Design Online - April 2019
The Value Behind Ecologically-Based Site Analysis By Marie Chieppo, Sustainability Committee Without question, one of our main goals as designers today is to mitigate the effects of climate change. The trend we now see of southern plants migrating north is mostly due to increased ambient temperatures. A good deal of them however, will likely not have successive reproduction. Thus, we will likely see an increase in the loss of species and a decline in biodiversity. When we conduct an ecologically-based site analysis, such trends are important to note. Only in knowing what currently exists (and/or did exist) on a property can we prioritize what needs to be done and gain a realistic view. Take a close look at what is growing there and ask yourself why—or what is not there. Ninety percent of herbivorous insects specialize in one or only a few native plant lineages. If those lineages do not exist on a property or anywhere close by, the insect population drastically falls. As a result, migratory and terrestrial bird populations are adversely affected. It has been shown that properties dominated by non-native plants have a significantly reduced insect diversity, abundance and biomass (1). An ecologically-based site analysis offers invaluable information about the landscape. It can help steer the direction of where to begin. Each item below provides valuable information in the analysis:
• Sun and shade conditions on the property
• Map and identification of vegetation native and nonnative species shrubs, plants, vines, trees and groundcovers. Make note of invasive species. Include the name, size, quantity, health and canopy size, existence of plant communities.
• Soil composition—the type, PH, percent of organic matter, degree of compaction • Topography—the shape of the land, rises and dips, outcrops • Hydrology—amount of moisture available to plants
• Prevailing wind direction
• On-site water sources
• Orientation of the house/building
• Microclimates—areas within a landscape with a small ecological variation that has an influence on the vegetation.
• Presence of wildlife • Overall diversity—make note of it
As one continues to work with a landscape, what is realistic and compatible with the desires of the client becomes clearer. Through the careful examination of the overall environment and the use of an ecological lens, it will be reassuring that we aren’t imposing on nature, but working with it. 1. Nonnative plants reduce population growth of an insectivorous bird. Desirée L. Narango, Douglas W. Tallamy, and Peter P. Marra. PNAS. November 6, 2018.