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Grassland is the largest ecosystem on the Qinghai–Tibetan Plateau (QTP) and provides multiple ecosystem functions and services. Understanding the endowment of the QTP grassland and how to revitalize it have profound implications for the sustainable use and efficient conservation of these unique and globally valuable ecosystems. In this paper, we highlight the importance of the QTP grassland in regional and global settings, stress the values of the QTP grassland in ecological and socioeconomic dimensions, and emphasize the actions needed to restore degraded grassland in the QTP region. The QTP is the largest single area of alpine grassland in the world and an important gene pool of alpine biological resources. The QTP grassland covers two critical ecoregions for conserving the best and most representative habitats for alpine biodiversity on the planet. The QTP grassland is also regarded as one of the best carriers and objects of socio‐ecological systems in the world. To promote the resilience and sustainability of the QTP grassland through adaptation, different parties need to work together to find feasible options to resist shock, stresses, and disturbance and to maintain the fundamental functions and basic structures of the QTP grassland. [ABSTRACT FROM AUTHOR]

Fencing and grass plantation are two key interventions to preserve the degraded grassland on the Qinghai-Tibetan Plateau (QTP). Climate warming and N deposition have substantially affected the alpine grassland ecosystems. However, molecular composition of soil organic carbon (SOC), the indicator of degradation of SOC, and its responses to climate change are still largely unclear. In this study, we conducted the experiments in three types of land use on the QTP: alpine meadow (AM), alpine steppe (AS), and cultivated grassland (CG) under 2 °C climatic warming, 5 levels of nitrogen deposition rates at 8, 24, 40, 56, and 72 kg N ha − 1 year − 1 , as well as a combination of climatic warming and N deposition (8 kg N ha − 1 year − 1 ). Our findings indicate that all three types of land use were dominated by O-alkyl carbon. The alkyl/O-alkyl ratio, aromaticity and hydrophobicity index of the CG were larger than those of the AM and AS, and this difference was generally stable under different treatments. Most of the SOC in the alpine grasslands was derived from fresh plants, and the carbon in the CG was more stable than that in the AM and AS. The compositions of all the alpine ecosystems were stable under short-term climatic changes, suggesting the short-term climate warming and nitrogen deposition likely did not affect the molecular composition of the SOC in the restored grasslands. [ABSTRACT FROM AUTHOR]

Increases in nitrogen (N) deposition along with climate warming can change the dynamics of carbon and nitrogen in the soil, and alter greenhouse gases (GHGs) fluxes. To examine how N deposition and warming affect GHGs (CH 4 , CO 2 and N 2 O) fluxes in alpine grasslands, we conducted experiments in an alpine meadow (AM), alpine-steppe (AS), and alpine cultivated grassland (CG) on the Qinghai-Tibetan Plateau (QTP). We simulated N deposition by treating soil with ammonium nitrate (NH 4 NO 3 ) (8 kg N ha − 1 year − 1 ), a warming treatment using an open top chamber (OTC) was carried out, and a combined treatment of warming and N deposition (8 kg N ha − 1 year − 1 ) was conducted. The GHGs were collected during early, peak, and late plant growing seasons, i.e., May, August, and October of 2015, respectively, using a static chamber. We found, in general, neither N deposition nor warming solely altered CH 4 and N 2 O fluxes in the alpine grasslands. The N deposition under warming conditions reduced CO 2 emission significantly. The reduction of CO 2 emission was most significant in the alpine steppe. The effects of climatic warming and N deposition on the GHGs varied greatly across the grassland types and the growing seasons. The cultivated grasslands were much more unstable than the native grasslands in CH 4 uptake. In can be concluded the N deposition associated with human activities may buffer the CO 2 emission in the alpine grassland ecosystems in terms of climate changes on the QTP. [ABSTRACT FROM AUTHOR]

Alpine ecosystems are known to be sensitive to climate change and human disturbances. However, the knowledge about the changes of their underground microbial communities is inadequate. We explored the diversity and structure of soil bacterial and fungal communities using Ilumina MiSeq sequencing in native alpine grasslands (i.e. the alpine meadow, alpine steppe) and cultivated grassland of the Qinghai-Tibetan Plateau (QTP) under three-year treatments of overgrazing, warming and enhanced rainfall. Enhanced rainfall rather than warming significantly reduced soil microbial diversity in native alpine grasslands. Variable warming significantly reduced it in the cultivated grassland. Over 20% and 40% variations of microbial diversity could be explained by soil nutrients and moisture in the alpine meadow and cultivated grassland, separately. Soil microbial communities could be clustered into different groups according to different treatments in the alpine meadow and cultivated grassland. For the alpine steppe, with the lowest soil nutrients and moistures, < 10% variations of microbial diversity was explained by soil properties; and the soil microbial communities among different treatments were similar. The soil microbial community in the cultivated grassland was varied from it in native grasslands. Over 50% variations of soil microbial communities among different treatments were explained by soil nutrients and moisture in each grassland type. Our results suggest that climate change and human activities strongly affected soil microbial communities by changing soil nutrients and moistures in alpine grassland ecosystems. [ABSTRACT FROM AUTHOR]

The plateau pika ( Ochotona curzoniae ) is considered a keystone species on the Qinghai–Tibetan Plateau (QTP). Under a moderate burrow density condition, we investigated plant community and soil properties surrounding pika's burrows in comparison to the control sites (without pika's burrows) in an alpine meadow ecosystem. The results demonstrated that plant biomass, especially aboveground biomass around pika's burrow, was improved. The contents of available soil nutrients around the pika's burrow were improved as well. The highest aboveground biomass and highest contents of NH 4 -N, available phosphorus and available potassium was detected at the back of the burrow. The compositions of plant community were not changed significantly around the pika burrow, excluding at the front of the burrow. Our findings revealed that the activities of plateau pika can improve the production of alpine meadow and increase the soil fertility at individual burrow level when the burrow density was not out of control. [ABSTRACT FROM AUTHOR]