Species Identity and Initial Size Rather Than Neighborhood Interactions Influence Survival in a Response-Surface Examination of Competition

Abstract

To measure intraspecific and interspecific interaction coefficients among tree species is the key to explore the underlying mechanisms for species coexistence and biodiversity maintenance in forests. Through the response surface experimental design, we established a long-term field experiment by planting 27,300 seedlings of four tree species (Erythrophleum fordii, Pinus massoniana, Castanopsis fissa, and Castanopsis carlesii) in 504 plots in different species combinations (six pairwise combinations of four species), abundance proportions (five abundance proportions of two species, i.e. A: B = 1:0, 3:1, 1:1, 1:3, 0:1), and stand densities (25, 36, 64, and 100 seedlings per plot). In this initial report, we aimed to quantify the relative importance of biotic and abiotic factors on seedling survival at the early stage of growth, which is a critical period for seedling establishment. We found that plot-level seedling survival rate was determined by species combination and their abundance proportion rather than stand density. At the individual level, individual survival probability was mainly explained by species identity, initial seedling size, and soil conditions rather than neighborhood competition. Our study highlights that the seedling intrinsic properties may be the key factors in determining seedling survival rate, while neighborhood effects were not yet prominent at the seedling life stage.

Diversity stabilizes but does not increase sapling survival in a tree diversity experiment

“…However, both factors explained only a tiny fraction of the variation in survival relative to the amount explained by species identity alone. This contrasts with other studies of tree survival that have found that site conditions like slope, elevation, distance to forest edge, and soil conditions impact survival (Shen et al 2020;Wang et al 2022). However, the variation in elevation (from 5 to 25 m) at our site is much smaller than in previous studies with a significant elevation effect.…”

“…Instead, species identity was the variable that explained most variation in survival across all models, similar to other tree diversity experiments (Potvin & Gotelli 2008;Philipson et al 2014;Shen et al 2020). The substantial range in mortality rates among individual species in our study adds to the body of evidence that individual characteristics are more important determinants of sapling survival than neighborhood diversity (Philipson et al 2014;Shen et al 2020). Our study also went beyond some previous work to evaluate functional and phylogenetic diversity impacts on survival, but we still found no evidence that diversity impacts survival.…”

“…We initially hypothesized that increased diversity at either the plot or neighborhood level would result in greater survival, yet no diversity metric had a significant impact on survival odds. Instead, species identity was the variable that explained most variation in survival across all models, similar to other tree diversity experiments (Potvin & Gotelli 2008;Philipson et al 2014;Shen et al 2020). The substantial range in mortality rates among individual species in our study adds to the body of evidence that individual characteristics are more important determinants of sapling survival than neighborhood diversity (Philipson et al 2014;Shen et al 2020).…”

Biodiversity effects on seedling biomass growth are modulated by light environment across functional groups

“…Pretzsch et al, 2015; Sapijanskas et al, 2013; Van de Peer et al, 2018). Beyond species richness, species functional composition influenced the survival and growth of communities (Fig S1, Fig S2) (Potvin & Gotelli, 2008; Salisbury & Potvin, 2015; Shen et al, 2020; Yang et al, 2013). However, despite considerable differences in growth rates among experimental species, inclusion of fast-growing species alone did not explain the observed increase in biomass in high-diversity treatments (Fig 3).…”

Review on Factors Affecting Early Survival of Tree /Shrub Seedlings and it’s Remedy in Restoration Sites of Ethiopia

“…The intrinsic properties of the seedling, such as species identity and initial seedling size, may be the key factors in determining the seedling survival rate in the field (Shen et al, 2020). Gardiner et al (2019), indicates that planting seedlings between 25 and 35 cm tall will increase the early survival and growth rate of the seedlings in restoration projects in degraded areas.…”