Bumblebees, with their distinct fuzzy bodies and industrious buzzing, are familiar sights in gardens and natural landscapes. These insects are recognized for their role in the environment, prompting questions about their current well-being. Understanding their status requires a closer look at the challenges they face.
Understanding Their Conservation Status
The conservation status of bumblebees is complex, varying significantly among species. While some bumblebee populations remain stable, many are experiencing considerable declines globally and regionally. For example, the rusty patched bumblebee (Bombus affinis) in North America has seen a decline across an estimated 87% of its historic range and was listed as endangered under the U.S. Endangered Species Act in 2017, making it the first bee in the continental United States to receive such protection.
In Europe, the situation is similarly concerning, with 24% of bumblebee species currently threatened with extinction. Nearly half of Europe’s bumblebee populations are in decline, and projections suggest that over three-quarters of European bumblebee species could be threatened by 2080 if current trends continue.
Key Factors Driving Decline
Bumblebee populations are facing a range of pressures, with habitat loss and fragmentation being a primary factor. Agricultural expansion and urbanization have led to the destruction and degradation of flower-rich habitats, which bumblebees rely on for food and nesting sites. This reduction in suitable environments impacts their ability to find food and establish colonies.
Pesticide use, particularly neonicotinoids, contributes to bumblebee decline. These systemic chemicals can be present in pollen and nectar, causing adverse effects even at low concentrations. Exposure to neonicotinoids can reduce food consumption, impair foraging activity, decrease queen production, and even affect the bees’ ability to perform buzz pollination.
Climate change contributes to the challenges by altering temperatures and precipitation patterns. Rising temperatures can push bumblebees to their physiological limits, leading to range contractions and impacting their ability to reproduce successfully. Higher nest temperatures can be lethal to larval bumblebees, causing colony collapse. Furthermore, changes in climate can disrupt the synchronization between bumblebee foraging patterns and flower availability, creating a mismatch in resources. Diseases also pose a threat, with Nosema bombi being linked to declines in species like the rusty patched bumblebee.
Their Role in Ecosystems
Bumblebees are important pollinators for wild plants and agricultural crops. They are particularly effective pollinators due to their ability to forage in cooler temperatures and lower light conditions, extending their activity earlier and later in the season compared to other bees.
Many bumblebee species perform “buzz pollination” or sonication, vibrating flowers at a specific frequency to release pollen. This method is essential for the pollination of certain crops such as tomatoes, blueberries, cranberries, and eggplants, which other pollinators cannot effectively service. Their large, hairy bodies also enable them to carry and transfer more pollen, increasing pollination efficiency. Their decline has broader implications for biodiversity and agricultural productivity, potentially leading to reduced plant reproduction and lower crop yields.
How You Can Help
Individuals can contribute to bumblebee conservation through practical actions. Planting a diverse range of pollinator-friendly flowers, ensuring a continuous supply of nectar and pollen from early spring through late autumn. Native plants such as milkweed, goldenrod, bee balm, nasturtiums, and crocuses are particularly attractive to bumblebees.
Reducing or eliminating the use of pesticides, especially neonicotinoids, in gardens and yards helps protect bumblebees from harmful chemical exposure. Creating and maintaining nesting habitats provides support. Bumblebees often nest in undisturbed areas, such as abandoned rodent burrows, dense grass, or brush piles. Leaving some areas of your garden a little untidy can provide these nesting and overwintering sites for queen bumblebees. Supporting local conservation initiatives and organizations amplifies these efforts.