Globally, tree fecundity exceeds productivity gradients

Area of Science:

• Ecology
• Global Change Biology
• Forest Science

Background:

• Understanding global variation in forest regeneration and biodiversity requires data on tree fecundity across climatic gradients.
• Seed supply is a critical, yet understudied, factor influencing ecological dynamics and species interactions.

Discussion:

• A global synthesis of seed production data reveals a 250-fold increase from cold-dry to warm-wet climates.
• This increase is primarily driven by a 100-fold rise in seed production per tree, not forest productivity.
• This suggests adaptive evolution from species interactions or direct climatic effects on tree reproduction.

Key Insights:

• Seed abundance is strongly correlated with climate, with warm-wet regions exhibiting significantly higher seed production.
• Tree size-specific seed output escalates dramatically with increasing temperature and moisture.
• The findings challenge the assumption that forest productivity alone drives reproductive output.

Outlook:

• Investigating the evolutionary and physiological mechanisms behind increased fecundity in tropical forests is crucial.
• The massive variation in seed supply likely has profound, cascading effects on food webs and tropical biodiversity.
• Future research should integrate seed production dynamics into models of forest regeneration and ecosystem function.