Biogeographic processes underlying global patterns of plant diversity.

Area of Science:

• Biogeography
• Evolutionary Biology
• Ecology

Background:

• The uneven global distribution of plant species is a long-standing puzzle in biogeography.
• Understanding the processes shaping biodiversity patterns is crucial for conservation efforts.

Purpose of the Study:

• To investigate the primary drivers of extant plant diversity across global realms.
• To quantify the relative contributions of speciation, dispersal, and extinction to biogeographic patterns.

Main Methods:

• Utilized dated phylogenies for over 300,000 plant species.
• Employed ancestral biogeographical stochastic mapping to reconstruct historical events.
• Analyzed biogeographic events across different global realms.

Main Results:

• In situ speciation is the predominant process, responsible for 78% of biogeographic events.
• The Neotropics emerged as a significant center for in situ speciation (37% of events).
• Dispersal accounted for 16% of events, facilitating inter-realm floristic exchange, particularly in the Eastern Hemisphere. Extinction was least frequent but higher in East Asia.

Conclusions:

• Findings support the tropical conservatism hypothesis, suggesting many clades originated in the tropics.
• Limited time and biome conservatism in temperate zones may restrict speciation and diversity.
• The study highlights the importance of in situ speciation in generating current plant diversity patterns.