Alpine grassland management based on ecosystem service relationships on the southern slopes of the Qilian Mountains, China.

Grassland management is one of the most important means to address grassland degradation on the Qinghai-Tibet Plateau, but at present, the primary goal is still to improve grassland productivity, and little research has been conducted on grassland management based on its ecosystem service relationships. Based on remote sensing and meteorological data, we calculated and analyzed the spatial and temporal changes, trade-offs and synergistic relationships between livestock production and water retention services in alpine grassland on the southern slopes of the Qilian Mountains (SSQM), and designed a grazing management plan for sustainable development in the region. The results showed that the value of livestock production and water retention services of alpine grassland decreased from east to west, and their relationship is dominated by synergy and complemented by trade-offs. The synergistic relationships are concentrated in the Qinghai Lake Basin in the south and the river valleys in the north, while the trade-offs are scattered in the steeper terrain in the western and eastern parts of the study area. The scenario of preserving all water retention services and losing some livestock production services is sustainable. Based on this scenario we divided the alpine grassland of the study area into maintenance grazing, rotational grazing and grazing exclusion of 65.8%, 32.0% and 2.2%, respectively. Our study demonstrates that ecosystem service relationships have the potential to guide grassland management, and the results will provide new approaches to alpine grassland management.

Impacts of climate change and human factors on land cover change in inland mountain protected areas: a case study of the Qilian Mountain National Nature Reserve in China.

Over the past few decades, natural reserves have been affected by both climate change and human activities, and their land cover has changed dramatically, especially in mountain reserves, which are more sensitive to climate change and human activities. This paper used long-term Landsat and MODIS NDVI remote sensing data to monitor the changes of land cover and vegetation conditions in the Qilian Mountain National Nature Reserve (QMNNR) in China from 1975 to 2015, and analysed the impacts of climate change and human activities in combination with meteorological and socioeconomic data. The results show that the land cover structure of the QMNNR has remained stable over the past 40 years, but the total area of natural vegetation has decreased by 49.55 km2, the artificial surface and cropland has expanded by 13.68 and 32.57 km2 in some areas, respectively, and the glacier has retreated by 33.34 km2 as a whole. The warming and humidification trend of the climate is the leading factor for glacial retreat and the improvement of the overall vegetation condition, while population growth and economic benefits lead to the expansion of cropland and artificial surfaces in some areas, thus causing the reduction of 18.80 and 28.30 km2 in shrubland and grassland. This study proves that the system of protected areas plays a key role in maintaining the stability of the ecosystem structure and that reducing the population density around the protected areas and changing the mode of economic development can effectively reduce the intensity of human interference. Under the background of climate warming, the change of the ecosystem function in mountain protected areas is full of uncertainty, so management and protection strategies need to be studied in depth.

Monitoring the response of vegetation dynamics to ecological engineering in the Mu Us Sandy Land of China from 1982 to 2014.

The Mu Us Sandy Land (MUSL) has undergone climate changes and shifts in human activities driven by a series of ecological restoration projects in recent decades. We analyze the spatiotemporal dynamics of vegetation in this region using the satellite-retrieved normalized difference vegetation index (NDVI) from the Global Inventory Modeling and Mapping Studies (GIMMS) and Moderate Resolution Imaging and Spectroradiometer (MODIS) datasets during the past 33 years. The results show that (1) the vegetation in 53.46% of the MUSL exhibited an upward trend, and 34.45% of the area displayed a large increase, mainly in the eastern part of the MUSL region, including most of Shenmu County, Yuyang District, Hengshan County, and Jingbian County. (2) By the end of 2014, the rapid increase in vegetation encompassed 16.85% of the total area of the study region due to the construction of ecological engineering projects. (3) Based on the residual regression method, the area of positive effects accounted for 55.07% of the total area, and the vegetation in the study area was positively affected by human activities. Our study suggests that these multiple ecological restoration programs contributed to the accelerated greening trend in the MUSL region and highlights the importance of human intervention in regional vegetation growth under climate change conditions.

Monitoring coal mine changes and their impact on landscape patterns in an alpine region: a case study of the Muli coal mine in the Qinghai-Tibet Plateau.

The Muli coal mine is the largest open-cast coal mine in the Qinghai-Tibet Plateau, and it consists of two independent mining sites named Juhugeng and Jiangcang. It has received much attention due to the ecological problems caused by rapid expansion in recent years. The objective of this paper was to monitor the mining area and its surrounding land cover over the period 1976-2016 utilizing Landsat images, and the network structure of land cover changes was determined to visualize the relationships and pattern of the mining-induced land cover changes. In addition, the responses of the surrounding landscape pattern were analysed by constructing gradient transects. The results show that the mining area was increasing in size, especially after 2000 (increased by 71.68 km2), and this caused shrinkage of the surrounding lands, including alpine meadow wetland (53.44 km2), alpine meadow (6.28 km2) and water (6.24 km2). The network structure of the mining area revealed the changes in lands surrounding the mining area. The impact of mining development on landscape patterns was mainly distributed within a range of 1-6 km. Alpine meadow wetland was most affected in Juhugeng, while alpine meadow was most affected in Jiangcang. The results of this study provide a reference for the ecological assessment and restoration of the Muli coal mine land.

Ecosystem services relationship characteristics of the degraded alpine shrub meadow on the Qinghai-Tibetan Plateau.

Alpine shrub meadows hold significant importance as grassland ecosystems on the Qinghai-Tibetan Plateau (QTP). They provide a range of vital ecosystem services (ESs) and are commonly utilized as summer pastures by herders, resulting in short grazing periods and high grazing intensities. Unfortunately, these practices have led to varying degrees of degradation, thereby affecting the sustainable provision of ESs. However, the current knowledge regarding changes in ESs and their characteristics under the influence of degradation, particularly the differences between alpine shrub and alpine meadow ecosystems, is insufficient. To address this gap, this study aimed to investigate and analyse changes in four ESs within alpine shrub meadows across different levels of degradation, as well as explore their relationships. The research was conducted in a summer pasture located in the northeastern QTP. The findings revealed a substantial reduction of 85.9% in forage supply due to degradation in alpine shrub meadows. Moreover, regulating services experienced a decline followed by an increase in instances of heavy degradation. Trade-offs were observed between provisioning and regulating services, while synergistic relationships were identified among different regulating services. Degradation exacerbated imbalances between provisioning and regulating services, whereas light degradation allowed for a better equilibrium between the two. Comparatively, alpine meadows exhibited higher levels of forage supply and carbon storage services, whereas alpine shrub ecosystems displayed greater nutrient supply and water retention services. It was observed that changes in ESs and relationship patterns within alpine shrub meadows were significantly influenced by the presence of alpine meadows. Consequently, safeguarding the structural integrity of alpine meadows and addressing conflicts over ESs is essential to ensure coordination and sustainability of ESs within alpine shrub meadows. The outcomes of this study provide valuable insights for ecosystem management and ecological restoration initiatives in alpine shrub meadows on the QTP.

Phytochemical profiles and the hypoglycemic effects of tree peony seed coats.

As emerging woody oil crops, the tree peony seeds recently have been attracting great attention for their metabolites and bioactivities. In this research, the phytochemical profiles of the seed coats of tree peonies from different production regions were investigated systematically. Twelve phytochemicals were separated and prepared, mainly belonging to stilbenes. A great variation in stilbene content was detected in the three Paeonia plants, and Paeonia ostii seed coats (POSC) had significantly higher contents of the stilbene compounds than other species. There were nineteen significant correlations between ecogeographical factors and the predominant compounds. A clear discrimination among the species was observed in their HPLC fingerprint and chemometric analysis. Furthermore, POSC extracts could significantly reduce the starch mediated PBG (postprandial blood glucose) levels in normal/diabetic mice. Meanwhile, in vitro enzyme tests revealed that the predominant compounds, suffruticosol B and ampelopsin D, could effectively and competitively inhibit α-glucosidase, indicating that POSC could be a natural source of hypoglycemics in the food and drug fields.

Characterization of the spatial distribution of plateau pika burrows along an alpine grassland degradation gradient on the Qinghai-Tibet Plateau.

Plateau pika burrows are common feature of degraded grassland in the Qinghai-Tibet Plateau (QTP) and serve as an important indicator of pika activity and grassland degradation. However, the current understanding of the spatial pattern changes of pika burrows and their critical thresholds across a degradation gradient in alpine grassland is deficient. In this study, we investigated and quantified changes in the spatial pattern of plateau pika burrows under typical degraded alpine shrub meadows in the northeastern QTP using an unmanned aerial vehicle and landscape pattern metrics. The degradation of the alpine shrub meadow leads to a change in landscape pattern from a two-layered structure of alpine shrub and alpine meadow to a mosaic of alpine meadow and bare soil, with plateau pika burrows scattered throughout. Moderate degradation is the tipping point for changes in surface landscape patterns, followed by the disappearance of alpine shrub, the retreat of alpine meadows and the encroachment of bare soil, and the increasing density and size of pika burrows. The area characteristics of alpine meadows have influenced changes in the spatial pattern of pika burrow, and maintaining its proportional area is a vital measure to control the threat of pika burrows to pastures. The results of this paper provide a methodological reference and guidance for the sustainable utilization of grassland on the QTP.

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. 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.

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 (36.06) than intemperate grassland (16.60), alpine meadow (13.35), and meadow steppe (19.46). The temperate grassland had deeper root distribution than the other three grasslands, with about 91.45% roots distributed in the top 30 cm soil layer. (b) The slopes between log AGB and log BGB in the temperate grassland and meadow steppe were 1.09 and 1, respectively, whereas that in the desert grassland was 1.12, which was significantly different from the isometric allocation relationship. A competitive relationship between AGB and BGB was observed in the alpine meadow with a slope of -1.83, indicating a trade-off between AGB and BGB in the alpine meadow. (c) A positive productivity-richness relationship existed across the four grassland types, suggesting that the positive productivity-richness relationship might not be affected by the environmental factors at the plant location. Our results provide a new insight for biomass allocation and biodiversity-ecosystem functioning research.