Professor Stefan Arndt is an ecologist with 20 years of experience in applied ecosystem science. His research centres around how plants and entire ecosystems cope with changes in environmental conditions and how they respond to climate extremes like drought or heat stress. He investigates plant performance under environmental stress to predict which plant species will be best suited to survive and thrive in a future climate in forests, revegetation projects or urban areas. His research has three major areas of focus. In ecophysiology and plant adaptation he investigates the mechanisms that enable plants to grow and thrive in their environment. In applied ecophysiology he studies plant species, provenances or cultivars that are best adapted to a future climate. And in ecosystem ecology he investigates the impact that climate and climate change have on key ecosystem processes like carbon cycling and greenhouse gas emissions.
TREENET Symposium Speaker: Prof Stefan Arndt
Urban tree species selection for future climates – more difficult than you think
Climate change presents significant challenges for plants and plant selection. Temperatures are increasing more rapidly and rainfall is changing faster than plant species can adapt. This means that many species that we plant today may be maladapted and unable to cope with the new climate in a few decades. This may be exacerbated in urban environments where impervious surfaces and the urban heat island effect create stressful environments for plants. One novel method to select trees for future climates is based on climate niche analysis. Using global databases, the current climate niche of a tree species is extracted and compared against the predicted future climate at a given location. If the climate niche of a tree is outside the future climate niche of a city, then that tree species is deemed no longer suitable. These types of climate niche analysis are very common, and they are already influencing management and tree selection decisions. For example, in the City of Melbourne over half of the current species have been deemed ‘unsuitable’ for a future climate based on climate niche predictions and species are getting replaced. Botanic gardens have developed climate niche tools for selecting ‘climate proof’ tree species. However, this approach is not without problems and many very suitable tree species are excluded because their distribution in nature is different from the tolerances a tree has to a city environment. In this presentation I will critically examine this tree selection approach and highlight the “good, the bad and the ugly” of this and other methods and give examples of how species selection could be improved.