Abstract
Seedlings are vulnerable to many biotic and abiotic agents, and studying seedling dynamics helps understand mechanisms of species coexistence. In this study, the relative importance of biotic neighbors and habitat heterogeneity to seedling survival was examined by generalized linear mixed models for 33 species in a spruce‐fir valley forest in northeastern China. The results showed that the relative importance of these factors varied with species and functional groups. Conspecific negative density dependence (CNDD) was important to the survival of Abies nephrolepis and Picea koraiensis seedling, whereas phylogenetic negative density dependence (PNDD) was critical to Pinus koraiensis and Betula platyphylla, as well as functional groups of tree, deciduous, and shade‐intolerant seedlings. For shrubs and Acer ukurunduense, habitat heterogeneity was significant. Despite of the significance of CNDD, PNDD, and habitat heterogeneity on seedling survival, large proportions of the total variance were not accounted for by the studied variables, suggesting the needs to examine the influences of other factors such as pests, diseases, herbivores, forest structure, species functional traits, and microclimatic conditions on seedling survival in the future.
Highlights
Understanding the mechanisms of the maintenance of diversity in plant communities and their relative importance remains a major challenge for ecologists
Some recent studies have found that neighbors that are more closely phylogenetically related to a focal individual have a stronger negative impact on focal plant survival, a phenomenon called phylogenetic negative density dependence (PNDD; Liu et al, 2012; Paine et al, 2012; Zhu, Comita, Hubbell, Ma, & Shefferson, 2015), which can be seen as an extension of Conspecific negative density dependence (CNDD) across evolutionary distance between two neighboring species (Liu et al, 2012; Metz et al, 2010; Webb et al, 2006)
The seedling survival of A. nephrolepis species increased with heterospecific seedling density, conspecific adult tree density, and elevation (Figure 6a), while that, for P. koraiensis decreased with conspecific seedling density and
Summary
Understanding the mechanisms of the maintenance of diversity in plant communities and their relative importance remains a major challenge for ecologists. Some recent studies have found that neighbors that are more closely phylogenetically related to a focal individual have a stronger negative impact on focal plant survival, a phenomenon called phylogenetic negative density dependence (PNDD; Liu et al, 2012; Paine et al, 2012; Zhu, Comita, Hubbell, Ma, & Shefferson, 2015), which can be seen as an extension of CNDD across evolutionary distance between two neighboring species (Liu et al, 2012; Metz et al, 2010; Webb et al, 2006). Seedlings may suffer more from NDD effects and abiotic factors (Wright, 2002); it is essential to explore the process of maintaining diversity and species coexistence in the early stages of plant communities. Our specific questions are as follows: CNDD or PNDD higher for trees than for shrubs, for deciduous trees than for evergreen trees, and for shade-intolerant trees than for shade-tolerant trees?
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
