1. Introduction
Territorial spaces are important places for human survival and development, which provide a fundamental guarantee for economic and social development. Since the entering of the Anthropocene, the global spatial layout has been changing rapidly, bringing economic growth and social well-being [
1]. Uncontrolled space expansion and resource depletion, however, have posed significant challenges to the stability and sustainability of the ecosystem [
2]. With the deepening of our understanding of the relationship between socio-economics, resources, and environmental well-being, the concepts of the green economy are evolving, and green development is receiving increasing attention. The United Nations Development Programme (UNDP) first proposed the concept of “green development” in the “China Human Development Report 2002: Making Green Development a Choice,” pointing the way for an environmentally friendly green socioeconomic development path [
3].
As the world’s largest developing country, China has experienced accelerated industrialization and urbanization since the end of the 20th century, which has dramatically changed the territorial space pattern. The proportion of construction land space rose from about 3.12% in 2000 to about 8.46% in 2019, with a significant expansion of urban, industrial, and mining space, leading to the country’s disparate spatial layout, uneven structural ratios, and ecological damage [
4]. To alleviate the contradiction between development and conservation, the 19th National Congress first proposed the new concept of high-quality development. The 14th National Five-Year Plan emphasized that economic and social development should be aimed at promoting high-quality development and promoted speeding up the construction of a new pattern of development and utilization of territorial space with obvious functions, complementary advantages, and high-quality development. This plan indicates that there is an urgent demand to establish an orderly and coordinated territorial spatial order. Therefore, it is necessary to optimize the territorial space pattern and coordinate territorial space development, for which an in-depth analysis of the mechanism of territorial space development is essential.
Extensive research has been conducted on territorial space, which has primarily focused on land use; the evolution of territorial space function; and territorial space planning, development, and consolidation. According to the above three perspectives, to explore land use changes, the territorial space can be divided into cultivated land, forestland, grassland, water area, construction land, and unused land [
5]. However, to examine the three zones and three lines, the territorial space can be divided into urban, agricultural, and ecological space [
6]. The “three zones” refer to three types of territorial space: urban space, agricultural space, and ecological space, and the “three lines” are the three control lines corresponding to the urban development boundary, permanent basic agricultural land, and ecological protection red line, respectively. Since the 18th National Congress of the Communist Party of China proposed to accelerate the construction of “intensive and efficient production space, livable and moderate living space, and beautiful ecological space,” the coordination of production, living, and ecological space has needed to adapt to the management and research of territorial space. Thus, the research based on the perspective of “production–living–ecological” space has become the focus of government and academia. Although there are significant differences in the recognition of “production–living–ecological” space in academia [
7], the connotation of production, living, and ecological spaces currently has formed a relatively unified framework [
8]. The classification and identification of “production–living–ecological” space provide the basis for further research on territorial space. Among this research, classification based on land use [
9], ecosystems [
10], or landscape values [
11] has divided the territorial space function, whereas identification has used mostly quantitative measurements and inclusive classification to identify single function spaces or dominant function spaces.
Existing research on “production–living–ecological” spaces has focused mainly on evolution, driving force, effect, and optimization. Research on evolution has revealed the changing characteristics of the “production–living–ecological” space function [
12] and the law of coupling and coordination [
13] and has examined the connection between the topographic gradient and the “production–living–ecological” space [
14]. Research on driving forces has identified human factors, such as migration and farmer behavior [
15]; natural factors, such as the climate; and human-natural interactions that all have significant effects on the “production–living–ecological” space [
16]. Research on these effects has demonstrated that changes in the “production–living–ecological” space will cause climate changes [
17], hydrology [
18], and ecological quality, which will have an impact on the environment [
19] and sustainability. Research on optimization and management has been based mainly on the analysis of human–natural system coupling [
20], territorial space planning [
21], and double evaluation [
22] perspectives, which involve national [
23], interregional [
24], provincial [
25], urban [
26], county [
27], and township [
28] areas to propose optimal management countermeasures according to local conditions.
The Yangtze River Economic Belt (YREB) is one of the most active regions in China for the development and utilization of territorial space and also is the most important east west–axis of territorial space development, accounting for 21% of the national area, 40% of the national population, and more than 40% of the total economic output. Since 2000, driven by national policies, the YREB has developed rapidly. In 2020, the region achieved a total gross domestic product (GDP) of CNY 471,580 billion, accounting for 46.6% of the country. At the same time, however, the YREB is also responsible for serious ecological problems [
29], and the uncoordinated territorial space development has seriously restricted the high-quality development of the region. Establishing the YREB as a model economic zone of high-quality development is an inevitable requirement against the backdrop of national development in the new era. In 2018, the YREB began “promoting well-coordinated environmental conservation and avoiding excessive development”; high-quality development officially became a national strategy; efficient and reasonable development and utilization of territorial space were established as the foundation of the Yangtze River’s ecological protection. In 2022, scientific planning of territorial space development and protection pattern, establishment and improvement of territorial space management and control mechanism, and speeding up the formulation of a territorial space plan were established as the essential requirements necessary to promote high-quality regional development of the YREB. This series of measures represents the transition of the development of the YREB from a high–speed development stage focusing on territorial space development since 2000 to a high-quality development stage with equal emphasis on development and protection today. Optimizing the territorial spatial pattern and achieving equal emphasis on development and protection is the key to achieving high-quality development of the Yangtze River Economic Belt.
Against the above backdrop, exploring the characteristics and driving mechanisms of territorial space development in the YREB can provide a scientific reference and theoretical support for the rational optimization of the territorial space pattern. Currently, the research on the territorial space of the YREB has featured the following three characteristics: First, in terms of research perspective, it has focused on the analysis of the single space of production, life, or ecology or the connections between two spaces. Research on the mutual influence of these three living spaces, however, has been lacking. Second, in terms of research content, it has focused mostly on the analysis of the evolution and optimization of territorial space, but less on the analysis of the driving mechanism. Third, in terms of research scale, most of the research has focused on the development of territorial space in each river basin, and few studies have examined the whole area on a large scale. Therefore, in general, the research on the process of changing territorial space patterns and the mechanism of regional differentiation in the YREB remains weak.
This study examined the evolutionary characteristics of the territorial space pattern of the YREB since 2000 and revealed the formation mechanism according to the territorial space research model, landscape pattern analysis, and geodetector. A scientific understanding of the evolution pattern and driving factors of the territorial space pattern of the YREB has promoted the formulation and implementation of territorial space planning, optimized the territorial space pattern, implemented the strategy of high-quality development of the YREB, and further promoted high-quality development in China.
5. Conclusions
Based on land use and socioeconomic data, in this study, we systematically analyzed the dynamic change characteristics of the YREB territorial space by applying the theory and method of territorial space pattern evolution. Additionally, we explored the factors affecting the territorial space through geographic detectors. The main conclusions of this study are as follows:
First, the territorial space in the YREB is characterized by a rather obvious geographical hierarchical distribution in terrain gradient. The dominant types of territorial space in the low and middle terrain areas included agriculture, industrial and mining, urban and rural space, and water areas, which were the dominant distribution areas of production and living space. The high terrain areas featured forestland, grassland, and other space, which were the dominant distribution areas of ecological space. With the increase of altitude and slope, production and living space contracted, and ecological space expanded.
Second, since 2000, the territorial space of the YREB has changed dramatically. From the perspective of time sequence, living space has tended to increase, while production and ecological space have tended to decrease, but ecological space has always been dominant. From the perspective of space, production space was distributed primarily in the middle and lower reaches, living space was distributed primarily in the lower reaches, and ecological space was distributed primarily in the middle and upper reaches. The inter-transformation behavior between territorial spaces has been frequent, and the transformation trajectory showed diversification, with production space transforming mainly to ecological space and living and ecological space transforming primarily to production space.
Third, in the past 20 years, the pattern of territorial spatial in the YREB has changed significantly. Among these changes, the level of fragmentation, the degree of regularity of shape, and the spatial dispersion of patches in the production space landscape have increased. The irregularity of the shape of living space patches has decreased and the degree of fragmentation has become weaker and has tended to be spatially concentrated. The shape of ecological space patches has become complex, the spatial pattern has become dispersed, and the level of landscape fragmentation has increased. On the whole, the fragmentation, heterogeneity, and dispersion of landscape patches have increased, and the balance and diversity of space utilization have increased.
Finally, natural factors promote or inhibit the effects of change on territorial space to different degrees, but the degree of these effects has tended to diminish over time. Human factors have played a strong driving role, and the degree of interference gradually increased. From 2000 to 2010, the dominance of natural factors was stronger, especially the influence of topographical conditions was the most significant, and the effect of human factors was the strongest. From 2010 to 2020, the dominance of human factors increased. Population, economic development, and consumption levels work together to drive territorial space development. There are significant differences in the extent of the role of these different factors on the territorial space of the whole region and each basin, and the role of the same factor on the territorial space of different regions also was different. ln general, natural and human factors jointly promoted the formation and development of the territorial space pattern.
The study of the evolution characteristics and formation mechanism of the territorial space pattern of the YREB provide a reference basis for sustainable territorial space development. The key to the high-quality development of the YREB, however, lies in the optimization of territorial space patterns. Seeking spatial optimization ideas, clarifying spatial optimization goals, formulating differentiated spatial control policies, promoting the coordination of territorial space utilization, and actively promoting the efficient development of territorial space is essential to achieve high-quality development. Therefore, in the future, it is necessary to quantitatively evaluate the degree of coordination among territorial spaces, scientifically evaluate the level of territorial space utilization, identify the positioning of the main functions of territorial space, and build a scientific and reasonable territorial space layout system. This specific process then will be studied in depth to provide a theoretical basis for achieving the high-quality development of the YREB.