*3.1. Spatiotemporal Evolution Characteristic of the PLES*

According to the classification system of the PLES, the land-use types in the UCC were divided into four spatial types. Spatiotemporal evolution characteristic of the PLES in the study area is shown in Figure 3. The spatial distribution of PES was the most extensive. ES was mainly distributed in the areas where the Yangtze River and Jialing River flow through. EPS was strip-shaped from north to south. The concentration of LPS was the highest in Yuzhong District and its vicinity. sive. ES was mainly distributed in the areas where the Yangtze River and Jialing River flow through. EPS was strip–shaped from north to south. The concentration of LPS was the highest in Yuzhong District and its vicinity.

According to the classification system of the PLES, the land-use types in the UCC were divided into four spatial types. Spatiotemporal evolution characteristic of the PLES in the study area is shown in Figure 3. The spatial distribution of PES was the most exten-

reflecting the spatial agglomeration relationship and the active degree of the LUCs zones. On another, if there is a more significant conflict difference between adjacent units, the interference of land–use patterns in its adjacent units will be stronger, and the possibility of causing LUCs will be higher [23]. Thus, the methods of cold– and hot–spot analysis and neighborhood analysis were used to reflect the spatial agglomeration relationship and potential risk of LUCs in the UCC. Taking the "3 × 3" rectangular component as the range, the standard deviation of the central element can be obtained through the neighborhood analysis function, to judge the influence degree of the surrounding units on the main unit [23,47]. The potential land–use conflicts risk index (PLUCRI) was constructed to analyze

∑ |<sup>−</sup>

sity of the i–th evaluation unit, and it is represented by eight LUCs zones (for quantitative calculation, I–VIII is represented by 1, 2,…8, respectively). is the conflict intensity of

is the PLUCRI of the *i*–th evaluation unit, and the larger the value is, the greater


(8)

denotes the conflict inten-

is the number of neighborhood

=

the possibility of conflict in the evaluation unit would be.

the *j*–th neighborhood unit's *i*-th evaluation unit.

*3.1. Spatiotemporal Evolution Characteristic of the PLES*

units of the i-th evaluation unit [23].

**Figure 3.** Spatial–temporal evolution of the PLES from 2000 to 2020. **Figure 3.** Spatial-temporal evolution of the PLES from 2000 to 2020.

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the potential LUCs. The specific formula is below:

where

**3. Results**

As Table 2 shows, from 2000 to 2020, the LPS expanded significantly by 673.68 km<sup>2</sup> (+254.22%), while the PES was compressed by LPS and reduced by 671.35 km<sup>2</sup> (−17.12%). Due to the ecological protection policy, the proportion of ES increased sustainably in the past 20 years. It shows that rapid urbanization mainly eroded the PES and EPS in the UCC. As Table 2 shows, from 2000 to 2020, the LPS expanded significantly by 673.68 km<sup>2</sup> (+254.22%), while the PES was compressed by LPS and reduced by 671.35 km<sup>2</sup> (−17.12%). Due to the ecological protection policy, the proportion of ES increased sustainably in the past 20 years. It shows that rapid urbanization mainly eroded the PES and EPS in the UCC.

**Table 2.** The area ratio of the PLES in the UCC from 2000 to 2020. **Table 2.** The area ratio of the PLES in the UCC from 2000 to 2020.


To analyze the transformation of the PLES, the land transfer matrix was used. From 2000 to 2010, the LPS in the UCC increased by 268.15 km<sup>2</sup> , while the PES decreased by 268.66 km<sup>2</sup> . The percentage difference between the transfer-in and transfer–out ratio of PES was −6.82%, the LPS was 49.76%, the ES was −1.86%, and the EPS was −2.47%. The *LCDI<sup>i</sup>* of the LPS was the largest. It showed that the rate of change in the LPS was the greatest in this decade. In the process of rapid urbanization, it mainly aimed to meet the regional expansion of LPS. The *BLCDI<sup>i</sup>* of the LPS was 10.33%, and was the largest during this period. It showed that the transformation between LPS and other spaces was the strongest. The conversion of PES to LPS was the primary source of the increase in the LPS area. It showed that urban expansion was mainly based on the interconversion of LPS, ES, and PES, and the transfer area of LPS was more significant than the other two (Table 3, Figure 4).

In the transfer of the PLES in the UCC from 2010 to 2020, the area of the LPS and the ES still increased, while the area of the PES and the EPS still decreased. The percentage difference between the transfer-in and transfer-out ratio of PES was −10.84%, the LPS was 42.08%, the ES was 0.81%, and the EPS was −0.38%. The LCDI of the LPS was the largest, which showed that the growth of construction land was the primary trend in the process of urbanization in this period. The *BLCDI<sup>i</sup>* of the LPS was 8.12% and the largest during this period. It showed that the conversion between LPS and other spaces was the strongest and most frequent, although the *LCDI<sup>i</sup>* of the EPS is −0.04%, the *LCDI<sup>i</sup>* of the ES is 0.09%, the

*BLCDI<sup>i</sup>* of the EPS is 1.12%, and the *BLCDI<sup>i</sup>* of the ES is 0.99%. It shows that although the rate of change of the ES is faster than the rate of change of the EPS over these ten years; however, between the EPS and other spaces is stronger than the transfer intensity between the ES and other spaces (Table 4, Figure 4).


**Table 3.** Spatial transfer matrix of the PLES in the study area from 2000 to 2010 (unit: km<sup>2</sup> ).

**Figure 4.** Sangji map of the PLES transfer from 2000 to 2020. **Figure 4.** Sangji map of the PLES transfer from 2000 to 2020.



out–of–control to the basic control. From 2010 to 2020, the basic out–of–control zone was

#### widely distributed in the UCC gradually. The serious out–of–control zone was distributed *3.2. Spatiotemporal Distribution Characteristics of the LUCs*

on the northern side of the UCC, especially in the Yubei District and Beibei District. Therefore, the spatial distribution pattern was "high in the north and low in the south" in 2020. The relatively high LUCs in the northern regions were also dominated by the serious outof-control zone, and the basic out–of–control zone. The main gathering areas of the basic out–of–control zone and the serious out–of–control zone gradually expanded from Dadukou District, Jiulongpo District, and Yuzhong District to Shapingba District, Beibei District, Yubei District, Nan'an District, and Banan District. From 2000 to 2020, Chongqing's economy developed rapidly, the urban traffic network changed from simple to complex, the medical facilities changed from few to many, and the construction land changed from scattered to concentrated. The rapid urbanization process caused serious conflict between the PLES. The area of controllable decreased, while the area of out–of–control increased in the UCC from 2000 to 2020. According to Formulas (3)–(7), the LUCs in the UCC were calculated and visually expressed (Figure 5). We derived spatial patterns of the UCC's land-use conflicts from 2000 to 2020. The distribution pattern was "high in the south and low in the north" in 2000. The LUCs was higher on the southern side of the UCC, especially in the center area of the UCC and the northeastern of Banan District. The relatively high LUCs in the south of regions were dominated by the basic out-of-control zone and the serious out-of-control zone. From 2000 to 2010, the basic out-of-control zone had spread around. It is worth noting that by 2010, the level of the LUCs in the Yuzhong District changed from the basic out-of-control to the basic control. From 2010 to 2020, the basic out-of-control zone was widely distributed in the UCC gradually. The serious out-of-control zone was distributed on the northern side of the UCC, especially in the Yubei District and Beibei District. Therefore, the spatial distribution pattern was "high in the north and low in the south" in 2020. The relatively high LUCs in the northern regions were also dominated by the serious out-of-control zone, and the basic out-of-control zone. The main gathering areas of the basic out-of-control zone

**Figure 5.** Spatial–temporal distribution characteristics of the LUCs from 2000 to 2020**.**

and the serious out-of-control zone gradually expanded from Dadukou District, Jiulongpo District, and Yuzhong District to Shapingba District, Beibei District, Yubei District, Nan'an District, and Banan District. From 2000 to 2020, Chongqing's economy developed rapidly, the urban traffic network changed from simple to complex, the medical facilities changed from few to many, and the construction land changed from scattered to concentrated. The rapid urbanization process caused serious conflict between the PLES. The area of controllable decreased, while the area of out-of-control increased in the UCC from 2000 to 2020. out–of–control zone and the serious out–of–control zone gradually expanded from Dadukou District, Jiulongpo District, and Yuzhong District to Shapingba District, Beibei District, Yubei District, Nan'an District, and Banan District. From 2000 to 2020, Chongqing's economy developed rapidly, the urban traffic network changed from simple to complex, the medical facilities changed from few to many, and the construction land changed from scattered to concentrated. The rapid urbanization process caused serious conflict between the PLES. The area of controllable decreased, while the area of out–of–control increased in the UCC from 2000 to 2020.

According to Formulas (3)–(7), the LUCs in the UCC were calculated and visually expressed (Figure 5). We derived spatial patterns of the UCC's land–use conflicts from 2000 to 2020. The distribution pattern was "high in the south and low in the north" in 2000. The LUCs was higher on the southern side of the UCC, especially in the center area of the UCC and the northeastern of Banan District. The relatively high LUCs in the south of regions were dominated by the basic out–of–control zone and the serious out–of–control zone. From 2000 to 2010, the basic out–of–control zone had spread around. It is worth noting that by 2010, the level of the LUCs in the Yuzhong District changed from the basic out–of–control to the basic control. From 2010 to 2020, the basic out–of–control zone was widely distributed in the UCC gradually. The serious out–of–control zone was distributed on the northern side of the UCC, especially in the Yubei District and Beibei District. Therefore, the spatial distribution pattern was "high in the north and low in the south" in 2020. The relatively high LUCs in the northern regions were also dominated by the serious outof-control zone, and the basic out–of–control zone. The main gathering areas of the basic

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**Figure 4.** Sangji map of the PLES transfer from 2000 to 2020.

*3.2. Spatiotemporal Distribution Characteristics of the LUCs*

**Figure 5. Figure 5.** Spatial Spatial-temporal distribution characteristics of the LUCs from 2000 to 2020. –temporal distribution characteristics of the LUCs from 2000 to 2020**.**

According to the result presented in Table 5, the average conflict level in Chongqing urban center from 2000 to 2020 increased from 0.62 to 0.69. In the process of rapid urbanization, the characteristics of "two decreases and two increases" appeared. The characteristic of "two decreases" means the area of the stable control zone and area of the basic control zone declined. The characteristic of "two increases" means the area of the basic out-ofcontrol zone and the area of the serious out-of-control zone increased. From 2000 to 2020, the area of stable control zone was maintained at 6–7%. The area of basic control zone was reduced by 18.48%, while the area of out-of-control zone increased by 19.24%. The area of basic and serious out-of-control zone occupied almost 56% of the study area. It posed a serious threat to the ecological environment of Chongqing. Compared with the conflict change over the three periods, it showed that the out-of-control level was mainly clustered in the LPS and PES area. It is due to the conflicting living–ecological, production–ecological functions. The area far away from the LPS and PES was mainly the controllable level, and this type of area was dominated by ecological function land.


**Table 5.** Land-use conflicts level in the study area from 2000 to 2020.

The spatial distribution characteristics of the PLES in the LUCs zones in the UCC (Figure 6) and the corresponding area ratio changes (Table 6) were analyzed by spatial superposition analysis.

**Figure 6.** The evolution characteristics of the PLES in the LUCs zone from 2000 to 2020. **Figure 6.** The evolution characteristics of the PLES in the LUCs zone from 2000 to 2020.

**Table 6.** The area ratio statistics of LUCs zones from 2000 to 2020. **Table 6.** The area ratio statistics of LUCs zones from 2000 to 2020.


PES 64.66 56.72 54.11 −10.55

In the stable controllable zone, EPS occupied the absolute number, accounting for 50.99% in 2020. The land-use type of EPS was mainly forest, which has strong ecological functions. From 2000 to 2020, due to the decrease of PES and the increase of LPS, the range of the basic controllable areas was also shrinking.

From 2000 to 2020, in the basic out-of-control zone and the serious out-of-control zone, LPS increased by 27.93% in total, while the other three types decreased. Among them, PES decreased by 17.24%, EPS decreased by 10.48%, and ES decreased by 0.21%. The out-of-control zone was mainly distributed in the core and peripheral areas of urban economic development, which were the critical area of Chongqing's future production and living development.

In the past 20 years, Chongqing has been in rapid development of the economy and society. With the level of industrialization and urbanization further improved, the demand for the land for production and living increased. In the continuous improvement of transportation facilities and growing construction land, the ecological land and agriculture land were eroded heavily by urban land. The ES, EPS, and PES were gradually fragmented. The proportion of the out-of-control level in the study area was becoming heavier and heavier. The mutual occupation between the production, living, and ecological land made the LUCs more intense. It resulted in more prominent contradictions between humans and land. The man-land relations were becoming increasingly tense in the UCC.
