Functional traits for understanding urban ecosystem services and their resilience?
Lists of species still provide the most common type of data for understanding and managing urban ecosystems. However, this information is not really sufficient for addressing more nuanced concerns such as specific ecological functions or processes or particular ecosystem services. To better relate biodiversity to system dynamics functional traits have been suggested as a way to address both ecological functions and changes in these functions as organisms respond differently to disturbances and drivers of change. In this framework effect traits relate to the different functions while response traits indicate how organisms may respond to different environmental conditions and changes. Cities and urban environments impose environmental filters that select for certain response traits and thus promote certain species rather than others. Effect traits in turn can help us understand how these species contribute to the functioning of urban ecosystems, but to get from an understanding of function to one of ecosystem service supply is not yet explored in depth. This article explores from existing scholarship what – in terms of functional traits – we actually know about urban ecosystem services and how they are connected to biodiversity and species communities.
We demonstrate and categorize how some ecosystem services have been connected to effect traits, highlight other cases where we have some, yet incomplete, evidence for ecosystem service – traits connections, and discuss the services where we to date do not know how to link services to traits as they have traditionally been defined. Finally, we return to response traits and how they can be used to assess the resilience of different services. We outline a further developed traits framework that addresses identified gaps, can help us understand and navigate future urban development, and can assist us in managing and designing city landscapes for a resilient supply of said services.