Among the multiple ecological processes that determine species coexistence and community dynamics, conspecific negative density dependence (CNDD) and niche partitioning are perhaps among the most important. However, the relative strength of these mechanisms may change across life stages and depend on species ecological strategies. We used a dataset that includes information on stage-specific functional traits and a long-term, spatially explicit data of plant survival including 7971 individuals and 41 species monitored for seedling and adult life stages to examine the relative role of these mechanisms influencing individual survival across ontogenetic stages in a 9-ha temperate forest plot in China.
Results/Conclusions
Our results showed that for seedlings, CNDD became weaker for species with larger leaf area, while for adults, the conspecific neighbors had a positive effect on survival and this effect became stronger with decreasing seed mass. Also, the results examing the effects of neighboring heterospecifics suggest a prevalence of niche partitioning at the seedling stage but a prevalence of environmental filtering or hierarchical competition for adult stage. In particular, the strength of these processes at adult life stage increased with higher maximum height and smaller specific leaf area species. Finally, we did not find any significant direct effect of traits on individual survival for seedling and adult life stages. Overall, our results demonstrates that the ecological processes tend to have a stronger diversifying effect for seedlings than for adults and these effects depends on stage-specific species traits. Considering trait variation and their interacting effects with biotic and abiotic factors across life stages provides further insights into ecological mechanisms shaping plant community assembly and driving its dynamics.