Design and management of ornamental landscape systems for functional biodiversity

The explosive twenty-first-Century growth of cities presents opportunities for sustainable design to maximize human health, prosperity, and happiness. Key components of cities are the non-human organisms that supply such vital Ecosystem Services as flood and erosion control, microclimate buffering, carbon sequestration, air purification, pest management, and beauty. The urban environment, with its large areal extent of impervious and heat-absorbing pavements, and compacted, low-fertility, high pH soils, can be inhospitable to the grasses, shrubs and trees that dominate landscapes and support animal life. Outside of remnant natural areas, urban habitats can be categorized into two types according to harshness and management requirements: intensely managed plantings on fortified soils, such as parks, ball fields, and lines of street trees; and abandoned or neglected spaces such as railroad rights-of-way, uncared-for ornamental landscapes, median strips, and compacted walkways, which support highly adapted and mostly early successional species that are uneconomical to manage continuously. Further, trade has led to introduction of exotic plant species into both intensely managed and neglected cityscapes, begging the question of whether this has any bearing on the Functional Biodiversity of these landscapes. Here I restate a hypothesis on the relationship between plant provenance and pest management, discuss the sorts of data needed to test it, and make some preliminary recommendations on how these might be applied to urban landscape design.