 1-11.
  2. Olimpi, E.M., K. Garcia, D. Gonthier, K.T. De Master, A. Echeverri, C. Kremen, A.R. Sciligo, W.E. Snyder, E. Wilson-Rankin, and D.S. Karp (2020) Shifts in species interactions and farming contexts mediate net effects of birds in agroecosystems. Ecological Applications 30: e02115.
  3. Gonthier, D., A. Sciligo, D.S. Karp, A. Lu, K. Garcia, G. Juarez, T. Chiba, and C. Kremen (2019) Bird services and disservices to strawberry farming in Californian agricultural systems. Journal of Applied Ecology. 56: 1948-1959
  4. 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
  5. Karp, D.S.*, P. Baur*, E.R. Atwill, K. DeMaster, S. Gennet, A. Iles, J. Nelson, A. Sciligo, and C. Kremen (2015) Unintended ecological and social impacts of food safety regulations in the California Central Coast. BioScience 65: 1173-1183.
  6. Karp, D.S., C.D. Mendenhall, E. Callaway, L. Frishkoff, P.M. Kareiva, P.R. Ehrlich and G.C. Daily (2015) Confronting and resolving competing values behind conservation objectives. PNAS 112: 11132-11137.
  7. Karp, D.S., C.D. Mendenhall, E. Callaway, L. Frishkoff, P.M. Kareiva, P.R. Ehrlich and G.C. Daily (2015) Reply to Kirchkoff: Homogenous and mutually exclusive conservation typologies are neither possible nor desirable. PNAS 112: e5906.
  8. Karp, D.S., S. Gennet, C. Kilonzo, M. Partyka, N. Chaumont, E.R. Atwill, and C. Kremen. (2015) Co-managing agriculture for nature conservation and food safety. PNAS 112: 11126-11131.
  9. Garbach, K., J.C. Milder, M. Montenegro, D.S. Karp, and F. DeClerke. (2014) Ecosystem Services in Agricultural Lands. In: The Encyclopedia of Agriculture.