Plants are essential in urban systems; providing a variety of valuable ecosystem services like shade and cooling, mitigation of carbon dioxide, air purification, and aesthetics. Yet, the mechanistic coupling of plant growth and water loss demands costs associated with urban green space. In many cities, where street trees rely on irrigation water for transpiration, the most substantial of these costs is water. Given that rainfall is projected to decrease and temperature is expected to increase in most areas under climate change, the demand for landscape irrigation will increase across globally and many street trees will be threatened if water is not carefully managed. In collaboration with the Los Angeles Arboretum and Botanical Garden and the LA Center for Urban Natural Resource Sustainability, my work in urban ecosystems aims to build mechanistic scaling models that allow for assessment of plant water use and species suitability for improved water management, and identification of species at risk given future efforts to reduce irrigation costs using easy to measure plant functional traits.
Beyond their ecosystem services, urban systems represent a special and powerful tool for evolutionary study. In many urban ecosystems irrigation practices and a legacy of landscape design driven by social and economic factors has produced unprecedented species diversity. The resulting ‘global common garden’ is ideally suited for testing relationships between plant functional traits over evolutionary time. I am currently working in collaboration with Lawren Sack and Jeremy Beaulieu to extend my database of urban tree traits and place these important relationships between functional traits across species in the context of the plant tree of life.
Want your city to be included in this work? Contact me about citizen science below!