Valuing the benefits that wildlife provide to farmers could incentivize conservation in working landscapes. As insects destroy 8–15% of crops globally, much of our research focuses on how conservation could mitigate pest outbreaks on farms. For example, we have shown that conserving natural habitat around farms may bolster the natural enemies of coffee pests, resulting in fewer pests and higher yields (Figure 1).

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.

Pest Figure

In 2020, we  worked as part of a larger team at the Socio-Environmental Synthesis Center to design decision-support tools that would help managers visualize how habitat conservation affects insect pests worldwide. Our team compiled the most comprehensive global pest-control database of its kind, with 132 studies across 6789 sites in 31 countries. Qualitative and quantitative analyses of this database upended an agroecological paradigm by suggesting that the effect of natural habitat on pests is incredibly context-dependent (rather than being uniformly beneficial).

Our subsequent work has sought to explain this surprising finding. In one paper, we report that functional traits may mediate pest responses, with generalist pests benefitting from natural habitat and non-native specialists declining. In another, we suggest that pests may only be suppressed when natural habitat enhances predator diversity. Finally, our recent work indicates eco-informatic analyses of large databases may be needed to uncover landscape effects because pest populations are so variable .

Despite all of the attention given to landscape effects on crop pests, pest control is still rarely considered in landscape management. Part of the problem is that ecologists rarely measure outcomes that directly affect the public or that drive farming decisions. For example, farmers often apply excessive amounts of insecticides to avoid very rare but catastrophic outbreaks that result in total crop failure. Though crop failure events are usually too rare to be studied, we were able to use a large government database of ~1300 Spanish olive orchards and vineyards monitored for ~13 years to show landscape simplification (i.e., cultivating monocultures) increases insecticide applications, pest population volatility, and crop failure. Now, we are working on a USDA-funded project to build a global data repository that will integrate academic studies and ‘big data’ from governments or industry. In doing so, we will create a resource to develop decision-support tools that enable pest management at landscape scales.

News Coverage

Amigos Newsletter, Audubon MagazineCool Green Science, Cosmos MagazineMonga BayLa NaciónNature News, PBS NewsHourSan Vito Bird Club, Stanford Report, UC Davis News