If you walk into a forest on a cold winter day, you won’t see bees. However, once the flowers start to bloom and pollen fills the air, that same forest will be buzzing with pollinators. Depending on where and when you enter a forest, you may come away with the impression that forests are not very important to pollinators. After all, flowers are less abundant in shady forests than in more open habitats.
However, a new global review discusses why forests are incredibly important to pollinators and how forest pollinators can provide substantial economic benefits to neighboring agricultural areas.
“There’s a common misconception that bees don’t live in forests,” says USDA Forest Service researcher and lead author Michael Ulyshen. “Addressing that misconception is one of the main drivers for this review.”
Forests are important to many pollinator species, which require dead wood and other nesting habitats found only in forests. And forest pollinators are easy to overlook – they are often highly seasonal, especially in temperate regions, and many are active far above our heads in the forest canopy.
Just as trains, planes, trucks, and cars transport materials that sustain human life, bees, moths, flies, and beetles transport pollen that sustains entire species of trees and plants. Pollinators are vitally important to both natural systems and the economy.
As Ulyshen discusses in the review, forest pollinators play a huge role in pollinating crops and increasing yields. In the tropics, the productivity of 10 different crops increased with forest cover. Additionally, bee diversity has a positive effect on agriculture by supporting a variety of crops. This highlights the importance of sustaining the diversity of pollinators.
During restoration and conservation activities, keeping the needs of forest pollinators in mind will benefit adjacent crop fields. Even retaining individual trees can help bees.
“Trees provide shelter from extreme conditions for traveling bees that are sensitive to overheating,” Ulyshen says. Trees may also provide pollen, nectar, and places where bees can nest.
It remains unknown how much forest cover is needed to protect forest pollinators, but studies from multiple countries suggest that these insects can be lost when deforestation reaches a certain level. However, sometimes there is a shift in the bee community where forest-dependent pollinators are replaced by species that benefit from human activity, including some nonnative bee species. This shift can keep the overall number of species high, even as native, forest-dependent species disappear.
A topic for further research is the need for restoration and conservation. Some areas might need conservation to sustain pollinator diversity. Others might be reaching critical levels and require restoration before habitats are destroyed and certain species are completely lost from an area.
“The status of most species remains unknown,” says Ulyshen.