In this new post Caicai Zhang, from Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, and the Institute of Eastern-Himalaya Biodiversity Research at Dali University, shares insights from her recently published paper, ‘Functional traits and ecological niches as correlates of the interspecific growth–mortality trade-off among seedlings of 14 tropical tree species‘. She emphasizes the importance of biomass allocation traits, particularly specific stem length (SSL) and soil-defined ecological niche determinants of the growth-mortality trade-off among seedlings of dominant tropical tree species. Additionally, she shares her research experiences and encourages young colleagues to love and keep exploring the forest.
About the paper
The trade-off between growth and mortality rates among tree species has been observed in many forests across multiple tree developmental stages. This trade-off is thought to contribute to species coexistence. However, the underlying drivers of this trade-off remain poorly understood. Previous studies have tried to relate variation in functional traits and ecological niches to performance but found that both traits and niches were often not good predictors of species growth rates, mortality rates, and their trade-offs.
About the research
We investigated the putative drivers of the growth-mortality trade-off to functional traits and ecological niches for 14 tree species in a 20-ha tropical forest in southwest China. We found evidence for an interspecific growth-mortality trade-off at the seedling stage. This trade-off was not cor with organ-level functional traits, instead, it was strongly to biomass allocation traits (specific stem length, leaf mass fraction, leaf area ratio and stem mass fraction). Specifically, SSL was a significant trait, representing the seedling height growth achieved per unit mass invested in the stem.
This highlights the importance of SSL for seedlings in deeply shaded understories of closed-canopy forests with low disturbance rates. Furthermore, we found that soil-defined niches (soil bulk density, soil organic matter content, soil total nitrogen and slope) were cor with growth, mortality, and their trade-off, rather than light-defined niches. This indicates that soil fertility also plays a crucial role in determining the seedling demographic trade-offs in tropical forests.
About the author
I obtained my PhD degree from the Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences in 2018, under the supervision of Professor Min Cao and Professor Luxiang Lin. I am very grateful for the excellent research environment they provided, and their dedication to their work has always inspired me. In 2017, with funding from the National Natural Science Foundation of China, I studied for a year at the University of Nebraska as a joint PhD student under the supervision of Professor Sabrina E. Russo. She is my role model, I admired her for her lifelong dedication to ecological research and her patience and kindness with students. After graduating, I joined the Institute of Eastern-Himalaya Biodiversity Research at Dali University because I believe Yunnan is a paradise for plant research. Currently, I am primarily studying species diversity patterns and community assembly in the 20-ha semi-humid evergreen broad-leaved forest dynamics plot and the 20-ha subalpine cold-temperate coniferous forest dynamics plot in Yunnan. I hope to uncover and share more fascinating scientific stories from these forests.
Like the blog post? Read the research here.
