34 research outputs found

    Soil and Water Conservation and Integrated Management in Watershed Ecosystem of the Loess Plateau, China

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    The Loess Plateau is well known for severe soil erosion and ecosystem degradation. The key issues in this region are the food security (grain), ecological security and a sustainable economy. This paper reviews a range of studies on ecological restoration, and management and the benefit at watershed scale on the Loess Plateau. This includes several successful cases and failures in soil conservation. The paper presents practical soil conservation measures and related benefit analysis, and discusses some effective methods adopted in soil erosion control, research directions and future perspectives for the Loess Plateau

    Sustainable land use changes in the north west provinces of China under the conversion of cropland to forest and grassland program

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    With increasing resource use pressure, land degradation in China has become increasingly severe in the past few decades especially in North West China. The Conversion of Cropland to Forest and Grassland Program (CCFGP), also known as the Grain for Green Program, was formally launched in 2002 to address the land degradation issue. Under the CCFGP, participating farmers are supported by the Government to grow trees and grass on land previously used for annual cropping. With government funding for the CCFGP drawing to an end in 2007, increasing attention amongst the Chinese policy makers, as well as the wider Chinese and international communities, has been devoted to the long-term sustainability of the land use changes triggered by the CCFGP. Question also remains as to whether there are better ways to deliver the anticipated policy outcome. In this thesis, a cost benefit analysis of the CCFGP is conducted to justify government intervention in providing the environmental goods and services through public finance. The potential efficiency gain of the Program is examined, based on which the sustainability of the land use changes under the Program together with the cost-effectiveness of the Program is explored. This partial cost benefit analysis of the CCFGP is conducted over a 20-year time period in the North West Provinces of China. Costs and benefits included in the analysis encompass the welfare impact of the land use changes on agricultural production and the environmental costs and benefits arising from the land use changes under the Program. Due to the limitation of data availability, some components of the environmental benefits and costs of runoff reductions are not included in the analysis. It has been found through this research that the livelihoods of participating farm households are improved by the CCFGP and the Program has positive impact on the social welfare of the local communities. The biophysical changes under the Program bring about both on-site and off-site benefits and costs. While the Program has been found to generate significant non-market environmental values, it also causes economic losses from reduced agricultural production arising from runoff reductions. Overall, the CCFGP improves the social welfare of people across Northern China over a 20-year time period since its implementation. Conclusion is drawn that government intervention through the CCFGP can be justified and the Program should be supported by the Chinese Government. Theoretically the sustainability of the Program can be achieved. However, sustainable land use changes will also depend on the implementation and design of the CCFGP. Future financing of the CCFGP is needed for some areas where the Program is found to decrease the social welfare of the local communities. Finally, there is room for better environmental targeting of the Program to improve the cost-effectiveness of the Program. The institution of an auction mechanism to allocate CCFGP funds more efficiently offers one potential solution

    Driving Factors of Land Change in China’s Loess Plateau: Quantification Using Geographically Weighted Regression and Management Implications

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    Land change is a key topic in research on global environmental change, and the restoration of degraded land is the core component of the global Land Degradation Neutrality target under the UN 2030 Agenda for Sustainable Development. In this study, remote-sensing-derived land-use data were used to characterize the land-change processes in China’s Loess Plateau, which is experiencing large-scale ecological restoration. Geographically Weighted Regression was applied to capture the spatiotemporal variations in land change and driving-force relationships. First, we explored land-use change in the Loess Plateau for the period 1990–2015. Grassland, cropland and forestland were dominant land cover in the region, with a total percentage area of 88%. The region experienced dramatic land-use transitions during the study period: degraded grassland and wetland, expansion of cropland and built-up land and weak restoration of forestland during 1990–2000; and increases in grassland, built-up land, forestland and wetland, concurrent with shrinking cropland during 2000–2015. A Geographically Weighted Regression (GWR) analysis revealed altitude to be the common dominant factor associated with the four major land-use types (forestland, grassland, cropland and built-up land). Altitude and slope were found to be positively associated with forestland, while being negatively associated with cropland in the high, steep central region. For both forestland and grassland, temperature and precipitation behaved in a similar manner, with a positive hotspot in the northwest. Altitude, slope and distance to road were all negatively associated with built-up land across the region. The GWR captured the spatial non-stationarity on different socioeconomic driving forces. Spatial heterogeneity and temporal variation of the impact of socioeconomic drivers indicate that the ecological restoration projects positively affected the region’s greening trend with hotspots in the center and west, and also improved farmer well-being. Notably, urban population showed undesired effects, expressed in accelerating grassland degradation in central and western regions for 1990–2000, hindering forestland and grassland restoration in the south during 2000–2015, and highlighting the long-term sustainability of the vegetation restoration progress. Such local results have the potential to provide a methodological contribution (e.g., nesting local-level approaches, i.e., GWR, within land system research) and spatially explicit evidence for context-related and proactive land management (e.g., balancing urbanization and ecological restoration processes and advancing agricultural development and rural welfare improvement)

    Evaluating the suitability of marginal land for a perennial energy crop on the Loess Plateau of China

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    Abstract With a large marginal land area, the Loess Plateau in China holds great potential for biomass production and environmental improvement. Identifying suitable locations for biomass production on marginal land is important for decision‐makers from the viewpoint of land‐use planning. However, there is limited information on the suitability of marginal land within the Loess Plateau for biomass production. Therefore, this study aims to evaluate the suitability of the promising perennial energy crop switchgrass (Panicum virgatum L.) on marginal land across the Loess Plateau. A fuzzy logical model was developed and validated based on field trials on the Loess Plateau and applied to the marginal land of this region, owing to its ability of dealing with the continuous nature of soil, landscape variations, and uncertainties of the input data. This study identified that approximately 12.8–20.8 Mha of the Loess Plateau as available marginal land, of which 2.8–4.7 Mha is theoretically suitable for switchgrass cultivation. These parts of the total marginal land are mainly distributed in northeast and southwest of the Loess Plateau. The potential yield of switchgrass ranges between 44 and 77 Tg. This study showed that switchgrass can grow on a large proportion of the marginal land of the Loess Plateau and therefore offers great potential for biomass provision. The spatial suitability maps produced in this study provide information to farmers and policymakers to enable a more sustainable development of biomass production on the Loess Plateau. In addition, the fuzzy‐theory‐based model developed in this study provided a good framework for evaluating the suitability of marginal land

    Quantifying the impact of grain for green program on ecosystem service management: a case study of Exibei region, China

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    Evaluating the impact of an ecological restoration program on ecosystem services is crucial, given the role of such a program in boosting sustainable ecosystem management. This study examines the impact of one of the large-scale ecological restoration programs in China, the Grain for Green Program (GGP), on ecosystem service management in the Exibei region of China. This region is studied, as it is a key source water area with rich biodiversity and has been experiencing GGP for 20 years. To achieve the stated goal the changes of land use and ecosystem services value (ESV) and the ecosystem services scarcity value (ESSV) in the Exibei region were quantified and assessed based on remote sensing images from 1990, 1995, 2000, 2005, 2010, 2015 and field survey data. The results indicated that the expansion of construction land and the increase of water body were the dominant land use changes throughout the study period. Farmland, forestland and grassland decreased by 2.61%, 0.47% and 1.41% after the GGP, respectively. The ESV of the entire Exibei region increased slightly in response to land use change during 1990-2015, with an annual loss of 0.08% before the implementation of GGP and an annual growth of 0.03% after the implementation of GGP. Moreover, forestland was the dominant contributor to ESSV after the implementation of the GGP. Its annual growth rate was four times higher than before the commencement of GGP. The results of this study contribute to the protection of the Exibei region ecosystem, and more importantly, the future management of the ecosystem service in the hilly regions of southern China

    A spatiotemporal epidemiological investigation of the impact of environmental change on the transmission dynamics of Echinococcus spp. in Ningxia Hui Autonomous Region, China

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    Background: Human echinococcoses are zoonotic parasitic diseases of major public health importance globally. According to recent estimates, the geographical distribution of echinococcosis is expanding and becoming an emerging and re-emerging problem in several regions of the world. Echinococcosis endemicity is geographically heterogeneous and might be affected by global environmental change over time. The aims of my research were: 1) to assess and quantify the spatiotemporal variation in land cover and climate change in Ningxia Hui Autonomous Region (NHAR); 2) to identify highly endemic areas for human echinococcoses in NHAR, and to determine the environmental covariates that have shaped the local geographical distribution of the disease; 3) to develop spatial statistical models that explain and predict the spatiotemporal variation of human exposure to Echinococcus spp. in a highly endemic county of NHAR; and 4) to analyse associations between the environment and the spatiotemporal variation of human exposure to the parasites and dog infections with Echinococcus granulosus and Echinococcus multilocularis in four echinococcosis-endemic counties of NHAR. Methods: Data on echinococcosis infections and human exposure to E. granulosus and E. multilocularis were obtained from different sources: 1) A hospital-based retrospective survey of human echinococcosis cases in NHAR between 1992 and 2013; 2) three cross-sectional surveys of school children conducted in Xiji County in 2002–2003, 2006–2007 and 2012–2013; and 3) A cross-sectional survey of human exposure and dog infections with E. granulosus and E. multilocularis conducted in Xiji, Haiyuan, Guyuan and Tongxin Counties. Environmental data were derived from high-resolution (30 m) imagery from Landsat 4/5-TM and 8-OLI and meteorological reports provided by the Chinese Academy of Sciences. Image analysis techniques and a Bayesian statistical framework were used to conduct a land cover change detection analyses and to develop regression models that described and quantified climate trends and the environmental factors associated with echinococcosis risk at different spatial scales. Results: The land cover changes observed in NHAR from 1991 to 2015 concurred with the main goals of a national policy on payments for ecosystem services, implemented in the Autonomous Region, in increasing forest and herbaceous vegetation coverages and in regenerating bareland. Statistically significant positive trends were observed in annual, summer and winter temperatures in most of the region, and a small magnitude change was found in annual precipitation, in the same 25-year period. The south of NHAR was identified as a highly endemic area for cystic echinococcosis (CE; caused by E. granulosus) and alveolar echinococcosis (AE; caused by E. multilocularis). Selected environmental covariates explained most of the spatial variation in AE risk, while the risk of CE appeared to be less spatially variable at the township level. The risk of exposure to E. granulosus expanded across Xiji County from 2002–2013, while the risk of exposure to E. multilocularis became more confined in communities located in the south of this highly endemic area. In 2012–2013, the predicted seroprevalences of human exposure to E. granulosus and dog infection with this parasite were characterised by similar geographical patterns across Xiji, Haiyuan, Guyuan and Tongxin Counties. By contrast, the predicted high seroprevalence areas for human exposure and dog infection with E. multilocularis did not coincide spatially. Climate, land cover and landscape fragmentation played a key role in explaining some of the observed spatial variation in the risk of infection with Echinococcus spp. among schoolchildren and dogs in the south of NHAR at the village level. Conclusions: The findings of this research defined populations at a high risk of human exposure to E. granulosus and E. multilocularis in NHAR. The research provides evidence on the potential effects of landscape regeneration projects on the incidence of human echinococcoses due to the associations found between the infections and regenerated land. This information will be essential to track future requirements for scaling up and targeting the control strategies proposed by the National Action Plan for Echinococcosis Control in China and may facilitate the design of future ecosystem management and protection policies and a more effective response to emerging local environmental risks. The predictive models developed as part of this research can also be used to monitor echinococcosis infections and the emergence in Echinococcus spp. transmission in the most affected areas

    Impacts of ecological restoration programs on water-related ecosystem services: A case study in northern Shaanxi, China

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    Pour restaurer les fonctions écosystémiques altérées, la Chine a instauré plusieurs programmes de restauration écologique (PRE) à grande échelle. Ces programmes ont généré des changements significatifs sur l’occupation du sol et sur les services écosystémiques (SE) définis comme étant les bénéfices procurés aux humains par les écosystèmes. Les écosystèmes sont critiques pour le bien-être humain, mais notre connaissance actuelle de la fourniture des SE dans le paysage contient des lacunes qui limitent notre capacité à mieux comprendre l’impact des PRE sur ce bien-être humain. Plus particulièrement, la compréhension des impacts des changements d’occupation du sol sur la fourniture des SE en régions semi-arides et arides en Chine reste floue. Dans la présente thèse, le but général de recherche est l’évaluation à long terme de l’impact des PRE sur les SE liés à l’eau, particulièrement l’érosion du sol et l’apport en eau dans une région semi-aride chinoise, le Shaanxi septentrional. Afin d’atteindre cet objectif, les étapes du projet sont: l’analyse des changements d’occupation du sol avant et après l’implantation des PRE, l’estimation de l’érosion du sol et de l’apport en eau à différentes échelles spatiales et temporelles, l’analyse des relations entre le changement d’occupation du sol et les SE liés à l’eau et des relations entre l’érosion du sol et l’apport en eau et finalement l’analyse des impacts potentiels futurs des PRE sur les SE liés à l’eau à l’aide de différents scénarios. Les résultats ont montré que l’implantation des PRE dans le Shaanxi du nord avait provoqué une augmentation des prairies et des terres boisées et une diminution des terres cultivées. Dans le même temps, la principale caractéristique du changement de SE lié à l’eau au cours de la période d’implantation des ERP était la diminution de l’érosion du sol et de l’apport en eau dans le site d’étude. Cependant, en se basant sur une analyse à l’échelle des sous-bassins versants, il a été constaté que les zones boisées et les prairies n’avait pas augmenté dans tous les sous-bassins au cours de la période d’implantation des ERP. De plus, l'érosion des sols dans trois sous-bassins versants a même augmenté après la mise en œuvre des PRE, alors que l'apport en eau dans tous les sous-bassins versants a diminué durant la même période. Les relations entre les types d’occupation du sol et les SE liés à l'eau ont varié d'un sous-bassin à l'autre. En ce qui concerne l'érosion du sol, 95% de la zone d'étude a montré une relation positive, indiquant que l'augmentation de la superficie des terres cultivées est liée à une augmentation de l'érosion du sol. En d'autres termes, la diminution des superficies cultivées peut aider à réduire le risque d'érosion des sols. Cependant, les relations négatives observées entre les terres boisées et l'érosion du sol et entre les prairies et l'érosion du sol n’ont été observées que dans la plupart des sous-bassins nord, ce qui suggère que l'augmentation des zones boisées et des prairies dans la plupart des sous-bassins versants du nord peut aider à réduire le risque d'érosion du sol. Ainsi, la mise en œuvre des ERP dans les régions du nord du site d'étude a eu des impacts positifs sur l'érosion des sols. En ce qui concerne l'apport en eau, 65% de la zone d'étude (21 sous-bassins versants) présentaient une relation négative entre les terres boisées et l'apport en eau, tandis que 40% de la zone d'étude (neuf sous-bassins versants) a montré une relation négative entre les prairies et l’apport en eau durant la période d’activité des PRE. Ces résultats indiquent que l'augmentation des terres boisées et des prairies peut diminuer l'apport en eau dans la plupart des sous-bassins versants du nord du Shaanxi. Enfin, il a également été constaté que des compromis existaient entre l’érosion du sol et l’apport en eau, ce qui signifie qu’une amélioration du service de l’érosion est obtenue au prix d’une diminution de l’approvisionnement en eau dans le nord du Shaanxi. Sur la base de notre analyse de scénarios, les PRE sont susceptibles de continuer à être d’importants et d’influents facteurs sur l'érosion des sols et l'approvisionnement en eau dans le cadre des scénarios de protection et de statu quo. Par rapport à l'année de référence (2015), l'érosion du sol a montré une tendance à la baisse dans les scénarios de protection et de statu quo, mais les résultats de la simulation ont montré des différences relativement faibles dans les deux scénarios. De plus, l’apport en eau parmi trente sous-bassins diminuerait de 28% (scénario sans changement d’occupation du sol), de 29% (scénario de statu quo) et de 37% (scénario de protection). Ces résultats indiquent également que le climat (par exemple les précipitations et l'évapotranspiration), les PRE et leurs interactions exerceront probablement des pressions considérables sur l'approvisionnement en eau d'ici 2050. Ainsi, les pratiques de restauration écologique actuelles pourraient soutenir la conservation des sols et de l'eau dans le nord du Shaanxi.Abstract: To repair the damaged ecosystem functions, China has implemented several largescale ecological restoration programs (ERPs). These programs have exerted significant changes on land use and land cover (LULC) and ecosystem services (ES), benefits that people obtain from ecosystems. Ecosystems are critical to human well-being, but our current knowledge of the provision of ES across landscapes contains gaps that limit our ability to better understand the impact of ERPs on human well-being. In particular, how the changes in LULC affect multiple ES provision in semi-arid and arid regions in China remains unclear. In this thesis, the overall research goal is to evaluate the impacts of ERPs on waterrelated ES, namely soil erosion and water yield, in a semiarid region (northern Shaanxi, China), in the long-term period. To attain this goal, the specific steps are: analyse LULC changes before and after implementation of ERPs, estimate soil erosion and water yield at different temporal and spatial scales, assess the relationship between LULC change and water-related ES and the relationship between soil erosion and water yield, and finally, analyse potential impacts of ERPs on water-related ES in the future through different conservation scenarios. Results showed that the implementation of ERPs in northern Shaanxi caused grasslands and woodlands increase as well as croplands decrease. At the same time, the major characteristic of water-related ES change during the ERPs period was that both soil erosion and water yield decreased in the study site. However, based on sub-watershed scale analysis, it was found that woodland and grassland in each sub-watershed did not always increase during the ERPs period. Moreover, soil erosion in three sub-watersheds actually increased after implementation of the ERPs, while water yield in all sub-watersheds decreased during the ERPs period. Relationships between LULC types and water-related ES varied from one subwatershed to another. As for soil erosion, 95% of the study area showed a positive relationship, indicating that higher cropland increase is linked to higher soil erosion increase. In other words, decreasing cropland areas can help reduce the risk of soil erosion. However, the negative relationships between woodlands and soil erosion and between grasslands and soil erosion only existed in most north sub-watersheds, indicating that higher woodland/grassland increase is related to lower soil erosion increase. This result suggested that increased woodlands and grasslands in most north sub-watersheds can help reduce the risk of soil erosion. Thus, implementation of the ERPs in north regions in the study site has positive impacts on soil erosion. As for water yield, 65% of the study area (twenty-one sub-watersheds) showed a negative relationship between woodlands and water yield, while 40% of the study area (nine sub-watersheds) showed a negative relationship between grasslands and water yield after implementation of ERPs. These results indicated that increased of woodland and grassland can decrease water yield in most sub-watersheds in northern Shaanxi. Lastly, it was also found that trade-offs existed between soil erosion and water yield, which means that an improvement in erosion service is achieved at the expense of a decrease in the provision of water in northern Shaanxi. Based on our scenario analysis, the ERPs are likely to be continued as important and influential on soil erosion and water provision under protection and business-as-usual (BAU) scenarios. Compared with the baseline year (2015), soil erosion showed a decrease tendency under protection and BAU scenarios, but simulation results showed relatively small differences under both scenarios. Moreover, water yield among thirty sub-watersheds would decrease by 28% (No LULC change scenario), 29% (BAU scenario), and 37% (protection scenario). These results also indicate that climate (i.e. precipitation and evapotranspiration), the ERPs and their interactions are likely to place substantial pressures on the provision of water by 2050. Thus, current ecological restoration practices might support soil and water conservation in the future in northern Shaanxi
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