Plant size: a key determinant of diversification?

Area of Science:

• Evolutionary Biology
• Botany
• Ecology

Background:

• Explaining diversification rates in plants is a key botanical goal.
• Previous theories focused on complex extrinsic and intrinsic factors.
• Plant height, a simple trait, has been overlooked in diversification theories.

Purpose of the Study:

• To investigate the impact of plant size on plant diversification rates.
• To propose that decreasing plant size increases speciation and decreases extinction.
• To provide a new perspective on plant speciation theory.

Main Methods:

• Theoretical arguments linking plant size to population genetic processes.
• Empirical analysis of plant height and net diversification rates.
• Examining correlates of plant size such as dispersal, population size, and generation time.

Main Results:

• Plant height is negatively correlated with net diversification rate in angiosperm families.
• Theoretical links between plant size and speciation/extinction drivers confirmed.
• Evidence supports the hypothesis that smaller plant size promotes diversification.

Conclusions:

• Plant height is a significant, yet neglected, factor in plant diversification.
• Decreasing plant size generally leads to increased speciation and decreased extinction.
• Future research should test this hypothesis at micro- and macroevolutionary scales.