Use Plants with a Punch

“Modernism is efficient because it aims for simplification. The central assumption is that technological solutions are universal, and so are independent of social context. This is what makes it appealing—mass production for us all. But modernist thinking inevitably leads to arrogance about the social and natural world.” –Tim O’Riordan, Susanne Stoll-Kleemann; Biodiversity, Sustainability and Human Communities

 (Kiley landscape, Chicago Art Institute)

Dan Kiley was a prominent 20^th century landscape architect that represented the height of modernism. His designs complemented sleek modern architecture and were clean, gridded—and mostly bereft of plant biodiversity. This use of mass plantings of the same species were common to Italian, French, Modernist and Minimalist traditions; and still influence landscapes today. Many city landscape ordinances promote biodiversity in plantings by encouraging the use of multiple species—mostly to prevent urban forestry disasters that occur with single-tree use (Dutch elm disease, Emerald ash borer, etc.).

Ecologists have documented the decline of native plant species diversity in urban areas as well. As shown in the chart below, McKinney (2002) gleaned from the available literature these observations:  that species richness declines the closer one gets to dense urban areas, and the urban biota changes as well. 

Zipperer and Gunstenspergen did their own empirical research by comparing both native and non-native species richness in five community gradients. Their conclusions showed a slight revision to McKinney’s model, one that shows native species richness declining as it approaches the urban core, and non-native species increasing as it approaches the urban core.

To enhance native urban biodiversity, US federal agencies (EPA, USDA, and DOT--in some states) are promoting the use of native plants; as well as NGO’s such as the National Wildlife Federation and Audubon. Wilde, Gandhi, and Colson (2015) propose that landscape plants (the ones that are primarily used in urban areas) should be bred with ecological function. Many landscape plant species are bred for form and ornamental characteristics (larger or more flowers, fruit, or other showy aspects). Similar to our shiny modern grocery store fruit-- taste and nutrition are bred out, but consumer curb-appeal is in. Wilde et al propose not only to scale up the use of native plants in urban landscapes, but to ensure that their genotypes also include the pollinator services and genetic diversity of their rural cousins.