Niche Overlap in Forest Tree Species Precludes a Positive Diversity-Productivity Relationship

Area of Science:

• Ecology
• Forestry
• Plant Science

Background:

• Niche complementarity is a key theory explaining overyielding in diverse ecosystems.
• Resource use efficiency and reduced competition are proposed mechanisms for niche complementarity.

Purpose of the Study:

• To investigate the drivers of overyielding in tree species mixtures.
• To determine if niche overlap or niche complementarity explains the observed lack of overyielding.

Main Methods:

• Experimental planting to assess productivity and species diversity.
• Analysis of Forest Inventory and Analysis data for natural species co-occurrence.
• Comparison of functional traits across species in multi-dimensional trait space.

Main Results:

• No significant relationship was found between species diversity and productivity (leaf, wood, root).
• Species showed no significant co-occurrence patterns in natural stands.
• Species exhibited no significant differences in multi-dimensional trait space.

Conclusions:

• Niche overlap is the most probable cause for the lack of overyielding.
• The findings suggest niche overlap precludes coexistence and positive diversity-productivity relationships in these tree species.