Literature review: 'Invertebrates in urban areas: A review'

This is the second in a series of literature reviews exploring the personal and environmental benefits of flowers. This post will look at "Invertebrates in urban areas: A review," an article by Elizabeth L. Jones and Simon R. Leather in the European Journal of Entomology.

Let's think about the pollinators that help the flowers that help us -- the birds and the bees, the butterflies and the moths, among the many other insects, both vertebrates and invertebrates, that not only play an important role in pollination but also aid in nutrient cycling, the cycling of organic matter, and soil aeration. In cities these nonhumans, whom often dwell in green spaces scattered throughout what we might call a concrete jungle, help to maintain the health of the urban eco-system. This paper considers invertebrate bioindicators and addresses factors in urban areas that influence biodiversity and the ability of green space to serve as wildlife reserves.

"As urbanization has occurred throughout history, habitat types within these areas have changed, meaning that wildlife is influenced. Some habitats have been lost altogether, while others have been reduced and new ones created" (463). These new habitats include urban green spaces. "As urbanization increases, green spaces within urban areas will become increasingly important as wildlife habitats. Urban green spaces are important for biodiversity primarily as wildlife refugia and wildlife movement corridors" (463).

Urban farms, gardens, parks and parkways provide habitat for these invertebrate populations and are therefore extremely important in the urban environment. "Invertebrates act as a food source for higher trophic levels and changes in their numbers can influence both these organisms as well as plants" (464). Consequently, "it is reasonable that ecological value of these areas should be included in urban planning and investments" (463).

The authors consider habitat fragmentation in urban areas as it "decreases the area of habitat available to invertebrates" (470). An example of fragmentation is given in the paper regarding bumblebees: "Bumblebee movement investigated in Boston, Massachusetts, USA, found that individuals only cross roads and railways if they were displaced or forced to find new flower resources" (470). 

Here are the factors influencing urban invertebrates that are mentioned in the paper:
- site age
- site area
- fragmentation, isolation and surrounding land use
- pollution / traffic
- grass mowing
- cultivated plants, other exotics and green roofs

Read the full article here.

For more information about bees and other pollinators in New York City and ways to improve habitat for them, check out the Great Pollinator Project. 

Works Cited: Jones, Elizabeth L., and Simon R. Leather. "Invertebrates in urban areas: A review." Eur. J. Entomol 109.4 (2012): 463-478. <http://www.eje.cz/scripts/viewabstract.php?abstract=1732>

Photos: Caitlin Keller