Linking functional traits and cultural ecosystem services in urban areas through human preferences

Sammanfattning: Urban areas are now the daily lived experience for the majority of the world’s people, and it is therefore important to explore what kind of ecological communities and corresponding ecosystem functions and services are being generated in these environments. Urban areas are shaped by a variety of factors, but arguably one of the most influential is that of people, in terms of how their preferences and active selective choices for biota play out in the landscape. A better understanding of these processes and dynamics can contribute toward better scientific knowledge as well as inform management decisions for creating more robust and resilient landscapes of ecosystem function and services. A functional traits approach, which links particular aspects of organisms related to fitness to ecosystem processes, functions, and services, may provide one way of interpreting the significance of biodiversity in the urban landscape. While this approach has traditionally linked traits to processes and functions, recently it has been conceptually extended to include services. Links between traits and provisioning, regulating, and supporting services have been well-characterized, but connections to cultural services have been less explored. This thesis addresses this critical information gap and how human preferences could be connected to the traits framework through an examination of the connections between functional traits and cultural ecosystem services. Paper I, a literature review, investigates scholarship outside the explicit field of functional traits to identify potential trait-cultural service linkages. It finds the strongest base of support for connections between traits and aesthetic benefits (particularly visual); though connections to spiritual, heritage, and wellbeing benefits are also identified. It suggests that what is considered a “functional trait” may need to be revisited in light of the expansion of to include not only ecosystem processes and functions, but services as well. The paper also explores how functional traits could be operationalized in a management context, with the development of trait-service indicators. Paper II builds upon the work of Paper I, and provides an empirical, case study interrogation of connections between traits and cultural ecosystem services in Cape Town, South Africa. It examines people’s expressed preferences for plant traits, and finds that traits related to visual and aesthetic appeal are described as the most common reason for selection, though traits related to use (e.g. as food) and low resource input are also cited. It also points to other factors beyond preference that may influence human selection for plants in the landscape. Together, these two papers provide a more detailed understanding of human preferences for traits in urban areas, and which traits may be connected to which services. This builds knowledge within the functional traits field and provides a basis for further study in research. It also points to trait-cultural ecosystem service connections that can be harnessed in management actions to select for trait combinations that will provide both ecosystem services and ecosystem resilience.