Detection of nonlinearities in temperature responses in phenology using European time series
Phenology has attracted increasing interest in recent years. Air temperature is the most important factor influencing plant phenology; thus, recent warming has considerable effects on onset dates of recurring natural events such as flowering or leaf unfolding.
One nearly linear relationship seems to have been stable for long: The higher the temperature, the earlier the phenological onset date. However, new questions emerge when extrapolating this obviously robust statistical relationship outside the present temperature range: Will plants flower earlier and earlier with increasing temperatures? Or is there a specific limit, an absolute minimum onset date, even with still higher temperatures? If yes, only temperature based linear models cannot adequately predict phenological onset dates in a warmer climate.
To describe future impacts on phenology, it is crucial to determine those nonlinearities in temperature responses. Thus, we analyse long-term European data records (PEP725) within the project IAS-SIGMOID in detail. Nonlinearities might be especially encountered at the southern extreme of a plant’s natural distribution.
Dr. Susanne Jochner