3.5.2. Analysis of Socio-Economic Factors

Additionally, we analyzed the following factors: X6 (year-end total population), X7 (population density), X8 (gross domestic product, GDP), X9 (non-agricultural proportion), and X10 (road network density). From the perspective of factor interpretation, X6–X10 had a great impact on the eco-environmental quality of the study area, which was the main driving force. The impact of X6 and X7 on the ecological environment of the study area fluctuated, but the overall level remained above 0.100, indicating that X6 and X7 had a great impact on the ecological environment of the study area. However, the q value of X7 decreased to 0.089 in 2020, indicating that the influence of X7 on the ecological and environmental quality weakened in 2020. Notably, X8, X9, and X10 portrayed an initial increasing trend, followed by a decreasing trend from 1980 to 2020; however, the values increased to different degrees, compared with 1980, indicating that the influence of X8–X10 on the eco-environmental quality of the study area was increasing.

#### 3.5.3. Human–Natural Coupling Interaction Detection Results

Different factors have different effects on ecological and environmental quality; notably, there are complex interaction relationships among these factors, leading to differences in the magnitude, intensity, and direction of their effects. The interaction between factors may increase the impact on the ecological and environmental quality. From 1980 to 2020, the interaction between the natural and human factors in Qinghai portrayed two modes of non-linear and double factor enhancements; notably, there was no independent or weakening relationship, indicating that the influence of the interaction between the two factors was greater than the influence of each single factor. According to the results of factor detection and interaction detection, X5 and X1 (among natural factors) and X8 and X10 (among socio-economic factors) were the factors that portrayed the greatest influence on human-natural coupling interaction and factor detection (Table 7).


#### **4. Discussion**

Territorial space is an important carrier of regional human activities and ecological environments. The interaction between people and the natural environment in territorial space changes the function of regional territorial spaces and shapes the production, activity, and ecological spaces through the changes in the land use types in a region [32,54]. In 1999, the European Spatial Development Perspective (ESDP) clearly stated that spatial planning can promote sustainable and balanced development among regions [55]. As an effective means for the construction of ecological civilization and spatial planning, PLE space is classified on the basis of different utilization functions of territorial space to optimize the development pattern, control the development intensity, and adjust the spatial structure of territorial space [39,56]. In this study, we used the PLE functional space classification to merge and classify the land use spatial data, which accounted for the lack of the consideration of the ecological function in land use classification, and realized the connection between land function and land use classifications. Therefore, this method is widely used in land function regulation, determining the eco–environment effects, and other related fields [57–59].

According to relevant studies, the rapid development of social economy and urbanization is accompanied by the deterioration of eco-environmental quality to a certain extent [25,60,61]. This degradation is usually caused by the change of territorial spatial patterns due to land use transformation (Figure 7). Qinghai Province is located inland of north-west China, and most of its areas are restricted development zones (areas with weak resource and environment carrying capacities, with poor conditions for large-scale ag-glomeration of economy and population, but related to ecological security in a large area of the country) [62,63]. The causes of eco-environmental quality changes in Qinghai Province are consistent with those in regions and cities with rapid economic development and high urbanization rate in China, such as Yellow River Delta, Beijing-Tianjin-Hebei region, Yangtze River delta economic zone, etc. It is mainly due to economic expansion and urban occupation of ecological space that APS and ecological land are converted into ULS and RLS in territorial space. However, because most of the area in Qinghai is a restricted development zone, it also has a certain comprehensiveness and complexity, for example, unfavourable ecological space maintenance leads to grassland and forestland degradation and wetland atrophy.

The change of ecological environment quality reflects the interaction between natural environment and human society in territorial space, and its change is complex and dynamic. Such changes are caused by the natural constraints force provided by natural factors, the human driving force provided by socioeconomic factors, and the coupling interaction force between humans and nature. The effect of natural factors on the change of eco-environment quality is smaller than that of socioeconomic factors, but it creates the basic conditions of ecological environment quality. Socioeconomic factors have a more direct impact on eco-environmental quality and play a leading role in the change of it. The human-nature coupling interaction force has a strengthening effect on the eco-environment quality, which is often accompanied by a guiding and decision-making power. Guiding and decisionmaking power refer to the influence of local political environment [25]. The direction and speed of the evolution of territorial spatial pattern and eco-environment quality are determined by the joint participation of these forces.

**Figure 7.** Mechanism of eco-environmental quality change under territorial spatial evolution in Qinghai.

#### *4.1. Natural Factors Are the Natural Constraints Force Affecting the Eco-Environment Quality*

Due to the characteristics of natural environments, the territorial space of Qinghai Province portrayed significant horizontal regional differentiation and vertical gradient differences. Simultaneously, due to the characteristics of small population density and the relatively concentrated population, the territorial spatial pattern indicated the characteristics of relative agglomeration of the production and living spaces and absolute dominance of ecological spaces. The production and living spaces portrayed significant convergences and were mainly distributed in Qinghai city (prefecture) in the county administrative centre. The eco-environmental quality of Qinghai Province portrayed an overall steady increase, but due to the fragile ecological environment, although the high-quality areas expanded, the overall area remained small. The low-quality area and the low-medium quality area continued to shrink, but the proportion of the areas were still large, indicating that the eco-environmental quality needed to be improved further.

#### *4.2. Socioeconomic Factors Are the Human Driving Forces Affecting Eco-Environment Quality*

From 1980 to 2020, the living space continued to expand due to urbanization and population growth, and the growth range and speed of the ULS was much greater than that of RLS in Qinghai. Both the production and ecological spaces portrayed fluctuations. The former space increased, while the latter slightly decreased. The eco-environmental quality of Qinghai Province portrayed an overall steady increase, albeit a slight decrease in 2000; this was partly because the eco-logical civilization concept was in its infancy stage in China and because in 1992, China officially proposed to establish the goal of the socialist market economy, which resulted from the people expecting high economic benefits, with little consideration for the protection of the ecological environment.

#### *4.3. Human-Nature Coupling Interaction Force Are the Crucial Guiding Forces Affecting Eco-Environment Quality*

At the national level, in terms of the vast spatial areas of Qinghai Province, the topography is generally complex; notably, the region is also one of the multi-ethnic populated provinces in mainland China and has a unique natural geographic and socio-economic structure. Relevant national policies, such as Western development, returning farmland to forest (grass-land), ecological civilization construction and high-quality development of the Yellow River Basin, all have a significant impact on socioeconomic factors by combining the characteristics of regional natural environment and form a crucial guiding force for the change of eco-environment quality. The increase in the production space from 1980 to 2000 was mainly caused by crowding out the GES, which led to the continuous decline of GES during this period. At the beginning of the 21st century, China put forward the construction of ecological civilization, and with the vigorous promotion of ecological civilization construction, the ecological spaces of grassland, woodland, and water area improved to different degrees, through the conversion of other ecological spaces (unused land). Qinghai Province is located in the upper reaches of the Yellow River, and its location has important political, ecological, economic and social significance. The implementation of relevant regional policies makes Qinghai's overall environmental quality portray a continuous upward trend. Additionally, we observed non-linear enhancement and double enhancement effects among the factors, indicating that human-nature coupling interaction force are the crucial guiding forces affecting eco-environment quality.

#### **5. Conclusions**

Based on the "PLE" spatial classification, we employed the land transfer matrix, ecoenvironmental quality index, and ecological contribution rate of land use transformation to quantitatively analyze the changes of territorial spatial pattern and eco-environmental effects in Qinghai Province, and used geographic detectors to explain the driving forces of eco-environmental quality evolution. (1) the spatial distribution of the province was characterized by the relative agglomeration of the production and living spaces and the absolute dominance of ecological spaces. It shows that there is a trend of expansion of production and living space and contraction of ecological space. (2) The eco-environmental quality of the region portrayed a steady improvement, with a significant reduction in the medium–low and low-quality areas. Spatially, the medium quality areas are mainly distributed in most of Haixi Prefecture, while the high-quality and medium-high-quality Area areas are mainly distributed in the eastern part of Qinghai and the southern part of Three Rivers Source region. (3) The annual average precipitation, proportion of non-agricultural area, and socio-economic factors had a significant impact on the eco-environmental quality of the region; meanwhile, national economy and ecological policies are important indirect driving forces of eco-environmental quality. Although the influence of natural factors on the eco-environmental quality of Qinghai Province is less than that of human factors, the support and constraint of natural geographical basis on the ecological environment cannot be ignored. Additionally, we observed non-linear enhancement and double enhancement effects among the factors, indicating that the human-nature coupling interaction force had a strengthening effect on the changes in the eco-environmental quality.

In the future development of Qinghai province, the key to the continuous improvement of ecological environment quality in the area are to optimize the layout of the PLE spaces, construct a reasonable territorial space protection pattern, and promote the sustainable development of human-natural coupling.

**Author Contributions:** Conceptualization, X.W. and Q.W.; investigation, X.W.; methodology, X.W.; validation, J.D. and L.S.; formal analysis, X.W.; resources, L.S. and B.L.; data curation, X.W.; visualization, X.W.; writing—original draft preparation, X.W.; writing—review and editing, X.W., Y.W. and J.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by National Natural Science Foundation of China, grant number "42271221".

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data and materials will be made available from the corresponding author(s) upon reasonable request.

**Conflicts of Interest:** The authors declare that they have no conflict of interest.

#### **References**

