The Spatial-Temporal Evolution of Population in the Yangtze River Delta, China: An Urban Hierarchy Perspective
Round 1
Reviewer 1 Report
The manuscript aimed to investigate population dynamics across urban hierarchies and its influencing factors in the Yangtze River Delta. The topic is very interesting under the context of rapid urbanisation. Some issues should be improved before moving to further steps.
(1) In the introduction section, the authors should tell the readers why use China as a case? what is its representative for international studies? Likewise, why choose Yangtze River?
(2) Regarding the subsection title "Research setting", please check. I am not sure it is right or wrong, it sounds wired.
(3) The authors proposed a conceptual framework based on the theory of urban amenity. But, the questions are why apply the theory of urban amenity to the research? On lines 127-129, who argued "Population dynamics across urban hierarchy derives from that to what extent different ranking cities meet individual preference and utility"? From the previous sentences, it is hard to get this point. Further, from the framework, I can not see which one or how to evaluate the mutildimensional amenity across urban hierarchy.
Author Response
Foremost, we would like to thank you for the time and effort spent in reviewing the manuscript, and sincerely appreciate the comments and suggestions from both editors and reviewers that are of great help in advancing the quality of our work. In this letter, we reply all the insightful comments in red front. And all changes in the manuscript are highlighted in yellow. Please check!
The manuscript aimed to investigate population dynamics across urban hierarchies and its influencing factors in the Yangtze River Delta. The topic is very interesting under the context of rapid urbanisation. Some issues should be improved before moving to further steps.
Point 1: In the introduction section, the authors should tell the readers why use China as a case? what is its representative for international studies? Likewise, why choose Yangtze River?
Response 1: Thanks for the suggestion. Accordingly, we added some interpretations in lines 82-85 and 96-101 to highlight the representative of China and the YRD region. Foremost, this work on China might be helpful in making comparative studies within different context and enriching the cases of study on urban system evolution. Regarding the reason why the YRD is selected as the study area, we argue that the urban system in YRD is on one hand a typical example within the context of marketization and urbanization in China and a representative of the changes in the world's urban system on the other. In addition, the YRD, as one of the six megalopolises across the globe, is widely recognized as polycentric region, making it an ideal case to study the attractiveness of different rank of cities to population.
Point 2: Regarding the subsection title "Research setting", please check. I am not sure it is right or wrong, it sounds wired.
Response 2: Thank you for your suggestion. We have replaced “Research Setting” with “Methodology and Materials” (see details in Section 2, line 112).
Point 3: The authors proposed a conceptual framework based on the theory of urban amenity. But, the questions are why apply the theory of urban amenity to the research? On lines 127-129, who argued "Population dynamics across urban hierarchy derives from that to what extent different ranking cities meet individual preference and utility"? From the previous sentences, it is hard to get this point. Further, from the framework, I can not see which one or how to evaluate the mutildimensional amenity across urban hierarchy.
Response 3: Thanks for this insightful comment. Actually, population dynamics is the result of tradeoffs between costs and benefits in meeting different needs of individuals. Thus, we aim to detect the extent to which cities of different ranks meet people's heterogeneous needs. The theory of urban amenity can help to address this issue. Regarding the aforementioned sentence, we revised it as “In other words, people choose to settle in cities of different ranks in order to meet their heterogeneous needs” (see details in lines 147-149). For your last confusion, we would like to argue that we never tried to measure or evaluate the level of amenity across urban hierarchy. Rather, we hereby employ population size as the result of “voting with feet”, and further reveal the role of multidimensional amenity in attracting population. That is, people gather in small and medium sized cities in the early stage in pursuit of economic opportunities as a basic need, and then migrate to bigger cities for other higher-level needs like better public service, open-minded social atmosphere, and high-quality environment. This is very similar with Maslow's hierarchy of needs.
Author Response File: 
Author Response.docx
Reviewer 2 Report
It is a good paper studying the population dynamics in YRD, China. The patterns are clearly explained, and the framework is well constructed. However, I would suggest two points to further the theoretical contribution of this paper. First, the view of this paper is completely from an urban hierarchy perspective - I would say it is correct in China, but it might be good to add some view of polycentricity in the discussion. Second, institutional factors, for example, as mentioned by the authors, the migration policies and the Hukou system, could be discussed deeper.
A minor point:
The resolutions of figures 2, 3, and 7 are relatively low and need to be improved.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
The paper is interesting and the topic are challenging. But there are some remarks for author(s):
General comment:
The paper must follow the established structure that can be easier to follow (Introduction, Materials and methods, Results, Discussion and Conclusions).
Other remarks for author(s):
1. A workflow schema would clarify the steps follows by the authors, both in data sources and processing and data analysis.
2. Conclusion section: Can you explain the importance of your study in terms of methodology or results? How does your work help future studies with similar problems?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Strengths
Interesting topic
Weaknesses
Structure of the paper
Not exhaustive bibliographic overview
L 40 please check the phrase
Instead of “we” please use “authors”
Figure 2 is not clear, also the methodology doesn’t consider traffic
From L 169 should be Methodology and materials
Chapter 3 should be Results
Subsection 3.1. should be named
4 is Discussion, L 279-289 should be in results, and from 290 Discussion
Conclusion is partially repeating introduction, please use concise language
Please increase literature review
Author Response
Foremost, we would like to thank you for the time and effort spent in reviewing the manuscript, and sincerely appreciate the comments and suggestions from both editors and reviewers that are of great help in advancing the quality of our work. In this letter, we reply all the insightful comments in red front. And all changes in the manuscript are highlighted in yellow. Please check!
Strengths
Interesting topic
Weaknesses
Structure of the paper
Point 1: Not exhaustive bibliographic overview
Response 1: Thank you very much for finding this error. We are not sure that if the error is the page of online journal, such as “e2274” in the first reference. We have rechecked the bibliographic overview. Some papers were remodified. But there are still a few papers which only have the online page.
Point 2: L 40 please check the phrase
Response 2: Thank you very much for finding this error. We are sorry for this grammar problem. We have checked the phrase in lines 34-35. And the sentence has been modified to “in an era of aging population and low fertility rate, the changes of population have a more prominent effect on the variation in city size than ever before”.
Point 3: Instead of “we” please use “authors”
Response 3: Thanks for your kind advice. We have re-read the paper and replace “we” to “the authors” in lines 18, 121, 206 and et al.
Point 4: Figure 2 is not clear, also the methodology doesn’t consider traffic
Response 4: We apologize if our original figure 2 is not clear. We have improved the resolution of Figure 2. As for traffic, we are not sure that if population mobility is not considered in the methodology. If it is, we do Not aim to discuss migration because this article studies how total population changes across urban hierarchy. The total population is used to measure the dynamics of ranks of cities. And population growth is applied to measure the changes of population across urban hierarchy.
Point 5: From L 169 should be Methodology and materials
Response 5: Thanks for your advice. We have replaced “Research Setting” with “Methodology and Materials” in line 112.
Point 6: Chapter 3 should be Results
Response 6: Thank you for the suggestion. We have combined section 3 and 4 into the third section, titled "Results and Analysis". In this article, section 3 contains the patterns of population dynamics, and section 4 referred to the driving factors of population dynamics.
Point 7: Subsection 3.1. should be named
Response 7: Thanks for your suggestion. And we have named subsection 3.1 as “3.1.1. Population dynamics across hierarchies” (see details in line 222).
Point 8: 4 is Discussion, L 279-289 should be in results, and from 290 Discussion
Response 8: We appreciate the reviewer’s insightful suggestion. We have combined section 3 and 4 to the new section 3 (see details in lines 220-413). And we have added some interpretation in subsection 4.1 to make comparative research from consumer city and polycentricity (see details in lines 414-448). The section 4 is one part of empirical results for two things: â‘ this chapter studies the driving factors of population dynamics; â‘¡the part concludes results and analysis of the model.
Point 9: Conclusion is partially repeating introduction, please use concise language
Response 9: Thanks for your advice. We are not sure if the two paragraphs in Conclusion is repeating abstract. If it is, we have refined the content repeating abstract. We retained the background of population dynamics in the first paragraph (see details in lines 453-463) and remodified the comparative results to the difference from consumer cities in the second paragraph (see details in lines 464-471)
Point 10: Please increase literature review
Response 10: We appreciate the reviewer’s insightful suggestion. We have increased literature review about population distribution and its influencing factors in the third paragraph in the introduction (see details in lines 66-81).
Author Response File: Author Response.docx
Reviewer 5 Report
This paper investigate population dynamics across urban hierarchies and its 382 determinants in Yangtze River Delta. The topic of this paper is very interesting. However, there are some problems to be further improved as well.
1.The abstract is not refined enough, the background description is too much, and the originality, the author's contribution and the main methods used are not highlighted, especially the quantitative conclusions should be provided.
2.It is more appropriate to submit this paper to a journal of demography or demographic geography.
3.As a map, the legend in Figure 1 should be complete, such as the provincial boundary, city boundary and other boundary lines in the map. In addition, the illustrations in the paper are very unclear.
4.The paper must enhance the international perspective. What enlightenment does China's case and the conclusions drawn have for similar studies in the world?
5.The theme of this paper is the dynamic pattern of the population. Therefore, it is necessary to analyze and summarize the characteristics and patterns of the dynamic evolution of the population in the Yangtze River Delta. However, the authors focuses on the distribution and influencing factors of the population. The content of population migration and mobility is not involved at all, which is suspected to be inconsistent with the title of the paper.
6.Urban public service capacity, residents' income level, employment opportunities, urban vitality, urban centrality and urban scale should be important factors to promote population mobility, which are mostly not mentioned in the index system of this paper.
7.This paper lacks a discussion section, which should be a very big defect.
8.It is suggested that in close combination with the main conclusions and findings in the paper, differentiated and targeted policy enlightenment related to urban planning or regional planning should be proposed.
Author Response
Please see attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have improved a lot and addressed all my concerns.
Author Response
We sincerely hope that this revised manuscript has addressed all your comments and suggestions. We appreciated for reviewers’ warm work earnestly, and hope that the correction will meet with approval. Once again, thank you very much for your comments and suggestions.
Point 1: The authors have improved a lot and addressed all my concerns.
Response 1: Thanks very much for your comment, which is highly appreciated.
Author Response File: Author Response.docx
Reviewer 4 Report
The manuscript has been improved
Literature review is still abit weak, it should be expanded
The traffic issue (not being taken into consideration) – it should be stated in the description of the research that this is a limit of the research
Author Response
We sincerely hope that this revised manuscript has addressed all your comments and suggestions. We appreciated for reviewers’ warm work earnestly, and hope that the correction will meet with approval. Once again, thank you very much for your comments and suggestions.
The manuscript has been improved
Point 1: Literature review is still a bit weak, it should be expanded
Response 1: Thank you very much for the positive comments and constructive suggestions. We have expanded the literature review with several empirical studies in lines 70-72, 77-78, 82-84 and 88-90. The complementary components contain the distribution patterns of population in different countries or regions and various influencing factors of international cases in the process of urbanization.
Point 2: The traffic issue (not being taken into consideration) – it should be stated in the description of the research that this is a limit of the research.
Response 2: Thanks for your constructive suggestion, which is highly appreciated. Indeed, traffic infrastructure matters. However, this article aims to explore spatial-temporal evolution of population rather than population mobility. The impact of traffic mainly effects population mobility by intercity and commuter traffic. Thus, transport infrastructure development is not taken into consideration, which will be left for future research. And we have pointed out some of the main limitation of the presented analysis (see details in line 492-493).
Author Response File: Author Response.docx
Reviewer 5 Report
The author revised or explained the comments or suggestions put forward by the reviewers. Some issues have been addressed, but these changes have not substantially improved the quality of the article, and important concerns have not been well responded to.
1. It is more appropriate to submit this paper to a journal of demography or demographic geography.
2. The theme of this paper is the dynamic pattern of the population. Therefore, it is necessary to analyze and summarize the characteristics and patterns of the dynamic evolution of the population in the Yangtze River Delta. However, the authors focuse on the distribution and influencing factors of the population. The content of population migration and mobility is not involved at all, which is suspected to be inconsistent with the title of the paper.
3. Urban public service capacity, residents' income level, employment opportunities, urban vitality, urban centrality and urban scale should be important factors to promote population mobility, which are mostly not mentioned in the index system of this paper.
Author Response
We sincerely hope that this revised manuscript has addressed all your comments and suggestions. We appreciated for reviewers’ warm work earnestly, and hope that the correction will meet with approval. Once again, thank you very much for your comments and suggestions.
The author revised or explained the comments or suggestions put forward by the reviewers. Some issues have been addressed, but these changes have not substantially improved the quality of the article, and important concerns have not been well responded to.
Point 1: It is more appropriate to submit this paper to a journal of demography or demographic geography.
Response 1: Thanks for this insightful comment. Land is really not a population-theme journal. However, we submitted the article to the special issue named “Regional Sustainable Development of Yangtze River Delta, China”. This issue contains population migration patterns and spatial pattern changes in the Yangtze River Delta region. The theme of the article is appropriate to the scope of the issue because it the selected the Yangtze River Delta region as the study area to explore spatial-temporal evolution of population across urban hierarchy and its influencing factors.
Point 2: The theme of this paper is the dynamic pattern of the population. Therefore, it is necessary to analyze and summarize the characteristics and patterns of the dynamic evolution of the population in the Yangtze River Delta. However, the authors focus on the distribution and influencing factors of the population. The content of population migration and mobility is not involved at all, which is suspected to be inconsistent with the title of the paper.
Response 2: We would like to thank the reviewer for the suggestion. Indeed, population migration and mobility are related to population dynamics. However, we do Not aim to discuss population migration and movement. Instead, we hereby analyze the characteristics of spatial-temporal evolution of population and explain the influencing factors based on the conceptual framework of urban amenity. Therefore, we have adjusted the tittle of both the article and subsections to better reflect the purposes and content of the study. We have replaced “Population Dynamics in the Yangtze River Delta, China: From an Urban Hierarchy Perspective” with “Spatial-temporal Evolution of Population in the Yangtze River Delta, China: From an Urban Hierarchy Perspective” in the tittle of this article (see details in lines 2-3). In addition, the tittles of subsection 3.1.1 and 3.1.2 have been modified for “Temporal evolution of population across hierarchies” and “Spatial evolution of population” respectively (see details in lines 231 and 293).
Point 3: Urban public service capacity, residents' income level, employment opportunities, urban vitality, urban centrality and urban scale should be important factors to promote population mobility, which are mostly not mentioned in the index system of this paper.
Response 3: Thanks for this insightful comment. The reviewer’ statement is correct in that urban public service capacity, residents' income level and so forth should be important factors to promote population mobility. Actually, these factors have been taken into consideration in this article. But owing to data limit, education expenditure and medical beds are used to indicate public service, which is consistent with the argument of Glaeser et al (in the 33th reference). That is, good schools and more medical beds are linked with good public services. According to the measurement of Korpi (in the 30th reference), we have applied GDP and number of employees to demonstrate the prosect of income and employment in economic amenity. Regarding to urban vitality and urban centrality, we have not account for the two factors directly. However, they have been shown to be highly related to city size, which we have measured in the mode as the control variable (see details in raw 13 of Table 2). That is, higher-rank cities have shown to be able to provide more goods and services and to be more attractive to creative talents and highly educated workforces.
Author Response File: Author Response.docx
