Effects of Soil Physico-Chemical Properties on Plant Species Diversity Along an Elevation Gradient Over Alpine Grassland on the Qinghai-Tibetan Plateau, China.

Wangya Han,Guohua Liu,Tao Li,Songlin Shi,Dan Liu,Xukun Su,Tiantian Jin,Li Chen

doi:10.3389/fpls.2022.822268

Abstract

Elevation gradient can reflect the effects of soil physico-chemical properties on plant species diversity. Alpine grassland on the QTP has suffered from a serious decline in plant species diversity. In this study, we investigated 112 sites recording plant community characteristics and collecting soil samples along an elevation gradient (3,500–5,200 m asl) in alpine meadow on the QTP. We analyzed the effects of soil physico-chemical properties on plant species composition and diversity by canonical ordination and spatial regression along an elevation gradient. The results showed that species richness of the overall plant communities decreased with the increasing elevation, and the Simpson dissimilarity index (βsim) had a maximum at low elevation (3,500–4,000 m) with the value of 0.37. Soil available nitrogen content was the primary soil parameter affecting plant species composition and diversity in alpine grassland. The effect of soil available nitrogen content on plant species richness varied at different elevations. For Gramineae plants (G), plant species richness declined with the increase in soil available nitrogen content at low elevation (3,500–4,000 m), but rose at middle elevation (4,000–4,500 m). Soil available nitrogen content had a more significant limiting effect on species richness at high elevation (>4,500 m). These findings increase our understanding about the drivers of plant species diversity changes in alpine grassland on the QTP, and will provide insights into grassland restoration and sustainable management.

Highlights

Plant species diversity is the crucial factor that has important impact on plant community structure and types, focusing on species coexistence in alpine grassland ecosystem (Xu et al, 2011; Dong et al, 2019)
Kobresia pygmaea + miscellaneous plants (KpM), Carex moorcroftii (Cm), and M were dominated by the Cyperaceae; the Cyperaceae and Compositae proportions were similar for Kobresia setchwanensis (Ks); and Gramineae (22.66%) was predominant in G
For Kobresia pygmaea (Kp) and KpM, the Compositae proportions decreased as elevation increased, but the Compositae proportion in Cm obviously increased with an average growth rate of 30.44%

Summary

Introduction

Plant species diversity is the crucial factor that has important impact on plant community structure and types, focusing on species coexistence in alpine grassland ecosystem (Xu et al, 2011; Dong et al, 2019). Some studies have documented that plant species diversity is affected by environmental parameters, such as temperature, humidity, solar radiation, and soil nutrients (Dong et al, 2019). A series of studies have analyzed the relationship between plant species diversity and environmental parameters. The relationships between plant species diversity and soil physicochemical properties have been analyzed in terms of topographic parameters (Li X. et al, 2018), such as geological structure and lithology (Do Carmo and Jacobi, 2016; Hanaka et al, 2019). The elevation gradient plays an important role in exploring how species diversity affected by environmental parameters (Supriya et al, 2019; Lai et al, 2021). The community dissimilarity can be quantified by β-diversity (Haider et al, 2018), so the diversity variation should be carried out combining both α-diversity and β-diversity of plant communities

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Discussion

Conclusion