Verifying the Synthesized Effects of Intensive Urban Land Use on Quality of Life, Ecology, and Urban-Land-Use Scale in China

Round 1

Reviewer 1 Report

The manuscript presents an assessment of the intensive land use on ecology, quality of life and land use scale using SEM. The study is interesting and can contribute to the knowledge of urban land-use change and analysis. The authors can improve the manuscript by considering the following comments.

1. Though the authors mention the inadequacy of the indices as part of the limitations, some indices might be too important to be neglected. For example, the unemployment rate should be an index of quality of life. The authors should consider this.
2. The authors should consider acknowledging that, at least, one of the indices can be relevant to two aspects of sustainable development used in the study. For example, the green area is relevant to both quality of life and ecology. Probably this is a source of the indirect effect alluded to by the authors. 
3. The author(s) should improve on the discussion of the results in the context of the existing literature. Only a few studies are cited in the discussion section. In line 388, the authors mention "previous studies" without citing any of the previous studies.
4. In line 335, the statement "while land output indirectly increased urban land scale by improving ecology and harmed ecology by controlling urban land sprawl." is confusing. The output improves and harms ecology!

Author Response

Response to Reviewer 1’s Comments

 

Point 1: Though the authors mention the inadequacy of the indices as part of the limitations, some indices might be too important to be neglected. For example, the unemployment rate should be an index of quality of life. The authors should consider this.

 

Response 1: Thank you for this insightful comment. We have added two indices in the measurement of quality of life, unemployment rate and average wage (Table 2). They reflect the employment pressure caused by high-density development and the living standards respectively.

Due to the change of observable indices, we continuously optimized the SEM fitting results. All modifications were based on the theoretical significance of the variables. Accordingly, the analysis of SEM was also revised (Section 5).

 

 

Point 2: The authors should consider acknowledging that, at least, one of the indices can be relevant to two aspects of sustainable development used in the study. For example, the green area is relevant to both quality of life and ecology. Probably this is a source of the indirect effect alluded to by the authors.

 

Response 2: Thank you for this insightful comment. By comparing literatures related to quality of life, it is found that ecology is considered as a part of quality of life in some studies. However, there are also a large number of literatures make a specialty of ecology. In order to highlight the important dimension of ecology, we took it as a special dependent variable. In the quality of life, the urban infrastructure and living standard were mainly considered.

There may be some correlations between the dependent variables. For example, there may be competitive relationships between ecological, production and living spaces in a city; the traffic condition and the layout of living space may affect regional eco-environment; and urban land scale may affect traffic condition and energy consumption. We have recognized these correlations and believe that they are the source of the indirect effect. In order to clarify the direct effect, indirect effect and total effect, we explained them in “3.1 Verifying the effects using an analysis framework” (Line 170-182).

 

Point 3: The author(s) should improve on the discussion of the results in the context of the existing literature. Only a few studies are cited in the discussion section. In line 388, the authors mention "previous studies" without citing any of the previous studies.

 

Response 3: Following this comment, we improved the discussion of the results as “6.1 Comparison with previous studies” (Line 413-425). First of all, we cited some representative studies (Line 415-418). Then, we briefly compared the previous results with the results in this paper (Line 421-425).

 

Point 4: In line 335, the statement "while land output indirectly increased urban land scale by improving ecology and harmed ecology by controlling urban land sprawl." is confusing. The output improves and harms ecology!

 

Response 4: Thank you for this comment. First, we defined the direct effect, indirect effect and total effect in “3.1 Verifying the effects using an analysis framework” (Line 170-182).

Second, in order to clearly explain the indirect impact, we also improved its description in the results. For SEM in 2010, we explained the indirect effect as “This reveals that intensive urban land use had an indirect effect on ecology by improving urban land sprawl. After intensive urban land use affected urban land scale, the ecology improved with the expansion of urban land area.” (Line 356-360). For SEM in 2015, we explained the indirect effect as “Second, there was a weak and negative correlation between quality of life and urban land scale, with a path from η3 to η1 with a coefficient of -0.29, indicating that intensive urban land use indirectly affected quality of life by changing urban land sprawl. After intensive urban land use affected urban land scale, the quality of life decreased with the expansion of urban land area.” (Line 378-382). For SEM in 2019, we explained the indirect effect as “It indicated that ecological protection was emphasized in land use and intensive urban land use indirectly improved quality of life by promoting urban land sprawl. After intensive urban land use affected urban land scale, the quality of life improved with the expansion of urban land area.” (Line 395-399).

 

Author Response File: Author Response.doc

Reviewer 2 Report

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2’s Comments

 

Point 1: However, I would like to suggest the analytic problem in designating the dependent and independent variables. Two variables of land output would fit for dependent variables, GPP and Finance income.

 

Response 1: Thank you for this insightful comment. Combined with China’s intensive urban land use policy and the trial technical regulation for evaluating the potential of intensive use of urban land promulgated by China’s Ministry of Land and Resources, the economic output in average urban land areas has always been an important standard to judge the degree of intensive urban land use in this country. Therefore, we chose “Gross regional product in average urban land areas” and “Public finance income in average urban land areas” to reflect the level of land output.

To make this choice easier to be understood, we revised section 1 (Line 54-59) and section 2 (Line 91-106). We explained that “Adding the labor and capital input and economic output of unit land was expected to promote more compact urban areas and slower urban land sprawl.” in section 1 (Line 54-56) and “(1) Intensive urban land use has been considered as a result of getting more output under unit land. Some studies selected one or more representative indicators that are easy to measure to analyze the intensity degree, such as finance income per unit area of land, GDP per unit area of land, etc.” in section 2 (Line 91-94)

For this comment, we have added two indices, unemployment rate and average wage in the measurement of dependent variable quality of life (Table 2). They reflect the employment pressure caused by high-density development and the living standards respectively. Accordingly, the results and analysis of SEM have been revised (Section 5).

 

Point 2: I was confused with the definition of dependent variables, I have a fundamental question on the quality of life and ecology. Is there any ground to accept the key factor of quality of life, as you mentioned, traffic congestion, living space and health infrastructure? Instead of quality of life, “quantity of urban infra” would be proper for these variables. Also, on the ecology variables, soot emission can be affected by the urban infra (traffic congestion and living space). Two variables of urban land scale could be independent variables to affect the quality of life and ecology.

    Response 2: Thank you for this insightful comment! This is a very critical issue that we failed to describe clearly. The index system was proposed based on the literature review (section 2). According to section 2, we determined the contents from which to select indices. We supplied a detailed description of the dependent variables and independent variables (section 3, Line 191-206). According to some representative studies, we determined specific indices. The representative studies are showed in Table 1.

At present, the indices used to measure quality of life are related to urban infrastructure. Though we have mentioned the inadequacy of the indices as part of the limitations, we still try to continuously improve the index system. Two important indices, unemployment rate and average wage have been used in the measurement of quality of life (Table 2). They reflect the quality of life in terms of socio-economic development. Accordingly, the results and analysis of SEM have been revised (Section 5).

There may be some correlations between three dependent variables. For example, there may be competitive relationships between ecological, production and living spaces in a city; the traffic condition and the layout of living space may affect regional eco-environment; and urban land scale may affect traffic condition and energy consumption. We have recognized these correlations and believe that they are the source of the indirect effect. In order to clarify the direct effect, indirect effect and total effect, we explained them in “3.1 Verifying the effects using an analysis framework” (Line 170-182).

In order to clearly explain the indirect impact, we also improved its description in the results. For SEM in 2010, we explained the indirect effect as “This reveals that intensive urban land use had an indirect effect on ecology by improving urban land sprawl. After intensive urban land use affected urban land scale, the ecology improved with the expansion of urban land area.” (Line 356-360). For SEM in 2015, we explained the indirect effect as “Second, there was a weak and negative correlation between quality of life and urban land scale, with a path from η3 to η1 with a coefficient of -0.29, indicating that intensive urban land use indirectly affected quality of life by changing urban land sprawl. After intensive urban land use affected urban land scale, the quality of life decreased with the expansion of urban land area.” (Line 378-382). For SEM in 2019, we explained the indirect effect as “It indicated that ecological protection was emphasized in land use and intensive urban land use indirectly improved quality of life by promoting urban land sprawl. After intensive urban land use affected urban land scale, the quality of life improved with the expansion of urban land area.” (Line 395-399).

Finally, due to the change of observable indices, we continuously optimized the SEM fitting results. All modifications were based on the theoretical significance of the variables.

 

Point 3: Two words of “Compound system” and “Synthesized effects” should be reconsidered to use at the ms, and what is a difference in the analysis of ‘direct’ and ‘indirect’ effects and total effects.

 

Response 3: Following this comment, we checked the relevant material of “Compound system” and replaced this statement with “Analytical framework” (Line 160).  This statement has been revised in the full manuscript.

For “Synthesized effects”, we want to emphasize that what we studied were the effects of intensive urban land use on quality of life, ecology, and urban land scale together, rather than individual exploration. Therefore, we tend to retain this expression. Thank you for this comment!

 

Point 4: Figure 1. The too narrative description on your research concept, please refer and see the below figure, and “…” expressions are not good for readers.

 

Response 4: Excellent point. This adds significantly to our paper. Thank you. Following this comment, we revised Figure 1（Line 156）

Comparatively, this figure is concise and clear. There is no “…” in the figure. By summarizing the literature review, the impact of intensive urban land use on quality of life changes with urban spatial density. The impact on ecology comes from the increase of spatial density and utilization efficiency of resources and energy. The impact on urban land scale is a combination of substitution effect and aggregation effect.

 

Point 5: L 211~212, According to figure 1 and table 1, there was an evidently structural relationship between the independent variables and dependent variables; A word of “evidently” represents the leap of logical analysis or viewpoint on the independent and dependent variables. Do three dependent variables show the same level of the hierarchy?

 

Response 5: Considering that this sentence was not expressed clearly, we deleted it in the manuscript (Line 239-240). In fact, the other two items were enough to explain why SEM was selected in this research.

Quality of life, ecology, and urban land scale were in the same level of the hierarchy, for they were important aspects that intensive urban land use affect. By comparing literatures related to quality of life, it is found that ecology is considered as a part of quality of life in some studies. However, there are also a large number of literatures make a specialty of ecology. In order to highlight the important dimension of ecology, we took it as a special dependent variable.

Author Response File: Author Response.doc

Round 2

Reviewer 2 Report

Each point was well described and edited at the revised ms. Good to read and you can develop and suggest the further research at the discussion part.

Author Response

 

Response to Reviewer 2’s Comments

 

Point 1: Each point was well described and edited at the revised ms. Good to read and you can develop and suggest the further research at the discussion part.

 

Response 1: Thank you for this insightful comment. Following this comment, we suggested the further research in “6.3 Limitations of the research” (Line 491-514). There were two limitations in the research. First, we verified the effects of intensive urban land use on quality of life, ecology, and urban land scale by linear relationship rather than non-linearity. We suggested that “some models, such as panel data model and threshold test model, can be used to explore the nonlinear relationships between multiple independent variables and a dependent variable. If there is a method to integrate the functions of SEM and the above models, it will be helpful to explore the nonlinear influence characteristics between multiple independent variables and multiple dependent variables.” (Line 499-504). Second, there were restrictions regarding the indices used for analysis. We suggested that “In terms of ecology, indices related to CO2 emission and heat island effect are deserved to be added in combination with China’s development goals of carbon peaking and carbon neutrality. In terms of quality of life, indices related to crime rate and social interconnectivity deserve to be added.” (Line 511-514). Thank you for this comment!

 

Author Response File: Author Response.doc