Redesign of a Commercial Cranberry Bog to Promote Bombus Mutualism

The existing Bombus (bumblebee) and human relationship is heavily tilted toward the human, where agroindustrial use of the pollinator ignores its importance in the greater ecosystem and the full life cycle needs of the species. This project reconsiders the Bombus/human relationship and proposes a mutualistic interspecies design for a cranberry bog in southeastern Massachusetts, where through the provision of nesting and foraging habitat the needs of native Bombus populations (e.g., Bombus impatiens and Bombus pensylvanicus) are supported year-round, and cranberry crops are pollinated with less need for commercial pollination inputs.

The project investigated the unique rearing processes of commercial bumblebees as compared to the life cycle of wild native bumblebee populations. In the natural life cycle, a young bumblebee queen will emerge from hibernation and establish a colony. Queens produce workers in early spring and summer and males and new queens in the late summer. Workers forage on flowers to feed the larvae and protect the colony. After the queen and male mate, all except the young queen will die before the winter arrives; the queen hibernates underground, and the cycle restarts next year (Williams et al. 2014). The commercial bumblebee industry disregards this cycle and prioritizes production, shipment,

Figure 1.

Cranberry bog distribution in southern Massachusetts (shown in red) and cranberry plant seasonal growth and production (shown across bottom).

Figure 2.

Proposed sand pile strategies, functions, maintenance schedules and locations.

and release of purchased pollinators, often Bombus impatiens, into agricultural landscapes for pollination services, particularly the pollination of crops that require buzz pollination, like blueberries and cranberries (Velthuis and van Doorn 2006). Buzz pollination is a type of pollination where bees vibrate flowers to gather pollen. Commercial bumblebees are imported each year before the cranberry blooming season. According to local cranberry growers in Plymouth, Massachusetts, two hives are applied per acre to satisfy the pollination needs. Due to human intervention, the commercial bumblebee population is increasing. Habitat loss, agricultural monocultures, and pathogen infection from commercial bees are thought to contribute to the decline of other Bombus species (Hatfield et al. 2012). During the development of this design project, the native American bumblebee, Bombus pensylvanicus was nominated for listing on the Endangered Species list, as its populations have dropped by 89% over a twenty-year period. While both species (Bombus impatiens and Bombus pensylvanicus) are native to the United States, the former has increased in population numbers, but the latter has decreased.

Cranberry farms have a long history of cultivation in Massachusetts and carry economic, cultural, and historical value. Bumblebees are the critical pollinators of cranberries during the mass blooming time from mid-May to end of June, as bumblebees most efficiently pollinate the flowers with buzz pollination techniques that European honeybees cannot perform. While the farmers rely on these pollination services, today farmers import commercially reared Bombus species, as the cranberry fields and surrounding environs fail to provide food for Bombus during the other time of the year and support persistent populations. The traditional mono-agriculture mode uses problematic pesticide inputs and intensive maintenance, which accelerates the problem of native Bombus decline. In addition, the cranberry industry faces severe problems including climate change, overproduction, and competition with other cranberry producers. This project reconsiders the traditional agricultural business mode of cranberry farming in this context and proposes that the farm support self-sustaining populations of the pollinators it requires.

Bombus habitat includes open land, bushland, and forest openings, which offer different opportunities for nesting and foraging throughout the year. For foraging, it is critical to have sufficient floral resources across the year within the flight distance. Both the early spring and late fall floral resources are important for the queen to establish the colony and to prepare for hibernation. For nesting, undisturbed ground with well-drained soil is required for ground nesting bumblebees and undisturbed long grassy areas are suitable for grass nesting bumblebees (Dibble et al. 2018).

Figure 3.

Proposed dike typologies, distributions and plants selection...