Effects of changing water conditions on Hamburg’s urban vegetation

Climate change is a persistent challenge for natural and social systems and thus for urban vegetation and its management. In the City of Hamburg, the consequences of climate change are gradually becoming apparent in the form of heat waves and droughts. At the same time, increased storm surges, river floods and heavy rainfall events as well as a rise in groundwater are anticipated. But the effects of these locally varying changes in water conditions on vegetation have not yet been sufficiently studied for Hamburg.

In the last two decades, remote sensing techniques have been increasingly applied to study urban green spaces. Multispectral satellite missions such as Landsat and Sentinel-2 generate temporal high-resolution data series and, in the case of Landsat in particular, enable a spatially extensive analysis of vegetation change over a long time period. Using a hybrid approach with the aid of further, more detailed data sources (airborne imagery, in-situ vegetation surveys, SAR data), changes in species composition and health status of the vegetation will be determined to 1.) investigate the reaction of the vegetation to climatic variations using statistical correlations and to 2.) determine small-scale water changes in the urban area using the indicator character of the vegetation. The aim of the current project is to identify areas of concern that require special attention in the management of urban green spaces in order to preserve their important functions in the future.