The rapid expansion of transportation infrastructure has brought sustained and multidimensional impacts of railway construction on surrounding ecosystems. This study examined ecological changes across the pre-construction, construction and post-construction phases of the Lalin Railway in an ecologically fragile region. Based on multi-temporal monitoring data, we applied the Random Forest model and Geographical Detector to explore land use changes, landscape pattern dynamics, variations in the remote sensing ecological index (RSEI) and their driving factors. The results show continuous land use evolution, with the comprehensive annual land use change rate exceeding 1% from 2014 to 2022. The transition rates of cropland, built-up land and unused land were all above 40%, and built-up land increased by 2.45%. Forestland and grassland remained the dominant land cover types, with forestland expanding by 1.89% and grassland declining by 1.67%. Railway construction increased landscape diversity and fragmentation, with the most pronounced effects within the 1 km buffer zone along the railway. The regional RSEI, a key indicator of ecological quality, decreased from 0.52 in 2014 to 0.45 in 2022, following a trend of initial decline and subsequent recovery. This reveals that the local ecosystem has gradually recovered after construction but has not been fully restored to its original state. Driving factor analysis demonstrates that land use structure dominates the spatial pattern of regional ecological quality. Based on these findings, we propose targeted ecological protection strategies, offering scientific guidance for the green and ecologically integrated development of linear transportation infrastructure.

AbstractGrain self‐sufficiency (GSS) is gaining increased attention throughout the world, and this holds particularly true for China. This study, therefore, investigated spatial and temporal patterns of GSS at the county level in China from 1980s to the 2010s; then explored future GSS changes in the 2035s according to China's 2016 dietary nutrition guidelines, under the circumstances of maximum, average and minimum grain yield increase rate; and finally discussed the ability of a county to purchase grain to meet its demands. The results indicate that the number of counties with self‐insufficiency for total grain and ration decreased, and the amount of counties with high‐level self‐sufficiency for total grain and ration increased. However, the change in the number of counties with feed grain self‐insufficiency and high‐level self‐sufficiency is opposite to that of ration and total grain. Eastern China was characterised by high GSS of total grain, ration and feed grain. As for different kinds of grain, high level of GSS distributed in main grain producing areas, such as rice in south China, wheat in western China and Huang Huai Hai Plain, maize in north and northwest China and soybean in northeast China. Qinghai‐Tibet plateau has undergone poor food security in the last 30 years. In the 2035s, China's total GSS level and ration self‐sufficiency level will be improved under the maximum and average grain yield increase rate, whilst for feed grain, the self‐sufficiency level will be improved only under the maximum grain yield increase rate. The Qinghai‐Tibet plateau has always been a fragile area of food security. This study plays the vital function in understanding China's food security and contributes to the optimisation of agricultural production as well as the utilisation of both internal and external markets.

Research on spatial flow as it relates to the relationship between the supply and demand of ecosystem services supports a significant connection between the supply of ecosystem services and human well-being. Understanding the entire process of the production and flow, as well as the use of ecosystem services, accurately assessing the balance of supply and demand of ecosystem services, and establishing a two-way feedback relationship between supply and demand are vital for the scientific management of the ecosystem and ensuring the sustainable development of regional resources. Based on a large number of relevant publications, this paper comprehensively summarizes the concepts and assessment methods of ecosystem service supply and demand from the perspective of ecosystem service supply and demand, and discusses the impacts of land use and climate change on the temporal and spatial changes of ecosystem services under the background of global change. Then, an analysis of the research progress in the ecosystem services spatial flow indicated that there are still deficiencies in the quantification of cultural services, the dynamics of ecosystem service flow and the driving mechanism of ecosystem services. We also propose that clarifying the driving mechanism and transfer process of ecosystem services, and realizing the mutual conversion between different spatial-temporal scales of ecosystem services, is an important approach for improving the application of ecosystem services research in practice in the future.

Ecosystem service research is essential to identify the contribution of the ecosystem to human welfare. As an important ecological barrier zone, the Qinghai-Tibet Plateau (QTP) supports the use of a crucial wind erosion prevention service (WEPS) to improve the ecological environment quality. This study simulated the spatiotemporal patterns of the WEPS based on the Revised Wind Erosion Equation (RWEQ) and its driving factors. From 2000 to 2015, the total WEPS provided in the QTP ranged from 1.75 × 109 kg to 2.52 × 109 kg, showing an increasing and then decreasing trend. The average WEPS service per unit area was between 0.72 kg m−2 and 1.06 kg m−2. The high-value areas were concentrated in the northwest and north of the QTP, and the total WEPS in different areas varied significantly from year to year. The average retention rate of the WEPS in the QTP was estimated to be 57.24–62.10%, and high-value areas were mainly located in the southeast of the QTP. The total monetary value of the WEPS in the QTP was calculated to be between 223.56 × 109 CNY and 321.73 × 109 CNY, and the average WEPS per unit area was between 0.08 CNY m−2 and 0.13 CNY m−2, showing a declining–rising–declining trend. The high-value areas gradually expanded to the west and east of the QTP. The slope was the most important factor controlling the spatial differentiation of the WEPS, followed by the landform type, average annual precipitation, and average annual wind speed, and human activities such as land-use change could improve the WEPS by returning farmland to grassland and desertification control in the QTP.

防风固沙服务是干旱半干旱地区生态系统提供的最重要的防护型服务，对风蚀地区及周边区域的生态环境安全具有重要意义。基于修正的土壤风蚀方程（RWEQ）模型模拟了1980—2018年浑善达克地区防风固沙服务的时空变化，利用地理探测器分析了包括数值和类型变量的自然与社会经济因素对该区防风固沙服务空间格局的影响及交互作用。研究结果显示：（1）1980—2018年，单位面积防风固沙量波动下降，2015年单位面积防风固沙量最小，为13.01 kg/m~2。同时，防风固沙保有率波动增加，2018年保有率达到最大值，为94.28%;（2）土壤类型、年末牲畜数量、年降水量与人工造林面积是影响防风固沙服务空间变化的主要因素，其中，土壤类型对防风固沙服务空间变化的影响最大，q值为75.15%;（3）各驱动因素间的交互作用都会放大单因子对浑善达克地区防风固沙服务空间分布的影响。其中，年均温对防风固沙服务空间分布变化具有较强的间接影响。因此，在土壤类型、年均温的间接作用下，1980—2018年浑善达克重点生态功能区防风固沙能力整体提高、风蚀程度有所缓解与年均风速、年降水量变化，以及2000年之后京津风沙源工程引起的人工造林面积、年末牲畜数量的空间分布格局变化有密切关系。

An understanding of the relationships among multiple ecosystem services (ES) facilitates ecosystem management and decision-making. The study of ES bundles can well explain the complex interactions between different ES in a region. Shenyang is a significant economic development and food production area in Northeast China, with a diverse range of ES types. In this study, we quantified eleven ES from Shenyang, China (two provisioning services, eight regulating services, and one cultural service). The trade-offs and synergies among ES were analyzed by Spearman's correlation analysis. The ES bundles were identified using principal component analysis and k-means cluster analysis. Finally, the random forest method was employed to identify the driving factors affecting the ES bundles. The results showed: (1) all ES in Shenyang improved between 2000 and 2019; (2) the most obvious trade-off was found between sand fixation and water conservation; (3) the ES in the study region could be clustered into five different ES bundles which were primarily affected by land-use type; and (4) social-ecological factors largely explained and predicted the formation and distribution of ES bundles. The study provides reference information for the management and optimization of Shenyang's ecosystems and land use regulation.

Inner Mongolia is the important ecological barrier zone in northern China,which plays an important role in the prevention and control of wind in the regional ecosystem.Based on the Revised Wind Erosion Equation(RWEQ)model and the cost-recovery method,this study simulated the wind erosion prevention service(WEPS)in Inner Mongolia in 2010 and 2015,investigated the spatial pattern of material and monetary value of WEPS,and analyzed the differences among various cities and various ecosystems.The results indicated that the total WEPS of Inner Mongolia was estimated to be 73.87×108t in 2015,which was 4.61×108t less than in 2010,while the mone-tary value of WEPS was calculated to be 738.66×108 yuan in 2015,which was 46.16×108 yuan less than in 2010.Among all the leagues and cities,Xilin Gol League supported the highest WEPS,reaching 18.65×108t in 2015,while Wuhai provided the lowest.The WEPS of Hulunbeier increased the most,by 4.37×108 t from 2010 to 2015.The WEPS in the grassland ecosystem was the highest among the different ecosystems,accounting for more than 55％of the total WEPS in Inner Mongolia,but it was reduced by 1.05x108t during the same period.The WEPS in the forest ecosystem increased the most,reaching 0.19×108t.This study found that the implementation of projects such as returning farmland to forests and grasses and sand control effectively increased the WEPS by increasing the forest area.However,unsuitable land use increased the desertification of ecosystems which resulted in a re-duction of WEPS in Inner Mongolia.

The transregional flow of ecosystem services (ESs) results in the diffusion of ES benefits. Many National Key Ecological Function Areas (NKEFAs) are located in northwestern China, which faces a high risk of wind erosion. Therefore, the windbreak and sand fixation service (WSFS) is important not only for the local NKEFAs but also for the downwind areas. This study assessed the benefit diffusion process of the WSFS in NKEFAs by combining the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) and the Revised Wind Erosion Equation (RWEQ) models. In 2010, 1689 WSFS diffusion paths were simulated first by using HYSPLIT, with the path directions varying from northeast to east and southeast and passing through most areas of northern China. By interpolating the diffusion paths, the beneficiary areas of the WSFS amounted to 617.81 x 10(4)-1570.99 x 10(4) km(2) in 2010 and spread beyond China, mainly extending to the East Asian region. Incorporation of the RWEQ model showed that the amount of WSFS benefit diffusion from each NKEFA varied greatly and was mainly concentrated in northeastern, central or northwestern China. In addition, the distribution frequency of the diffusion paths and the benefit diffusion effects exhibit obvious distance attenuation characteristics. Based on this study, we can establish a direct connection between the WSFS in the NKEFAs and the downwind beneficiary areas and provide a reference for the interregional ecological compensation policy, thereby guaranteeing the sustainable development of both wind erosion areas and the downwind affected areas.

Afforestation in the Three North Region (TNR) of China has received wide concern due to the low survival rate and threats to water security associated with the lack of available precipitation for vegetation. It is crucial to provide a spatial layout for revegetation according to the available precipitation to achieve the vegetation cover target. This study investigated the spatial pattern of precipitation, determined the suitable vegetation distribution based on the ecological water requirements and precipitation, and proposed an optimized revegetation scheme by comparing the actual and suitable vegetation patterns. The results indicated that the actual vegetation that matched the pixel-level precipitation accounted for 67.24% of the total vegetation area in the TNR. However, 18.50% of the actual forest, 21.82% of the actual shrublands, and 19.95% of the actual grasslands were overloaded with respect to precipitation. The total suitable vegetation area was reduced slightly compared to the actual vegetation area. There is still some potential for the revegetation of forest and shrublands, mainly those in the eastern and south-eastern parts of the TNR. The optimized revegetation area in the TNR was 3.04 × 106 km2, including a maintenance management type of 2.19 × 106 km2, an upgrade type of 0.49 × 106 km2, and a degradation type of 0.37 × 106 km2. Maintenance management (natural restoration) and transformation to vegetation types with lower ecological water requirements were recognized as important revegetation practices in the TNR. This study provides guidelines to adjust the Three North Shelterbelt Project policies based on precipitation data to reduce the negative impact of revegetation on the hydrological cycle.

Ecosystem service (ES) flow reveals the transregional benefits transferred from service supply areas (SSAs) to service benefiting areas (SBAs), which correspond to the sellers and buyers of interregional ecological compensation, respectively. However, current ecological compensation policies usually ignore this close connection. This study took the water supply services (WSSs) with the most obvious flow characteristics as an example and established a universal framework for interregional ecological compensation by combining WSSs flow simulation and regional disparity. The simulation process was programmed with Interactive Data Language (IDL) and analyzed with ArcGIS. Most regions serve as a dual role in the WSSs flow process, the water suppliers and users are relative and scale-dependent. Taking Ningxia as an example, As water benefiting areas (WBAs)/buyers, the total material inflow to Ningxia was 135.86 × 108 ~ 294.22 × 108 m3 from 2000 to 2015 and the value inflow ranged from 1077.39 × 108 ~ 2333.16 × 108 CNY, requiring 101.64 × 108 ~ 293.51 × 108 CNY ecological compensation paid by Ningxia. As water supply areas (WSAs)/sellers, the total material outflow from Ningxia was 72.83 × 108 ~ 200.46 × 108 m3 from 2000 to 2015, and the value outflow was between 577.54 × 108 CNY and 1589.65 × 108 CNY, requiring 63.80 × 108 ~ 112.34 × 108 CNY of ecological compensation to be paid by the downstream basins, especially the Shizuishan – Hekou Town subbasin. Overall, Ningxia was a beneficiary area of WSSs flow and the payers of interregional ecological compensation, with a net payment amount of 37.84 × 108 ~ 181.16 × 108 CNY. This study provides a direct spatial-visualized reference to water resource management for policy-makers and promotes the integration of ES flow and interregional ecological compensation. Furthermore, it can improve the public recognition of interregional ecological compensation with the spatial mapping of the levy and allocation and conducive to the sustainable provisioning of ESs ultimately.

城市生态系统服务指人类从城市生态系统中获取的利益,城市绿色空间是提供城市生态系统服务的主要载体.而城市化进程的加快对城市绿色空间的存量造成威胁,城市生态系统服务难以达到居民需求.传统的城市绿色空间评价指标集中于对城市绿地面积的评价,指标偏向整体性和二维化,忽视了三维绿量,也鲜少关注生态系统服务质量.基于以上背景提出了一个城市生态系统服务功能评价指标——城市生态舒适度,通过人体的主观感受对城市生态系统服务功能做出质量反馈,并结合灰色关联分析法构建了该指标的评价模型.通过样本的条件对比分析得出,当绿视率水平低于30％时,城市生态舒适度的主要影响因子为绿视率;当绿视率水平高于30％时,则是湿度、PM2.5浓度和风力等级.将评价模型的模拟结果与实测值进行对比验证,结果显示二者的变化趋势基本相同,表明评价模型科学有效.

Ecosystem services (ESs) represent a complex network of multiple natural and socioeconomic driving factors. These interactions have become more common in an increasingly metacoupled world and have led to various ecosystem service bundles (ESBs). This study selected and assessed 8 representative ES types in Ningxia, including agricultural product provision (AP), water provision (WP), hay production (HP), livestock product provision (LP), wind erosion prevention (WEP), water conservation (WCON), soil retention (SR) and carbon sequestration (CS). Then, we used Spearman rank correlation coefficients to reveal the tradeoff or synergistic relationships between paired ESs at the grid, county and reginal scale and explored their linkages with socioecological driving factors. Based on the ES evaluation and ES relationship analysis, we mapped the spatiotemporal dynamic changes in ESBs in Ningxia in 2000, 2005, 2010, and 2015. The results reflected the significant differences in natural and socioeconomic conditions from south to north in Ningxia. There were both positive and negative areas for a single relationship. On the whole, the supply of agricultural products were mainly negatively correlated at all the 3 scales. Most ES pairs were mainly positively correlated at all the scales, highlighting the coupled relationships among these ESs and certain achievements in ecological construction in Ningxia. There was strong consistency and correspondence between the ES distribution patterns and their pairwise relationships. The mechanism patterns tended to be spatially inversely distributed for the tradeoff-relationship ESs, while be more similarly distributed for the synergy-relationship ESs. Based on cluster analysis, three ESBs with similar ESs and driving factors were identified, including the Northern Agricultural Bundle (NA), Central Arid Sandstorm Prevention Bundle (CASP), and Southern Mountainous High Provision-Regulation Synergy Bundle (SMHPS). This study emphasized the spatiotemporal dynamic changes in the ESBs and tried to map the ES relationships at different scales to more precisely reveal the superposition areas of tradeoffs and synergies and their linkage with driving factors. Mapping the spatiotemporal dynamic changes in ESBs can enhance the understanding of the complex ES relationships and contribute to establishing a foundation for targeted ecosystem management in different areas.

In an increasingly meta-coupled world, the balance of interregional environmental development is becoming increasingly important, and an ecological cooperation community is emerging. Mapping the flow of an ecosystem service (ES) can aid in understanding the spatiotemporal transport paths from generation to use, thereby facilitating a visualization of the interregional relationship on environmental management. In this study, we evaluated the material quantity and value of the wind-break and sand-fixing service (WSS) of Inner Mongolia, simulated the material and value flow and identified the service benefitting regions (SBRs). The benefitting land, population and economy in China were used to reflect the WSS flow effect. The results showed that: the total material quantity of WSS in Inner Mongolia was 7.83 x 10(12) kg in 2010 and 7.37 x 10(12) kg in 2015, with a total value of 7.83 x 10(10) CNY and 7.37 x 10(10) CNY, respectively, of which 79.18% in 2010 and 79.92% in 2015 flowed to the downwind SBRs out of Inner Mongolia. The spatial transport paths and SBRs were mainly located in northern China, the Korean Peninsula, Japan, Mongolia and the Russian Far East in 2010 and 2015. The material and value flow rate of the WSS had spatial proximity features, resulting in differences in the benefits received by benefitting countries and provinces. The SBRs in China covered 67.50% and 65.67% of the total area of China in 2010 and 2015, respectively. The people benefitting amounted to 88.01% of the total population in China in 2010 and 86.58% in 2015, corresponding to a beneficial gross domestic product (GDP) of 92.00% and 90.50%, respectively, of China's total GDP in each year. Based on the spatiotemporal movements of the material and value flows of the WSS, this study revealed the spatial and temporal correspondences between the area's supply and benefits from the WSS of Inner Mongolia. It provides a scientific basis for decision-makers to coordinate interregional benefit transfers through wind erosion control in Inner Mongolia and ensure continuing flow of benefits to SBRs.

Transregional Ecosystem Service (ES) flows are ubiquitous and are receiving more attention in an increasingly metacoupled world. Water has typical flow properties and is a common flow medium of Water-related Ecosystem Services (WES), such as water supply, water conservation, etc. Ningxia is in a transition zone from semi-arid to arid areas of the Yellow River basin of China. Its role in the water transfer from the Qinghai-Tibet Plateau to the downstream city and agriculture is important in allocating the scarce water resources in (semi-)arid regions. This study described the water flow process to/from Ningxia and revealed the supply-demand balance of water in Ningxia and its adjacent basins. On the grid scale, the total dynamic residual water in Ningxia from 2000 to 2015 was 2.20×1012 m3~6.26×1012 m3. However, there was still a dynamic water demand gap of -72.25×108 m3 ~ -59.08×108 m3, which could only be supplemented by manual water intake. At the regional scale, Ningxia had two sides, which was both the beneficiary of the upper Xiaheyan basin, Qingshui River - Kushui River basin, Xiaheyan - Shizuishan basin, Hexi Inland River-Shiyang River basin, Hexi Inland Rive-Hexi desert basin and internal flow area, and the supplier of the downstream Shizuishan - Hekou town, Longmen to Sanmenxia subbasin. As the benefitting district, the total net inflow water supply service in the supply area from 2000 to 2015 was 135.86×108 m3 ~ 294.22×108 m3, among which the non-Ningxia region in the sub-basin above the Xiaheyan basin was the main source region of water supply service in Ningxia. As the supply area, the net outflow volume of water supply service in Ningxia from 2000 to 2015 was 72.83×108 m3~200.46×108 m3, mainly flowing to non-Ningxia regions from Shizuishan to Hekou town. Overall, the net volume of water supply service flowing into Ningxia from 2000 to 2015 ranged from 63.03×108 m3 to 93.76×108 m3. This study can enhance the understanding of trans-boundary telecoupling relationship of WES in Ningxia and contribute to form a foundation for interregional management and allocation of WES in (semi-)arid regions to promote equity in sustainable regional development.

Simulating the flows of ecosystem services (ESs) can help understand their spatiotemporal flow paths from generation to use, thereby facilitating payments from beneficiaries to providers of ESs. In this study, an analytical framework incorporated with ES flows and regional disparity was established to compute payments for wind erosion prevention service (WEPS). The results showed that between 2010 and 2015, both the potential and actual wind erosion amounts in Yanchi County decreased considerably, and the total amount of sand fixed by WEPS decreased significantly from 3.71 × 109 kg to 0.08 × 109 kg; additionally, the economic value of the WEPS also decreased from CNY 479.46 million to CNY 10.22 million. Based on the spatiotemporal movements of the physical and economic value flows of the WEPS, this study revealed spatiotemporal relationships between areas providing and benefiting from the WEPS of Yanchi County and provided a direct, scientific basis for decision makers to formulate payment systems for WEPS. The total amount paid for WEPS by beneficiaries in China should theoretically be CNY 38.16 million in 2010 and CNY 1.00 million in 2015 based on the economic value flow of WEPS and the regional disparity coefficient. This framework can provide a scientific and objective basis for establishing horizontal ecological compensation policies.

Ecosystem service (ES) flows across geophysical and administrative boundaries are ubiquitous and are receiving more attention in an increasingly metacoupled world. Omitting trans-boundary ES flows from ES assessments will lead to unilateral conclusions and underestimation of ES contributions over distances. Inner Mongolia is an important ecological security barrier of China and Eurasia, but the trans-boundary effect of this barrier is difficult to be quantitatively evaluated and is rarely assessed. This study assessed the ecological security barrier function of Inner Mongolia from the perspective of trans-boundary ES flows, including wind prevention and sand fixation (WPSF), water provision (WP), carbon sequestration (CS) and livestock product provision (LPP) service flows. The trans-boundary value flows for the WPSF, WP, CS and LPP services in 2010 were 6.20 × 1010 CNY (Chinese currency, yuan), 0.21 × 1010 CNY, 1.29 × 1010 CNY and 1.27 × 1010 CNY, respectively, and 5.89 × 1010 CNY, 0.16 × 1010 CNY, 0.37 × 1010 CNY and 1.33 × 1010 CNY, respectively, in 2015; correspondingly, the percentages of these trans-boundary value flows in terms of the total value flow were 69.12%, 2.34%, 14.38% and 14.16%, respectively, in 2010 and 76.00%, 2.06%, 4.77% and 17.16%, respectively, in 2015. Therefore, WPSF service plays a more important role in the trans-boundary ecological security barrier function of Inner Mongolia. This study can enhance the understanding of trans-boundary telecoupling in an integral socio-ecological system and identify the critical ESs to form a foundation for ecological conservation measures considering sustainable development.

宁夏草地在区域防风固沙中发挥了重要的作用.现有研究大多是基于微观尺度,针对区域尺度的宁夏草地防风固沙时空格局及其变化规律尚不清楚.本文基于RWEQ模型,利用ArcGIS和ENVI,对2000-2015年间宁夏草地防风固沙服务功能进行了定量化的估算.结果 表明:①2000-2015年宁夏草地年潜在风蚀总量为1028.30～7540.50万t,年实际风蚀总量为269.75～3318.71万t;②2000-2015年宁夏草地年防风固沙物质总量为729.80～4120.04万t,16年间共增加了124.13万t,平均单位面积年防风固沙物质量在0.33～1.77 kg/m2之间,空间分布呈现出“中高南北低”的特点;防风固沙保有率平均值为0.65～0.79;③草地防风固沙等级以“中等”和“较弱”为主,占总固沙量的47％～65％;“中等”及以上的草地面积波动增加,“弱”和“较弱”等级的草地面积减少;④中部干旱区和南部山区草地防风固沙量占总量的90％以上,北部灌区草地防风固沙量则呈现“先增后减”的趋势.北部灌区和中部干旱区是未来风沙治理需更加关注的区域.本文揭示了宁夏草地防风固沙的时空格局,为未来区域风沙治理提供了参考.

防风固沙型重点生态功能区是我国主要的防沙屏障带,对保障全国的生态环境安全具有重要意义.基于RWEQ模型评估了防风固沙型重点生态功能区防风固沙服务的空间格局,利用HYSPLIT模型模拟了防风固沙型重点生态功能区防风固沙服务的空间流动路径,从生态系统服务流动的角度建立了防风固沙型重点生态功能区及其防风固沙服务受益区之间的时空联系.研究表明,2010年防风固沙型重点生态功能区的防风固沙总量为5.55× 1012 kg,受益区总面积为32.16× 106 km2,涉及防风固沙服务流动路径755条.受益区主要位于中国的西北、华北、东北的广大区域,朝鲜半岛,日本,俄罗斯远东地区和北太平洋的广大海域,其中中国境内的受益区占比24.12％,受益草地面积最大,受益建设用地占中国建设用地总面积的比例最高,受益效益更为明显.在空间分布上,防风固沙服务流动效益以各防风固沙型重点生态功能区为中心呈现明显的圈层式递减特征.防风固沙型重点生态功能区的防风固沙服务流动对下风向受益区的生产生活具有重要的保障作用,研究能够为防风固沙型重点生态功能区的区域间生态补偿政策制定提供科学的参考依据,从而进一步提升防风固沙型重点生态功能区的屏障作用,保障国家生态安全.

生态系统可通过植被蒸腾与土壤蒸发作用调节区域温度与湿度。三北工程黄土高原丘陵沟壑区属于干旱和半干旱区,森林降温增湿功能有助于改善区域生存环境。在分析研究区森林覆被变化基础上,利用Penman-Monteith公式模拟了森林实际蒸散量,研究了森林增湿与降温效果。研究结果显示:（1）1980—2015年研究区森林面积增加了2.25%,主要来自荒草地、耕地和荒漠;（2）1980—2015年研究区森林6—9月实际蒸散总量为1.19×10 10 —1.40×10 10 t/a,平均实际蒸散量为219—257 mm,可使区域6—9月绝对湿度每日增加0.47—0.55 g/m~3,相对湿度每日增加2.87%—3.32%;（3）森林通过蒸散作用吸热量为29.15×10 15 —34.26×10 15 kJ/a,单位面积蒸散吸热量为53.72×10~8—63.13×10~8 kJ hm -2 a -1 ,通过蒸散吸热日降温量为0.92—1.08℃/d;（4）研究区森林蒸散量在1980—2010年逐渐增加,但在2015年明显下降,这主要是由降水减少导致;森林面积较大的山西和陕西森林蒸散降温增湿效果较好。通过对比相同年份不同土地覆被发现,森林实际蒸散量显著高于其他土地覆被类型。因此,未来研究区可在水资源承载能力范围内适当增加森林面积,充分发挥森林调节区域气候的作用。

生态工程费用效益评价是对生态工程实施有效性及合理性的评估.基于费用效益理论,分析了呼伦贝尔草原草甸生态功能区建设费用投入情况,在区分气候与人类活动因素对生态效益变化的贡献率的基础上,采用遥感和统计数据从生态、经济和社会三个方面评价了该功能区的综合效益,计算功能区建设工程的效益-费用比,综合评估了呼伦贝尔草原草甸生态功能区建设的经济性.结果 表明:(1)2010-2014年该功能区重点生态功能区相关领域建设总投入为84.31亿元,其中重点生态功能区建设投入为1.18亿元,占总投入的1.40％;(2)利用残差趋势分析法计算出人类活动因素对研究区产生生态效益变化的贡献率为37.25％,2011-2015年该功能区重点生态功能区建设产生的生态效益为12458.13万元;(3) 2011-2015年该功能区重点生态功能区建设产生的经济效益和社会效益分别为4877.74万元和2804.85万元;(4)呼伦贝尔草原草甸生态功能区建设的工程效益-费用比为1.71,效益高于费用,证明该工程具有一定的经济性.研究将为国家重点生态功能区工程的不断完善以及加快推进实现国家重点生态功能区的功能定位提供一定的科学支撑.