DrivenByPollinators · Driven by mutualists: how declines in pollinators impact plant communities and ecosystem functioning

Pollinator declines in response to land-use intensification have raised concern about the persistence of plant species dependent on insect pollination, in particular by bees, for their reproduction. Recent empirical studies show that reduced pollinator abundance decreases densities of seedlings of insect-pollinated plants and thereby changes the composition of grassland plant communities. Cascading effects on ecosystem functioning and associated organisms are expected, but to which extent and under which conditions this is the case is yet unexplored. Here, I propose a bold, multi-year, landscape-scale experimental assessment of the extent of pollinator-driven plant community changes, their consequences for associated organisms and important ecosystem functions, and their likely contingency on other factors (soil fertility, herbivory).Specifically I will:(1) Set up a network of long-term research plots in landscapes differing in pollinator abundance to measure the changes in plant reproduction over successive years, and assessing experimentally how herbivory and soil fertility mediate these effects.(2) Explore the individual processes linking pollinators, plant communities and ecosystem functioning using long-term experiments controlling pollinator, herbivore and nutrient availability, focusing on a sample of plant species covering both the dominant species and a diversity of functional traits.(3) Assess the context-dependence of pollinator-mediated plant community determination by building and applying process-based models based on observational and experimental data, and combine with existing spatially-explicit pollinator models to demonstrate the applicability to assess agri-environmental measures.This powerful blend of complementary approaches will for the first time shed light on the cornerstone role of this major mutualism in maintaining diverse communities and the functions they support, and pinpoint the risks threatening them and the need for mitigation.