HUI ZHAO

Chinese Academy of Sciences | CAS

Grasslands cover one-third of the terrestrial area, though half of them have been degraded and primarily due to overgrazing. The Tibetan Plateau (TP) is home to the largest area of alpine grassland on Earth, experiencing a typical degradation-restoration story over the past three decades. With the large-scale implementation and long-term duration o...

The elevation gradient has long been known to be vital in shaping the structure and function of terrestrial ecosystems, but little is known about the elevation-dependent pattern of net CO2 uptake, denoted by net ecosystem productivity (NEP). Here, by analyzing data from 203 eddy covariance sites across China, we report a negative linear elevation-d...

Wetlands within dryland regions are highly sensitive to climate change and human activities. Based on three types of land use data sources from satellite images and a spatial data analysis, the spatiotemporal characteristics of wetland evolution in China’s drylands and their relationship with human interference and climate change from 1990 to 2020...

Averaged over 4000 m in elevation, Tibetan Plateau (TP) functions as an important ecological security barrier in China. Alpine ecosystems present a trend of overall improvement under the influence of climate change and human activities, yet there are localized deteriorations. To improve the ecological function of the TP, large-scale ecological rest...

Ecosystem services (ESs) are the cornerstone of human well-being. On the Tibetan Plateau and in its subregions, understanding the effects of the spatiotemporal continuity in the trade-offs/synergies of ESs, and identifying their drivers, is crucial for ecosystem conservation and sustainable development. In this study, we investigated the spatiotemp...

Averaged over 4000 m in elevation, Tibetan Plateau (TP) functions as an important ecological security barrier in China. Alpine ecosystems present a trend of overall improvement under the influence of climate change and human activities, yet there are localized deteriorations. To improve the ecological function of the TP, large‐scale ecological rest...

青藏高原实施了林草保护与修复、沙化治理和水土保持等生态工程，是我国乃至全球最大的生态工程区之一。其中，退牧还草简单有效且成本较低，在近20年的高寒草地生态恢复中广泛应用。长时间、大规模实施的退牧还草生态工程极大地改变了下垫面状态，并影响着碳水热交换过程。团队通过典型生态工程对比监测和数据资源整合，系统研究了退牧还草工程地气间的碳水热效应，取得系列科学发现。（1）青藏高原高寒草地是重要的净CO2汇，生态恢复工程能够显著提升CO2汇40%～60%，水分多寡影响生态恢复的碳汇强度。（2）高寒草甸和高寒草原是可观的CH4汇，草地恢复通过提升土壤通透性和阻断速效氮返还促进CH4吸收，高寒草原、高寒草甸禁牧区分别提升约20%。高寒湿地整体是CH4的弱源，草地恢复通过增加维管植物传输氧化减少CH4排放高达...

Qinghai-Tibetan Plateau is an important ecological security barrier in China, and alpine ecosystem presents a trend of overall improvement under the influence of climate change and human activities, yet there are localized deteriorations. In order to improve the ecological function of the Tibetan Plateau, large-scale ecological restoration projects...

Background and aims An increase in nitrogen deposition is expected to increase the phosphorus-limited primary productivity of grassland ecosystems. However, it remains unclear as to whether the primary productivity of grasslands is co-limited by nitrogen and phosphorus, or only by one or the other. Methods Nitrogen and phosphorus addition experime...

It is uncertain that plant biomass of grassland was co-limited by nitrogen (N) and phosphorus (P) or only limited by N or P. Moreover, it is also unclear why plant biomass was not limited by the P when the N was added at grassland ecosystem. The N and P additional experiment was conducted at the alpine steppe from 2013 to 2017. Results from analyzi...

Significance Cold regions contain vast stores of permafrost carbon. Rapid warming will cause permafrost to thaw and plant respiration to accelerate, with a resultant loss of CO 2 , but could also increase the fixation of CO 2 by plants. A network of 32 eddy covariance sites on the Tibetan Plateau, which has the largest store of alpine permafrost ca...

The Tibetan Plateau (TP) is home to the most extensive alpine permafrost, where there are over 30% of China's marshlands. Though climate warming of 0.26°C per decade may have altered the carbon (C) balance by promoting permafrost C release. To date, most studies have been conducted in the eastern TP region (<3,500 m in altitude), even though 51% of...

The identification of plant species in alpine steppes of Northern Tibet is of great significance for revealing community structures and for monitoring vegetation degradation and restoration from remote sensing images. Plants in the alpine steppe of Northern Tibet are short, sparse, and highly heterogeneous in spatial distribution. This peculiarity...

The alpine wetlands of the Tibetan Plateau (TP) contribute 30%–40% of China’s natural wetlands, and they are experiencing changes in climate, i.e. warming of 0.26 °C 10 yr−1 (since the 1950s), as well as considerable human impacts. Consequently, alpine wetland extent show strong response to these impacts in most part, a reduction since the 1970s, f...

The world’s largest alpine pastures are found on the Tibetan Plateau, where considerable climate changes and human impacts have been experienced. Identifying their contributions to terrestrial productivity is essential if we are to adapt to, or mitigate the effects of, climate change. In this work, we begin by showing how the current warming and we...

Earth hummocks are widely distributed in arctic, sub-Arctic and alpine regions and have important roles in determining plant diversity and the nutrient content of soils. We investigated the impact of the spatial heterogeneity on soil properties and plant communities caused by the hummocks on the Tibetan Plateau. The results indicated alpine hummock...

Understanding wetland changes under urbanization is important for wetland management. In this study, net transition intensity (NTI) and total transition intensity (TTI) are presented to characterize wetland transitions based on spatial data obtained from Landsat satellite images of Pearl River estuary in South China. NTI is commonly used to represe...

Yak and Tibetan sheep graze extensively on natural grasslands in the Qinghai-Tibetan Plateau, and large amounts of excrement are directly deposited onto alpine grasslands. However, information on greenhouse gas (GHG) emissions from this excrement is limited. This study evaluated the short-term effects of yak and Tibetan sheep dung on nitrous oxide...

In the last 30 years, water environment and wetland patterns have been experiencing dramatic changes resulted from rapid urbanization, industrialization and population growth in the Pearl River Delta. To investigate the changes of wetland network pattern associated with water quality in this region, the structure indices and intercepting amount of...

In this paper, a wetland network is designed to mitigate saltwater intrusion based on the relationship between river discharge and salinity in Modaomen waterway (MDMW), the Pearl River estuary (PRE) of southern China. The designed network consists of existing and expanded wetlands, river channels and their tributaries. The freshwater stored in wetl...

Water pollution has been a serious problem with rapid urban development in the Pearl River Delta. In the paper, a river channel‐wetland network (RCWN) was constructed to improve the situation of water pollution. At first, the assimilative capacity of each river was calculated for the main pollutants (biological oxygen demand and ammonia nitrogen se...

The Pearl River Delta (PRD) region is one of the most industrialized areas in China, and the river water is increasingly deteriorated due to anthropogenic pollution from the rapid economic development. Principal component analysis (PCA) and cluster analysis (CA) were used to identify characteristics of water quality and to assess water quality spat...

There are many parameters determining salt intrusion in alluvial estuaries, including river discharge, channel shape, tidal forcing. In this paper, according to a well-tested theory for the calculation of salt intrusion in estuary regions, the salt intrusion length can be computed by the model that drives from this well-tested theory. There is an a...

Hani terraced paddy fields are one of the most important ways for agricultural products and greatly influence regional landscapes in mountainous areas of Southwestern China. However, the knowledge of soil nutrient conditions from Hani terraced paddy fields is limited. This paper investigates such soil nutrient parameters as organic matter (OM), tot...

Based on landscape data produced from integrated Landsat MSS/TM/ETM+ images and spatial metrics, this paper presented a synthesis of wetland landscape changes in the Pearl River estuary from 1979 to 2009, and explored the spatio-temporal characteristics of wetland change. The classified images were used to generate maps of wetland degradation, and...

Samples collected from sites of 26 for water, soils and two native plants (Scirpus tripueter Linn. and Cyperus malaccensis Lam.) in riparian wetlands were analyzed to investigate the distribution of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in Panyu-Nansha area of Pearl River estuary. The results indicated that concentrations of heavy metals among t...

Most pollutants entering natural water system may be absorbed onto suspended solid particles and sediment. When the external pollution sources have been effectively controlled, eutrophication and deterioration of water quality may still maintain for a long time because of the existence and release of inner nutrient in sediments. Therefore, the sedi...

Groundwater is a valuable natural resource providing a primary source of water for agriculture, domestic and industrial purposes. To Jinan, it is more significant because of the famous springs. But springs have drained off for several years because of groundwater over-extraction. Surface water and groundwater is an integrated system and the environ...

Metal distributions (Cd, Cr, Cu, Ni, Pb and Zn) in the soils and plants were investigated in roadside surface soils and grass herbage collected from two study sites adjacent to Mangshi–Ruili and Dali–Baoshan highways. At each study site, soil and plant samples were collected along two roadside slopes with distances of 5, 10, 20, 50, 100, and 200m a...

This paper studied the distribution of the heavy metals including As, Cd, Cr, Cu, Pb, and Zn in the paddy soils of Hani Terrace core zone, which is comprised of four sections, Niujiaozhai River patch, Malizhai River patch, Amengkong River patch, Dawazhe River patch. Means of heavy metals in the soils collected from four zones were compared with the...

Taking Da-Bao expressway in the Longitudinal Range-Gorge Region (LRGR) as an example, the effects of the expressway on three kinds of soil-plant systems along the road are analyzed by seven types of indexes, which are soil nutrient, heavy metals of soil, soil moisture and pH of soil, plant nutrient, heavy metal of plant and plant diversity. Firstly...