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1.
A thorough understanding of the vegetation succession in relation to both climatic changes and anthropogenic activities is vital for the formulation of adaptation strategies that address potential ecosystem challenges. Various climatic factors such as temperature, precipitation, and solar radiation, as well as anthropogenic factors such as ecological engineering and population migration, will affect the conditions for vegetation. However, the relationships among various factors remain unclear and the response of vegetation to climate change and anthropogenic activities in the Loess Plateau of China has not been well established. This study investigated the spatio-temporal characteristics and relationships between vegetation coverage and climatic factors in the Loess Plateau for the period of 1985–2015. Further analysis separated the anthropogenic and climatic factors on vegetation succession based on residual analysis. The results showed that the normalized difference vegetation index(NDVI) followed a significant upward trend with annual change rates of 0.15% during 1985–2015. The trend of human-induced NDVI increase was consistent with the spatial distribution of increasing forest areas in the eastern part of the Loess Plateau. Eco-restoration projects were the main driving factors that promoted vegetation coverage on the Loess Plateau. Furthermore, these results demonstrated that migrants to cities in the Loess Plateau could relieve ecological pressures and promote vegetation restoration. Therefore, the government should strive to increase population mobility and restore vegetation to sustain this particularly fragile ecological environment.  相似文献   

2.
Infiltration, as a major component of the hydrological cycle, plays an important role in ecosystems, river flooding, and soil erosion. Therefore, this process has been studied on different soils, with different vegetation cover, and under different climate conditions. However, it is still necessary to know how infiltration rates depend on land degradation, vegetation cover, forest management, and forest restoration, since soil infiltration is related to soil hydrological function and hydrological ecosystem services. The aim of our study is to analyze the way reforestation and check dam construction have helped to improve soil infiltration rates in comparison with old, degraded land, different soils and vegetation covers in Central Spain. Therefore, three infiltration tests were carried out by means of a simple methacrylate infiltrometer ring, in four sampling plots, for five types of land use:(i) native holm oak forest,(ii) 60-year-old reforested pine wood,(iii) shrubs,(iv) sediment wedges of check dams, and(v) gullies and degraded hillslopes. Our results show much higher infiltration rates in the soil of 60-yearold pine reforestation sites(1198.00 mm·h~(-1)), and in the sediment wedges of check dams(1088.00 mm·h~(-1)), than in those of degraded hillslopes(365.00 mm·h~(-1)) and shrubland(420.80 mm·h~(-1)). The rates were also shown to be close to those from the remaining patches of native holm oak woodland(770.40 mm·h~(-1)). We also found that organic matter, humus and litter depth, and height of vegetation and cover, all improve soil infiltration rates, while slope degree, presence of coarse elements, stoniness, clay content, bulk density, and electric conductivity inhibit the rates. It was additionally seen that pine reforestation and check dam construction caused degraded land to recover its hydrological conditions to a level that is quite close to that of the ancient oak holm native forest, alongside ameliorating the hydrological cycle in the watershed. This information will be very useful for decisionmaking processes related to land restoration projects, forest management, and environmental policy.  相似文献   

3.
Dominated by an arid and semiarid continental climate, the Beijing-Tianjin Sandstorm Source Region(BTSSR) is a typical ecologically fragile region with frequently occurring droughts. To provide information for regional vegetation protection and drought prevention, we assessed the relations between vegetation cover change(measured by the Normalized Difference Vegetation Index,NDVI) and the Standardized Precipitation Evapotranspiration Index(SPEI) at different time-scales, in different growth stages, in different subregions and for different vegetation types based on the Pearson's correlation coefficient in the BTSSR from 2000 to 2017. Results showed that 88.19% of the vegetated areas experienced increased NDVI in the growing season; 48.3% of the vegetated areas experienced significantly increased NDVI(P 0.05) and were mainly in the south of the BTSSR. During the growing season, a wetter climate contributed to the increased vegetation cover from 2000 to 2017, and NDVI anomalies were closely related to SPEI. The maximum correlation coefficient in the growing season(Rmax) was significantly positive(P 0.05) in 97.84% of the total vegetated areas. In the vegetated areas with significantly positive Rmax, pixels with short time-scales(1–3 mon) accounted for the largest proportion(33.9%).The sensitivity of vegetation to the impact of drought rose first and then decreased in the growing season, with a peak in July. Compared with two subregions in the south, subregions in the north of the BTSSR were more sensitive to the impacts of drought variations,especially in the Xilingol Plateau and Wuzhumuqin Basin. All four major vegetation types were sensitive to the effects of drought variations, especially grasslands. The time-scales of the most impacting droughts varied with growth stages, regions, and vegetation types.These results can help us understand the relations between vegetation and droughts, which are important for ecological restoration and drought prevention.  相似文献   

4.
Examining the direct and indirect effects of climatic factors on vegetation growth is critical to understand the complex linkage between climate change and vegetation dynamics. Based on the Moderate Resolution Imaging Spectroradiometer(MODIS) Normalized Difference Vegetation Index(NDVI) data and meteorological data(temperature and precipitation) from 2001 to 2012, the trend of vegetation dynamics were examined in the Ziya-Daqing basins, China. The path analysis was used to obtain the information on the relationships among climatic factors and their effects on vegetation growth. It was found that the trends of growing season NDVI were insignificant in most plain dry land, while the upward trends were significant in forest, grass and dry land in Taihang Mountains. According to the path analysis, in 23% of the basins the inter-annual NDVI variation was dominated by the direct effect of precipitation, in 5% by the direct effects of precipitation and temperature, and in less than 1% by the direct effect of temperature or indirect effects of these two climatic factors. It indicated that precipitation significantly affected the vegetation growth in the whole basins, and this effect was not regulated by temperature. Precipitation increase(especially in July, August and September) was favorable to greenness enhancement. Summer temperature rising showed negative effect on plant productivity enhancement, but temperature rise in April was beneficial for the vegetation growth. When April temperature increases by 1℃, the onset date of greenness for natural vegetation will be 2 days in advance. There was a lag-time effect of precipitation or temperature on monthly NDVI for all land use types except grass.  相似文献   

5.
The protection, restoration and sustainable use are key issues of all the wetlands worldwide. Ecological, agronomic, and engineering techniques have been integrated in the development of a structurally sound, ecologically beneficial engineering restoration method for restoring and utilizing a degraded saline wetland in the western Songnen Plain of China. Hydrological restoration was performed by developing a system of biannual irrigation and drainage using civil engineering measures to bring wetlands into contact with river water and improve the irrigation and drainage system in the wetlands. Agronomic measures such as plowing the reed fields, reed rhizome transplantation, and fertilization were used to restore the reed vegetation. Biological measures, including the release of crab and fish fry and natural proliferation, were used to restore the aquatic communities. The results of the restoration were clear and positive. By the year 2009, the reed yield had increased by 20.9 times. Remarkable ecological benefits occurred simultaneously. Vegetation primary-production capacity increased, local climate regulation and water purification enhanced, and biodiversity increased. This demonstration of engineering techniques illustrates the basic route for the restoration of degraded wetlands, that the biodiversity should be reconstructed by the comprehensive application of engineering, biological, and agronomic measures based on habitat restoration under the guidance of process-oriented strategies. The complex ecological system including reeds, fish and crabs is based on the biological principles of coexistence and material recycling and provides a reasonable ecological engineering model suitable for the sustainable utilization of degraded saline reed wetlands.  相似文献   

6.
Multi-temporal series of satellite SPOT-VEGETATION normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data from 1998 to 2007 were used for analyzing vegetation change of the ecotone in the west of the Northeast China Plain. The yearly and monthly maximal values,anomalies and change rates of NDVI and NDWI were calculated to reveal the interannual and seasonal changes in vegetation cover and vegetation water content. Linear regression method was adopted to characterize the trends in vegetation change. The yearly maximal NDVI decreased from 0.41 in 1998 to 0.37 in 2007,implying the decreasing trend of vegetation activity. There was a significant decrease of maximal NDVI in spring and summer over the study period,while an increase trend was observed in autumn. The vegetation-improved regions and vegetation-degraded regions occupied 17.03% and 20.30% of the study area,respectively. The maximal NDWI over growing season dropped by 0.027 in 1998–2007,and about 15.15% of the study area showed a decreasing trend of water content. Vegetation water stress in autumn was better than that in spring. Vegetation cover and water content variations were sensitive to annual precipitation,autumn precipitation and summer temperature. The vegetation degradation trend in this ecotone might be induced by the warm-drying climate especially continuous spring and summer drought in the recent ten years.  相似文献   

7.
Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing exclusion on plant productivity, species diversity and soil organic carbon （SOC） and soil total nitrogen （STN） storage along a transect spanning from east to west of alpine meadows in northern Tibet, China. After six years of grazing exclusion, plant cover, aboveground biomass （AGB）, belowground biomass （BGB）, SOC and STN were increased, but species diversity indices declined. The enhancement of AGB and SOC caused by grazing exclusion was correlated positively with mean annual precipitation （MAP）. Grazing exclusion led to remarkable biomass increase of sedge species, especially Kobresia pygmaea, whereas decrease of biomass in forbs and no obvious change in grass, leguminous and noxious species. Root biomass was concentrated in the near surface layer （10 cm） after grazing exclusion. The effects of grazing exclusion on SOC storage were confined to shallow soil layer in sites with lower MAP. It is indicated that grazing exclusion is an effective measure to increase forage production and enhance soil carbon sequestration in the studied region. The effect is more efficient in sites with higher precipitation. However, the results revealed a tradeoff between vegetation restoration and ecological biodiversity. Therefore, carbon pools recover more quickly than plant biodiversity in the alpine meadows. We suggest that grazing exclusion should be combined with other measures to reconcile grassland restoration and biodiversitv conservation.  相似文献   

8.
Understanding of the vegetation dynamics is essential for addressing the potential threats of terrestrial ecosystem.In recent years,the vegetation coverage of the Yangtze River Basin(YRB) has increased significantly,yet the spatio-temporal variations and potential driving meteorological factors of carbon use efficiency(CUE) under the context of global warming are still not clear.In this study,MODIS-based public-domain data during 2000–2015 was used to analyze these aspects in the YRB,a large river basin with powerful ecological functions in China.Spatio-temporal variations of CUE in different sub-basins and land cover types were investigated and the correlations with potential driving meteorological factors were examined.Results revealed that CUE in the YRB had strong spatiotemporal variability and varied remarkably in different land cover types.For the whole YRB,the average CUE of vegetated land was 0.519,while the long-term change trend of CUE was obscure.Along the rising altitude,CUE generally showed an increasing trend until the altitude of 3900 m and then followed by a decreasing trend.CUE of grasslands was generally higher than that of croplands,and then forest lands.The inter-annual variation of CUE in the YRB is likely to be driven by precipitation as a strong positive partial correlation between the inter-annual variability of CUE and precipitation was observed in most of sub-basins and land cover types in the YRB.The influence of temperature and relative humidity is also outstanding in certain regions and land cover types.Our findings are useful from the view point of carbon cycle and reasonable land cover management under the context of global warming.  相似文献   

9.
Land change is a cause and consequence of global environmental change.Land use and land cover have changed considerably due to increasing human activities and climate change,which has become the core issue of major international research projects.This study interprets land use and land cover status and the changes within the Koshi River Basin(KRB)using Landsat remote sensing(RS)image data,and employs logistic regression model to analyze the influence of natural and socioeconomic driving forces on major land cover changes.The results showed that the areas of built-up land,bare land and forest in KRB increased from 1990 to 2015,including the largest increases in forest and the highest growth rate in construction land.Areas of glacier,grassland,sparse vegetation,shrub land,cropland,and wetland all decreased over the study period.From the perspective of driving analysis,the role of human activities in land use and land cover change is significant than climate factors.Cropland expansion is the reclamation of cropland by farmers,mainly from early deforestation.However,labor force separation,geological disasters and drought are the main factors of cropland shrinkage.The increase of forest area in India and Nepal was attributed to the government’s forest protection policies,such as Nepal’s community forestry has achieved remarkable results.The expansion and contraction of grassland were both dominated by climatic factors.The probability of grassland expansion increases with temperature and precipitation,while the probability of grassland contraction decreases with temperature and precipitation.  相似文献   

10.
The Tarim River Basin, located in the typical arid region, is one of the key regions of LUCC research in China and plays an important role in maintaining the sustainable development of the westem China. In recent years, the ecological environment of the Tarim River Basin has degraded greatly. In the lower reaches, in particular,the riverbed has been dried up for more than 20 years, which accelerated the desertification and has been a great threat to people‘s lives. Taking the section of the Tarim River between Qiala Lake and Taitema Lake as a typical region, an investigation on land cover changes was carried out with the support of remote sensing information of 1988 and 2000 respectively. The changes of land cover in this region were obtained: 1) Cropland tended to increase. 2)Urban or Built-up Area in 2000 was 324.4ha more than that in 1988.3) Waters expanded by 3476.51ha. 4) Woodland and Grassland decreased, while Barren Land increased by 3824.9ha. The total amount of land use/land cover change between 1988 and 2000 is small, which is only 0.355% of the total area. It shows that the developmental pace of the lower reaches of the Tarim River is relative slow. Based on these results, the authors assessed the landscape dynamics of this region and pointed out that the degree of desertification was strengthened and the landscape dominated by sand land was further characterized by salt desert.  相似文献   

11.
Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods and sedimentation in Yangtze Rive are well known. A quantitative assessment of soil erosion intensity is still scanty for developing appropriate soil erosion control measures for different land use types and zohes in this region. This article constructs a localized USLE and estimates the average soil loss in the Jinsha River Region in Yunnan Province, one of the priority areas for soil erosion control in the middle and upper reaches of Yangtze River. The estimation is done under different land uses and zones in this basin. The estimation shows that while soil erosion in the cultivated land is the most severe, 36～40% of the garden and forest land suffers from soil erosion of various degrees due to lack of ground cover and other factors. Soil erosion in the pasture is modest when the ground cover is well maintained. It also confirmed that terracing can reduce soil erosion intensity significantly on the cultivated land. Research findings suggest that sufficient attention must be paid to regeneration of the ground cover in reforestation programs. In addition to mass reforestation efforts, restoration of grassland and terracing of the cultivated land should also play an important role in erosion control.  相似文献   

12.
Topography, especially altitude, will influence the way, process and characteristics of land cover changes in mountainous area, simultaneously, the vertical difference of land cover changes will affect soil quality and regional ecological environment. Therefore, the gradient relationship analysis between land cover changes and altitude is very important for regional sustainability. This study investigated land cover dynamics based on land cover data from a typical mountainous area in the Guizhou-Guangxi karst mountain area, China, in 2000 and 2010, then explored the relationship between altitude and land cover change and analyzed different drivers of land cover change at different altitudes. Our findings are as follows. 1) From 2000 to 2010, the total area of land cover transition was 7167.04 km~2 or 2.8% of the region. The increasing area of build-up land(926.23 km~2) was larger than that of forest(859.38 km~2), suggesting that the urban construction speed was higher than that of reforestation. 2) Intensity of land cover transition in northwestern Guizhou-Guangxi karst mountain area was much larger than that of southeast part and their transition trend was also significantly different, which was consistent with regional population and economy. 3) Human activity was the most dramatic at altitudes between 0–500 m. For 500–1000 m, grassland mainly converted to forest and build-up land. Area of land cover transition was the greatest between 1000–1500 m, while above 1500 m, the transition of grassland was the most obvious. 4) The drivers of land cover change varied. Land cover change was positively correlated with gross domestic product and population density but was inversely related to relief amplitude. There were correlations between land cover change and distance to roads and rivers, and their correlations varied with altitude. By revealing patterns and causes of land cover changes in different altitudes, we hope to understand the vertical dependence of land cover changes, so as to improve land productivity and protect land ecological environment scientifically.  相似文献   

13.
The semi-arid grasslands in Inner Mongolia, China have been degraded by long-term grazing. A series of ecological restoration strategies have been implemented to improve grassland service. However, little is known about the effect of these ecological restoration practices on soil carbon and nitrogen storage. In this study, characteristics of vegetation and soil properties under continued grazing and exclusion of livestock for six years due to a nationwide conservation program—′Returning Grazing Lands to Grasslands(RGLG)′ were examined in semi-arid Hulun Buir grassland in Inner Mongolia, China. The results show that removal of grazing for six years resulted in a significant recovery in vegetation with higher above and below-ground biomass, but a lower soil bulk density and pH value. After six years of grazing exclusion, soil organic C and total N storage increased by 13.9% and 17.1%, respectively, which could be partly explained by decreased loss and increased input of C and N to soil. The effects of grazing exclusion on soil C and N concentration and storage primarily occurred in the upper soil depths. The results indicate that removal of grazing pressure within the RGLG program was an effective restoration approach to control grassland degradation in this region. However, more comprehensive studies are needed to evaluate the effectiveness of the RGLG program and to improve the management strategies for grassland restoration in this area.  相似文献   

14.
There are more people but less land in China,so food safety has always been a most important issue government concerned.With continuous population increase,economic development and environment protection,cropland occupation and supplement are unavoidable.It not only leads to the variation of cropland area,but also makes the light-temperature potential productivity per unit area different due to regional climate differentiation,therefore impacts the total potential productivity and food output eventually.So,it is necessary to analyze the climate differentiation between occupation and supplement cropland areas and to study its impact on total potential productivity,which is significant to reasonably develop natural resources and instruct agricultural arrangement.This study firstly discussed the variation and distribution of occupation and supplement croplands in China from 2000 to 2008,then analyzed the climate differentiation between occupation and supplement cropland areas and its effect on light-temperature potential productivity.The results demonstrate:1) From 2000 to 2008,the cropland variation presented occupation in the south and supplement in the north,but overall decreased.Supplement cropland was mainly from ecological reclamation(77.78%) and was mainly distributed in Northeast China and Northwest China with poor climatic and natural conditions.Occupation cropland was mainly used for construction(52.88%) and ecological restoration(44.78%) purposes,and was mainly distributed in the Huang-Huai-Hai Plain,and the middle and lower reaches of the Changjiang(Yangtze) River with better climatic and natural conditions.2) The climate conditions were quite different in supplement and occupation cropland areas.The annual precipitation,annual accumulated temperature and average annual temperature were lower in the supplement cropland area,and its average po-tential productivity per unit was only 62% of occupation cropland area,which was the main reason for the decrease of total potential productivity.3) Cropland occupation and supplement led to the variation of total potential productivity and its spatial distribution.The productivity decreased in the south and increased in the north,but had a net loss of 4.38315×107 t in the whole country.The increase of cropland area was at the cost of reclaiming natural forest and grassland resources,and destroying natural ecological environment,while the decrease of cropland area was mainly due to a lot of cropland occupied by urban-rural construction,which threatened the sustainable use of cropland resources.  相似文献   

15.
Land use/land cover change (LUCC) is a focus of the research of global environmental changes.The middle and upper reaches of the Yangtze River,which are the most ecologically fragile mountainous area in China as well as one of the areas in China with most notable LUCC, have been on the Chinese Government‘s list of priority areas for ecological restoration. This paper is to reveal the trend of LUCC and the ecological degradation arising from it, and to provide a basis for the future sustainable use of land resources in the region based on a detailed analysis of Yiliang County. Based on the county‘s land use/cover maps in 1960, 1980 and 2000 drawn with the aid of aerial photograph interpretation, field investigation and GIS based spatial-temporal data analysis, LUCC during 1960-2000 period and the ecological degradation arising from it were analyzed. Using the Markv model, the paper brings out a forecast of what the county‘s LUCC would be like if the county‘s current land use continues, as well as the reasons and countermeasures for restoring degraded ecosystems.  相似文献   

16.
In China,many scenic and tourism areas are suffering from the urbanization that results from physical development of tourism projects,leading to the removal of the vegetative cover,the creation of areas impermeable to water,in-stream modifications,and other problems. In this paper,the risk of soil erosion and its ecological risks in the West Lake Scenic Spots (WLSS) area were quantitatively evaluated by integrating the revised universal soil loss equation (RUSLE) with a digital elevation model (DEM) and geographical information system (GIS) software. The standard RUSLE factors were modified to account for local climatic and topographic characteristics reflected in the DEM maps,and for the soil types and vegetation cover types. An interface was created between the Arcinfo software and RUSLE so that the level of soil erosion and its ecological risk in the WLSS area could be mapped immediately once the model factors were defined for the area. The results from an analysis using the Arcinfo-RUSLE interface showed that the risk value in 93 % of the expanding western part of the WLSS area was moderate or more severe and the soil erosion risk in this area was thus large compared with that in the rest of the area. This paper mainly aimed to increase the awareness of the soil erosion risk in urbanizing areas and suggest that the local governments should consider the probable ecological risk resulting from soil erosion when enlarging and developing tourism areas.  相似文献   

17.
Spatial heterogeneity is widely used in diverse applications, such as recognizing ecological process, guiding ecological restoration, managing land use, etc. Many researches have focused on the inherent scale multiplicity of spatial heterogeneity by using various environmental variables. How these variables affect their corresponding spatial heterogeneities, however, have received little attention. In this paper, we examined the effects of characteristics of normalized difference vegetation index (NDVI) and its related bands variable images, namely red and near infrared (NIR), on their corresponding spatial heterogeneity detection based on variogram models. In a coastal wetland region, two groups of study sites with distinct fractal vegetation cover were tested and analyzed. The results show that: 1) in high fractal vegetation cover (H-FVC) area, NDVI and NIR variables display a similar ability in detecting the spatial heterogeneity caused by vegetation growing status structure; 2) in low fractal vegetation cover (L-FVC) area, the NIR and red variables outperform NDVI in the survey of soil spatial heterogeneity; and 3) generally, NIR variable is ubiquitously applicable for vegetation spatial heterogeneity investigation in different fractal vegetation covers. Moreover, as variable selection for remote sensing applications should fully take the characteristics of variables and the study object into account, the proposed variogram analysis method can make the variable selection objectively and scientifically, especially in studies related to spatial heterogeneity using remotely sensed data.  相似文献   

18.
In China, many scenic and tourism areas are suffering from the urbanization that results from physical development of tourism projects, leading to the removal of the vegetative cover, the creation of areas impermeable to water, in-stream modifications, and other problems. In this paper, the risk of soil erosion and its ecological risks in the West Lake Scenic Spots （WLSS） area were quantitatively evaluated by integrating the revised universal soil loss equation （RUSLE） with a digital elevation model （DEM） and geographical information system （GIS） software. The standard RUSLE factors were modified to account for local climatic and topographic characteristics reflected in the DEM maps, and for the soil types and vegetation cover types. An interface was created between the Areinfo software and RUSLE so that the level of soil erosion and its ecological risk in the WLSS area could be mapped immediately once the model factors were defined for the area. The results from an analysis using the Areinfo-RUSLE interface showed that the risk value in 93 % of the expanding western part of the WLSS area was moderate or more severe and the soil erosion risk in this area was thus large compared with that in the rest of the area. This paper mainly aimed to increase the awareness of the soil erosion risk in urbanizing areas and suggest that the local governments should consider the probable ecological risk resulting from soil erosion when enlarging and developing tourism areas.  相似文献   

19.
The Revised Universal Soil Loss Equation(RUSLE) was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system(GIS) and remote sensing(RS) technologies.To improve the accuracy of soil-erosion estimates,a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index(NDVI) datasets.The new C-factor was then applied in the RUSLE to integrate rainfall,soil,vegetation,and topography data of different periods,and thus monitor the distribution of soil erosion patterns and their dynamics during a 30-year period of the upstream watershed of Miyun Reservoir(UWMR),China.The results showed that the new C-factor estimation method,which considers land cover status and dynamics,and explicitly incorporates within-land cover variability,was more rational,quantitative,and reliable.An average annual soil loss in UWMR of 25.68,21.04,and 16.80 t ha-1a-1was estimated for 1990,2000 and 2010,respectively,corroborated by comparing spatial and temporal variation in sediment yield.Between 2000 and 2010,a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1a-1,while during 1990-2000 such lands only increased on average by 0.46%.Areas that classified as severe,very severe and extremely severe accounted for 5.68% of the total UWMR in 2010,and primarily occurred in dry areas or grasslands of sloping fields.The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners.Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land,afforestation,or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.  相似文献   

20.
The Chinese government adopted six ecological restoration programs to improve its natural environments. Although these programs have proven successful in improving local environments, some studies have questioned their performance when regions suffer from drought. Whether we should consider the effects of drought on vegetation change in assessments of the benefits of ecological restoration programs is unclear. Therefore, taking the Grain for Green Program(GGP) region as a study area, we estimated vegetation growth in the region from 2000–2010 to clarify the trends in vegetation and their driving forces. Results showed that: 1) vegetation growth increased in the GGP region during 2000–2010, with 59.4% of the area showing an increase in the Normalized Difference Vegetation Index(NDVI). This confirmed the benefits of the ecological restoration program. 2) Drought can affect the vegetation change trend, but human activity plays a significant role in altering vegetation growth, and the slight downward trend in the NDVI was not consistent with the severity of the drought. Positive human activity led to increased NDVI in 89.13% of areas. Of these, 22.52% suffered drought, but positive human activity offset the damage in part. 3) Results of this research suggest that appropriate human activity can maximize the benefits of ecological restoration programs and minimize the effects of extreme weather. We therefore recommend incorporating eco-risk assessment and scientific management mechanisms in the design and management of ecosystem restoration programs.  相似文献   

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