Putting seedlings on the map: Trade‐offs in demographic rates between ontogenetic size classes in five tropical forests

BACKGROUND:

The study examines tropical forests in regions such as Panama, Puerto Rico, Malaysia, Taiwan, and Ecuador, which are characterized by their high biodiversity and significant environmental challenges like cyclonic storms. These forests are ideal for investigating demographic trade-offs due to their diverse coexisting tree species that align along growth, survival, and stature recruitment axes. The forests have experienced varying levels of disturbance from natural events, making them unique examples for studying tree species’ life-history strategies and the mechanisms that facilitate species coexistence.

GOALS AND METHODS:

The study aims to explore demographic trade-offs among tropical tree species across different ontogenetic stages to understand life-history strategies and species coexistence mechanisms. The authors compile seed, seedling, and tree census data from five tropical forests in Asia and America, applying principal components and correlation analyses to identify and quantify growth-survival and stature-recruitment trade-offs. The paper investigates how seedling growth and survival rates relate to larger tree demographic rates and the predictive power of key functional traits such as maximum diameter at breast height, wood density, seed mass, and specific leaf area for positioning species along these demographic trade-off gradients.

CONCLUSIONS AND TAKEAWAYS:

The study concludes that demographic trade-offs significantly influence life-history strategies across different developmental stages of tropical tree species. In four out of five examined forests, the growth-survival trade-off was predominant, confirming that species investing in faster growth generally achieve lower survival rates, and vice versa. The research further identifies an ontogenetic dimension of life-history variation, suggesting that species prioritize growth and survival at the seedling stage differently compared to larger size classes, which contributes to species coexistence in diverse plant communities.