2008–2009
"Multi-species phenological data analysis and new plant phenological metrics for climate
change impact studies"
Supported by the Swiss National Science Foundation www.snf.ch

Plant phenological observations provide important evidence of climate change affecting
seasonal vegetation dynamics from all continents. A number of large multi-species data sets
were published in peer-reviewed scientific journals and provide evidence for a better
understanding of global change at single locations. Up to now linear trend coefficients,
correlation and regression analyses with climate impact factors were mostly applied on
ground observed phenological observations. However, no inter-site analyses with more
sophisticated methods that account for the subjectivity of the observations were published. In
addition, there is still a lack for developing phenological metrics that can be compared with
remotely sensed measurements and vegetation model outputs.
Therefore, this projects aims at addressing the following scientific question: What are the
most appropriate statistical methods for the analysis of large, phenological multi-species data
sets for inter-site comparisons and the definition of new plant phenological metrics in
temperate and mediterranean climate regions? To address this research topic, two tasks will
be tackled within the frame of this project.
1) We will digitize the multi-species data set of
Christian Röthlisberger (Grossaffoltern, Switzerland) including plant and animal phenological
observations from 1977 up to today.
2) We will apply the most appropriate multivariate
statistical methods and provide new phenological metrics for climate impact assessment,
remote sensing vegetation data validation and vegetation model verification.

2004–2007
"Past, Present and Future Climate Impact on Spring and Summer Vegetation – a Phenological Approach"
Supported by the Swiss National Science Foundation www.snf.ch
(Contract Number 205321-105691 / 1)

Plant phenological records such as flowering dates or coloring dates of the leaves integrate the whole set of climate parameters, and can, thus, directly show the impact of a changing climate for plant species and ecosystems in the midlatitudes. Very precise long-term observations of Swiss observers reaching back to the 1700s offer the unique possibility to establish one of the longest and most significant phenological time series in the world.
The proposed project focuses on the impact of changing large-scale climate on plants and aims at addressing the following scientific questions:
- How did past climate determine the beginning of the growing season North of the Alps?
- What are the main climatic factors determining the phenological phases in Switzerland within the 20th century?
- How does the beginning of the growing season change in the 21st century under the expected continental warming?
[Summary of the Project Proposal]

See Publications for results of the project