In recent years, due to the continuous urbanization, natural ecosystems are under enormous pressure, even resulting in ecological catastrophes. Moreover, with the start of the New Urbanization and Ecological Civilization Construction work in China, the demand for improvement of ecosystem services to promote human well-being is increasing. Hence, there is an intensifying contradiction between economic development and ecological protection. Ecological security patterns (ESPs) as a bridge linking ecosystem services and human society, has become one of the effective ways of constructing the protective barriers for terrestrial ecosystems. The ESPs construction directly affects the balance between social development and ecological conservation, and thus it has become the key to solving ecological problems and improving human well-being. To improve and enrich the theory of ESPs, we systematically combed the similarities and differences in the connotation of ESPs and other four main relevant concepts, namely urban growth boundary (UGB), ecological networks (EN), green infrastructure (GI), and ecological control lines (ECL). Furthermore, a research paradigm of regional ESPs construction was proposed based on literature review. According to this paradigm, research progresses on four main aspects were summarized systematically. These four aspects were research hotspots, ecological sources identification, ecological resistance surface setting, and practical application. Then the main deficiencies were indicated and summarized as follows: (1) The research objects selected in previous studies were mainly concentrated in the province, city and county levels, and were more confined to a specific administrative region, lacking larger-scale researches across administrative boundaries. (2) The selection of ecological index was mostly based on the intrinsic characteristics of ecological patches, less considering its relationship with surrounding objects and its status and functions in the whole pattern. And many studies ignored the coupling of human ecological demand and ecological processes. (3) The ecological resistance surface was assigned mainly based on land-use type, which covered up the difference between the internal space of the same land use type. The amended case studies based on impervious surface area and nighttime light were still insufficient to reveal the real situation. (4) Most of the provided policy recommendations for the protection and management of ESPs were broad and lack of the effective real-time monitoring and comparison to ecological security pattern. Based on the main disadvantage of regional ESPs construction in the current researches, we put forward four main directions for future research: setting important thresholds, evaluating the effectiveness of ESPs, constructing ESPs across multi-scales, and coupling the ESPs with ecological processes.
Scientific evaluation of the relationship between nature protection zones and national ecological security is the important foundation to guide the development of nature protection zones and the construction of national ecological security pattern. In the case of the national key ecological function zones, biodiversity conservation priority zones and national reserves, spatio-temporal distribution of natural protection zones and its important role in safeguarding national ecological security were analyzed quantitatively. This article also identified the lack of national ecological security pattern based on ecological system service assessment, put forward the ecological protection management and control suggestions for the demand of national ecological security construction and security. Results show that: (1) The total area of natural protection zones was 4.88 million square kilometers, accounting for 51.38% of the national land area. Grassland, forest and desert were the main ecosystems and had an area of 3.71 million square kilometers, accounting for 76.0% of the national protection zones area. Between 2000 and 2010, ecological system was basically stable in the national protection zones. There was only a small amount of transformation between different ecosystems. The characteristics of ecosystem transformation in different natural protection zones were slightly different. This had played an important role in protecting the stability of the ecological space and ecological security pattern. (2) Comprehensive consideration of ecosystem services importance in water conservation, soil conservation and biodiversity maintenance showed that the area of extremely important and important ecosystem services zones of natural protection zones was 3.21 million square kilometers, accounting for 66.02% of the national land area. Forest, grassland and shrub were the subject of the ecosystem services. Overall, during the 2000-2010 period, water conservation and soil conservation had improved. There was no obvious change of biodiversity maintenance. (3) The area of extremely important ecosystem services zones was 3.26 million square kilometers, accounting for 34.4% of the national land area. The 31.7% area of extremely important ecosystem services zones was not in the natural protection zones. Complementing and improving the existing natural protection zones were needed to construct the national ecological security pattern based on scientific demonstration. (4) It is urgent to establish a strict protection system for national ecological security construction and safeguard demand based on national governance model. Also, we should raise the cognitive level of natural law to enhance the comprehensive management of ecological system, upgrade the classification and zoning management to upgrade natural protection zones, improve the ecological compensation mechanism for establishing cooperative protection system, and strengthen the comprehensive supervision of ecological protection to minimize ecological damage.
At the current level of accelerating urbanization, regional ecological security is being seriously damaged. As the benefits people obtained from ecosystems, ecosystem service is the premise and guarantee of ecological security. To scientifically construct the ecological security pattern, it is firstly necessary to accurately identify the ecosystem service value (ESV). Presently, most domestic studies have used the ecosystem service static value for the estimation of the average value per unit area. Few studies have considered the importance of every single ecosystem service; most have simply considered each ecosystem service of equal importance. However, since ecosystems are dynamic, this will lead to objective differences in the change rate among each kind of ecosystem service. Therefore, the fast decreasing service will not be effectively protected if we simply consider each service of equal importance. In addition, the spatial agglomeration of ecosystem service will also influence the recognition of ecological sources by affecting their functions. In our study, based on the Liangjiang New Area, we first calculated the ecological static service values from 2009 to 2012. We then established two indexes: the significance index based on the average change rate of each ecosystem service, and the spatial richness index based on the spatial agglomeration of each ecosystem service, to reconstruct the ecosystem service value in 2012, which was then applied to the reconstruction of low, medium, and high levels of ecological security patterns. Thus, the reconstructed ESV was qualified with the same currency unit and included abundant spatial information. The results showed that: (1) the total ecosystem service static values from 2009 to 2012 decreased annually, among which the food production, soil formation and protection, and carbon fixation had the fastest loss rates; (2) the reconstructed ecosystem service values in 2012 ranged from 201 to 23634 yuan/hm2, whereas most regions were dominated by low and middle values; (3) the areas of low, middle, and high levels of security sources were 174.73 km2, 208.69 km2 and 222.20 km2, respectively. The ecological security patterns of different levels satisfy the multiple construction needs and provide fundamental assurance for the normal function of the ecological service for the future construction of the Liangjiang New Area, which would benefit the sustainable development of the area in the long term.
Constructing regional ecological security pattern, as well as optimizing the eco-spatial structure in urban agglomerations, will promote the harmonious development of the social economy and ecological environment. Based on RS and GIS technology, the study takes the Guanzhong urban agglomeration in western China as an example to identify the ecological source area according to the importance of ecosystem services and eco-environment sensitivity evaluation. We constructed the regional ecological security pattern by using the minimum cumulative resistance model, and optimized the layout of eco-spatial structure in the region. Results showed that: (1) the ecological source area was 26191.19 km2, accounting for 47.51% of the region's area; (2) except the ecological source region, the areas of low, moderate and high level ecological lands accounted for 39.14%, 9.86% and 3.49%, respectively; (3) the corridors between the ecological source region lie mostly in south-north directions and have low connectivity; (4) we aimed to construct the system of "the mode of corridor group network with green cores" with "four belts, three regions, seven groups, ten corridors, and multi centers", so as to optimize the optimization layout. This study provides a reference case for regional ecological protection and sustainable development of urban agglomerations.
Optimization of national land use spatial pattern and protection of natural ecological system and environment are two critical tasks for ecological civilization construction in China. In recent years, ecological land research has become a hot spot in the field of land use and ecosystem management in China. In this study, a multi-scale classification scheme of ecological land was developed based on combination of the land use classification and the ecological function zoning in China. The ecological function zoning was done at three scales (from large to small): ecological system, ecological grid unit and ecological land type. The term "ecological land type" is the land unit and geographical space being important to maintain the key ecological processes in land eco-system. The spatial and temporal distribution of major-functional ecological land types (including river, lake, shoaly land, swampland) and multi-functional ecological land types (including forest land, natural grassland, paddy field) were analyzed based on the national land survey and annual land use change survey by the Ministry of Land and Resources of China. The results indicated that the spatial distribution of each ecological land type was characterized with regional imbalance in China. The multi-functional ecological land types are mostly distributed in the monsoon region of eastern China. In addition, the ecosystem service supply regions do not match with population distribution. The spatial and temporal variations of each ecological land type in the period of 1996-2012 were characterized with imbalance. The area of major functional ecological land types besides forest land decreased largely. The ecosystem services supply in the main ecological function zones decreased at different degrees. Especially, in the period of 2000-2005, the area of ecological land type largely decreased. In details, the areas of natural grassland and paddy field decreased significantly. Additionally, the proportions of shoaly land and swampland decreased largely. The spatial and temporal changes in ecological land types were closely related to the regional differences of natural, social and economic conditions and the implementation of the policies. On the basis of the above analysis, the suggestions on ecological land protection and management for different eco-systems were proposed to provide supports for integrated management of natural resources in China.
Construction of ecological security patterns is an important approach to protecting urban ecological security and achieving urban sustainable development, which is one of key topics in the research of landscape ecology. The identification of ecological sources and the construction of spatial resistance surface have been the technical difficulties in the study of ecological security pattern. Yunfu city is the significant ecological hinterland of Guangdong Province with the backward economy, which is facing the pressure of ecological conservation as well as economic development. Thus, construction of ecological security pattern in Yunfu city can guide urban development and is also meaningful for protecting provincial ecological security. Based on GIS, ecological sources were identified from the aspects of ecosystem services' importance, ecological sensitivity, and landscape connectivity. On the basis of DMSP/OLS Nighttime Light data, ecological resistance surface was modified, and using minimum cumulative resistance model, ecological corridors were identified. The ecological sources with corridors constituted regional ecological security patterns. The results showed that, the area of ecological sources accounted for 36.47% of the total area, mainly distributed in mountainous area in western and southern Yunfu, which took forest as the main land cover type. The length of ecological corridors was 508.87 km, including 315.58 km landscape corridors and 193.29 km cluster corridors. It was also found that all the 16 nature reserves were in the range of ecological sources, and the constructed ecological security patterns and the layout of urban master planning complemented each other. The framework of importance-sensitivity-connectivity can provide a new method for the construction of regional ecological security patterns, and the study results can provide related planning with effective spatial guidance.
Coastal zone is the most popular area and also the fastest urbanization area in China and even in the whole world. The ecological risk and security in the coastal region is the key component for the people and regional sustainable development. This study uses the theories and methodologies of landscape ecology and landscape security patterns and applies them to Xiamen city, which is under rapid urbanization progress, as a strategic transformation from its original island-based city to a new larger bay-area-based city. Xiamen case study highlights the need for effective methods for early-warning analysis at landscape level, with reference to the long-term urban development of the bay-area city. This study proposes a landscape ecological risk spatial warning model based on the integrated impervious surface area (ISA) change, risk receptor sensitivity and ecological red line governance to predict ecological early warning in Xiamen city during the rapid urbanization context of 2006-2015. The results overlap with landscape ecological security pattern built by "source" and "sink" theory to reveal current and potential risk pushing the implementation of governance. Our research reveals the following two findings: (1) The level of regional ecological risk deepens while the high risk warning values are in accordance with ISA distribution on the rapid urbanization areas. Tongan Bay, Xinglin Bay and Maluan Bay are typical areas faced with high ecological risk due to the reclamation and sprawl of ISA. (2) Overlaid with landscape ecological security pattern, we identify the likely landscape early-warning characteristics of changes to strategic sources, key nodes, ecological corridors and buffer zones of bay-area wetlands, and the consequent effect on the wetlands and regional ecosystem, resulting from the urban sprawl and proposed urban development. In the identification and assessment of landscape change and safety, it is important to take into account the design of a potential safety pattern within the landscape. The implementation of landscape ecological restoration and rehabilitation of wetlands in the early-warning region would allow a better integration of landscape and ecological safety into urban-regional planning and decision-making, which can further promote a sustainable planning system.
Coastal zone is an important land reserve resources. Its improvement and development has become a hot topic in many countries. Rudong coastal reclamation area was selected as the study area in this study. The canonical correspondence analysis was applied to analyze the relationship between soil salinization and landscape pattern at different scales, and to determine the contribution of the landscape index to the degree of soil salinization. The results showed that the patch density (PD), edge density (ED), landscape shape index (LSI), aggregation index (AI) and interspersion and juxtaposition index (IJI) of the study area were higher and varied in land use types that indicated the higher level of landscape fragmentation and more complex of landscape structure; The landscape structure was dominantly affected by anthropogenic activities. Soil Na+ and Cl- was the main component of soil salinity, accounting for 87.4% and 90.1% of the total cations and anions, respectively. The coefficient of variation of soil salinization index varied from 53.49% to 129.03%, which reflected the non-homogeneous distribution of soil salinity caused by anthropogenic activities. The result of canonical correspondence analysis showed that, landscape pattern variables in 100 m and 200 m buffer zones could explain 66.6% and 80.1% variations of soil salinization, respectively. The positive relationship was observed among the ratio of agricultural construction land, irrigated land and the level of soil salinity, while that of dry land was negatively correlated with the level of soil salinity. Soil salinization had a positive correlation with largest patch index (LPI) and contagion index (CONTAG), while as it had a negative correlation with PD, ED, LSI and Shannon's diversity index (SHDI) on landscape level. On patch class level, LPI, ED and LSI were the Colinear indicators affecting the soil salinization. Finally, the study on the relationship between landscape patterns and soil salinization may be of great significance to optimize the land use pattern and to reduce the degree of soil salinization.
Under the background of rapid globalization and urbanization around the world, these recent years have seen the worsening contradiction between fast-growing population and over-exploiting resources, especially in terms of increasingly deterioration of environment and ecosystem. As the main carrier of urbanization, urban agglomeration experiences the prompt socio-economy increase as well as the dramatic conflicts between human and land. It is obvious that as one of the three strongest motives of regional economy of China, Beijing-Tianjin-Hebei Urban Agglomeration profoundly embodies the characteristics of modern urban agglomeration development. Moreover, with the continuous strengthening of policy such as Collaborative Development of Beijing, Tianjin and Hebei Province, the spatial expansion of Beijing-Tianjin-Hebei Urban Agglomeration will take place in the long run unceasingly but also present a series of new features and dynamics. It is of great importance to construct the quantitative model for spatial evolution analysis and multi-scenario simulation, which contributes to diving deep into the micro mechanism of urbanization and historically spatial dynamics. Meanwhile, such model has very strong realistic and practical guiding significance in the context of Regional Collaborative Development. Therefore, after introducing urban and regional growth simulation theory as well as method with spatial-temporal dynamic characteristics, the paper collectively establishes Scenario Analysis and Simulation of Urban Agglomeration Spatial Evolution Model (SASUASE model) for Beijing-Tianjin-Hebei Urban Agglomeration, which is built on the basis of Constrained Cellular Automata (CC-CA). More than that, this model integrates the neighboring concept of CA, clustering analysis of geographical spatial partition, logistic regression analysis for parameter identification and iterative algorithm based on temporal evolution, which jointly build up the synthesized algorithm for SASUASE model. The result of parameter identification and model verification shows that the proposed models perform well after applying various factors such as transportation leading, socio-economy, ecological restraints and urban affective intensity into SASUASE model. To be more specific, in order to prove the effectiveness of the proposed model, the paper carries out the experimental simulation and compares the simulation and reality of 2013 from the perspective of urban construction land alone. As it shows, the simulation accuracy is 81.2% and the location precision is 72.6%, which indicates that the simulation effect is good. Also, the parameters of logistic regression analysis represent the main driving force of urban expansion both in orientation and strength. As the result shows, city arterial road and highway play significant roles in driving the development of urban agglomeration, which is followed by the socio-economy factors including per capita GDP. Therefore, the paper safely makes full use of SASUASE model in simulating the expansion of urban built-up area under multi-scenarios for Beijing-Tianjin-Hebei Urban Agglomeration in 2030. According to the simulated outcomes, the paper compares the changes of spatial development pattern in different scenarios respectively based on urbanization development speed, ecological protection pattern and planning policy guidance. On the whole, the amount of new urban construction land falls significantly while the increment of each city is badly differentiated, which shows the effect of capital dispersal policy is obvious. To be specific, the increment of new urban construction land is 226.5 km2/a, which is far below the average level between 2000-2013. The most obvious increase is found in Beijing and Tianjin, the total proportion falls from 42% to 26%, while Baoding and Langfang become the main force of the urban expansion. As for the layout features of urban expansion, the new urban construction land spreads mainly along the industrial development zones and urban agglomeration axis. The ecological protection pattern scenario greatly affects the development of cities with strong ecological protection constraints, while the planning policy guidance scenario mainly affects the micro spatial layout of new urban construction land. Decision-making supports for the adjustment of the current urban development direction, sustainable development and allocation of major infrastructure are expected in combination with the simulation results in different scenarios.
Urban land expansion can be considered as direct manifestation of the regional space of urbanization, which is also a key ecological process that affects the urban ecological security patterns. It is of great significance to optimize urban ecological security patterns through simulation and forecast researches on the basis of ecological security oriented spatial expansion of cities. This paper tried to forecast urban landscape transition by establishing an ecological security oriented simulation model with Guangzhou as the sample site based on the framework of Dyna-CLUE model so as to explore the urban land expansion patterns. The results lead to three main conclusions: (1) The quantitative regulation of land use by government is more important than space zoning with the goal of ecological security under present urbanization level. (2) The percentage of adjacent index indicates a trend of aggregation of construction land patches while the patch density index shows another trend of increase then decrease, which reveals some kind of variation of urban spatial characteristics. (3) The results of analysis on landscape patterns and urban land expansion modes reveal that three urban expansion modes, namely infilling, edge-expanding and leapfrogging, have common effects on the city's space. And during 1990-2005, edge-expanding and leapfrogging are the main urban expansion modes while from 2005 to 2020 edge-expanding and infilling have become the main modes. In the former period, urban expansion results in a large number of construction land patches due to the increase of aggregation and patch number per unit area. In the latter period, urban expansion continues with land-use transition from non-construction to construction land use with the trend of aggregation. However, as urban expansion modes are changing, many patches of construction land, including existing patches and newly added patches, will be connected with others. That is the reason why no increase of patch quantity per unit area has been observed for the patch density index. Together with pattern analysis, these results show that the urban expansions have changed from edge-expanding mode in external surrounding area to in-filling mode with intensive and economical internal expansion, which indicates a preliminary success of construction of urban ecological civilization.
Urban land growth is driven by many factors entailing spatial complexity and regional specificity. Because of difficulties in bridging the divide between transformation rules derived from bottom-up processes and top-down urban development policies using the SLEUTH model, accurate assessment of the impacts of top-down urban development policies on urban expansion is a challenging task. In contexts of top-down growth-oriented urban land management, urban land growth mainly manifests as the growth of new regions, especially as clumping growth. It is, therefore, necessary to incorporate other urban land growth models to improve the predictive ability of the SLEUTH model relating to urban development policies. We used a loose coupling of the potential-limitation and SLEUTH models to investigate urban change in Nanjing and its surroundings. Applying the potential-limitation model, we first integrated potential factors associated with urban development and ecological constraints into city development strategies, quantitatively evaluating the suitability of construction land in relation to different ecological security patterns in the study area. We subsequently, blended different scenarios for these ecological security patterns into the excluded layers, and used the SLEUTH model to simulate the urban space sprawl of this area from 2013 to 2040. We obtained the following results. First, the loose coupling of the two models improved the accuracy of calibration at the pixel scale. Moreover, reconstruction results obtained with the SLEUTH model were consistent with the actual situation. Second, "marginal growth" and "fill-in growth" patterns dominated the urban land sprawl. Simultaneously, a number of new city development centers were emerging outside the city, presenting rapid and conspicuous development. These findings demonstrate that loosely coupled models are better than the SLEUTH model, used alone, to capture the movement of the city center induced by urban development policies and the locations for the emergence of new urban growth centers. Consequently, the SLEUTH model performs better in relation to urban development policies, and is able to bridge the divide, to some extent, between conversion rules derived through bottom-up processes and top-down urban development policies. Third, while the simulation results for the three ecological security pattern scenarios indicated an increasing trend for urban sprawl, differences in their growth rates were significant. For the scenario with a high ecological security pattern, the newly added urban land area and the growth rate were both minimal, indicating that ecological sensitivity analysis applied as a layer constraining urban development could effectively protect the natural ecological space in the research area, and dramatically reduce the ecological security risk. These results can be used to guide and support future urban space sprawl management, urban planning, and land use planning decisions in the study area.
Comprehensive function zoning of national land space plays a significant role in optimizing development and spatial pattern of national land space. Taking Wuhan metropolitan region as a case study area, we performed an empirical study of the comprehensive function zoning of land space. Firstly, from the perspective of production, livelihood, and ecology functions, we selected 24 indicators to represent multiple thematic elements, such as land resources, water resources, eco-environment, and socio-economic factors. Second, we built up an evaluation system based on these factors and functions. We then calculated and presented the percentages of 10 kinds of sub-functions (namely, supply of primary, secondary, and tertiary products, provision of forestry, livestock, and aquatic products, supply of mineral resources, urban and rural residence, and ecological regulation) for the evaluated units. Next, we evaluated the carrying capacity of the production-livelihood-ecology function provided by national land space using the BP neural network approach. Finally, with dual-constraint spatial cluster algorithm, we confirmed the final comprehensive function zones of national land space, and correspondingly provided specific regional regulation policies and implication for each function zone. Theoretically, in this study, based on these 10 key functions of national land space and the consistent indicators and evaluation system, we initially presented the multiple functions of the zones in percentages from the county level, and then scaled up to the city level, which facilitates the integration and disaggregation of multiple functions for zones across levels. Practically, the results showed that Wuhan metropolitan region can be divided into western production-livelihood zone, northeast production-ecology zone, and southeast livelihood-ecology zone at the first level, and seven sub-zones at the second level. Furthermore, four corresponding types of policy, including "key protection", "general protection", "general development” and "key development", were attached to each sub-zone. This study will shed light on theoretical framework and practices of national land planning and national land resources regulation, and also provide reference forland development pattern and optimal allocation of land resources for Wuhan metropolitan region.
Landscape pattern optimization is one of the important ways in achieving regional ecological security. In order to optimize landscape spatial layout of economic development, ecological protection and overall consideration scenario, a case study was carried out in Longquanyi District of Chengdu based on landscape suitability assessment and landscape quantity optimization. The method of particle swarm optimization (PSO) was used to establish landscape pattern spatial optimization model and algorithm. The results showed that, the landscape pattern spatial optimization model and algorithm based on PSO was the effective method of landscape pattern optimization. The model and algorithm could efficiently simulate landscape distribution by using particle space positions, conduct spatial pattern optimization, and realize united coupling of quantity structure and spatial distribution optimization. The dominant landscapes in economic development scenario were orchard, urban-rural residential and industrial-mining area in a target year. The landscape pattern showed that farmland, urban-rural residential and industrial-mining area dominated the western flatland region, while eastern mountainous area was mainly dominated by orchard. The dominant landscapes in ecological protection scenario were forest, urban-rural residential and industrial-mining area. The landscape pattern showed that the western flatland region was mainly dominated by farmland, orchard, urban-rural residential and industrial-mining area, while the eastern mountainous area was dominated by forest. The dominant landscapes in overall consideration scenario were forest, orchard, urban-rural residential and industrial-mining area. The landscape pattern showed that farmland, urban-rural residential and industrial-mining area dominated the western flatland region, while eastern mountainous area was dominated by forest and orchard. Compared with other scenarios, the overall consideration scenario could be the largest potential possibility in the future, since the economic, ecological and comprehensive benefits here would be the most optimized and promoted, implying the best spatial layout scheme for landscape pattern in the study area in the target year.
Ecological corridor plays an important role in biodiversity protection and disordered extension of city area prevention, as it is a bridge to link ecological patches, also an important division of urban group segregation. Therefore, it is helpful to evaluate the significance of ecological corridor in highly urbanized areas for ecological security pattern protection. In this paper, Shenzhen is taken as a case to explore significance evaluation method of ecological corridor, for it is a highly urbanized region with high species diversity. The significance evaluation method of ecological corridor has been constructed and applied, in order to provide scientific basis for fine management and layout optimization of ecological corridor, and also enrich the research on significance evaluation of ecological corridor. Some conclusions can be drawn from the evaluation results as follows: (1) Most of the corridors between the ecological source region identified by the minimum cumulative resistance surface model have been almost overlapped with planned corridors, and the others should be planned for the ecological corridors with strict control. (2) Each urban group has been separated by a large ecological plaque or planned group segregate corridor, and construction land scale should be controlled in group segregate corridors. (3) Eight ecological corridors have been divided into the first level ecological corridor based on the evaluation results, as they have two functions, which are irreplaceable, and keep a good condition. The first level ecological corridors should be managed strictly for their important role in biodiversity protection and disordered extension of construction land prevention.
The identification of ecological belts as components of an ecologically livable city is important in urban space management. However, the lack of appropriate implementation of space for ecological corridors has led to the isolation of those that exist currently. Furthermore, the lack of scenario analysis for urban growth patterns has made it difficult to adjust planning. Taking Hangzhou as a case, using Landsat TM image data, this paper delimited urban ecological belts based on green infrastructure assessment with scenario analysis. The results suggested that: (1) the risk of development in the northern and eastern parts of the central city is relatively low, while the southern, eastern and southwestern parts need intensive protection; (2) in the model of ecological management, the erosion of ecological space has increased gradually and the regional ecological patterns in the third and fourth scenarios have faced great challenges, and (3) five ecological belts were identified, including "Northern Linping" ecological belt, "Eastern Yipeng" ecological belt, "Southern Linpu" ecological belt, "Southwestern Fuyang" ecological belt and "Northwestern Liangzhu" ecological belt.
The Guanzhong Basin is the economic center of Northwest China. In recent years, with the development of the economy, many ecological environment problems have emerged in this region. Therefore, it is important to examine the dynamic changes of trade-off and synergy of ecosystem services in the Guanzhong Basin and explore their influencing factors. In this paper, many models are used to estimate the net primary production (NPP), soil retention and food supply in the basin from 2000 to 2012. And research is conducted on the spatial and temporal change of ecosystem services in different types of land covers by using Rose diagram. Then, we explored the trade-off and synergy among three ecosystem services by correlation diagram made by R software and analyzed its dynamic characteristics in the 13 years. At last, we analyzed the effect of the land cover change on the relationship of trade-off and synergy to explore its driving mechanism. The results indicate that: (1) The annual average NPP per unit area, the annual average value of soil retention per unit area and the annual average value of food supply per unit area were 1720.495 yuan/hm2, 768.889 yuan/hm2 and 167.874 yuan/hm2, respectively. From the perspective of space, the high value regions of NPP and soil retention were distributed over mountains and low value regions were over the central part of the basin. But the food supply presented the opposite pattern. From the perspective of time, three ecosystem services were increased in the 13 years. The annual average NPP per unit area, the annual average value of soil retention per unit area and the annual average value of food supply per unit area increased by 21%, 46.7% and 245.7%, respectively. (2) There were trade-off between NPP and food supply, soil retention and food supply. And there were synergy between NPP and soil retention. (3) On the whole, the trade-off of ecosystem services enhanced and the synergy weakened during the 13 years in the Guanzhong Basin. The degree of synergy between NPP and soil retention decreased. The degree of trade-off between NPP and food supply increased. And the trade-off relationship between soil retention and food supply remained stable during the 13 years. (4) From the perspective of land cover changes, the reduction of cultivated land and forest land is the main driving force of the change of relationship among ecosystem services. At the same time, it is significant to balance conflicts in land resource to use land resource better.
