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Li J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Li J.,Northeast Normal University | Li J.,Key Laboratory of Vegetation Ecology | He N.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 3 more authors.
PLoS ONE | Year: 2015

Qinghai-Tibet Plateau grasslands are unique geographical regions and store substantial soil organic matter (SOM) in the soil surface, which make them very sensitive to global climate change. Here, we focused on three main grassland types (alpine meadow, steppe, and desert) and conducted a soil incubation experiment at five different temperatures (5, 10, 15, 20, and 25°C) to investigate SOM decomposition rates (R), temperature sensitivity (Q10), and activation energy (Ea). The results showed that grassland type and incubation temperature had significant impact on R (P < 0.001), and the values of R were exponential correlated with incubation temperature in three alpine grasslands. At the same temperature, R was in the following order: alpine meadow > alpinesteppe > alpine desert. The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 0.09) < alpine steppe (1.88 0.23) < alpine desert (2.39 0.32). Moreover, the Ea values differed significantly across different grassland types (P < 0.001) and increased with increasing incubation time. The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate- quality temperature hypothesis is applicable to the alpine grasslands. Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau. © 2015 Li et al.

Sun S.,Key Laboratory of Vegetation Ecology | Xing F.,Key Laboratory of Vegetation Ecology | Zhao H.,Key Laboratory of Vegetation Ecology | Gao Y.,Key Laboratory of Vegetation Ecology | And 2 more authors.
Journal of Soil Science and Plant Nutrition | Year: 2014

Nitrogen (N) deposition greatly affects the above ground biological composition of grasslands and soil properties. However, its influence on the relationship among soil, plant and bacterial communities remain controversy. We calculated Shannon-wiener index to measure the soil bacterial diversity based on denaturing gradient gel electrophoresis, and investigate the roles of vegetation and soil properties on the soil bacterial community under N addition. A three-year simulated N deposition experiment was conducted in a forbs community dominated by Leymus chinensis (Trin.) Tzvel. and Artemisia scoparia Wald. Et. Kit. N was added at five levels (0, 23, 46, 69, 92 kg ha-1 yr-1). Our results showed that N addition increased the soil microbial biomass carbon (SMBC) and soil bacterial diversity. Moderate N (23, 46, 69 kg ha-1 yr-1) addition increased the soil bacterial diversity, whereas excess N (92 kg ha-1 yr-1) addition inhibited it. The SMBC and soil bacterial diversity were related to richness of plant functional groups. In particular, SMBC had positive correlation with biomass of annuals and biennials, suggesting that the effects of the plant community on the soil bacteria could be explained by a relationship between the soil bacterial community and a subset of plant species rather than all species. © 2014, Sociedad Chilena de la Ciencia del Suelo. All rights reserved.

Liu L.,Northeast Normal University | Liu L.,State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration | Jie D.,Northeast Normal University | Jie D.,State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration | And 12 more authors.
Ecological Indicators | Year: 2016

Phytoliths have proved to be reliable indicators of environmental conditions both at present and in the past, and can provide evidence for the distribution of taxa or vegetation. Understanding the environmental significance of phytoliths within plants helps in drawing more reliable inferences about palaeovegetation and in reconstructing the palaeo-environment. The present study examined the relationship between phytoliths and environmental factors to assess the environmental significance of different types of phytoliths. Phytoliths were extracted from Phragmites communis growing in xerophytic and aquatic habitats at twelve sampling sites in north-eastern China and their implications for the environment were assessed using quantitative data mainly including phytolith concentration and environmental factors and statistical analyses. Principal component analysis (PCA) of several environmental factors (including the climate, micro terrain, and the physicochemical properties of soils) revealed that other factors being constant, P. communis phytolith concentrations were influenced largely by the average annual temperature and precipitation. Orthogonal experiment analysis and three-way analyses of variance of the concentrations confirmed the reliability of the results of the PCA. More specifically, the concentrations of the saddle and rondel types of phytoliths (the short-cell phytoliths) were closely linked to the average annual temperature whereas those of the elongate, lanceolate, and bulliform phytoliths (the non-short-cell phytoliths) were more sensitive to the variations in water status. The results contribute to further confirming the major environmental implications of phytoliths and, in turn, providing a reference for growth and development of wetland plants. Our findings also provide critical information that could help managers and policymakers assess and modify ecological restoration practices. © 2016 Published by Elsevier Ltd.

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