Can niche plasticity promote biodiversity-productivity relationships through increased complementarity?

Area of Science:

• Ecology
• Forestry
• Plant Ecology

Background:

• Most biodiversity-ecosystem functioning research focuses on herbaceous plants.
• Forests are crucial for global biogeochemical cycles, yet their response to species loss is understudied.

Purpose of the Study:

• To investigate the effects of tree species richness on aboveground productivity and biomass allocation in experimental subtropical forests.
• To analyze the role of vertical leaf and wood distribution and interspecific competition in driving biodiversity-ecosystem functioning relationships.

Main Methods:

• Experimental design with 33 tree species mixtures (1, 2, or 4 species) under natural light or shade.
• Measurement of aboveground biomass, vertical distribution of leaves and wood, and decomposition of biodiversity effects using additive partitioning.
• Analysis of competition-driven phenotypic plasticity and functional traits using structural equation models.

Main Results:

• Aboveground productivity increased with species richness.
• Community-level vertical leaf and wood distribution depended on species composition, with mixtures outperforming monocultures when vertical leaf distributions differed.
• Positive complementarity effects were higher in light than shade; selection effects were negligible.
• Interspecific niche complementarity, enhanced by architectural plasticity and differing growth strategies, promoted productivity in mixed stands.

Conclusions:

• Species richness enhances forest productivity through interspecific niche complementarity, particularly at early stand development stages.
• Vertical stratification of leaf biomass and competition-driven plasticity are key mechanisms promoting complementarity.
• Understanding these dynamics is crucial for predicting forest responses to biodiversity changes and for forest management.