Identification of root-colonizing AM fungal communities and their responses to short-term climate change and grazing on Tibetan plateau

Response of plant diversity and soil microbial diversity to warming and increased precipitation in alpine grasslands on the Qinghai-Xizang Plateau - A review

Plant diversity and soil microbial diversity are closely related, and they maintain the health and stability of terrestrial ecosystems. As a hotspot region of global biodiversity research, both air temperature and precipitation of the Qinghai-Xizang Plateau tend to increase in future. Based on an overview of the responses of grassland/alpine ecosystems to seasonal asymmetric warming and increased precipitation worldwide, we elaborated the advancements and uncertainties on the responses of plant diversity and soil microbial diversity to warming and increased precipitation in alpine grasslands on the Qinghai-Xizang Plateau. The future research focus of plant diversity and soil microbial diversity in the alpine grasslands of the Qinghai-Xizang Plateau under climate warming and increased precipitation was proposed. Generally, previous studies found that the responses of plant species diversity and soil microbial species diversity to warming and increased precipitation differed between alpine meadows and alpine steppes, but few studies focused on their responses to warming and increased precipitation in alpine desert steppes. Previous studies mainly focused on species diversity, although phylogenetic and functional diversities are also important aspects of biodiversity. Previous studies mainly explained responses of plant diversity and soil microbial diversity to warming and increased precipitation based on niche theory, although neutral theory is also the other important mechanism in regulating biodiversity. Moreover, previous studies almost ignored the coupling relationship between plant diversity and soil microbial diversity. Therefore, the following four aspects need to be strengthened, including the responses of plant diversity and soil microbial diversity to warming and increased precipitation in alpine desert steppes, the responses of plant and soil microbial phylogenetic diversity and functional diversity to warming and increased precipitation, combining the niche theory and neutral theory to examining the mechanism of biodiversity, and the coupling relationships between plant diversity and soil microbial diversity under warming and increased precipitation.

Alterations to arbuscular mycorrhizal fungal community composition is driven by warming at specific elevations

Background

Global warming can alter plant productivity, and community composition which has consequences for soil-plant associated microorganisms. Arbuscular mycorrhizal fungi (AMF) are distributed widely and form symbiotic relationships with more than 80% of vascular plants and play a key role in nutrient cycling processes at the ecosystem scale.

Methods

A simulated warming experiment at multiple elevations (3,000, 3,500, 3,800, and 4,170 m) was conducted utilizing an in-situ open-top chamber (OTC) for exploring the effect of global warming on AMF community structure in the Qinghai-Tibet Plateau (QTP). This region has been identified as one of the most sensitive areas to climatic changes. Soil DNA was extracted and sequenced using next the Mi-Seq platform for diversity profiling.

Results

AMF richness was higher under the simulated warming chamber, however this only occurred in the elevation of 3,500 m. Warming did not alter other AMF alpha diversity indices (e.g. Shannon, Ace, and Simpson evenness index). Glomus and Acaulospora were the dominate AMF genera as assessed through their relative abundance and occurrence in control and warming treatments at the different elevations.

Conclusion

Warming changed significantly AMF community. The effects of warming on AMF community structure varied depend on elevations. Moreover, the occurrences of AMF in different genera were also presented the different responses to warming in four elevations.

Response of arbuscular mycorrhizal fungal community in soil and roots to grazing differs in a wetland on the Qinghai-Tibet plateau

Grazing as one of the most important disturbances affects the abundance, diversity and community composition of arbuscular mycorrhizal (AM) fungi in ecosystems, but the AM fungi in response to grazing in wetland ecosystems remain poorly documented. Here, we examined AM fungi in roots and soil in grazing and non-grazing plots in Zoige wetland on the Qinghai-Tibet plateau. Grazing significantly increased AM fungal spore density and glomalin-related soil proteins, but had no significant effect on the extra radical hyphal density of AM fungi. While AM fungal richness and community composition differed between roots and soil, grazing was found to influence only the community composition in soil. This study shows that moderate grazing can increase the biomass of AM fungi and soil carbon sequestration, and maintain the AM fungal diversity in the wetland ecosystem. This finding may enhance our understanding of the AM fungi in response to grazing in the wetland on the Qinghai-Tibet plateau.