Ecosystem Services Assessments (ESAs) are a way to determine the benefits particular ecosystems provide for biodiversity, human health, and society. ESAs assess and predict the impacts of preserving or developing natural features, such as forests, grassland, or mountain ranges. While a useful tool for measuring the benefits of nature preservation and conservation, and to project the detrimental effects of not doing so, most ESAs are performed at a regional scale, with few examples at the local or city-scale. Patrick J. O’Farrell, in collaboration with several colleagues and the Urban Ecology CityLab at the African Centre for Cities, recently conducted a rapid urban ESA of Cape Town, South Africa. The researchers describe their work as an exploratory study of whether “natural vegetation remnants,” or undeveloped bits of nature, might provide critical ecosystem services to wildlife and human society in the city of Cape Town.
Conservation International identifies Cape Town, South Africa as a “biodiversity hotspot,” within the Cape Floristic Region. Biodiversity hotspots are places with rich variety of wildlife that are seriously threatened by human impact. Cape Town’s city government features a Biodiversity Management Branch, which works to implement the city’s Biodiversity Strategy. O’Farrell et al. worked with Biodiversity Management Branch staff to conduct a rapid, simple ESA to assist city managers with decision-making and rationale for protection of natural vegetation remnants in Cape Town. While the researchers admit that a rapid approach does not allow for great depth of study, they suggest that such an assessment can assist with “quickly identifying issues, key focus areas, and opportunities” (O’Farrell 27).
O’Farrell and the research team used mapping resources to compare three scenarios for Cape Town’s ecosystem services: the original state of the land (before it was developed), the current state of the land, and future possible land use, assuming that areas not protected or formally managed would be developed. The researchers examined these scenarios, assuming the original state of the land as ideal, for their potential to provide a series of ecosystem benefits, including agricultural potential, flood mitigation, coastal zone protection, and groundwater recharge, among others. The study also considered how existing natural remnants might provide other benefits to society, such as cultural heritage, tourism, and educational opportunities.
The study concluded that preservation of natural remnants could provide benefits for the city and region’s ecosystem. The researchers noted that current land use in Cape Town already presents serious challenges for coastal zone protection and flood mitigation, and any future development of natural remnants with these benefits should be avoided. The researchers also determined that a number of existing natural remnants are proximate to culturally significant sites and schools, therefore conservation increases the potential for Cape Town residents to enjoy the benefits of nature.
O’Farrell et al. acknowledge the limitations of a “rapid” ESA, and suggest that such a method, though an important step, should be seen as a precursor to a full-scale ESA. The researchers also suggest that the data gathered demonstrate the need for collaboration between urban planners and experts in ecosystem health, for when difficult decisions need to be made about where and how to implement urban development (the researchers refer to the situation in Cape Town as a “low choice environment” presenting nearly irreconcilable decisions between preserving wildlife and addressing human needs), it is critical to consider potential of existing natural areas to provide ecosystem benefits.
Application of Ecosystem Services Assessment methodology to cities can provide a critical lens through which planners and decision makers determine the role of nature in urban environments. Understanding the critical role that natural remnants can play in providing wide-ranging services, from flood mitigation to educational opportunities, has the potential to strengthen arguments in favor of biophilic cities.
O’Farrell, Patrick J., Pippin M. L. Anderson, David C. Le Maitre, and Patricia M. Holmes. 2012. “Insights and Opportunities Offered by a Rapid Ecosystem Service Assessment in Promoting a Conservation Agenda in an Urban Biodiversity Hotspot.” Ecology and Society 17(3): 27-40.
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[hr] Additional Resources:
Millennium Ecosystem Services Assessment:
World Resources Institute Ecosystem Services Review for Impact Assessment:
Can Cape Town’s Unique Biodiversity Be Saved?
Urban Ecological and Social-Ecological Insights from CityLab:
Julia Triman, Biophilic Cities Project Researcher
Julia is a masters degree candidate in Urban and Environmental Planning at the University of Virginia.