Grassland Degradation Decrease the Diversity of Arbuscular Mycorrhizal Fungi Species in Tibet Plateau

Xiao-Bu Cai,Tao Zhang,Yue-Lin Peng,Min-Na Yang,Qiang Zhang

doi:10.15835/nbha.42.2.9458

Abstract

Arbuscular mycorrhizal (AM) fungi play a vital role in restoration of an ecosystem. Grassland degradation in alpine steppe is severe, but the influence of grassland degradation on AM fungi composition in Tibetan Plateau is still not well understood. This research studied the diversity of arbuscular mycorrhizal fungi in degraded alpine steppe, dominated by Stipa purpurea. The results showed that the species richness and abundance of AM fungi in degraded grasslands significantly decreased. In different typical grasslands species, diversity of AM fungi genus Glomus was much higher than other genera (Acaulospora and Scutellospora). Compared with normal grassland, the AM fungal species diversity in moderately degraded grassland decreased by 30%, but in lightly degraded and severely degraded grassland, it highly increased with 15.3% and 13.3%, respectively. The species diversity of genus Glomus in moderately degraded grassland and lightly degraded grassland were higher than for normal grassland. Significant differences were observed in a relative abundance of common dominant species among different degraded grasslands. The proportion of dominant species highly increased with the aggravation of grassland degradation. The results suggest that the grassland mild degradation increased the adaptability and stress resistance of species.

Highlights

Several studies focused on Arbuscular mycorrhizal (AM) fungal species diversity in Tibetan Plateau, which includes warm steppe, alpine meadow and alpine steppe (Gao et al, 2006; Gai et al, 2009; Cai et al, 2010), and 111 species AM fungi belonging to 12 genera were observed
Species diversity of AM fungi in Tibet alpine steppe showed the trend of lightly degraded grassland > severely degraded grassland > normal grassland > moderately degraded grassland, even though it was inconsistent with other previous results, that conclude that species diversity of AM fungi decline can be caused by overgrazing (Chaudhry et al, 2005; Su and Guo, 2007; Wearn and Gange, 2007)
The major conclusion from this study is that grassland degradation decreased AM fungal species richness and abundance, but the diversity of AM fungi in degraded grassland increased

Summary

Introduction

Arbuscular mycorrhizal (AM) fungi are the most influential members of the soil microbiota (Smith and Read, 2008), which play a key role in improving the resistance of plants to drought (Wu et al, 2008), salt (Evelin et al, 2009) and nutrient deficiency (Smith and Read, 2008), restoration of degraded ecosystem (Bingham and Biondini, 2009; Zhang et al, 2012) and sustaining plant diversity and the ecosystem’ stability (van der Heijden et al, 1998; O’Connor et al, 2002; Wagg et al, 2011). Several studies found that some other factors, such as drought, wind erosion and poor soil factors affect species diversity of AM fungi in grassland ecosystems (Landis et al, 2004; Uhlmann et al, 2004; Liu et al, 2009). Several studies focused on AM fungal species diversity in Tibetan Plateau, which includes warm steppe, alpine meadow and alpine steppe (Gao et al, 2006; Gai et al, 2009; Cai et al, 2010), and 111 species AM fungi belonging to 12 genera were observed. Stipa genus is one of the dominant species in arid and semiarid regions, which occupies the greatest area and plays a key role in the stability of the Tibetan Plateau ecosystem

Results

Discussion

Conclusion