Ecosystem complexity enhances the resilience of plant-pollinator systems

Summary Pollinator abundance has been declining worldwide as a result of land-use change, habitat destruction, pollution, and pesticide use with important impacts on global biodiversity, food security, and human livelihoods. While the collapse of plant-pollinator systems has been related to the complex network structure, the role of positive plant-reward-pollinator feedbacks (i.e., an extinction cascade based on feedbacks between plant and pollinator decline) remains poorly investigated. Here, we combine a phenomenological model with empirical plant-pollinator networks around the globe to show that plant-pollinator systems may undergo critical transitions to an undesired state with low species abundance as a result of increasing disturbance-induced mortality through positive plant-reward-pollinator feedbacks. Network complexity (i.e., connectance and/or species richness) enhances the capacity of plant-pollinator communities to withstand external disturbances. Our findings highlight the importance of critically evaluating land-use practices and maintaining complexity in plant-pollinator communities to conserve them and the diverse services they provide worldwide.