The quiet decline behind every third bite of food
Bees, along with butterflies, moths, flies, beetles, bats, and birds, pollinate an estimated 75 percent of the world's flowering plants and about 35 percent of global food crop production by volume, according to assessments coordinated by the Food and Agriculture Organization of the United Nations and the Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services (IPBES).
IPBES's 2016 global pollinator assessment found that more than 40 percent of invertebrate pollinator species, particularly bees and butterflies, face a risk of extinction in parts of their range. Long term monitoring in North America and Europe has recorded significant losses of both wild bee diversity and managed honey bee colonies in many regions over recent decades.
Researchers point to a combination of causes rather than one single culprit, habitat loss and fragmentation as wildflower meadows and hedgerows are converted to farmland or pavement, pesticide exposure, particularly certain systemic insecticides, the spread of pests and pathogens such as the Varroa mite, climate change shifting the timing between flowering and pollinator emergence, and the spread of large single crop monocultures that offer little food for most of the year.
Because habitat loss is one of the leading pressures, and because it is made up of millions of small decisions about land, small scale action adds up. A patchwork of gardens, verges, and balconies planted with the right flowers can restore a meaningful corridor of food and shelter, especially in cities and towns where it is otherwise scarce.