The impact of land degradation on the C pools in alpine grasslands of the Qinghai-Tibet Plateau

Peats have the unique ability of effectively storing water and carbon. Unfortunately, this ability has been undermined by worldwide peatland degradation. In the Zoige Basin, located in the northeastern Qinghai-Tibet Plateau, China, peatland degradation is particularly severe. Although climate change and (natural and artificial) drainage systems have been well-recognized as the main factors catalyzing this problem, little is known about the impact of the latter on peatland hydrology at larger spatial scales. To fill this gap, we examined the hydrological connectivity of artificial ditch networks using Google Earth imagery and recorded hydrological data in the Zoige Basin. After delineating from the images of 1392 ditches and 160 peatland patches in which these ditches were clustered, we calculated their lengths, widths, areas, and slopes, as well as two morphological parameters, ditch density (Dd) and drainage ability (Pa). The subsequent statistical analysis and examination of an index defined as the product Dd and Pa showed that structural hydrological connectivity, which was quantitatively represented by the value of this index, decreased when peatland patch areas increased, suggesting that ditches in small patches have higher degrees of hydrological connectivity. Using daily discharge data from three local gauging stations and Manning’s equation, we back-calculated the mean ditch water depths (Dm) during raining days of a year and estimated based on Dm the total water volume drained from ditches in each patch (V) during annual raining days. We then demonstrated that functional hydrological connectivity, which may be represented by V, generally decreased when patch areas increased, more sensitive to changes of ditch number and length in larger peatland patches. Furthermore, we found that the total water volume drained from all ditches during annual raining days only took a very small proportion of the total volume of stream flow out of the entire watershed (0.0012%) and this nature remained similar for the past 30 years, suggesting that during annual rainfall events, water drained from connected ditches is negligible. This revealed that the role of connected artificial ditches in draining peatland water mainly takes effect during the prolonged dry season of a year in the Zoige Basin.

Download Full-text

Research on land degradation and management countermeasures in Qinghai-Tibet plateau

Sustainable Development ◽

10.1142/9789814749916_0048 ◽

2016 ◽

Cited By ~ 1

Author(s):

J.P. Yan

Keyword(s):

Land Degradation ◽

Tibet Plateau ◽

Qinghai Tibet Plateau

Download Full-text

Light-dependent associations of germination proportion with seed mass in alpine grasslands of the Qinghai-Tibet plateau

Ecological Engineering ◽

10.1016/j.ecoleng.2017.04.028 ◽

2017 ◽

Vol 105 ◽

pp. 306-313 ◽

Cited By ~ 4

Author(s):

Chunhui Zhang ◽

Zhen Ma ◽

Guozhen Du

Keyword(s):

Seed Mass ◽

Tibet Plateau ◽

Alpine Grasslands ◽

Qinghai Tibet Plateau

Download Full-text

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

Frontiers in Plant Science ◽

10.3389/fpls.2021.778656 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiaowei Guo ◽

Huakun Zhou ◽

Licong Dai ◽

Jing Li ◽

Fawei Zhang ◽

...

Keyword(s):

Soil Water ◽

Water Conservation ◽

Water Storage ◽

Grazing Intensity ◽

Tibet Plateau ◽

Soil Water Storage ◽

Grassland Restoration ◽

Alpine Grasslands ◽

Degraded Grassland ◽

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. In this study, the water storage, vegetation, and meteorology of a non-degradation grassland (grazing intensity of 7.5 sheep/ha) and a severely degraded grassland (grazing intensity of 12–18 sheep/ha) were monitored in the Qinghai-Tibet Plateau for seven consecutive years. We used correlation, stepwise regression, and the boosted regression trees (BRT) model analyses, five environmental factors were considered to be the most important factors affecting water storage. The severely degraded grassland recovered by light grazing treatment for 7 years, with increases in biomass, litter, and vegetation cover, and a soil-water storage capacity 41.9% higher in 2018 compared to that in 2012. This increase in soil-water storage was primarily due to the increase in surface soil moisture content. The key factors that influenced water storage were listed in a decreasing order: air temperature, litter, soil heat flux, precipitation, and wind speed. Their percentage contributions to soil-water storage were 50.52, 24.02, 10.86, 7.82, and 6.77%, respectively. Current and future climate change threatens soil-water conservation in alpine grasslands; however, grassland restoration is an effective solution to improve the soil-water retention capacity in degraded grassland soils.

Download Full-text

Rapid response of arbuscular mycorrhizal fungal communities to short-term fertilization in an alpine grassland on the Qinghai-Tibet Plateau

PeerJ ◽

10.7717/peerj.2226 ◽

2016 ◽

Vol 4 ◽

pp. e2226 ◽

Cited By ~ 16

Author(s):

Xingjia Xiang ◽

Sean M. Gibbons ◽

Jin-Sheng He ◽

Chao Wang ◽

Dan He ◽

...

Keyword(s):

Arbuscular Mycorrhizal ◽

Illumina Miseq ◽

Tibet Plateau ◽

Available Phosphorus ◽

Short Term ◽

Amf Diversity ◽

Amf Communities ◽

Arbuscular Mycorrhizal Fungal ◽

The Impact ◽

Qinghai Tibet Plateau

Background:The Qinghai-Tibet Plateau (QTP) is home to the vast grassland in China. The QTP grassland ecosystem has been seriously degraded by human land use practices and climate change. Fertilization is used in this region to increase vegetation yields for grazers. The impact of long-term fertilization on plant and microbial communities has been studied extensively. However, the influence of short-term fertilization on arbuscular mycorrhizal fungal (AMF) communities in the QTP is largely unknown, despite their important functional role in grassland ecosystems.Methods:We investigated AMF community responses to three years of N and/or P addition at an experimental field site on the QTP, using the Illumina MiSeq platform (PE 300).Results:Fertilization resulted in a dramatic shift in AMF community composition and NP addition significantly increased AMF species richness and phylogenetic diversity. Aboveground biomass, available phosphorus, and NO3−were significantly correlated with changes in AMF community structure. Changes in these factors were driven by fertilization treatments. Thus, fertilization had a large impact on AMF communities, mediated by changes in aboveground productivity and soil chemistry.Discussion:Prior work has shown how plants often lower their reliance on AMF symbioses following fertilization, leading to decrease AMF abundance and diversity. However, our study reports a rise in AMF diversity with fertilization treatment. Because AMF can provide stress tolerance to their hosts, we suggest that extreme weather on the QTP may help drive a positive relationship between fertilizer amendment and AMF diversity.

Download Full-text

PIC v1.3: comprehensive R package for computing permafrost indices with daily weather observations and atmospheric forcing over the Qinghai–Tibet Plateau

Geoscientific Model Development ◽

10.5194/gmd-11-2475-2018 ◽

2018 ◽

Vol 11 (6) ◽

pp. 2475-2491 ◽

Cited By ~ 1

Author(s):

Lihui Luo ◽

Zhongqiong Zhang ◽

Wei Ma ◽

Shuhua Yi ◽

Yanli Zhuang

Keyword(s):

Ground Surface ◽

R Package ◽

Frozen Soil ◽

Tibet Plateau ◽

Trend Test ◽

Active Layer Thickness ◽

Permafrost Degradation ◽

Spatial Trends ◽

The Impact ◽

Qinghai Tibet Plateau

Abstract. An R package was developed for computing permafrost indices (PIC v1.3) that integrates meteorological observations, gridded meteorological datasets, soil databases, and field measurements to compute the factors or indices of permafrost and seasonal frozen soil. At present, 16 temperature- and depth-related indices are integrated into the PIC v1.3 R package to estimate the possible trends of frozen soil in the Qinghai–Tibet Plateau (QTP). These indices include the mean annual air temperature (MAAT), mean annual ground surface temperature (MAGST), mean annual ground temperature (MAGT), seasonal thawing–freezing n factor (nt∕nf), thawing–freezing degree-days for air and the ground surface (DDTa∕DDTs∕DDFa∕DDFs), temperature at the top of the permafrost (TTOP), active layer thickness (ALT), and maximum seasonal freeze depth. PIC v1.3 supports two computational modes, namely the stations and regional calculations that enable statistical analysis and intuitive visualization of the time series and spatial simulations. Datasets of 52 weather stations and a central region of the QTP were prepared and simulated to evaluate the temporal–spatial trends of permafrost with the climate. More than 10 statistical methods and a sequential Mann–Kendall trend test were adopted to evaluate these indices in stations, and spatial methods were adopted to assess the spatial trends. Multiple visual methods were used to display the temporal and spatial variability of the stations and region. Simulation results show extensive permafrost degradation in the QTP, and the temporal–spatial trends of the permafrost conditions in the QTP are close to those of previous studies. The transparency and repeatability of the PIC v1.3 package and its data can be used and extended to assess the impact of climate change on permafrost.

Download Full-text