The Research of Impact of Returning Cultivated Land to Forests in Poverty Areas around Beijing-Tianjin on Local Economy——A Case of Shunping County in Hebei Province, China

Taking Shunping County of Hebei Province as an example,according to the relevant survey data in the year 2008 after returning cultivated land and data in the year 2001 before returning cultivated land, the thesis analyzes the impact of implementation of project of returning cultivated land to forests on local land use structure, three industrial added value and famers' per capita income. The results show that returning cultivated land has played a certain positive role on the local economic development and the improvement of people's life level.However, there are also some shortcomings: although famers' income is increasing with low growth rate, a large portion of famers still have not shaken off poverty; the farmers depends on subsidies greatly and the compensation mechanism of returning cultivated land is not considered well. China should further perfect the ecological compensation plan, and build rational ecological compensation mechanism in order to make the areas of returning cultivated land have self-blood-producing function; Shunping County should make full use of the location advantage in areas around Beijing-Tianjin, develop deep processing based on fruit trees industry, strengthen farmers' skill training, and increase input in the agricultural infrastructure construction to propel the sustainable development of agriculture.

Evaluation and Selection of Introduced Tree Species in the Beijing-Tianjin Corridor

Based on the extensive analysis of natural and social conditions,regional development,and characteristics of tree species in the Beijing-Tianjin corridor,a comprehensive evaluation index system that consists of A,B,C,D layers was established for introduced tree species.Nine local representative introduced tree species were evaluated using the analytic hierarchy process(AHP).The results showed that Platanus orientalis,Quercus mongolicus,and Zizyphusjujube performed better comprehensively and were recommended as the dominant introduced tree species in the Beijing-Tianjin corridor.Other representative introduced tree species should be appropriately developed in the region.Main factors that should be taken into account for introduced tree species including drought tolerance,wintering habit,growth rate,leanness tolerance,pollution tolerance,saline tolerance,and disease resistance.

Response of Vegetation Cover Change to Drought at Different Time-scales in the Beijing-Tianjin Sandstorm Source Region,China

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 experi-enced 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.

Spatiotemporal changes in terrestrial water storage in the Beijing-Tianjin Sandstorm Source Region from GRACE satellites

The Sandstorm Source Control Project in and around the Beijing-Tianjin region was one of the most important ecological projects in China.Terrestrial water storage(TWS)has important impacts on the ecological construction,agriculture,industry,and resident's lives.Based on the Gravity Recovery and Climate Experiment(GRACE)data,meteorological and Moderate Resolution Imaging Spectroradiometer(MODIS)data,etc.,this paper analyzed spatiotemporal characteristics of TWS,groundwater storage,and precipitation,and explored the influencing factors of regional TWS combined with land use and land cover(LULC),social and economic data.The most important results were as follows:(1)From 2003 to 2016,TWS in the Beijing-Tianjin Sandstorm Source Region showed a decreasing trend with a rate of 3.14 mm yr-1.(2)The TWS decline was caused mainly by groundwater overexploitation,but not pre-cipitation variation.(3)Spatiotemporal variations of TWS were related to LULC.The area with the most serious decrease of TWS was mainly located in the southwestern part of the region,where farmland percentage and population density were greater.(4)Reducing the percent of farmland and tree planting,and adding the shrub and grass planting,could be a viable choice for the Beijing-Tianjin Sandstorm Source Control Project.These results provide a scientific basis for regional water resource and ecological management.

Soil organic carbon dynamics in Xilingol grassland of northern China induced by the Beijing-Tianjin Sand Source Control Program

To mitigate impacts of sandstorms on northern China, the Chinese government launched the Beijing- Tianjin Sand Source Control Program （BTSSCP） in 2000. The associated practices （i.e., cultivation, enclosure, and aerial seeding） were expected to greatly enhance grassland carbon sequestration. However, the BTSSCP-induced soil organic carbon （SOC） dynamics remain elusive at a regional level. Using the Xilingol League in Inner Mongolia for a case study, we examined the impacts from 2000 to 2006 of the BTSSCP on SOC stocks using the IPCC carbon budget inventory method. Results indicated that over all practices SOC storage increased by 1.7%, but there were large differences between practices. SOC increased most rapidly at the rate of 0.3 Mg C.ha-1 ＂yr-1 under cultivation, but decreased signifi- cantly under aerial seeding with moderate or heavy grazing （0.3 vs.0.6 Mg C-ha-I .yr-1）. SOC increases varied slightly for grassland types, ranging from 0.10 Mg C-ha-1 .yr-a for temperate desert steppe to 0.16 Mg C.ha-l.yr-1 for temperate meadow steppe and lowland meadow. The overall economic benefits of the SOC sink were estimated to be 4.0 million CNY. Aerial seeding with no grazing was found to be the most cost-effective practice. Finally, we indicated that at least 55.5 years （shortest for cultivation） were needed for the grasslands to reach their potential carbon stocks. Our findings highlight the importance and effectiveness of BTSSCP in promoting terrestrial carbon sequestration which may help mitigate climate change, and further stress the need for more attention to the effective- ness of specific practices.

2000–2015年京津走廊耕地和建设用地变化监测研究（英文）

Rapid peri-urbanization has become a new challenge for sustainable urban-rural development worldwide. To clarify how unprecedented urban sprawl at the metropolitan fringe impacts urban-rural landscape, this study took the Beijing-Tianjin corridor of Beijing-Tianjin-Hebei metropolitan area, one of the largest urban clusters in China, as a typical example. By using Landsat-based landscape metrics and a practical methodology, we investigated the landscape changes and discussed the potential reasons in the context of rapid peri-urbanization of China. Specifically, multi-temporal land use maps derived from Landsat images were used to calculate landscape metrics and analyze their characteristics along the urban-rural gradients. The practical methodology was used to monitor spatio-temporal characteristics of landscape change in large metropolitan areas. The results showed that landscape patterns in the area had changed greatly from 2000 to 2015 with characteristics of construction land sprawl and arable land shrinkage. The intensity and scale of landscape changes varied along the urban-rural gradients. Sampled plots in urbanized areas and rural areas demonstrated distinguishable landscape patterns and significant differences. Urban areas had more heterogeneous and fragmented landscapes than rural areas. Peri-urban areas in general experienced higher levels of land diversification than rural areas. Rural residential land appeared to be more aggregated near Beijing and Tianjin cities. Besides, our findings also indicated that urban expansion was largely responsible for landscape patterns.The findings of this study potentially provide strategical insights into landscape planning around mega cities and sustainable coordinated urban-rural development.

Examining the efficacy of revegetation practices in ecosystem restoration programs:insights from a hotspot of sandstorm in northern China

Retrospectively evaluating the efficacy of revegetation practices is helpful in planning and imple-menting future ecosystem restoration programs(ERP).Having a good understanding of how human activities can affect vegetation cover,both before and after ERP,is particularly important in sandstorm hotspot areas.The Beijing-Tianjin Sandstorm Source Region(BTSSR)is one such area.We conducted an investigation into vegetation dynamics within the BTSSR.This was done using remote sensing data in conjunction with climate data sets and land use data spanning the 1982-2014 period.The relationships between climatic factors(such as precipitation and temperature),and vegetative change were modeled using a neural network method.By a process of residual analysis,the proportions of human-induced vegetative change both before and after the ERP were established.Our results show that:1)before the ERP(1982-2000),40.96%of the study area exhibited significantly progressive vegetation changes(p<0.05).This proportion decreased to encom-pass only 20.23%of the study area in the period following the ERP(2001-2014).2)89.55%of the study area showed signs of human-induced vegetation degradation before the ERP.Between 2001 and 2014 however,following ERP,this figure fell to only 27.78%.3)ERP implementation led to visible improvements in vegetative conditions within the BTSSR,especially in areas where ecological restoration measures were directly and anthropogenically applied.These results highlight the benefits that positive human action(i.e.,revegetation initiatives implemented under the framework of an ERP)have brought to the BTSSR.