Fruit Size in Indo-Malayan Island Plants Is More Strongly Influenced by Filtering than by In Situ Evolution

Area of Science:

• Ecology
• Evolutionary Biology
• Biogeography

Background:

• Community trait assembly involves filtering from regional pools and local evolution.
• The relative importance of these processes is difficult to ascertain due to challenges in dating evolutionary and dispersal events.

Purpose of the Study:

• To investigate the roles of filtering and in situ evolution in shaping plant community trait distributions.
• To assess evolutionary and biogeographic transitions in woody plant species within the Indo-Malay archipelago.

Main Methods:

• Phylogenetic analysis of woody plant species across the Indo-Malay archipelago.
• Comparison of fruit size distributions between island communities and the regional source pool.
• Analysis of the timing of evolutionary trait changes relative to dispersal events.

Main Results:

• Fruit size in 2,650 angiosperm taxa was smaller in Sulawesi and Maluku island groups compared to the regional pool.
• Smaller-fruited lineages were disproportionately represented among island colonists.
• Most evolutionary shifts to smaller fruit size occurred prior to island colonization.

Conclusions:

• Filtering of traits from the regional pool plays a larger role than local evolution in determining island community trait distributions.
• Biotic interactions, such as seed disperser and predator assemblages, may influence filtering processes.