Predicting climate change impacts on crop pollination services

Background/Question/Methods

Three-quarters of the leading global crop plants are animal-pollinated, but how animal-mediated crop pollination might change with climate warming is unknown. Here we provide the first estimate of potential changes in crop pollination services caused by altered pollinator activity due to climate warming.  As a model crop plant, we used watermelon (Citrullus lanatus) which is completely dependent on insect pollinators for fruit production.  We developed models of pollinator activity as a function of temperature using a four-year data set on insect visitation to watermelon flowers at 18 farms in New Jersey and Pennsylvania, USA.  We then simulated future plant-pollinator interactions based on two IPCC climate change scenarios (A1 and B1) at two future time periods (2050 and 2100) to estimate the effect of rising temperatures on pollinator activity patterns and thus crop pollination services. 

Results/Conclusions

Under current conditions, pollinator species vary in their temperature-activity profiles; hence pollinators are predicted to respond differently to future climate warming.  Specifically, under the more extreme 2100 scenario, pollination services from the managed honey bee, Apis mellifera, are expected to decline by 14%, whereas pollination services from native, wild pollinator species are predicted to increase for six of the seven wild taxa we studied. Wild bees provide the majority of the crop pollination in our system, and thus overall, total pollination services are predicted to increase by 5% in the climate warming scenario, despite decreased pollination services from managed honey bees. The magnitude of the predicted changes in pollination services that we report here, which result from predicted changes in pollinator behavior, are small relative to the changes that could occur if climate change also affects wild pollinator abundance.