Spatial-temporal differentiation of ecologically-sustainable land across selected settlements in China: An urban-rural perspective

Ecological Indicators 112 (2020) 105783

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Original Articles

Spatial-temporal differentiation of ecologically-sustainable land across selected settlements in China: An urban-rural perspective

T

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Lulu Qua, Yurui Lib, , Weilun Fenga a b

Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

A R T I C LE I N FO

A B S T R A C T

Keywords: Ecologically-sustainable land Spatial-temporal differentiation Cross-settlement comparison China

Ecologically-sustainable land (eco-land) is a basic resource for human survival. Rapid urbanization has profoundly transformed the spatial pattern of urban-rural land use in China. This study examined the spatiotemporal characteristics of eco-land in urban-rural areas using comparative and spatial analysis based on ecoland change data for China’s prefecture-level settlements. From 2009 to 2016, eco-land in both urban and surrounding rural areas changed significantly, with change rates of 13% in the urban area and 24% in the surrounding rural area. From the six different settlement types in urban-rural eco-land, the urban growth type (UGT) accounted for 24%, the rural growth type (SGT) accounted for 22%, the urban growth & rural reduction type (UGT&SRT) accounted for 18%, the urban reduction & rural growth type (URT&SGT) accounted for 21%, the urban reduction type (URT) accounted for 7%, and the rural reduce type (SRT) accounted for 8%, respectively. As settlement scale increased, the differences between settlements decreased: the differences between metropolises were the lowest, differences between large and medium-sized settlements were in the middle, and differences between small settlements were the highest. The settlements were clustered into four types based on the change slope of urban-rural eco-land. Further, vital and major zones for green environment management were identified. These included settlements in Shandong, Hebei, and other central rising provinces as well as other large settlements in Inner Mongolia and Shaanxi Province. The major zones included the Pearl River Delta, the Yangtze River Delta, and most settlements in the Central Plain urban cluster. These results can support more effective land use decisions and provide a theoretical basis for policy decisions and sustainable settlement management.

1. Introduction Since the reform and opening-up in 1978, China’s urbanization has proceeded at an unprecedented rate, compressing into one century what has taken more developed countries three centuries to accomplish (Friedmann, 2006). From 1978 to 2012, urbanization increased from 17.9% to 52.6%, and China’s urban population could reach one billion in the next two decades if the current trend holds (Bai et al., 2014). The rapid urbanization has been accompanied by high concentrations of the urban population and built-up areas, and the loss of ecologically-sustainable land (eco-land) in settlements (Han et al., 2018; Liu and Yang, 2015). Accelerated urbanization associated with significant political, economic, and cultural development has not only profoundly altered land use patterns and structure, but also impacted resources and the environment (Long et al., 2018; Liu et al., 2015a,b). The expansion of settlements couples the original natural ecological system into a nature-

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society system, and significantly alters material and energy flows (Liu et al., 2011). This further affects air quality, water use, energy consumption, human health, and urban sustainability (Zhou et al., 2015; Xie et al., 2017). China's urbanization has been directed and controlled by the national government through urban policy, which has been perceived as a necessary stimulant for economic and industrial growth (Li et al., 2018; Liu and Li, 2017). In March 2014, the Central Committee of the Communist Party of China and the State Council jointly released “China’s national new-type urbanization plan (2014–2020)”. The new long-term national development strategy issued at the 18th National Congress of the Communist Party of China in 2013 set ecological civilization as one of the vital principles for guiding national urbanization and social development for the next 15 years. The ecological civilization characterized by rational land use and sustainable utilization (ERS) has been a new long-term national development strategy in China. Thus, questions

Corresponding author at: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. E-mail address: [email protected] (Y. Li).

https://doi.org/10.1016/j.ecolind.2019.105783 Received 19 November 2018; Received in revised form 23 September 2019; Accepted 28 September 2019 1470-160X/ © 2019 Elsevier Ltd. All rights reserved.

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2. Relevant concepts and methods

about how to develop in a low-carbon way, and protect, sustain, and rehabilitate eco-land, have become important subjects for scholars from different fields. While the regional differences between urban and rural eco-land are becoming increasingly prominent, efforts should be made to improve the urban environment and enhance citizens’ quality of life through eco-land planning. China is a vast country with spatial heterogeneity across different region, and during the process of rapid urbanization the development between urban and rural areas within settlements has been very unbalanced. Therefore, it is important to explore the characteristics of eco-land use and change in the process of urbanization. Previous studies of urbanization and eco-land in China mainly focused on land use change patterns (Yang et al., 2017; Chen et al., 2009), mechanisms and influencing factors (Liu et al., 2016; Feng et al., 2019), eco-environment benefits (Liu, 2018; Zhou et al., 2015), ecological classification (Liu et al., 2017; Long et al., 2015), and optimization of land allocation (Li et al., 2015; Thomas, 2015). Geographic information system (GIS) technologies have been widely used in land change science (Liu, 2018). Spatial and temporal environmental data can be easily obtained through remote sensing (Li et al., 2017; Liu et al., 2018b), and GIS provides an approach for spatial analysis, mapping, and modelling (Abdullahi and Pradhan, 2016; Cao et al., 2019). Furthermore, land use transition matrices are commonly used to characterize the changes in ecological land and spatial pattern dynamics (Qu et al., 2019). The recent rise and development of geographical statistical analysis (Li et al., 2015), such as spatial autocorrelation (Liu et al., 2018), Mann-Kendall trend analysis (Cao et al., 2018), variance analysis (Perry et al., 2002), pixel-based residual analysis (Liu et al., 2018a), and spatial detection analysis (Wang et al., 2019), have assisted in describing eco-land dynamics. All of the above are particularly useful in studies focusing on the spatial and temporal heterogeneity of eco-land. However, much of this research has been relatively narrow in scope, limited to a specific settlement scale or kind of settlement. There is no comprehensive understanding among settlements of different scale sizes or consideration of the differences between urban and rural areas, nor is this information used to guide urban and rural development strategy and accompanying the process environmental changes. Therefore, when analyzing the differences in eco-land, not only should the quantitative relationship of eco-land change be considered, but also the spatial relationship, and comparative study of the changes in urban and rural areas is needed. According to the national bureau of statistics, until the end of 2016, urban areas contained 57% of the population and contributed 75% of the Chinese national economy. Thus, a better understanding of eco-land change is necessary for Chinese decision-makers to address eco-environmental security and guide sustainable urban and rural development. In this study, we integrated time series analysis with spatial sequence analysis to characterize urbanrural eco-land patterns from 2009 to 2016. Given the limitations of existing eco-land studies, we analyzed ecoland in urban and rural areas from a different perspective. City settlements are defined as permanent large settlements compared to the countryside, and this definition is an abstract concept without spatial identification that includes urban and suburban components (Peng et al., 2018). According to China’s Land Survey and Planning Institute, urban areas make up settlement centers, and suburban rural areas are along the urban-rural fringe. In addition, eco-land at the city scale includes fundamental eco-land (grassland, forestland, and wetland) and recreational eco-land (natural parks and waterbody). This paper had three aims. The first was to show the changing characteristics of eco-land in urban and rural areas of China over the past decade and to highlight differences across settlements. The second was to the show the internal dynamics of different settlement scales by comparing and analyzing the changes in eco-land, built-up land, and residential land in urban and rural areas. The third was to illustrate the spatial variability across eco-land using GIS spatial analysis.

2.1. Relevant concepts 2.1.1. Defining eco-land There is still no common agreement on the definition of eco-land, although this terminology has been listed in China’s national political agenda since the 2000s. Chinese researchers first introduced the term “eco-land” in 1999 referring to the spatial carriers of physical elements (e.g., vegetation, soil, and water) and various ecological protection functions (Dong et al., 1999). Initially, use of the term began in western countries, such as the United Kingdom (Bunce et al., 1996), Canada, and the USA (Sims et al., 1996). Subsequently, the term has been used widely in academia, among the public, and by the government of China. Eco-land types vary over a wide range of spatial scales, including global, national, regional, city, and local green spaces. City eco-land has not yet been explicitly proposed, but it has already been considered in the land use classification system (Peng et al., 2018). City eco-lands can be classified into two categories: The first category provides services in the city system, including parks in residential and commercial areas and green open spaces (Swanwick et al., 2003). The second category plays a key role in maintaining the city ecosystem functions, which we refer to as “supporting eco-land” (Peng et al., 2017). Generally speaking, city eco-land usually includes natural parks, forests, water bodies, wetlands, and grasslands in the prefecture (Fig. 1). We can therefore define city eco-land as the natural basis for the city that provides the necessary ecosystem services for residents. Their functionalities include the maintenance of ecosystem stability and ecosystem services provision. In other words, city eco-lands have a farreaching influence on ecological sustainability. 2.1.2. Urban and rural areas definitions A city settlement is defined broadly as a permanent large settlement compared with the countryside, but this definition is an abstract concept without spatial identification (Peng et al., 2017). According to China’s Land Survey and Planning Institute, city settlements include both urban and rural areas. The identification of urban and rural areas was shown in Fig. 2. An urban-rural gradient approach was used to investigate the relationships between human activities and ecological processes across different development contexts. The approach recognizes that a variety of socio-ecological conditions change across the continuum, from densely-populated city centers to more rural environments, and examines how such changes shape ecosystem structure and function (Mcdonnell and Hahs, 2008). An urban-rural gradient approach suggests a more holistic perspective on subject tendencies within and across urban, suburban, and rural areas (Fig. 3). 2.2. Data The data used in this study were obtained from the land survey results sharing application service platform of China’s Land Survey and Planning Institute. The data spanned from 2009 to 2016 and included natural parks, water bodies, grasslands, forestland, wetlands, residential land, and construction land. Combined with data from the China Statistical Yearbook of 2016 (National Bureau of Statistics of China, 2017) and city administrative center location data from China's 1:4 million basic geography dataset, the locations of prefecture-level settlements in mainland China were extracted (Table 1). To ensure the data integrity and consistency, this study removed county-level settlements and settlements lacking data, and selected 282 prefecture-level settlements. The total eco-land included fundamental eco-land (grassland, forestland, and wetland) and recreational eco-land (natural parks and water bodies). Settlements of various sizes steadily grew during the post-reform era, especially in recent years. Thus, in this 2

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Fig. 1. Diagrammatic sketch of city eco-land. Source: Long et al. (2015). Note: The codes indicate woodlands (0 3 1), shrubbery lands (0 3 2), and sparsely forested lands (0 3 3), nature pasture lands (0 4 1), cultivated pasture lands (0 4 2) and other grasslands (0 4 3), rivers (1 1 1), lakes (1 1 2), reservoirs (1 1 3), ponds (1 1 4), beaches & tidal flats (1 1 5), inland mudflats (1 1 6), swamps and marshes (1 2 5), parks and green spaces (0 8 7), garden nurseries (G1), parks (G2), attached green spaces (G3), and protective green spaces (G4).

paper, we chose the most recent year of 2017 as the criterion. According to statistics for 2016 (National Bureau of Statistics of China, 2017), the settlements were divided into metropolis, large-settlements, middle-settlements, and small-settlements.

2.3. Study area China is a vast country covering an area of 9.63 million km2, with 334 prefecture-level administrative divisions and a population of 1.38 billion (National Bureau of Statistics of China, 2017). The prefecture is a specific unit in China’s administrative division, ranking between the province and county. In this study, the unit of our analysis was the prefecture. We selected 282 prefecture-level settlements in mainland China due to data availability (Fig. 4).

Fig. 2. Graphical representation of urban-rural areas identification.

Fig. 3. Map showing transects of urban-rural gradient. Source: From Gianotti and Hurley (2016). 3

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Table 1 Description of data used in this study. Data

Description

Year

Source

Prefecture-level boundaries Population scale data ECL

Shapefiles for provinces, prefectures in China 282 prefecture-level settlements population scale The total eco-land, including fundamental and recreational eco-land The locations of settlements at the prefecture-level in mainland China

2008 2009–2016 2009–2016

National Geomatics Center of China National Bureau of Statistics of China Land survey results sharing application service platform of China China’s 1:4 million basic geography dataset

Prefecture administrative center location data

2017

n

2.4. Methods

Slope =

2.4.1. Compararative analysis The comparative analysis included changes in eco-land, residential land, and built-up land in urban and rural areas. The changes in residential land reflect population immigration, while changes in built-up land reflect overall urban expansion and development. Eco-land change can be divided into six types: urban growth (UGT), rural growth (SGT), urban growth & rural reduction (UGT&SRT), urban reduce & rural growth (URT&SGT), urban reduction (URT), and rural reduction (SRT). UGT implies growth in both urban and rural areas, but urban area growth was larger than rural growth (U > 0, S > 0, R (U/ S) > 1). SGT implies growth in both urban and rural areas, but rural area growth was larger than urban growth (U > 0, S > 0, R (U/ S) < 1). UGT&SRT means growth in urban and reduction in rural (U > 0, S < 0). URT&SGT means a reduction in urban eco-land and an increase in rural eco-land (U < 0, S > 0). URT implies a reduction in both urban and rural eco-land, but the decrease in urban areas was larger than in rural areas (U < 0, S < 0, R (U/S) > 1). SRT implies a reduction in both urban and rural eco-land, but the decrease in rural areas was larger than in urban areas (U < 0, S < 0, R (U/S) > 1).

n

n

n × ∑t = 1 t × ECLt − (∑t = 1 t )(∑t = 1 ECLt ) n×

n ∑t = 1 t 2

−

n (∑t = 1

t)

2

(1)

where n is the length of the time series in years, t is one research time step, ECLt is the eco-land for year t. To analyze the ECL change, the spatial pattern of ECL variability was analyzed according to the absolute value of the slope, and the mean slope for each settlement’s urban and rural area was calculated using the Zonal Statistics as Tables tool in ArcGIS 10.2. In addition, we also used Pearson’s parametric correlation analysis to identify synergies between eco-land variability, where synergies indicate the interactions between two variables that could reveal their associations. 3. Results 3.1. Spatial pattern of different scale settlements Most of the settlements concerned in this study are located in eastern China. The BTH (Beijing-Tianjin-Hebei), YRD (Yangtze River Delta), PRD (Pearl River Delta) and CY (Chengdu-Chongqing) settlement groups were much larger than the other regions (Fig. 5). Settlements in the same group had closer interactions, more frequent exchanges, and more similar natural conditions. The eco-environmental problems caused by urbanization had a high degree of symbiosis and spatial consistency in these regions. The settlements were divided into four types by population size

2.4.2. Other statistical analysis methods ΔECL was defined as the difference between ECLu and ECLR to quantify the urban and rural eco-land (ECL) for each settlement. The ECL change slope was measured using linear regression analysis. Slope was the difference between the ECLu and ECLS, as described in Eq. (1).

Fig. 4. Distribution of the study area and selected prefectures. 4

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Fig. 5. Urban population scale of settlements in China.

medium, and small settlements was more significant than rural variability. The overall change in eco-land from 2009 to 2016 was less than residential and construction land changes, with an average of 5.73% (urban) and 4.52% (rural). Compared with the total change in residential land, eco-land change accounted for 8.23% (urban) and 6.78% (rural). Compared with the total change in construction land, eco-land accounted for 3.14% (urban) and 2.25% (rural). The overall changes in rural residential and construction areas were significantly greater than that in urban areas.

(metropolis, large settlement, medium settlement, and small settlement) using the natural break method. There were 4.6% of settlements with a population greater than 5 million, which were mostly distributed in eastern China. Settlements with a population greater than 10 million included Beijing, Tianjin, and Shanghai. Nearly a quarter (23.76%) of settlements had a population size of 0.16–5 million, and those ranging from 3 to 5 million inhabitants included Shijiazhuang, Qingdao, Shenzhen, Zhengzhou, Changchun, Dalian, Handan, GuangzhouFoshan, and Jinan. Fully 34.39% of settlements had populations less than 0.08 million, and these relatively small settlements were mainly distributed in western provinces such as Yunnan, Guizhou, Gansu, Ningxia, Xinjiang, and Qinghai. In accordance with the pyramid rule of settlement size, larger settlement populations had higher settlement levels and there were fewer total settlement numbers at the higher levels.

3.2.2. Contrastive analysis of land use change by item Fig. 7 shows that the growth rate of residential land in urban areas was higher than construction land, except during period II, and the middle and small settlements had large differences in the growth rate. The strongest positive eco-land growth rates occurred in small settlements during I and VII, which were significantly higher than the growth rates of residential and construction land during the same period. The strongest negative growth rates occurred in small settlements during V. The growth rates of rural construction land were greater than in residential land, except during IV and VII. The middle and small settlements had large differences in growth rate, and it is worth noting that the growth rate of metropolis residential land during Ⅴ was negative.

3.2. Comparative analysis of eco-land change at different settlement scales 3.2.1. Overall comparative analysis In both urban and rural areas, residential land and construction land exhibited stable positive growth, while the change in eco-land was unstable, with both positive and negative growth (Fig. 6). Which shows that the urban variability for residential and construction land in large,

Fig. 6. Three types of overall land use changes from 2009 to 2016 in urban (U) and rural (S). (M1 = metropolis; L = large settlement; M2 = middle settlement; S = small settlement). 5

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Fig. 7. Comparison of the change amount of eco-land (G), residential land (R) and construction land (C). (U = urban; S =rural; 1 = metropolis; 2 = large settlement; 3 = middle settlement; 4 = small settlement). 200

The strongest positive growth rates of eco-land occurred in small settlements during I and VII which were significantly higher than the growth rates of residential and construction land during the same period, and the strongest negative growth rates occurred in small settlements during Ⅴ.

U1

U2

U3

S1

S2

Change rate

Metropolis

Ratio

S3

L-settlement

M-settlement

S-settlement

-200

-400

residential land on average, and rural change was 3.0 times greater. Within the scope of settlements, the development gap between residential land, construction land and eco-land, the smallest gap is the small settlements, while the largest is the middle settlements.

S3

3.2.4. Contrast of urban-rural ECL in different settlement scales ECLu and ECLS values for the different settlements scales from 2009 to 2016 were counted and analyzed (Fig. 10). Mean ECL in urban areas was higher than that in rural areas regardless whether it was in large scale settlements (metropolis, large settlement) or small scale settlements (middle settlement, small settlement). Between urban and rural areas, ΔECL in small scale settlements was greater than that in large scale settlements. In large scale settlements, the large settlement ΔECL (0.68) was greater than the metropolis ΔECL (0.46), while in small scale settlements, the middle settlement ΔECL (1.16) was smaller than the small settlement ΔECL (1.31). ECL standard deviations (ECL-Std) for each settlement’s urban (ECLu-Std) and rural areas (ECLs-Std) were also calculated. For the larger scale settlements, ECL-Std values for urban areas in large settlements, rural areas in large settlements, urban areas in metropolises, and rural areas in metropolises were 1.12, 1.63, 2.04 and 2.17 respectively, while the comparable ECL-Std values for smaller scale settlements were 3.66, 3.56, 4.17 and 4.24, respectively. In general, largescale settlement ECL-Std values were less than those of small-scale settlements, ECL-Std values for large settlements were less than metropolis values, and urban ECL-Std values were lower than those of

24 20 16 12 8 4 2014

S2

Fig. 9. Change rate of classified land quantity for four types of settlements.

28

2012

S1

-800

32

2010

U3

-600

36

0 2008

U2

0

3.2.3. Comparative analysis of land use change There were significant differences in the ratios of different types of urban land, as shown in (Fig. 8). Ratios for construction land to residential land were basically the same in urban and rural areas, and changes tended to be stable, indicating that the expansion of urban and rural areas was in harmony with population growth. Ratios of construction land to eco-land, and residential land to eco-land were greater in rural than that in urban areas, and urban ratios were more stable, indicating that economic development, population expansion, and ecoland development were better coordinated in urban areas than that in rural areas. Land use change results from 2009 to 2016 for the four major settlement types are shown in Fig. 9. There was an imbalance between the change in eco-land and residential land in the rural middle settlements (−350.6), and construction land in the whole settlements (−734.8). The change in urban construction land was 2.6 times greater than 40

U1

2016

Year Fig. 8. The trend of the classified land use ratio change. 1 = residential land/ eco-land; 2 = construction land/eco-land; 3 = construction land/residential land. 6

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3.3.2. Distribution types of eco-land in settlements As seen in Fig. 12, there were significant differences in the distribution of eco-land types across China's prefecture-level settlements. Settlements with the highest growth rates were Changsha, Beijing, and Baise, and those with the largest differences were Harbin, Yinchuan, and Wuwei. The top three growth settlements were Kunming, Ningbo, and Heyuan, and settlements with the largest differences were Nanning, Shaoxing and Yingkou. Of the six growth types, UGT accounted for 24%, SGT accounted for 22%, UGT&SRT accounted for 18%, URT&SGT accounted for 21%, and URT accounted for 7%, in which the top three settlements were Chengdu, Taizhou and Dezhou, SRT accounted for 8%, and the top three settlements were Jilin, Changde and Shizuishan. 3.4. Settlement classification based on ECL change trend

3.2.5. Correlation analysis of urban-rural land Descriptive land change statistics for urban and rural areas from 2009 to 2016 are shown in Table 2. Mean values in rural land were always greater than urban land values. Standard deviations (SD) for rural eco-land (S-E) were less than urban eco-land (U-E), meaning that urban eco-land (U-E) was more dispersed than the rural area. Correlations between urban eco-land (U-E) and urban other land, rural ecoland (S-E) and rural other land, and urban eco-land (U-E) andrural ecoland (R-E) were analyzed. The results show that there were significant correlations between urban eco-land (U-E) and rural eco-land (S-E), with coefficients significant at the 1% level. The correlation of the rural eco-land (S-E) and rural construction land (S-C) was better than the urban eco-land (U-E) and urban construction land (U-C).

Based on ECL change in urban and rural areas, the selected settlements were divided into four types (designated as type A, type B, type C and type D) using the ArcGIS 10.2 (Fig. 13). Furthermore, considering that the Slope could substantially indicate the change trend of ECL change effect, the major zones and key temporal periods for eco-land management were identified through ECL change analysis. Settlements classified as Type A (N = 73) experienced ECL high growth rate in rural. These settlements were generally large such as Beijing, Tianjin and other megalopolises, as well as other big settlements in Inner Mongolia and Shaanxi Province with rich natural resources. Type B (N = 179) settlements were mainly distributed in the Central Plain Urban Agglomeration, as well as in the YRD, PRD and other southeastern coastal areas. which were characterized by large urban size and high-level urbanization stage, and would continue to be the core area of China's urbanization in the near future. These settlements exhibited that ECLu increased faster than ECLr, on the whole, the growth rate of eco-land in the settlement is small. Hence, eco-land (especially in urban) was expected to exacerbate in the future. Type C (N = 321) settlements were centrally situated in the arid and semi-arid area of northwestern China. Especially the settlements in the provinces of Ningxia and Gansu, which had small settlements size because of the restricted natural resources, these settlements had slow rate in the ecoland both in the urban and rural. Type D (N = 542) settlements were quite different from other types. Settlements in Type D had a high and increasing speed rate of the eco-land, especially in suburban. In the future, Type D settlements should be alleviated by controlling the intensity of human activities.

3.3. Spatial change of eco-land in prefecture-level settlements

4. Conclusions and discussion

3.3.1. Analysis of eco-land change There were significant differences between urban and rural areas in eco-land change in China's settlements (Fig. 11). The greatest changes to urban eco-land occurred in north China and the least changes were in the central and some south settlements. Settlements with rural growth were largely in Jiangxi Province and the Yangtze River Delta settlement cluster. Settlements dominated by urban growth were mainly concentrated in the Chongqing City, Jilin Province, and Heilongjiang Province.

Our analysis of eco-land change data for China's 282 prefecture level settlements used comparative methods and spatial analysis to explore the differences and mechanisms behind urban-rural eco-land change. The results showed that the change amount and rates of urban residential and construction land were both stable and positive, while eco-land was unstable. Thus, for future settlement development, settlement expansion and eco-land should be coordinated to promote sustainable development. To explain rates of eco-land change and the spatial patterns for each settlement, the six settlement growth types

Fig. 10. Mean eco-land (ECL) of urban and rural areas at different settlement scales from 2009 to 2016.

rural areas. ECL dispersion in the small settlements was greater than that of the large settlements. ECLu-Std values were less than ECLs-Std because urban green space was mainly influenced by anthropogenic activities and urban ecological policy. These artificial factors can strongly affect the natural environment in urban areas. In contrast, vegetation conditions and surface attributes in rural areas remain mostly natural, showing a distinctive regional heterogeneity.

Table 2 Pearson correlation coefficients for urban-rural land and other land.

U-E U-C U-R S-E S-C S-R

U-E

U-C

U-R

E

1

0.135(0.021)* 1

−0.024(0.688)

0.444(0.000)**

S-C

S-R

0.195(0.001)** 1

0.071(0.223)

1 1

1

Note: * – significant at the 0.05 level, ** – significant at the 0.01 level. 7

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Fig. 11. Eco-land change of settlements from 2009 to 2016.

Fig. 12. Types of settlements growth from 2009 to 2016.

types based on the change slope of urban-rural eco-land. Further, vital and major zones for green space management were identified. The vital zone included settlements in Shandong, Hebei, and other central rising provinces, as well as large settlements in Inner Mongolia and Shaanxi Province. The major zone included the Pearl River Delta, the Yangtze River Delta and most of the settlements in the Central Plain urban cluster. From the results of the study, we have identified vital and major zones for green management, however, how to face the contradiction and uneven growth of urban-rural ecologically-sustainable land areas with the rapid urbanization in different type zones should be taken seriously. Under the guidance of China’s national new-type urbanization, innovation, coordination, openness, and sharing and green sustainable

were compared. Of the six urban-rural eco-land types, UGT accounted for 24%, SGT accounted for 22%, UGT&SRT accounted for 18%, URT& SGT accounted for 21%, URT accounted for 7%, and SRT accounted for 8%. Ecologically-sustainable land in both urban and surrounding rural areas changed significantly, furthermore, we have obtained different growth types of ecological land at the national level in urban-rural perspective. Thus, for future urban land and the surrounding rural areas should be coordinated to the development of production-life-ecological space according to the different growth types of urban-rural ecologically-sustainable land. All settlements were further classified into four types based on ECL change trends, with type A and B settlements identified as the vital and major zones for ECL. After analyzing the spatial patterns of ECL change, settlements were clustered into four 8

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Fig. 13. Settlement classification based on eco-land (ECL) change trend from 2009 to 2016.

development are proposed as the heart of the country's development strategy, more and more attention has been paid to the ecologicallysustainable land. The innovative urban-rural perspective is integrated to study the spatial-temporal change of ecologically-sustainable land in China's prefecture-level settlements in the past few years and important information was obtained at the national level. Nevertheless, this is only a preliminary study. Influencing factors and mechanisms of urbanrural ecologically-sustainable land change need to be further strengthened. More efforts should be made to promote the management and control strategy of urban-rural ecologically-sustainable land.

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