SP 2: Plant growth and demography

Individual plant growth and plant demography as a function of species richness and composition


Principal investigator(s):

Prof. Dr. Werner Härdtle (University of Lueneburg)  

Co-Principal investigator(s):

PD Dr. Goddert von Oheimb (University of Lueneburg)  

Phd candidate(s):

Ying Li (University of Lueneburg)  

Contact adress:

Institute of Ecology and Environmental Chemistry, Leuphana University Lüneburg, Scharnhorststr. 1, D-21335 Lüneburg, Germany

Summary

Spatial pattern, size and identity of plant individuals in the local neighbourhood have a significant impact on plant growth and mortality, and thus productivity. This subproject addresses the influence of species richness on aboveground plant growth and branch demography at the individual and local neighbourhood level to test the hypothesis that the diversity effect at the plot level is the overall result of the diversity effect at the local neighbourhood level.

Direct measurements of architectural traits (stem, crown, branches) of individual plants and their neighbours will be completed by three-dimensional (3-D) terrestrial laser scanning techniques. Dense 3-D point cloud images will be used to analyse the 3-D architectural traits of groups of trees and shrubs. Repeated laser scanning over time will allow for the quantification of growth and mortality.

Objectives

The general objective of this subproject is to test the hypothesis that the diversity effect at the plot level is the overall result of the diversity effects at the local neighbourhood level. The specific objectives of this subproject are:

  • (1) To quantify within-plot variation in individual-tree and –shrub growth and mortality within and among species as a function of species richness.
  • (2) To quantify local neighbourhood interactions in terms of growth rates and branch demography and to test whether diversity reduces competition.
  • (3) To evaluate the importance of phenotypic plasticity of tree and shrub individuals in relation to competition, species richness and local terrain conditions.
  • (4) To analyse soil feed-backs (mycorrhiza, pedogenetic processes, soil chemistry and nutrient cycle) on aboveground individual-tree and –shrub growth and architecture.

Chinese workers measuring height of tree saplings (A. Lang)