Green Roofs - Living Architecture Monitor - Summer 2011 - (Page 4)

RESEARCH & DESIGN DESIGN STRATEGIES FOR WILD BEES BEE-KEEPING REQUIRES EXPERTISE AND TIME – BUT WITH A LITTLE KNOWLEDGE, GREEN ROOF PROFESSIONALS CAN SUPPORT LOCAL POLLINATORS BY MAKING IT EASIER FOR THEM TO FORAGE AND NEST By Scott MacIvor any in the green roof industry realize that bees are so-called “pollinators” but fewer still truly understand the critical ecosystem services they provide us with — all at no charge. There are many anecdotes to describe the importance of pollination services such as “for every third bite of food, thank a pollinator,” a nod to the important role pollinators play in crop fertilization in agriculture. Over 80 percent of flowering plants require insect pollination, but unfortunately the hard truth is that many pollinating species are disappearing from most, if not all landscapes. Further, Colony Collapse Disorder (CCD) – which is difficult to monitor or remedy – is the latest in a series of disasters for the honey bee-keeping industry in which bees simply disappear from their hives, never to return. There are literally hundreds of species of wild 4 LIVING ARCHITECTURE MONITOR SUMMER 2011 M bees in North America and the underlying reasons why their numbers are in decline is more fundamental and conceivably fixable; primarily, habitat loss and degradation. Wild bees need nesting sites, along with suitable pollen and nectar food sources within their foraging range. With a little creativity, green roof designers can provide an opportunity to help these species – whose pollination services are essential for promoting the diversity of flowering plants in almost all terrestrial ecosystems – by incorporating some beeattracting elements into their green roof designs. Adding honey-bee hives is also economical, and their fresh honey is delicious. Without a doubt, honey bees are in need of increased support from bee-keepers, because their populations are under perpetual threat as a result of numerous factors including the aforementioned CCD. That said, keeping honey bees could be an arduous task for the non-expert or casual mainte- nance person, particularly given the difficult environmental conditions present on green roofs. Moreover, with thousands of honey bees per colony, if hives are maintained at high-enough densities they might out-compete locally existing wild, native bees for floral resources: though this potential challenge is yet unstudied in the urban context. Therefore, an alternative approach to augmenting local pollinator populations using green roofs might include design elements that support the nesting and foraging needs of the dozens – if not hundreds – of other exceedingly important bee species that go unnoticed in our modern, urban landscapes. Without any design intent, we often see all kinds of bees on green roofs. This is because bees are highly mobile — meaning many are capable of reaching green roofs while foraging. Larger bees can forage farther than smaller bees. Social bees — bees that form colonies with a caste system of

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Summer 2011

Green Roofs - Living Architecture Monitor - Summer 2011
Water Worries
Cities Re-Imagined
Design Strategies for Wild Bees
Special Section: Cities Alive 2011 Conference Guide
Thin Flats
Sky Island at the Visionaire
Welcome New Members
New Corporate Members
Professional Calendar
Seven-Year Pitch

Green Roofs - Living Architecture Monitor - Summer 2011