Designing forest biodiversity experiments: general considerations illustrated by a new large experiment in subtropical China

Helge Bruelheide*, Karin Nadrowski, Thorsten Assmann, Juergen Bauhus, Sabine Both, Francois Buscot, Xiao-Yong Chen, Bingyang Ding, Walter Durka, Alexandra Erfmeier, Jessica L. M. Gutknecht, Dali Guo, Liang-Dong Guo, Werner Haerdtle, Jin-Sheng He, Alexandra-Maria Klein, Peter Kuehn, Yu Liang, Xiaojuan Liu, Stefan MichalskiPascal A. Niklaus, Kequan Pei, Michael Scherer-Lorenzen, Thomas Scholten, Andreas Schuldt, Gunnar Seidler, Stefan Trogisch, Goddert von Oheimb, Erik Welk, Christian Wirth, Tesfaye Wubet, Xuefei Yang, Mingjian Yu, Shouren Zhang, Hongzhang Zhou, Markus Fischer, Keping Ma, Bernhard Schmid

*Corresponding author for this work

Research output: Contribution to journalArticle

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Abstract

1. Biodiversity-ecosystem functioning (BEF) experiments address ecosystem-level consequences of species loss by comparing communities of high species richness with communities from which species have been gradually eliminated. BEF experiments originally started with microcosms in the laboratory and with grassland ecosystems. A new frontier in experimental BEF research is manipulating tree diversity in forest ecosystems, compelling researchers to think big and comprehensively.

2. We present and discuss some of the major issues to be considered in the design of BEF experiments with trees and illustrate these with a new forest biodiversity experiment established in subtropical China (Xingangshan, Jiangxi Province) in 2009/2010. Using a pool of 40 tree species, extinction scenarios were simulated with tree richness levels of 1, 2, 4, 8 and 16 species on a total of 566 plots of 25.8x25.8m each.

3. The goal of this experiment is to estimate effects of tree and shrub species richness on carbon storage and soil erosion; therefore, the experiment was established on sloped terrain. The following important design choices were made: (i) establishing many small rather than fewer larger plots, (ii) using high planting density and random mixing of species rather than lower planting density and patchwise mixing of species, (iii) establishing a map of the initial ecoscape' to characterize site heterogeneity before the onset of biodiversity effects and (iv) manipulating tree species richness not only in random but also in trait-oriented extinction scenarios.

4. Data management and analysis are particularly challenging in BEF experiments with their hierarchical designs nesting individuals within-species populations within plots within-species compositions. Statistical analysis best proceeds by partitioning these random terms into fixed-term contrasts, for example, species composition into contrasts for species richness and the presence of particular functional groups, which can then be tested against the remaining random variation among compositions.

5. We conclude that forest BEF experiments provide exciting and timely research options. They especially require careful thinking to allow multiple disciplines to measure and analyse data jointly and effectively. Achieving specific research goals and synergy with previous experiments involves trade-offs between different designs and requires manifold design decisions.

Original languageEnglish
Pages (from-to)74-89
Number of pages16
JournalMethods in Ecology and Evolution
Volume5
Issue number1
Early online date22 Nov 2013
DOIs
Publication statusPublished - Jan 2014

Keywords

  • BEF-China
  • ecoscape
  • genetic diversity
  • planting pattern
  • random partitions design
  • species richness
  • trait-oriented extinction sequence
  • experimental grassland communities
  • ecological field experiments
  • leaf economics spectrum
  • plant-species richness
  • ecosystem services
  • environmental heterogeneity
  • limiting similarity
  • tree plantation
  • central-Europe
  • diversity

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