The Effects of Climate Change on the Vegetation of Central European Cities
lnstitut für Ökologie der Technischen Universität Berlin, D-12165 Berlin, Germany
Deutscher Rat für Landespflege, D-53179 Bonn, Germany
Published online February 26, 2003
Since the 1850s the effects of global warming have been anticipated by the rise of temperature in many big cities. In addition, vegetation changes in central European cities have been well documented. This paper begins by exploring the changing urban distribution of some ruderal herbaceous species, then discusses changes in distribution and physiological changes in tree and shrub species in response to this rise in temperature. Examples of affected species covered here include Acer negundo, Ailanthus altissima, Amelanchier spicata, Berberis julianae, Buddleia davidii, Colutea arborescens, Cornus alba, C. stolonifera, Cotoneaster bullatus, Cytisus multiflorus, C. striatus, Juglans regia, Laburnum anagyroides, Ligustrum vulgare, Mahonia aquifolium, Paulownia tomentosa, Philadelphus coronarius, Platanus x hispanica, Populus x canadensis, Prunus armeniaca, P. laurocerasus, P. mahaleb, P. persica, P. serotina, Pyrus communis, Quercus cerris, Q. rubra, Q. robur, Ribes aureum, Robinia pseudacacia, Sambucus spp., Sorbus intermedia agg., Symphoricarpos albus and Syringa vulgaris. The responses of some woody scramblers and creepers are also examined. For many of these species, there was a long lag time between introduction and invasion in the wild. Phenological investigations are briefly reviewed, including studies of Aesculus hippocastanum and Tilia euchlora. Finally, the extent to which cities can act as simulators of global climate change is considered. We conclude that although other ecological and socioeconomic factors are affecting the vegetation in urban areas, many of the nonnative invasive species found colonizing cities (or naturalizing within them) originate in warmer areas and are benefiting from the more favorable climate.