Declining bee populations have been widely covered in the news. It is a pressing issue worldwide as one in three bites of food that we eat relies on bee pollination.
A key factor that affects bees is increasing urban development as people flock to cities. As cities develop, they sprawl into their surroundings, fragmenting animal habitats and replacing vegetation with hard surfaces such as concrete and asphalt. Insects, including a multitude of native bees, rely on soil and plants for foraging and nesting.
Bee on Flower. Photo by Ji?í Zelenka via Wikimedia Commons
Bee habitat and foraging opportunities become smaller and more distant from each other. These segments of green space have become known as “habitat patches,” disconnected pieces of habitat that animals can move between to achieve the effect of a larger ecosystem. These patches occur in cities and can take the form of ravines, parks, gardens and so on.
Despite the fact that pollinators such as birds, bees and butterflies are better at moving between patches than less mobile species, a continuous habitat is always preferable. Green roofs are seen as a way to make up for ecological habitat fragmentation. But studies and guidelines about where and how to best construct green roofs for pollinators are just emerging.
Though domesticated bee species such as the well known European honey bee (Apis mellifera) tend to receive greater attention when it comes to declining population, wild bee species are often fou...