This blogpost was inspired by this informative lecture given by conservation biologist, Claire Kremen (UC Berkeley). –Erin
Honeybees may be the first thing that comes to mind when you think of crop pollination, but the use of honeybees to pollinate crops is actually fairly recent. Humans began keeping bees thousands of years ago for honey and later, for candlewax, but it is only since the 1980s that domestic bees have been used on a large scale for crop pollination. Before this time, most farmers didn’t need to worry about seeking out pollinators, likely because small, diverse farms and variety of protected and managed areas on a regional scale supported habitat for plenty of wild bees. But in the mid-1970s farming changed drastically. Prompted by the “get big or get out” agricultural policy in the U.S., small diverse farms were quickly replaced by large-scale monocultures resulting in a dramatic decrease in both field and landscape-scale diversity. This eliminated much of the habitat needed to support wild pollinators, and created the need for large-scale beekeeping operations which now transport bees across the country to pollinate different crops at various times of year.
[Fun fact: Much as people hate on NJ, the small, often diverse farms in the Garden State often support wild bee populations.]
Ironically, however, the decrease in diversity may also be harming honeybees. Recently beekeepers across the U.S. and Europe have experienced large-scale collapses of hives (with a loss of 34% of U.S. the honeybee population in 2010). The mysterious killer, dubbed Colony Collapse Disorder (CCD), is characterized by worker bees simply disappearing from the hive. The jury is still out on the cause of CCD—it is likely due to a number of factors some of which, including the use of pesticides, may also be linked to industrial agriculture—but a lack of field and landscape-scale diversity may be one of the culprits. This is because vast expanses of annual monocultures create a “feast or famine” situation in which, when the one crop being grown is blooming, there is an abundance of nectar, but in other times, there is nothing but dirt.
Even with plenty of honeybees, a number of recent studies , have indicated that wild bees remain significant crop pollinators, and because the cause of, and cure for CCD remains unknown, wild bees are even more important. But remember that wild pollinators are also reliant on field and landscape scale diversity ,—it is likely this lack of diversity that likely prompted the need for honeybees in the first place. So what can we do?
Field-scale diversity could be enhanced by:
- Planting hedges and flowers, or even leaving weeds around crop fields
- Planting flowering cover-crops and allowing them to flower before they’re plowed under
- Transition from monocultures back to polycultures
Landscape-scale diversity could be enhanced by:
- Decreasing farm size
- Restoring natural habitat (e.g. along rivers)
- Setting aside some less-managed natural areas
Many of these strategies also have secondary benefits: they can reduce reliance on external inputs such as pesticides and even fertilizers (and all the problems associated with them), and can improve environmental services including pest control, soil fertility, nutrient cycling, and water management, not to mention enhancing aesthetic appeal.
Without wild pollinators we would have to pollinate the flowers of most fruits, veggies, and nuts, one-by-one with a paintbrush, and would lose a service of worth $1.6- $40 billion/year in the U.S. alone. For these reasons if nothing else, we owe both native and wild bees all the diversity they need!