Title of symposium:
Tropical tree life-history strategies: Causes and consequences of demographic diversity

Principal Organizer:
Nadja Rüger
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Germany,

Sean McMahon
Smithsonian Environmental Research Center (SERC), Maryland, USA

Symposium summary:
A major challenge to understanding tropical forest dynamics is identifying how numerous tree species differ and how they are similar in their life history strategies. Life-history strategies describe the way tree species have evolved to maximize fitness through different approaches to survival, growth, reproduction, and dispersal. These strategies balance trade-offs in allocation of resources to gain advantages in the face of challenges such as competition, disturbances, or natural enemies. Identifying life-history strategies and what their consequences are at the community level is critical to better understanding the evolution and maintenance of tropical forest diversity as well as predicting the future of these communities.
During the last decades, long-term forest monitoring plots have accumulated extensive data on the demography of tropical forest tree species, demonstrating life-history trade-offs, such as the growth-survival trade-off or the tolerance-fecundity trade-off. Features of these allocation strategies have also been linked to commonly collected functional traits. However, we are lacking a comprehensive understanding of tropical tree life-histories, their links to allocation strategies and functional traits as well as their consequences for species coexistence, forest dynamics, or ecosystem functions. The goal of this symposium is to synthesize knowledge on all aspects of life-history strategies. We bring together a diverse range of scientists to discuss the causes and consequences of ecological strategies of tropical trees, to identify critical questions, novel theories, and knowledge gaps. Contributions cover insights from empirical studies, mechanistic allocation models, and demography-based models.

List of speakers and presentation titles:

  1. Introduction by Sean McMahon and Nadja Rüger
  2. Stefan Kupers (German Centre for Integrative Biodiversity Research (iDiv), Germany), “Tropical tree seedlings trade off shade and drought tolerance: a demographic approach”
  3. Sophie Faucet (University of Leeds, UK), “Differences in leaf thermoregulation and water-use strategies between two co-occurring Atlantic forest tree species”
  4. Caicai Zhang (Xishuangbanna Tropical Botanical Garden, China), “Weak functional and environmental determinants of the growth-mortality trade-off among seedlings of 15 tropical woody species”
  5. Liza Comita (Yale University, USA), “Growth-mortality trade-offs influence conspecific density dependence across multiple life stages”
  6. Meghna Krishnadas (Yale University, USA), “Functional traits explain interspecific differences in seedling recruitment in relation to edge-effects and natural enemy activity”
  7. Chia-Hao Chang-Yang (National Taiwan University, Taiwan), “Diversity takes time: Temporal dynamics of seedling demography in a subtropical rain forest”
  8. Kaoru Kitajima (Kiyoto University, Japan), “Nutrient allocation to seed and life history strategies of tropical trees”
  9. Break
  10. Frank Sterck (Wageningen University, Netherlands), “Understanding the growth of trees and lianas from underlying carbon and water balances and functional plant traits”
  11. Nadja Rüger (German Centre for Integrative Biodiversity Research (iDiv), Germany), “Demographic trade-offs promote coexistence of tropical tree species”
  12. María Uriarte (Columbia University, USA), “Natural disturbance and tree life histories”
  13. Vanessa Rubio Ramos (University of Maryland, USA), “Functional traits, guilds, and the dynamics of tropical forests”
  14. Jessica Needham (SERC, USA), “Beyond the slow fast continuum: A global analysis of demographic rates in forest trees”
  15. Sabrina Russo (University of Nebraska, USA), “Global patterns in the slow-fast continuum of tropical tree demography: the roles of tolerance and responsiveness”
  16. NN
  17. Panel discussion on ‘ways forward’ and/or the potential for synthesis