Plant functional traits explain species abundance patterns and strategies shifts among saplings and adult trees in Araucaria forests

Aim: Maximum entropy (MaxEnt) models promise a novel approach for understanding community assembly and species abundance patterns. One of these models, the "Maximum Entropy Theory of Ecology" (METE) reproduces many observed species abundance patterns, but is based on an aggregated representation of community structure that does not resolve species identity or explicitly represent species-specific functional traits. In this paper, METE is compared to "Very Entropic Growth" (VEG), a MaxEnt model with a less aggregated representation of community structure that represents species (more correctly, functional types) in terms of their per capita metabolic rates. We examine the contribution of metabolic traits to the patterns of community assembly predicted by VEG and, through aggregation, compare the results with METE predictions in order to gain insight into the biological factors underlying observed patterns of community assembly. Innovation: We formally compare two MaxEnt-based community models, METE and VEG, that differ as to whether or not they represent species-specific functional traits. We empirically test and compare the metabolic predictions of both models, thereby elucidating the role of metabolic traits in patterns of community assembly. Main Conclusions: Our analysis reveals that a key determinant of community metabolic patterns is the "density of species" distribution, defined as the intrinsic number of species with metabolic rates in a given range that are available to a community prior to filtering by environmental constraints. Our analysis suggests that appropriate choice of of the density of species in VEG may lead to more realistic predictions than METE, for which this distribution is not defined, and thus opens up new ways to understanding the link between functional traits and patterns of community assembly.

Download Full-text

The Influences of Disturbance Histories and Soil Properties on Aboveground Biomass through Plant Functional Traits in a Tropical Rainforest

Forests ◽

10.3390/f10090774 ◽

2019 ◽

Vol 10 (9) ◽

pp. 774 ◽

Cited By ~ 1

Author(s):

Wensheng Bu ◽

Cancan Zhang ◽

Jihong Huang ◽

Runguo Zang ◽

Yi Ding ◽

...

Keyword(s):

Environmental Factors ◽

Soil Properties ◽

Functional Traits ◽

Environmental Conditions ◽

Aboveground Biomass ◽

Ecosystem Functioning ◽

Plant Functional Traits ◽

Old Growth ◽

Adult Trees ◽

Adult Tree

Research Highlights: We try to evaluate the relative contribution of environmental factors and functional traits on aboveground biomass in a species rich tropical forest ecosystem after a 40-years natural recovery. Background and Objectives: Functional traits have a potential to incorporate community dynamics into the impacts of disturbance histories or environmental conditions on ecosystem functioning, but few studies have been conducted to understand these processes. Materials and Methods: We measured plant functional traits and soil properties in the tropical montane rainforests on Hainan Island, China, which had experienced different disturbance histories (clear cutting, selective logging, and old-growth) 40 years ago. A structural equation model was used to elucidate how disturbance histories and soil factors influence aboveground biomass (AGB) across different size classes (saplings, treelets, and adult trees) through plant functional traits. Results: The results demonstrated logging stimulated seedling establishment but decreased AGB of adult trees and wood density at community-level (CWM_WD) of sapling and adult tree. Generally, CWM_WD of sapling, treelet, and adult tree decreased linearly with the increasing of specific leaf area at community-level (CWM_SLA) in old-growth forest and these two disturbed forests. Moreover, CWM_SLA explained more variation of CWM_WD with increasing intensity of logging within sapling, treelet, and adult tree. CWM_SLA and CWM_WD not only responded to environmental conditions and disturbance intensity but also affected AGB in all size classes; meanwhile, CWM_SLA was a major driver of AGB. CWM_SLA had a stronger effect on AGB in sapling and treelet classes than on the adult tree class. Conclusions: Our results suggested that disturbance history and environmental factors could directly or indirectly affect ecosystem functioning through plant functional traits. Functional traits always had a stronger effect on AGB than environmental conditions. Moreover, CWM_SLA is a key trait that can be used to link the relationship between environmental conditions and AGB.

Download Full-text

Species abundance is jointly determined by functional traits and negative density dependence in a subtropical forest in southern China

Journal of Plant Ecology ◽

10.1093/jpe/rtab009 ◽

2021 ◽

Author(s):

Weitao Wang ◽

Yun Jiang ◽

Buhang Li ◽

Nianxun Xi ◽

Yongfa Chen ◽

...

Keyword(s):

Density Dependence ◽

Leaf Area ◽

Functional Traits ◽

Southern China ◽

Species Abundance ◽

Plant Functional Traits ◽

Equation Modeling ◽

Dry Matter Content ◽

Combined Effects ◽

Negative Density Dependence

Abstract Aims The factors affecting species abundance are a subject of ongoing debates in community ecology. Empirical studies have demonstrated that tree abundance is affected by plant functional traits and negative density dependence (NDD). However, few studies have focused on the combined effects of negative density dependence and plant functional traits on species abundance. Methods In this study, we used tree functional traits and two census data from a 50-ha forest dynamic plot in the Heishiding (HSD) Nature Reserve to explore the combined effects of functional traits and NDD on species abundance. Using hierarchical Bayesian models, we analyzed how neighbor densities affected the survival of saplings from 130 species and extracted posterior means of the coefficients to represent NDD. The structural equation modeling (SEM) analysis was then applied to investigate the causal relationships among species functional traits, negative density dependence, and species abundance. Important findings SEM showed that tree functional traits, including specific leaf area (SLA), leaf area (LA), leaf dry matter content (LDMC), leaf N content (LNC), maximum electron transport rate (ETRmax), and conspecific adult negative density dependence (CNDDadult), together explained 20% of the total variation in tree abundance. Specifically, SLA affected tree abundance both directly and indirectly via CNDDadult, with a totally negative influence on abundance. LDMC and LNC had only indirect effects mediated by CNDDadult on tree abundance. ETRmax and LA had directly negative effects on abundance, but their direct connections with CNDDadult were not observed. In addition, CNDDadult was negatively correlated with species abundance, indicating that abundant species are under stronger negative density dependence. Among these investigated traits, SLA contributed the most to the variation in CNDDadult and abundance. We argued that our findings of trait-CNDDadult-abundance relationships can improve our understanding of the determinants of species commonness and rarity in forests.

Download Full-text