Do roads lead to grassland degradation or restoration? A case study in Inner Mongolia, China

We use satellite remote sensing data of grassland cover in Inner Mongolia, China to test whether the existence of and the size of roads in 1995 is associated with the nature of the grassland in 2000 and/or if it affects the rate of change of the grassland between 1995 and 2000. The regression results show that the impact of roads on grassland cover depends on the nature of the resource. When the grassland is composed of relatively high quality grassland, roads lead to degradation, whereas when grassland resources are sparse, access to a road results in the restoration of the resource

Quantitative Analysis of Driving Factors of Grassland Degradation: A Case Study in Xilin River Basin, Inner Mongolia

Current literature suggests that grassland degradation occurs in areas with poor soil conditions or noticeable environmental changes and is often a result of overgrazing or human disturbances. However, these views are questioned in our analyses. Based on the analysis of satellite vegetation maps from 1984, 1998, and 2004 for the Xilin River Basin, Inner Mongolia, China, and binary logistic regression (BLR) analysis, we observe the following: (1) grassland degradation is positively correlated with the growth density of climax communities; (2) our findings do not support a common notion that a decrease of biological productivity is a direct indicator of grassland degradation; (3) a causal relationship between grazing intensity and grassland degradation was not found; (4) degradation severity increased steadily towards roads but showed different trends near human settlements. This study found complex relationships between vegetation degradation and various microhabitat conditions, for example, elevation, slope, aspect, and proximity to water

Exacerbated grassland degradation and desertification in Central Asia during 2000-2014.

Grassland degradation and desertification is a complex process, including both state conversion (e.g., grasslands to deserts) and gradual within-state change (e.g., greenness dynamics). Existing studies hardly separated the two components and analyzed it as a whole based on time series vegetation index data, which cannot provide a clear and comprehensive picture for grassland degradation and desertification. Here we propose an integrated assessment strategy, by considering both state conversion and within-state change of grasslands, to investigate grassland degradation and desertification process in Central Asia. First, annual maps of grasslands and sparsely vegetated land were generated to track the state conversions between them. The results showed increasing grasslands were converted to sparsely vegetated lands from 2000 to 2014, with the desertification region concentrating in the latitude range of 43-48° N. A frequency analysis of grassland vs. sparsely vegetated land classification in the last 15 yr allowed a recognition of persistent desert zone (PDZ), persistent grassland zone (PGZ), and transitional zone (TZ). The TZ was identified in southern Kazakhstan as one hotspot that was unstable and vulnerable to desertification. Furthermore, the trend analysis of Enhanced Vegetation Index during thermal growing season (EVITGS ) was investigated in individual zones using linear regression and Mann-Kendall approaches. An overall degradation across the area was found; moreover, the second desertification hotspot was identified in northern Kazakhstan with significant decreasing in EVITGS , which was located in PGZ. Finally, attribution analyses of grassland degradation and desertification were conducted by considering precipitation, temperature, and three different drought indices. We found persistent droughts were the main factor for grassland degradation and desertification in Central Asia. Considering both state conversion and gradual within-state change processes, this study provided reference information for identification of desertification hotspots to support further grassland degradation and desertification treatment, and the method could be useful to be extended to other regions

ECOLOGICAL STOICHIOMETRY IN WATERSHEDS: FROM LAND TO WATER IN THE QINGHAI LAKE BASIN

We examined the influences of grassland status (as indexed by normalized difference vegetation index, NDVI) on carbon (C), nitrogen (N), and phosphorus (P) concentrations and stoichiometry, nutrient limitation, as well as microbial community structure in soil, stream, and/or lake ecosystems in the Qinghai Lake watershed, where grassland is the dominant landcover and more than half of the grassland is degraded. Chapter 2 showed that grassland degradation decreased C and N concentrations as well as C:N, C:P, and N:P ratios in soil. Moreover, grassland degradation decreased C, N, and P concentrations and influenced C:N and N:P ratios in soil microbial biomass. Soil microorganisms exhibited strong homeostatic behavior while variations of microbial biomass C:N and N:P ratios suggest changes in microbial activities and community structure. The soil became relatively more P rich and thus N limitation is anticipated to be more apparent with grassland degradation. Chapter 3 provided a picture of potentially differential influences of grassland degradation on DOC, TN, and TP in streamwater. The imbalances of C:N:P stoichiometry between streamwater and biofilms and the non-isometric relationships between biofilm C and P suggest that stream biofilms might be limited by P and sensitive to P variation. Chapter 4 indicated that grassland degradation has the potential to differentially influence the nutrients delivered to streams with substantial increases in P but decreases in N and N:P, alleviating P limitation of stream periphyton and, ultimately, stimulating P-limited phytoplankton growth in the lake. Chapter 5 revealed that grassland degradation shifted bacterial diversity and communities in soil, likely by changing soil moisture, soil organic carbon, total nitrogen, and total phosphorus. Chapter 6 showed that the variation of bacterial communities in stream biofilms was closely associated with rate of change in NDVI, pH, conductivity, as well as C, N, P contents and C:N ratio in biofilms per se. Alpha diversity was positively correlated with C, N, and P in biofilms. Abundant subcommunities of microbes were more strongly associated with environmental variables. Overall, my dissertation revealed strong impacts of grassland degradation on several aspects of nutrient dynamics and limitation as well as on microbial communities in terrestrial and aquatic ecosystems in the Qinghai Lake watershed

The on-farm impact of alternative grazing management options to improve sustainability in western Chinese grasslands

Chinese grasslands are suffering considerable pressures from human and livestock populations. It has been estimated that 90% of Chinese grasslands are suffering from light to heavy levels of degradation. Allied to this is the low household income of herders and farmers dependant upon livestock products for their livelihood. Although a range of reasons have been proposed for the high levels of grassland degradation, principal among these are the high stocking rates adopted by farmers. This not only results in high utilisation rates of the pasture biomass, leading to bare areas and soil erosion, but individual animal productivity rates also decline. This paper presents the results of a modelling study of a grassland system in Gansu Province and Inner Mongolia Autonomous Region in northern China. This shows that reducing stocking rates leads to not only an increase in livestock productivity, but whole-farm returns are also increased. From a sustainability perspective, the greater pasture biomass remaining on the grassland also reduces the incidence of soil erosion in the areas.sustainable grazing, bioeconomic model, China, Farm Management, Livestock Production/Industries, Resource /Energy Economics and Policy,

Combatting global grassland degradation

Grasslands are under severe threat from ongoing degradation, undermining their capacity to support biodiversity, ecosystem services and human well-being. Yet, grasslands are largely ignored in sustainable development agendas. In this Perspective, we examine the current state of global grasslands and explore the extent and dominant drivers of their degradation. Socio-ecological solutions are needed to combat degradation and promote restoration. Important strategies include: increasing recognition of grasslands in global policy; developing standardized indicators of degradation; using scientific innovation for effective restoration at regional and landscape scales; and enhancing knowledge transfer and data sharing on restoration experiences. Stakeholder needs can be balanced through standardized assessment and shared understanding of the potential ecosystem service trade-offs in degraded and restored grasslands. The integration of these actions into sustainability policy will aid in halting degradation and enhancing restoration success, and protect the socio-economic, cultural and ecological benefits that grasslands provide

Tibetan Plateau Grassland Protection: Tibetan Herders\u27 Ecological Conception Versus State Policies

The establishment of the “Three Rivers’ Sources Nature Reserve” in 2002 - one of China’s largest ecological protection projects - has had a major impact on the lives of Tibetan nomadic herders. This paper examines the ecological viewpoints of Tibetan herders, their conceptions of grassland protection and what they believe to be the best strategies to solve grazing problems. According to the Chinese authorities, the Nature Reserve was established to protect the grasslands, as well as the sources of China’s three major rivers – the Yellow River, the Yangtse and the Mekong. Grazing bans and flock reduction have been two recurring measures in this ecological protection project. Tibetan herders have also often been forced to settle down in new purpose built villages. These “ecological migrations”, as they are referred to in State environmental discourse, are also related to State policies to bolster security through population surveillance and territorial control. Therefore, in this complex context, ecological strategies are combined with political interests. To provide an alternative reading to the existing expert analyses of ecological problems and State reports on grassland and grazing problems, my paper focus on what Tibetan herders, resettled in new villages, think about these topics. Comparing their views against State discourse and policies, it is evident that herders have a different perception of the causes of the current ecological problems and propose alternative solutions, showing a high degree of consciousness of and active concern over grassland problems. Finally, I will argue that, although the ‘ecological migrations’ are often presented as the trigger of the settling of Tibetan nomads, the new resettlement villages are just the latest step in a much longer process of sedentarization, which had already started in the 1980s with the grasslands’ fencing policy

The Impacts of the Eco-Environmental Policy on Grassland Degradation and Livestock Production: An Empirical Analysis Based on the Simultaneous Equation Model

Grassland degradation has been deteriorating while the demands for meat products have been surging in China over the past few decades, leading to multiple policy initiatives to balance the grassland ecosystem and livestock production of the pastoral areas. This paper investigates the impacts of a prevailing eco-environmental program, i.e. Subsidy and Incentive System for Grassland Conservation (SISGC), in the pastoral areas of Inner Mongolia, on grassland condition and livestock production. The Normalized Difference Vegetation Index (NDVI), measured with remote sensing technology, is used to quantify grassland condition. Our empirical analysis was based on the data of 52 counties across a 15-year timespan covering 10 years before the introduction of SISGC and 5 years after its implementation. Simultaneous equation models are employed to study the mutual relationship between grassland condition and livestock production. The results suggest that the SISGC has significantly improved grassland condition. The total livestock population, especially the sheep population, has decreased due to SISGC, but the large animal population has not been impacted. On the other hand, growing meat prices (market demands) have resulted in an increase in the population of sheep, large animals, and total livestock. Implications are that the SISGC has been successful in preventing grassland degradation by controlling the increase in livestock population of the pastoral areas. Other policy initiatives need to consider how to prevent grassland degradation not only by controlling the livestock population given the soaring meat demand by the Chinese population and to address the high level of poverty among pastoralists

Elevated CO2 and Warming Altered Grassland Microbial Communities in Soil Top-Layers.

As two central issues of global climate change, the continuous increase of both atmospheric CO2 concentrations and global temperature has profound effects on various terrestrial ecosystems. Microbial communities play pivotal roles in these ecosystems by responding to environmental changes through regulation of soil biogeochemical processes. However, little is known about the effect of elevated CO2 (eCO2) and global warming on soil microbial communities, especially in semiarid zones. We used a functional gene array (GeoChip 3.0) to measure the functional gene composition, structure, and metabolic potential of soil microbial communities under warming, eCO2, and eCO2 + warming conditions in a semiarid grassland. The results showed that the composition and structure of microbial communities was dramatically altered by multiple climate factors, including elevated CO2 and increased temperature. Key functional genes, those involved in carbon (C) degradation and fixation, methane metabolism, nitrogen (N) fixation, denitrification and N mineralization, were all stimulated under eCO2, while those genes involved in denitrification and ammonification were inhibited under warming alone. The interaction effects of eCO2 and warming on soil functional processes were similar to eCO2 alone, whereas some genes involved in recalcitrant C degradation showed no significant changes. In addition, canonical correspondence analysis and Mantel test results suggested that NO3-N and moisture significantly correlated with variations in microbial functional genes. Overall, this study revealed the possible feedback of soil microbial communities to multiple climate change factors by the suppression of N cycling under warming, and enhancement of C and N cycling processes under either eCO2 alone or in interaction with warming. These findings may enhance our understanding of semiarid grassland ecosystem responses to integrated factors of global climate change