SP 3: Plant traits and functional diversity

Functional diversity in a subtropical forest based on anatomical and morphological species traits

Principal investigator(s):

Co-Principal investigator(s):

Phd candidate(s):

Contact adress:

Martin Luther University Halle-Wittenberg, Institute of Biology / Geobotany and Botanical Garden, Am Kirchtor 1, 06108 Halle (Saale), Germany

Summary

The main aim of BEF research is to establish links between biodiversity and ecosystem functioning. In the recent years, it has become more and more clear that accomplishing this aim will be more promising when focusing not only on species richness, but on the functional characteristics of the species in a community. In this subproject, functional traits, i.e. those characteristics that have a potential impact on ecosystem functions, are used to assess functional diversity as a composite variable that carries all the significant physiological information weighted by the abundances of these traits in the community. In the experiment with planted trees and shrubs, we can thus test the hypothesis that functionally rich mixtures have a better performance than functionally poor mixtures.

This subproject, together with its Chinese partner project of Dr. Shouren Zhang, has already compiled an extensive trait data set and is currently completing this data set for all tree and shrub species occurring in the Comparative Study Plots (CSPs) in Gutianshan (Böhnke et al. 2011, Kröber et al. 2012) as well as for those species planted in the experimental sites. The traits currently measured are phenolic and tannin contents of leaves as predictors for herbivory resistance and decomposability, stomatal conductance and plant water potentials as predictors for water use and biogeographical range characteristics as predictors for climatic tolerances. All traits traits are analysed for inter-relationships and trade-offs in the CSPs, aiming at a mechanistic understanding of subtropical forests. Knowledge on these trait-function relationships will allow to assess to which degree differences in herbivory, as a complex interplay between herbivore abundance and diversity, interact with plant species abundance, leaf palatability and other traits (Schuldt et al. 2012). The measured traits also allow to scale up the functions from the plant to the plot level. For example, transpiration measured at the individual leaf can then be translated into community water use at the level of the experimental plot. These data will contribute to a baseline knowledge of the ecosystem functioning at this early stage of the experiment, and thus contribute to the overall "ecoscape" approach in this stage of BEF-China. We hypothesize that, after a establishment period, in which abiotic environmental control effects will dominate over biotic interactions that result from diversity effects, the opposite will be the case, i.e. biotic interactions will be more important than the abiotic environment. The provision of data on this transition phase from abiotic to biotic control will be one contribution of this subproject. Further contributions are the analysis of functional traits as responses of site conditions, such as of the environmental gradient along the succession series in the CSPs and phylogenetic patterns in relation to traits and environment in the CSPs.