讲座题目：Neighborhood crowding links statistical models of tree growth and survival with individual-based models to understand the tree size distribution and forest dynamics
主讲人：Thorsten Wiegand 教授
主持人：沈国春 教授
开始时间：2025-09-16 09:00
讲座地址：闵行校区资源与环境大楼148
主办单位：生态与环境科学学院
报告人简介：
Thorsten’s research centers on spatial ecology and the role of species interactions, spatial processes and structures for population and community dynamics and biodiversity. He was PI of the ERC advanced grant SpatioDiversity (Towards a Unified Spatial Theory of Biodiversity) and is PI of the ERC advanced grant SpatioCoexistence (Towards a Spatial Theory for Species-Rich Communities). He authored the handbook of spatial point pattern analysis in ecology, programmed the software Programita to be used for spatial analyses, and has also extensive expertise in spatially-explicit multispecies individual-based models (IBMs).
报告内容：
Forests are well-studied ecosystems, yet the mechanistic links among their structural features remain unclear. Tree diameter distributions have long been used in ecology and forestry to characterize forests, as they, combined with tree allometries, help predict attributes such as leaf area, biomass, and tree density, as well as signs of disturbance. However, the connections between diameter distributions, tree growth, and competition still need deeper understanding. We aim to identify the simplest mechanisms that recreate observed diameter size distributions in ForestGEO plots and to compare these mechanisms across forests. We apply an individual-based model that simulates larger trees, where growth and survival depend on species interactions represented by neighborhood crowding, with growth modeled as a power law of size and crowding. We parameterized our model to match observed data from the tropical forest in Barro Colorado Island, Panama, and the temperate Changbaishan plot in China. The tree diameter distributions converged during our model simulations quickly into a steady state and matched the observed distributions and several other neighborhood spatial patterns. To our surprise, we found that species interactions (i.e., neighborhood crowding) drive only tree growth, but not mortality, which is basically a constant but size-dependent rate. Our results suggest that simple mechanisms may underlie the complex spatial structure and dynamics of plant communities.
