Spatiotemporal Variation in Land Use and Ecosystem Services during the Urbanization of Xining City

Round 1

Reviewer 1 Report

The Land use transfer matrix is not clearly elaborated. If it is a new matrix, that needs to be mentioned.

Tables lack the unit(s) of the numbers mentioned.

Figures are not clear at all. Especially the written parts in each figure (and the equations given as well) are blurred. 

In section 3.2, the 'Key' land use types need to be clarified, as within this section, Table 6 shows 'Major' land use types. Therefore, confusion arises. 

In section 3.3.2, the adjective- 'extremely' unbalanced needs further clarification, or differently stated.

Line 464: the unit of altitudes is missed.

'high-high' and 'low-low' agglomeration type of ESV have not been defined clearly!

The Discussion and Conclusion sections should be separated with more elaborative explanations of the results and the concluding remarks. Otherwise, it feels to be ended abruptly.

'English' should be checked and improved.

Author Response

Dear reviewer,

Thank you for your comments and suggestions! We have carefully revised the full text (see revised version) and responded as follows:

First, the Land use transfer matrix is not clearly elaborated. If it is a new matrix, that needs to be mentioned.

Thank you for your comments. We have added the relevant explanation of land use transfer matrix after the Table 3 as followed:

The values of each row represent the specific area and proportion of a certain type of land transformed into the other five types of land. Taking the first row as an example, the total area of forest in 1980 was 1656.13 km2, and the area of forest that did not change in 2020 was about 1650.62 km2. The area of forest trans-formed into grassland, water area, unused land, farmland, and developed area was 1.49km2, 0.99km2, 0.00km2, 1.00km2 and 2.03km2, respectively, with a total of 5.51km2. This value accounted for 4.11% of the total area transferred from the six types of land to other types of land in Xining from 1980 to 2020. The index of outflow (%) respectively indicates the proportion of forest transformed into grassland, water area, unused land, farmland, and developed area in the total outflow area of forest.

The values of each column represent the specific area and proportion of a certain type of land to be supplemented by the other types of land. Taking the first column of values as an example, a total of 1650.62 km2 of forests in 1980 were still forests by 2020, while the area of Grassland, Water area, Unused land, Farmland and Developed area transformed into forests was 3.25 km2, 0.03 km2, 0.00 km2, 0.85 km2, and 0.00 km2, respectively. The total area of land converted into forests was about 4.12 km2, accounting for 3.08% of the total area of six types of land supplemented by other types of land in Xining City from 1980 to 2020. To 2020, the total area of forest in Xining City is 1654.74 km2. The index of inflow (%) indicates that the area of grassland, water area, unused land, farmland, developed area converted into forests ac-counted for the proportion of the total area of non-forest land converted into forests. The interpretation of data from other rows and columns is similar.

Second, tables lack the unit(s) of the numbers mentioned.

Thank you very much! We have added the unit(s) of the numbers at the appropriate places in the tables.

Third, figures are not clear at all. Especially the written parts in each figure (and the equations given as well) are blurred.

We have redrawn higher resolution figures and improved the clarity of the written parts in the figures. In addition, we re-filled the equations in the article, and the content of the equations remained unchanged, but they were clearer.

Fourth, in section 3.2, the ‘Key’ land use types need to be clarified, as within this section, Table 6 shows ‘Major’ land use types. Therefore, confusion arises.

 Thank you for your comments. Due to the improper use of words, it caused confusion to the readers. The farmland and built-up area are the most active types of land in Xining. Therefore, we focus on the analysis of farmland and built-up area in section 3.2 of the article. Eventually we have replaced the ‘key’ or ‘Major’ with farmland and built-up area in the article.

Fifth, in section 3.3.2, the adjective- ‘extremely’ unbalanced needs further clarification, or differently stated.

 Thank you so much. We have already removed the ‘extremely’.

Sixth, line 464: the unit of altitudes is missed.

 Thank you for your patience and correction. We have added unit of altitudes to this sentence as followed:

The variation in Xining land use types mainly occurred in the range of land slopes between 0-15° and altitudes between 2000-2750 metres.

Seventh, ‘high-high’ and ‘low-low’ agglomeration type of ESV have not been defined clearly!

 Thank you for your valuable comments. We added the classification standard of different spatial clustering in ‘2.3.3. Spatial autocorrelation’ as followed:

Global spatial autocorrelation reflects the characteristics of the whole spatial pattern, but it cannot identify the location of specific clusters in the space. The concept of a local indicator of spatial association (LISA) was proposed by Anselin [37]. This index is used to prove whether local regional spatial autocorrelation exists and identify the specific distribution location of different clusters in space. By evaluating the size of the observation value of each observation point relative to the average value and the significance of the observation value, they are comprehensively divided into different agglomeration types, such as high-high, low-low, high-low, low-high and insignificant. High-high or low-low spatial clustering are the spatial clustering types of observation points whose observed values are relatively higher (or lower) than the average value and the Z-value test is significant. High-low spatial outliers refer to the type of observation points that are significantly tested by Z value and the observed values are relatively higher than the average value, and are surrounded by observation points that are significantly tested by Z value but the observed values are lower than the average value in space, while Low-High spatial outliers are just the opposite.

37. Anselin, L. Local Indicators of Spatial Association—LISA. Geographical Analysis 1995, 27,2, 93-115. DOI: https://doi.org/1 0.1111/j.1538-4632.1995.tb00338.x.

Eighth, the Discussion and Conclusion sections should be separated with more elaborative explanations of the results and the concluding remarks. Otherwise, it feels to be ended abruptly.

 Thank you for your suggestions about the discussion and conclusion. We have separated the conclusion and discussion, and added the limitations of the research methods and the conditions for the generalization of the research conclusions at the end of the paper as followed:

This study reveals the characteristics of land use and ecological service value changes in Xining, the largest city on the Qinghai Tibet Plateau, during the urbanization process, which has enlightening significance for promoting sustainable development on the plateau. Firstly, in the unique geographical environment of the plateau, urbanization does not necessarily mean a loss of ecological service value. This provides a reference for other cities on the plat-eau, as well as other cities in developing countries, on how to promote urbanization and better protect the environment. The built-up area only increased by 104.43 km² between 1980 and 2020, and the assignment of the value equivalent factor of built-up area doesn’t have remarkably significant impact on the ESV in Xining. If we study other cities with a large increase in developed area, the assignment of the value equivalent of developed area needs more careful consideration.

Secondly, due to the fragile ecological environment of the Qinghai Tibet Plateau, achieving a "win-win" situation of ecological environment protection and improving residents' living standards requires systematic policy design and a sustainable urbanization path. Other cities located in the plateau area, such as Lhasa, Shigatse, Shannan, Nyingchi and other cities in the valley, may face similar land use changes and ESV spatial and temporal evolution laws of Xining City. However, in plain areas, especially cities in the early stage of urbanization, the development goal is mainly to improve the level of economic development rather than to protect the environment, so the change law of land use and ESV may be different from that of Xining.

Ninth, 'English' should be checked and improved.

 Thank you for your suggestions again. We have revised the whole article.

Author Response File: Author Response.pdf

Reviewer 2 Report

The topic that the article deals with is of the utmost relevance and importance. I only have a few changes to suggest.

·       The graphic resolution of the figures and formulas is very low. It must be improved.

·       Figure 1. The location of Xining. If the purpose of this figure is to show the location of the study area, why is a slope map shown?

·       Figure 2. Changes in land use types in different counties or districts of Xining from 1980 to 2020. The purpose of this figure is to show changes in land use types, but this cannot be seen in the figure. Some of the types mentioned in the legend are not appreciable, for example “Water area”.

·       Discussion and conclusion:

o   The current version of the Conclusions establishes conclusions using Xining as the research object. But can this conclusion be extended to other cities? What characteristics should these cities have? In so doing, its importance could better appreciate by non-China nationality readers. 

o   The section could benefit from a more detailed discussion of the limitations or challenges of the approach.

Author Response

Dear reviewer,

Thank you for your comments and suggestions! We have carefully revised the full text (see revised version) and responded as follows:

First, the graphic resolution of the figures and formulas is very low. It must be improved.

Thank you for your suggestions. We have redrawn higher resolution figures and re-filled the equations in the article, and the content of the equations remained unchanged.

 Second, Figure 1. The location of Xining. If the purpose of this figure is to show the location of the study area, why is a slope map shown?

 We thank the reviewers for comments on why the slope of Xining is shown on the study area map. In the introduction to the study area, we mention the topography and altitude of Xining. Some conclusions drawn in this paper, such as "the transformation between different land use types mainly occurred in the land- slope range between 0-15° and altitudes between 2000-2750 metres" are closely related to the altitude and slope. So when we draw the location map of Xining, we not only showed the location of Xining in China, the administrative divisions within Xining, but also the elevation within Xining. Finally, we changed the name of Figure 1 to "Figure 1. The location and terrain of Xining".

Third, Figure 2. Changes in land use types in different counties or districts of Xining from 1980 to 2020. The purpose of this figure is to show changes in land use types, but this cannot be seen in the figure. Some of the types mentioned in the legend are not appreciable, for example “Water area”.

 Thank you for your suggestions about the Figure 2. We redrew the Figure 2 and highlighted the area through auxiliary figures where the changes in land use types are the most active. The revised Figure 2 can make us more clearly know that Xining City has formed a "cross-shaped" pattern of land use changes along the Huangshui, Beichuan River and Nanchuan River as the core of the Chengzhong District, with farmland occupied by developed area.

Fourth: Discussion and conclusion:

(1) The current version of the Conclusions establishes conclusions using Xining as the research object. But can this conclusion be extended to other cities? What characteristics should these cities have? In so doing, its importance could better appreciate by non-China nationality readers.

(2) The section could benefit from a more detailed discussion of the limitations or challenges of the approach.

We sincerely thank you for your valuable revision suggestions. We have further enriched the conclusion and discussion of the paper, and added an explanation of the limitations of the paper. Among the limitations, we introduce the deficiencies of approach and the conditions for extrapolating conclusions. This is shown in the following paragraph:

This study reveals the characteristics of land use and ecological service value changes in Xining, the largest city on the Qinghai Tibet Plateau, during the urbanization process, which has enlightening significance for promoting sustainable development on the plateau. Firstly, in the unique geographical environment of the plateau, urbanization does not necessarily mean a loss of ecological service value. This provides a reference for other cities on the plat-eau, as well as other cities in developing countries, on how to promote urbanization and better protect the environment. The built-up area only increased by 104.43 km² between 1980 and 2020, and the assignment of the value equivalent factor of built-up area doesn’t have remarkably significant impact on the ESV in Xining. If we study other cities with a large increase in developed area, the assignment of the value equivalent of developed area needs more careful consideration.

Secondly, due to the fragile ecological environment of the Qinghai Tibet Plateau, achieving a "win-win" situation of ecological environment protection and improving residents' living standards requires systematic policy design and a sustainable urbanization path. Other cities located in the plateau area, such as Lhasa, Shigatse, Shannan, Nyingchi and other cities in the valley, may face similar land use changes and ESV spatial and temporal evolution laws of Xining City. However, in plain areas, especially cities in the early stage of urbanization, the development goal is mainly to improve the level of economic development rather than to protect the environment, so the change law of land use and ESV may be different from that of Xining.

Author Response File: Author Response.pdf

Reviewer 3 Report

 The article "Spatiotemporal variation in land use and ecosystem services during the urbanization of Xining City" presents a study on the spatial-temporal changes in land use and ecosystem services in Xining City over the past 40 years. the article provides valuable insights into the spatiotemporal variation of land use and ESV during urbanization in Xining City. The study's methodology is sound, and the results are presented clearly and concisely. However, the article could benefit from a more detailed discussion of the implications of the findings and potential policy recommendations for sustainable urban development in Xining City.

-The article lacks a more detailed discussion of the implications of the findings and potential policy recommendations for sustainable urban development in Xining City.

-The article could benefit from a more comprehensive literature review that places the study's findings in the context of other relevant research on urbanization and ecosystem services.

-The article does not provide a clear discussion of the limitations of the study, which could limit the generalizability of the findings.

 - It will be more descriptive if the author(s) present the relationship between " land use" with “ecosystem services” by triangulations of the main keywords to highlight the importance of the study. There should be a justifiable discussion in the literature part of the study to develop the interrelation. The reason is that I still didn't get the main gap in the study. The relevance of the research problem for the discipline should be highlighted. Why this research is important and how urban planners can get benefit from the findings of this study need to be highlighted.   

-Contribution to academia needs to be highlighted in the abstract, introduction and conclusion part of the study. The contribution of the study needs to be explained in such a way that to increase the originality of the study.

- Citations in the text should follow the same guidelines stated by the journal.

-In order to increase the internal validity of the study I am highly suggesting to cite the following articles: the right to land: to whom belongs after a reconciliation law in egypt, morphological and gis-based land use analysis: a critical exploration of a rural neighborhood

- The ‘discussion part also needs to develop considering the aim of the article and how the author responds to the hypothesis of the manuscript. The functionality of the methodology and tactics used in the article needs to be discussed. Accordingly, the conclusion needs to restructure, some essential information which supposes to be in the conclusion part is missing. For example, what are the findings to support the hypothesis of the study? how the author(s) described the contribution of their study to the existing literature? etc., the Conclusion of the study could be much more descriptive in the findings that the author (s) mentioned in the discussion part.

-Suggestion for future study is also missing from the last line of the conclusion. It should be used to point out any important shortcomings of the manuscript, which could be addressed by further research or to indicate directions for further work could take.

Author Response

Dear reviewer,

Thank you for your comments and suggestions! We have carefully revised the full text (see revised version) and responded as follows:

First:

• The article lacks a more detailed discussion of the implications of the findings and potential policy recommendations for sustainable urban development in Xining City.
• The article does not provide a clear discussion of the limitations of the study, which could limit the generalizability of the findings.
• Suggestion for future study is also missing from the last line of the conclusion. It should be used to point out any important shortcomings of the manuscript, which could be addressed by further research or to indicate directions for further work could take.
• Contribution to academia needs to be highlighted in the abstract, introduction and conclusion part of the study. The contribution of the study needs to be explained in such a way that to increase the originality of the study.
• The ‘discussion part also needs to develop considering the aim of the article and how the author responds to the hypothesis of the manuscript. The functionality of the methodology and tactics used in the article needs to be discussed. Accordingly, the conclusion needs to restructure, some essential information which supposes to be in the conclusion part is missing. For example, what are the findings to support the hypothesis of the study? how the author(s) described the contribution of their study to the existing literature? etc., the Conclusion of the study could be much more descriptive in the findings that the author (s) mentioned in the discussion part.
• Suggestion for future study is also missing from the last line of the conclusion. It should be used to point out any important shortcomings of the manuscript, which could be addressed by further research or to indicate directions for further work could take.

Thank you for your suggestions. At the end of the paper, we have separated the conclusion and discussion, and discussed the limitations of the paper around the research methods and the extrapolation conditions of the conclusions. At the same time, we have identified which cities face similar characteristics and rules of spatiotemporal variation in land use and ESV with Xining, and which cities may be different from Xining in terms of land use and ESV changes. We also provided scientific basis for Xining City government and other city governments (Lhasa, Shigatse, Shannan, Nyingchi) to formulate land policies. The new additions are as follows:

This study reveals the characteristics of land use and ecological service value changes in Xining, the largest city on the Qinghai Tibet Plateau, during the urbanization process, which has enlightening significance for promoting sustainable development on the plateau. Firstly, in the unique geographical environment of the plateau, urbanization does not necessarily mean a loss of ecological service value. This provides a reference for other cities on the plat-eau, as well as other cities in developing countries, on how to promote urbanization and better protect the environment. The built-up area only increased by 104.43 km² between 1980 and 2020, and the assignment of the value equivalent factor of built-up area doesn’t have remarkably significant impact on the ESV in Xining. If we study other cities with a large increase in developed area, the assignment of the value equivalent of developed area needs more careful consideration.

Secondly, due to the fragile ecological environment of the Qinghai Tibet Plateau, achieving a "win-win" situation of ecological environment protection and improving residents' living standards requires systematic policy design and a sustainable urbanization path. Other cities located in the plateau area, such as Lhasa, Shigatse, Shannan, Nyingchi and other cities in the valley, may face similar land use changes and ESV spatial and temporal evolution laws of Xining City. However, in plain areas, especially cities in the early stage of urbanization, the development goal is mainly to improve the level of economic development rather than to protect the environment, so the change law of land use and ESV may be different from that of Xining.

Second

• The article could benefit from a more comprehensive literature review that places the study's findings in the context of other relevant research on urbanization and ecosystem services.
• It will be more descriptive if the author(s) present the relationship between " land use” with “ecosystem services” by triangulations of the main keywords to highlight the importance of the study. There should be a justifiable discussion in the literature part of the study to develop the interrelation. The reason is that I still didn't get the main gap in the study. The relevance of the research problem for the discipline should be highlighted. Why this research is important and how urban planners can get benefit from the findings of this study need to be highlighted.
• In order to increase the internal validity of the study I am highly suggesting to cite the following articles: The Right to Land: To Whom Belongs after a Reconciliation Law in Egypt, Morphological and GIS-based land use Analysis: A Critical Exploration of a Rural Neighborhood

Thank you for your comments. We revised the literature part of the study and added some literatures on the relationship between urbanization, land use and ecosystem services to further support the importance and value of the study. The revised paragraphs in the literature part and the newly added references are shown below：

Variations in the purpose, mode, and condition of land use by humans in different periods and regions lead to changes in the types of land use [5], along with changes in ecosystem service capabilities [6-8] ……….

Efforts have since carried out numerous studies on the value of ecosystem services at different geographical scales in China, such as considering urban agglomerations [11-13], specific provinces or cities [14-19], arid and semiarid areas [20-22], and watersheds [23-25]. Land use and ecological value changes in the process of urbanization are a hot research topic. Research has found that urbanization has triggered significant ecological and environmental aspects of land use changes [26], and there are significant spatial differences [27]. The changes in ecological service value caused by land use in different regions vary, even leading to Neighborhood and land right changes [28,29].

The Qinghai Tibet Plateau is the "third pole" of the earth, which has a significant impact on global change and sustainable development [30], and is currently in the process of rapid urbanization

……………….

Taking Xining City, the largest city on the Qinghai Tibet Plateau, as a case, studying the value of land use and ecological services can not only reveal the changing mechanism of the relationship between land use and ecological services during the process of plateau urbanization, but also provide policy inspiration for promoting sustainable development on the plateau.

6. Biedemariam, M.; Birhane, E.; Demissie, B.; Tadesse, T.; Gebresamuel, G.; Habtu, S. Ecosystem Service Values as Related to Land Use and Land Cover Changes in Ethiopia: A Review. Land 2022, 11,12, 2212.
7. Gashaw, T.; Tulu, T.; Argaw, M.; Worqlul, A. W.; Tolessa, T.; Kindu, M. Estimating the impacts of land use/land cover changes on Ecosystem Service Values: The case of the Andassa watershed in the Upper Blue Nile basin of Ethiopia. Ecosystem Services 2018, 31, 219-228. DOI: https:// doi.org/10.1016/j.ecos er.2018.05.001.
8. Wang, W.; Guo, H.; Chuai, X.; Dai, C.; Lai, L.; Zhang, M. The impact of land use change on the temporospatial variations of ecosystems services value in China and an optimized land use solution. Environmental Science & Policy 2014, 44, 62-72. DOI: https://doi.org/10.1016/j.envsc i.2014.07.004.
9. Du, X.; Huang, Z. Ecological and environmental effects of land use change in rapid urbanization: The case of hangzhou, China. Ecological Indicators 2017, 81, 243-251. DOI: https://doi.org/10. 1016/j.ecolind.2017.05.040.
10. Ouyang, X.; Tang, L.; Wei, X.; Li, Y. Spatial interaction between urbanization and ecosystem services in Chinese urban agglomerations. Land Use Policy 2021, 109, 105587. DOI: https://doi. org/10.1016/j.landusepol.2021.105587.
11. Agboola, O. P.; Rasidi, M. H.; Said, I.; Abogan, S. O.; Adejuwon, A. S. Morphological and GIS-Based Land Use Analysis: A Critical Exploration of a Rural Neighborhood. JCUA2018, 2, 106-121.
12. Soliman, A. M. The Right to Land: To Whom Belongs After a Reconciliation Law in Egypt. JCUA2022, 6, 96-111.
13. Fang, C. Special thinking and green development path of urbanization in Qinghai-Tibet Plateau. Acta Geographica Sinica 2022, 77,8, 1907-1919.

Third, citations in the text should follow the same guidelines stated by the journal.

Thank you so much. With your careful reminding, we have adjusted the format of citations according to the requirements of the journal.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors have adequately responded to my comments and suggestions and I believe that the article can be published in the current version. 

Author Response

Dear reviewers and editors

Thank you for your comments! We have revised the text (see revised version) and responded as follows:

To editors

First, the discussion and conclusions never belong to the same section, and conclusions' section is always the last section

Thank you for your comments. We have separated discussion and conclusions and made them into independent parts, and we have taken the conclusions as the last section of the article.

Second, discussion is a section for partly explanations for the results, and MORE IMPORTANTLY for the comparison of the current literature. It is highly recommended to find the possibility to write this section properly and to prove that why is this approach than previous ones, including international examples

Thank you very much! We have revised the discussion, further explained the research results, compared the research results and research methods with the current literature. We also pointed out the limitations and future research prospects. The discussion section is as follows:

4. Discussion

4.1 The relationship among urbanization, land use and ESV

Urbanization has been proved to be the main driving force for land use change in developed countries or regions [38,39]. Meanwhile, with the development of economy and urbanization, the impact of population urbanization or land urbanization on land use change has been increasingly identified and emphasized in many developing countries [40]. Land urbanization has a negative impact on ecosystem service value, and even this negative impact is more direct than population urbanization [41]. We analyzed the relationship between urbanization and the spatiotemporal characteristics of in land use and ESV in the context of rapid urbanization. 2000-2020 was the period of rapid development of urbanization in Xining City, and it was also a critical period when the land use change of Xining was the most drastic and the key period when ESV changed. The main type of land use change in Xining was the conversion of farmland into developed area, which mainly occurred in Chengbei District, Cheng-dong District, Chengdxi District and Chengzhong District that have entered the accelerated or late stage of urbanization. In the late stage of urbanization, the trend of farmland occupied by developed area was almost stagnant, but in the middle stage of urbanization, this trend was still quite active. This improves the possibility for government departments to predict the evolution trend of land use and ESV in advance according to the urbanization level of different districts and counties. With the rapid development of urbanization in Xining, the new urban construction land was mostly from farmland, which was the same as the research conclusion that some studies believed that agricultural land was the first victim of urbanization expansion [42]. It showed that the cities in the valley of the Qinghai-Tibet Plateau and other cities in the world have common points in land use change under the background of urbanization development.

4.2 The necessity of considering both nature and society in the analysis of urbanization, LUCC, and ESV

We analyzed the variations of land use and ESV under different natural attributes (different altitudes and slopes) and different social attributes (different administrative divisions and stages of urbanization), and founded that the mutual transformation between different land use types mainly occurred in the range of 0-15° slope and 2000-2750 metres altitudes. The spatial pattern of land use changes in cultivated land occupied by construction land in the form of a "cross shaped" pattern along the river in space, and forming a "core-periphery" and the phenomenon of hollowing ESV at the township scale. This is different from the current research that specializes in in-dependent analyses of LUCC and ESV in the same administrative district or in the same larger geographical type area [13,26,38], which lack integrated analyses between areas with different natural attributes and between different social attributes at the same time. Refining the scale of research, integrating natural and social attributes, and precisely identifying areas where changes in land use and ESV mainly occur have strong practical implications, which can help urban management decision-makers and urban planners to formulate more targeted land management and urbanization development plans areas with different topographic zones in districts and counties at different stages of urbanization.

4.3 Application of the revised equivalent factor method

Different from the equivalent factor method, the CPI index was used to eliminate the impact of price increases on ESV [10,34,35]. More attention should be paid to natural disturbances caused by rising food crop prices and changes in ecosystem service values over time in the calculation process [18,33]. The calculation results of ESV show that, In the unique geographical environment of the plateau, urbanization does not necessarily mean a loss of ecological service value.  This conclusion is different from a large number of current conclusions that urbanization will lead to the reduction of ESV [41,43,44]. There is no doubt that with the development of urbanization, the con-version of farmland into urban land will lead to the decrease of ESV. However, in the past 40 years, the urban area in Xining only increased by 104.43 km2, while the area of grassland and forest with high ecosystem service value changed little. With the natural disturbance of ecosystem service factors, the total ESV in Xining City in 2020 has increased compared to 1980 This is similar to a study in the San Antonio area that found that urban expansion does not necessarily lead to a significant decrease in the net value of ecosystem services [38]. Therefore, it is very necessary to protect land use types with high ecological value, such as grassland, forest land, wetland, in order to maintain the overall ESV in areas where urbanization is about to enter the accelerated development stage [17].

4.4 Limitations and future research directions

This study reveals the characteristics of land use and ecological service value changes in Xining, the largest city on the Qinghai Tibet Plateau, during the urbanization process, which has enlightening significance for promoting sustainable development on the plateau. Firstly, in the unique geographical environment of the plateau, urbanization does not necessarily mean a loss of ecological service value. This pro-vides a reference for other cities on the plateau, as well as other cities in developing countries, on how to promote urbanization and better protect the environment. The built-up area only increased by 104.43 km2 between 1980 and 2020, and the assignment of the value equivalent factor of built-up area doesn’t have remarkably significant impact on the ESV in Xining. If we study other cities with a large increase in developed area, the assignment of the value equivalent of developed area needs more careful consideration. The revised equivalent factor method based on the Costanza‘s method still needs to be further improved [9]. It is not accurate enough to obtain the ESV by calculating the area and value equivalent factor coefficients of land use types, and there may be deviations [45]. Especially although urban land has only increased by 104.43 km² over the past 40 years, the non-urban land occupied by it has an unparalleled ecosystem function such as food supply, raw material supply, and climate regulation. The occupation of non-urban land by urban will hinder the effective functioning of ecosystem services [45], further affecting the quality of life in the city [46]. Therefore, a more detailed measurement of the changes in the specific functions of the ecosystem service brought about by land use types with little change in area will more effectively reflect the changes in ESV.

Secondly, due to the fragile ecological environment of the Qinghai Tibet Plateau, achieving a "win-win" situation of ecological environment protection and improving residents' living standards requires systematic policy design and a sustainable urbanization path. Other cities located in the plateau area, such as Lhasa, Shigatse, Shannan, Nyingchi and other cities in the valley, may face similar land use changes and ESV spatial and temporal evolution laws of Xining City. However, in plain areas, especially cities in the early stage of urbanization, the development goal is to prioritize solving residents' living problems while protecting the environment, so the change law of land use and ESV may be different from that of Xining.

Third, the aims can be still polished, try to find scientific questions to be answered and it will help to write discussion, too ... and the research gap is still not clear for the submission.

At the end of the introduction, we have further explained the research questions, focusing on the influence of urbanization on the spatial-temporal change characteristics of land use and ESV.  In the discussion part of the article, the relationship among urbanization, land use and ESV is further explained, and their relationship is compared with the current literature.

Fourth, please avoid the 1-sentence paragraphs.

Thank you for your comments. According to the logical structure of the article, we have adjusted and merged single sentences into paragraphs to avoid the 1-sentence paragraphs.

Thank you for your comments again! We have revised the whole article.

Author Response File: Author Response.docx