Nitrogen addition favors terrestrial ecosystem carbon sink: A global meta-analysis.

Long-term atmospheric nitrogen (N) deposition has been known to enhance plant productivity by increasing available N in terrestrial ecosystems. However, the response of carbon process to N deposition in terrestrial ecosystems remains unclear, particularly about different climate regions and biomes. In this study, we synthesized 1281 pairwise observations from 218 published articles on experimental N addition globally, aiming to quantify the responses of the carbon process and its mechanisms to N addition.

Corrigendum: Comparison of 14 reference evapotranspiration with lysimeter measurements at a site in the humid alpine meadow, northeastern Qinghai-Tibetan Plateau.

[This corrects the article DOI: 10.3389/fpls.2022.

Comparison of Fourteen Reference Evapotranspiration Models With Lysimeter Measurements at a Site in the Humid Alpine Meadow, Northeastern Qinghai-Tibetan Plateau.

Evapotranspiration is a key component in the terrestrial water cycle, and accurate evapotranspiration estimates are critical for water irrigation management. Although many applicable evapotranspiration models have been developed, they are largely focused on low-altitude regions, with less attention given to alpine ecosystems. In this study, we evaluated the performance of fourteen reference evapotranspiration (ET) models by comparison with large weight lysimeter measurements.

Soil Moisture Variations in Response to Precipitation Across Different Vegetation Types on the Northeastern Qinghai-Tibet Plateau.

An understanding of soil moisture conditions is crucial for hydrological modeling and hydrological processes. However, few studies have compared the differences between the dynamics of soil moisture content and soil moisture response to precipitation infiltration under different types of vegetation on the Qinghai-Tibet Plateau (QTP). In this study, a soil moisture sensor was used for continuous volumetric soil moisture measurements during 2015 and 2016, with the aim of exploring variations in soil moisture and its response to precipitation infiltration across two vegetation types (alpine meadow and alpine shrub).

Restoration of Degraded Grassland Significantly Improves Water Storage in Alpine Grasslands in the Qinghai-Tibet Plateau.

Alpine grassland has very important water conservation function. Grassland degradation seriously affects the water conservation function; moreover, there is little understanding of the change of water state during grassland restoration. Our study aims to bridge this gap and improve our understanding of changes in soil moisture during the restoration process.

Moderate grazing increased alpine meadow soils bacterial abundance and diversity index on the Tibetan Plateau.

The response of grassland soil bacterial community characteristics to different grazing intensities is central ecological topics. However, the underlying mechanisms between bacterial abundance, diversity index, and grazing intensity remain unclear. We measured alpine meadow soil bacterial gene richness and diversity index under four grazing intensities using 16S rDNA sequence analysis on the Tibetan Plateau.

Biomass allocation and productivity-richness relationship across four grassland types at the Qinghai Plateau.

Aboveground biomass (AGB) and belowground biomass (BGB) allocation and productivity-richness relationship are controversial. Here, we assessed AGB and BGB allocation and the productivity-richness relationship at community level across four grassland types based on the biomass data collected from 80 sites across the Qinghai Plateau during 2011-2012. The reduced major axis regression and general linear models were used and showed that (a) the median values of AGB were significantly higher in alpine meadow than in other three grassland types; the ratio of root to shoot (R/S) was significantly higher in desert grassland (36.

Moderate grazing promotes the root biomass in meadow on the northern Qinghai-Tibet Plateau.

Grazing is an important modulator of both plant productivity and biodiversity in grassland community, yet how to determine a suitable grazing intensity in alpine grassland is still controversy. Here, we explore the effects of different grazing intensities on plant biomass and species composition, both at community level and functional group level, and examines the productivity-species richness relationship under four grazing patterns: no grazing (CK), light grazing (LG), moderate grazing, (MG) and heavy grazing (HG), attempt to determine a suitable grazing intensity in alpine grassland. The results were as follows.

Nitrogen controls the net primary production of an alpine meadow in the northern Qinghai-Tibet Plateau.

Net primary production (NPP) is a fundamental property of natural ecosystems. Understanding the temporal variations of NPP could provide new insights into the responses of communities to environmental factors. However, few studies based on long-term field biomass measurements have directly addressed this subject in the unique environment of the Qinghai-Tibet plateau (QTP).

Responses of biomass allocation across two vegetation types to climate fluctuations in the northern Qinghai-Tibet Plateau.

The Qinghai-Tibet Plateau (QTP) is particularly sensitive to global climate change, especially to elevated temperatures, when compared with other ecosystems. However, few studies use long-term field measurements to explore the interannual variations in plant biomass under climate fluctuations. Here, we examine the interannual variations of plant biomass within two vegetation types (alpine meadow and alpine shrub) during 2008-2017 and their relationships with climate variables.

The Response of Shallow Groundwater Levels to Soil Freeze-Thaw Process on the Qinghai-Tibet Plateau.

The Qinghai-Tibet plateau has the world's largest area of seasonally frozen ground. Here, shallow groundwater displays behavior that is distinct from that elsewhere in the world. In the present study, we explore the seasonal and interannual variation of the shallow groundwater levels from 2012 to 2016, and attempt to quantitatively evaluate the relative influences of individual driving factors on the shallow groundwater levels based on boosted regression trees.