scholarly journals Characterizing Hydrological Connectivity of Artificial Ditches in Zoige Peatlands of Qinghai-Tibet Plateau

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1364 ◽  
Author(s):  
Zhiwei Li ◽  
Peng Gao ◽  
Yuchi You
Keyword(s):  
Google Earth ◽  
Tibet Plateau ◽  
Annual Rainfall ◽  
Water Volume ◽  
Hydrological Connectivity ◽  
Total Water ◽  
Zoigê Basin ◽  
The Impact ◽  
Qinghai Tibet Plateau ◽  
Peatland Degradation

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.

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

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2226 ◽  
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.

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

2018 ◽  
Vol 11 (6) ◽  
pp. 2475-2491 ◽  
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.

The impact of land surface temperatures on suprapermafrost groundwater on the central Qinghai‐Tibet Plateau

2019 ◽  
Vol 34 (6) ◽  
pp. 1475-1488 ◽  
Author(s):  
Kewei Huang ◽  
Junchen Dai ◽  
Genxu Wang ◽  
Juan Chang ◽  
Yaqiong Lu ◽  
...  
Keyword(s):  
Land Surface ◽  
Tibet Plateau ◽  
Surface Temperatures ◽  
Land Surface Temperatures ◽  
The Impact ◽  
Qinghai Tibet Plateau

scholarly journals Mapping Highland Barley on the Qinghai–Tibet Combing Landsat OLI Data and Object-Oriented Classification Method

Land ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1022
Author(s):  
Weidong Ma ◽  
Wei Jia ◽  
Peng Su ◽  
Xingyun Feng ◽  
Fenggui Liu ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Arable Land ◽  
Object Oriented ◽  
Tibet Plateau ◽  
Study Results ◽  
Administrative Unit ◽  
Extraction Scheme ◽  
The Impact ◽  
Qinghai Tibet Plateau ◽  
Highland Barley

In this paper, we use the extraction method of multi-factors fusion to extract the Highland barley cultivation area on Qinghai–Tibet Plateau. The study results indicate that: (1) the method (extracting through multi-factors fusion) is efficient during the extracting process and is highly accurate in extraction results. This extraction scheme allows for not only the spatial heterogeneity of different physical geographic units, but also the impact of multi-factors on crop cultivation; (2) according to our research, the total Highland barley cultivation area on Qinghai–Tibet Plateau is about 2.74 × 105 ha. Based on the statistics, we draw the first distribution map of the Highland barley cultivation area on Qinghai–Tibet Plateau, which upgrades its spatial distribution pattern from administrative unit to patch unit; (3) Highland barley in various divisions has a distinct spatial heterogeneity in elevation. On the whole, the Highland barley on the plateau is planted at an elevation of 2500–4500 m, up to 5200 m. Due to the impact of topography diversity, temperature, moisture, light, arable land and irrigation conditions, its cultivation area at the same elevation varies in different divisions.

Response of organic carbon in drainage ditch water to rainfall events in Zoige Basin in the Qinghai-Tibet Plateau

2019 ◽  
Vol 579 ◽  
pp. 124187 ◽  
Author(s):  
Danyang Wang ◽  
Zhiwei Li ◽  
Zhongwu Li ◽  
Wenming Ma ◽  
Xiaodong Nie
Keyword(s):  
Organic Carbon ◽  
Tibet Plateau ◽  
Drainage Ditch ◽  
Rainfall Events ◽  
Zoigê Basin ◽  
Qinghai Tibet Plateau

scholarly journals The Impact of Climate Change on the Surface Albedo over the Qinghai-Tibet Plateau

2021 ◽  
Vol 13 (12) ◽  
pp. 2336
Author(s):  
Chaonan Chen ◽  
Li Tian ◽  
Lianqi Zhu ◽  
Yuanke Zhou
Keyword(s):  
Climate Change ◽  
Solar Radiation ◽  
Land Surface ◽  
Meteorological Data ◽  
Growing Season ◽  
High Elevation ◽  
Tibet Plateau ◽  
Decrease Rate ◽  
The Impact ◽  
Qinghai Tibet Plateau

Albedo is a characterization of the Earth’s surface ability to reflect solar radiation, and control the amount of solar radiation absorbed by the land surface. Within the context of global warming, the temporal and spatial changes of the albedo and its response to climate factors remain unclear. Based on MCD43A3 (V005) albedo and meteorological data (i.e., temperature and precipitation), we analyzed the spatiotemporal variations of albedo (2000–2016) and its responses to climate change during the growing season on the Qinghai-Tibet Plateau (QTP). The results indicated an overall downward trend in the annual albedo during the growing season, the decrease rate was 0.25%/decade, and the monthly albedo showed a similar trend, especially in May, when the decrease rate was 0.53%/decade. The changes also showed regional variations, such as for the annual albedo, the areas with significant decrease and increase in albedo were 181.52 × 103 km2 (13.10%) and 48.82 × 103 km2 (3.52%), respectively, and the intensity of albedo changes in low-elevation areas was more pronounced than in high-elevation areas. In addition, the annual albedo-temperature/precipitation relationships clearly differed at different elevations. The albedo below 2000 m and at 5000–6000 m was mainly negatively correlated with temperature, while at 2000–4000 m it was mainly negatively correlated with precipitation. The contemporaneous temperature could negatively impact the monthly albedo in significant ways at the beginning of the growing season (May and June), whereas in the middle of the growing season (July and August), the albedo was mainly negatively correlated with precipitation, and at the end of the growing season (September), the albedo showed a weak correlation with temperature/precipitation.

scholarly journals Climate Change and Livestock Management Drove Extensive Vegetation Recovery in the Qinghai-Tibet Plateau

2021 ◽  
Vol 13 (23) ◽  
pp. 4808
Author(s):  
Enqin Liu ◽  
Xiangming Xiao ◽  
Huaiyong Shao ◽  
Xin Yang ◽  
Yali Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibet Plateau ◽  
Positive Trend ◽  
Vegetation Degradation ◽  
Livestock Population ◽  
Northern Tibet ◽  
Rate Of Increase ◽  
The Impact ◽  
Qinghai Tibet Plateau ◽  
Impacts Of Climate Change

The vegetation of the Qinghai-Tibet Plateau (QTP), China, is diverse and sensitive to climate change. Because of extensive grassland degradation in the QTP, several ecological restoration projects, which affect the livestock population, have been implemented in the QTP. Although many studies have reported the impacts of climate change on vegetation in the QTP, our knowledge on the impacts of both climate change and livestock on vegetation remains very limited. Here, we investigated the impacts of climate change and livestock population on vegetation growth by using the annual maximum normalized difference vegetation index (NDVImax) and growing-season climate data from 1981 to 2019. We analyzed the relationship between NDVImax and climate and livestock population using the modified Mann-Kendall trend Test and Pearson correlation analysis. For the entire QTP, NDVImax had a two-phase trend, with a slow rise during 1981–2000 and a rapid rise during 2000–2019. Overall, NDVImax in the QTP increased and decreased in 63.7% and 6.7% of the area in 2000–2019. In areas with significant changes in NDVImax, it was strongly correlated with relative humidity and vapor pressure. The small positive trend in NDVImax during 1981–2000 was influenced by warmer and wetter climate, and the overgrazing by a large population of livestock slowed down the rate of increase in NDVImax. Livestock population for Qinghai and Tibet in recent years has been lower than in the 1980s.The warmer and wetter climate and substantial drops in the livestock population contributed to large recovery in vegetation during 2001–2019. Vegetation degradation in Qinghai during 1981–2000 and central-northern Tibet during 2000–2019 was driven mainly by drier and hotter climatic. Although 63.7% of the area in the QTP became greener, the vegetation degradation in central-northern Tibet should not be ignored and more measures should be taken to alleviate the impact of warming and drying climate. Our findings provide a better understanding of the factors that drove changes in vegetation in the QTP.

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