Species Diversity Regulates Ecological Strategy Spectra of Forest Vegetation Across Different Climatic Zones.

Xin Han,Runguo Zang,Yue Xu,Jihong Huang

doi:10.3389/fpls.2022.807369

Abstract

Ecological strategy is the tactics employed by species in adapting to abiotic and biotic conditions. The ecological strategy spectrum is defined as the relative proportion of species in different ecological strategy types within a community. Determinants of ecological strategy spectrum of plant community explored by most previous studies are about abiotic factors. Yet, the roles of biotic factors in driving variations of ecological strategy spectra of forest communities across different geographic regions remains unknown. In this study, we established 200 0.04-ha forest dynamics plots (FDPs) and measured three-leaf functional traits of tree and shrub species in four forest vegetation types across four climatic zones. Based on Grime’s competitor, stress-tolerator, ruderal (CSR) triangular framework, and the StrateFy method, we categorized species into four ecological strategy groups (i.e., C-, S-, Int-, and R-groups) and related the ecological spectra of the forests to three species diversity indices [i.e., species richness, Shannon-Wiener index, and stem density (stem abundance)]. Linear regression, redundancy analysis, and variance partition analysis were utilized for assessing the roles of species diversity in regulating ecological strategy spectra of forest communities across different climatic zones. We found that the proportion of species in the C- and Int-groups increased, while the proportion of species in the S-group decreased, with the increase of three indices of species diversity. Among the three species diversity indices, stem abundance played the most important role in driving variations in ecological strategy spectra of forests across different climatic zones. Our finding highlights the necessity of accounting for biotic factors, especially stem abundance, in modeling or predicting the geographical distributions of plant species with varied ecological adaptation strategies to future environmental changes.

Highlights

One of the challenges in ecological research is how to accurately predict future environmental changes on the abundances and spatial distributions of species, and the geographical patterns of biodiversity in the future (Cardinale et al, 2012; Urban et al, 2016)
Finding the likely driving factors of these changes is helpful in predicting the responses of species populations or biotic communities and in designing mitigation strategies to reduce the harmful effects of environmental change and human activities
Our objectives were to assess how species diversity impacted the variation of the ecological strategy spectra among different forest types by (1) assigning each species included in our data set into the CSR triangle to quantify the proportions of species in C, S, Int, and R-strategy group (R-group) in each forest type and identify the ecological strategy spectra of forests across different climatic zones; (2) exploring the associations between the proportions of C-strategists, S-strategists, Int-strategists, and R-strategists with each species diversity index; and (3) assessing the relative importance of the three selected species diversity indices in regulating ecological strategy spectra of forests across different climatic zones

Summary

Introduction

One of the challenges in ecological research is how to accurately predict future environmental changes on the abundances and spatial distributions of species, and the geographical patterns of biodiversity in the future (Cardinale et al, 2012; Urban et al, 2016). Similar to a lifeform spectrum (Raunkiaer, 1934), it summarizes the enormous complexity of species with diverse ecological strategies into a few general recurrent groups. It can reflect combinations of species’ adaptation tactics coping with specific environmental conditions, which can provide an effective way for comparing how species composition of vegetation differs in their spatial distributions across different biogeographic regions and for detecting the key drivers of these differences. Exploring the impacts of biotic factors on ecological strategy spectra of forests can further enhance our understanding of the population adaptation performance of plant species and the resultant community features and improve our ability in predicting species responses to environmental changes

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Discussion

Conclusion