A systematic review of the relationship between urban agriculture and biodiversity

Urban agriculture is a unique form of agriculture that can provide fresh, local produce for urban residents, and may benefit biodiversity by decreasing the need to expand agriculture into natural areas as well as enhancing biodiversity in urban areas. However, although urban agriculture is also often cited as promoting biodiversity in urban areas, the extent of empirical evidence for such claims has not been studied. Here we systematically review the relationship between urban agriculture and biodiversity in the scientific literature. We strictly define urban agriculture as areas in cities that grow produce specifically for human consumption. We examined 148 papers from 2000 to 2017, of which only 24 studies fit our definition of urban agriculture, and of those, only 18 both involved urban agriculture and measured biodiversity. Of the studies that did measure biodiversity, some showed increases in diversity compared to urban vacant lots, but other showed no difference. Moreover, these studies were mostly focused on plants and invertebrates and were conducted almost exclusively in North America. In order to use the generalization that urban agriculture will have a positive influence on urban biodiversity, more studies will need to be conducted across a wider geographic range worldwide (particularly in developing countries in the tropics) and on a greater diversity of species and taxa (e.g., herpetiles, birds and small mammals). Such studies will likely increase in conservation importance as urban expansion and agricultural demands increase globally.