main results phenology review
Climate change effects on seasonal activity in terrestrial ecosystems
are significant and well documented, especially in the middle and
higher latitudes. Temperature is a main driver of many plant
developmental processes, and in many cases higher temperatures have
been shown to speed up plant development and lead to earlier switching
to the next ontogenetic stage. Qualitatively consistent advancement of
vegetation activity in spring has been documented using three
independent methods, based on ground observations, remote sensing, and
analysis of the atmospheric CO2 signal. However, estimates of the
trends for advancement obtained using the same method differ
substantially. We propose that a high fraction of this uncertainty is
related to the time frame analysed and changes in trends at decadal
time scales. Furthermore, the correlation between estimates of the
initiation of spring activity derived from ground observations and
remote sensing at interannual time scales is often weak. We propose
that this is caused by qualitative differences in the traits observed
using the two methods, as well as the mixture of different ecosystems
and species within the satellite scenes.
