What are the main reasons for the worldwide decline in pollinator populations?

Abstract

Pollinator populations are declining worldwide and over 87% of flowering plant species and 87 of the leading global food crops rely on pollinators for seed production. Pollinator decline seriously impacts biodiversity conservation, reduces crop yield, and threatens food security. Understanding the drivers of pollinator decline can guide the development of strategies and action plans to protect and conserve pollinators and the essential ecosystem services they provide. This review introduces the diversity of pollinators, addresses the main drivers of pollinator decline, and presents strategies to reduce their negative impacts. We discuss how managed bees negatively affect wild bee species, and examine the impacts of habitat loss, pesticide use, pests and pathogens, pollution, and climate change on pollinator decline. Connections between humans and pollinator decline are addressed. Climate change emerges as the most prominent threat to pollinators and humans and the most difficult threat to control. The changes in water and temperature associated with climate change can lower the quantity and quality of resources available to pollinators, decrease the survival of larvae or adults, and modify suitable habitats. Climate change is a global issue and a serious threat to food security, and to world stability. Efforts to control the various factors that negatively impact pollinators must continue given the dire consequences.