Urban development has dramatically decreased habitat for native plants and other wildlife. One of the native insect groups affected by this change are the bees and wasps (Order: Hymenoptera), which provide valuable ecosystem services like pollination of crops and ornamental plants. These insects are experiencing rapid population declines in urbanizing areas. A major obstacle to restoring pollinator populations in cities is the scarcity of space available that can be managed as habitat. A potential solution to this is to create patches of native vegetation on green roofs. Green roofs consist of live plants, growing media, and a drainage layer on top of a waterproof membrane. Most green roofs are planted with a mixture of non-native succulent plants (mostly from the genus Sedum), which are favored for their high survivorship and low maintenance requirements. On roofs with somewhat deeper media, a greater diversity of plants, including native plants typical of local grasslands, can persist. Here, we report on the differences in abundance and diversity of Hymenoptera attracted to native green roofs, Sedum green roofs, non-vegetated roofs, and ground-level green spaces. Preliminary data indicate extensive insect use of green roofs, with higher abundances on roofs planted with native species. The next phase of this research will involve comparing how the landscape context provided by different neighborhoods affects the development of the green roof biological communities.
Smith, Melanie C. and Palmer, Matthew I.
"Restoring Native Plant and Pollinator Communities on New York City Green Roofs,"
Cities and the Environment (CATE):
1, Article 23.
Available at: https://digitalcommons.lmu.edu/cate/vol3/iss1/23