Establishing Ecological Security Patterns Based on Reconstructed Ecosystem Services Value in Rapidly Urbanizing Areas: A Case Study in Zhuhai City, China

Round 1

Reviewer 1 Report

the paper is well written and organized, the topic interesting even if very specialized and for many readers it may be necessary to go and read the references which are however presented in an adequate way

The paper has as its theme the evaluation of the ecosystem dynamics of the urbanized territory. A certain stability - in qualitative, dynamic and non-static terms - of ecosystem services is necessary for good environmental quality. The topic is relevant, both because the assessment of ecosystem services is a research area still in the process of maturing, and because the demographic trend, worldwide, suggests the need to evaluate the effects that progressive urbanization will have on our planet.

The paper proposes indicators and an evaluation procedure based on the state of the art of research in this field. Interesting is the application to a case study in order to both highlight the potential of the procedure and to show how some planning measures have led to changes in the quality of ecosystem services and how the procedure is able to detect these changes.

The paper is well written and well organized, so it is clear even if for many readers it may be necessary to go to the references to go into detail, as the theme of the assessment of ecosystem services is very specialized. ven if the case study is located in China, the evaluation procedure and conclusions are consistent and transferable to other cases.

Author Response

Response: We are very grateful to the reviewer for his or her valuable time and the approval on this manuscript. As suggested, the order of references has been adjusted partly and new references also been added in the Introduction section.

Along with the newly added text are 9 new references [10-13], [21-22], [31], [35-36]:

“10. Xu, C., Pu, L., Zhu, M., Li, J., Chen, X., Wang, X., & Xie, X. Ecological Security and Ecosystem Services in Response to Land Use Change in the Coastal Area of Jiangsu, China. Sustainability 2016, 8(8), 816. https://doi.org/10.3390/su8080816.

11. Parthasarathy, A.; Natesan, U. Coastal vulnerability assessment: A case study on erosion and coastal change along Tuticorin, Gulf of Mannar. Nat. Hazards 2015, 75, 1713–1729. https://doi.org/10.1007/s11069-014-1394-y.
12. Islam, A.M.; Mitra, D.; Dewan, A.; Akhter, S.H. Coastal multi-hazard vulnerability assessment along the Ganges deltaic coast of Bangladesh—A geospatial approach. Ocean & Coast Management 2016, 127, 1–15. https://doi.org/10.1016/j.ocecoaman.2016.03.012.
13. Hereher, M.E. Assessment of Egypt’s red sea coastal sensitivity to climate change. Environ Earth Sci 2015, 74, 2831–2843. https://doi.org/10.1007/s12665-015-4304-z.
14. Zhang, R., Pu, L., Li, J., Zhang, J., & Xu, Y. Landscape ecological security response to land use change in the tidal flat reclamation zone, China. Environmental Monitoring and Assessment 2015, 188(1). https://doi.org/10.1007/s10661-015-4999-z.
15. Su, Y., Chen, X., Liao, J., Zhang, H., Wang, C., Ye, Y., & Wang, Y. Modeling the optimal ecological security pattern for guiding the urban constructed land expansions. Urban Forestry & Urban Greening 2016, 19, 35–46. https://doi.org/10.1016/j.ufug.2016.06.013.
16. Grafius, D. R., Corstanje, R., Warren, P. H., Evans, K. L., Hancock, S., & Harris, J. A. The impact of land use/land cover scale on modelling urban ecosystem services. Landscape Ecology 2016, 31(7), 1509–1522. https://doi.org/10.1007/s10980-015-0337-7.
17. Costanza, R., de Groot, R., Braat, L., Kubiszewski, I., Fioramonti, L., Sutton, P., … Grasso, M. Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem Services 2017, 28, 1–16. https://doi.org/10.1016/j.ecoser.2017.09.008.
18. Grêt-Regamey, A., Altwegg, J., Sirén, E. A., van Strien, M. J., & Weibel, B. Integrating ecosystem services into spatial planning—A spatial decision support tool. Landscape and Urban Planning 2017, 165, 206–219. https://doi.org/10.1016/j.landurbplan.2016.05.003.”

Author Response File: Author Response.docx

Reviewer 2 Report

I see potential in this paper. However, readers need a more structured paper, going beyond the local case study. Readers are internationally based!

Revision should carried out in order to improve introduction with a broader literature review.

Conclusion should be expanded to encompass generalized comments broadening the perspective from China to the rest of the world.

Language usage should be improved throughout the text.

The paper provides an interesting study of the “ecological security pattern” in the large area of Zhuhai city, negatively affected by the loss of green lands following the rapid process of urbanization. The model is strong and results are clearly exposed.

The topic in the background of the paper, “how to reduce the impact of urbanization on the ecological environment”, is very relevant in the contemporary debate. However, “an integrated strategy for maintaining a balance between sustainable supply of Ecological Services and urbanization” requires more general considerations that go beyond the merely ecological and environmental issue.

In my opinion, what is missing in this paper is the wider meaning of the ecological services function. Ecological corridors are also green infrastructure into the cities, which include also a social function in terms of public spaces for citizens wellbeing; ecological nodes could also be urban parks for recreational activities. The ecological and environmental issues are strictly related to the social and cultural ones in wider meaning of “landscape”. It’s also important for urban planning to link the ecological network with the network of public services and mobility.

We must consider the secondary impact of the ecological network on the quality of the landscape and the resulting benefits on the quality of life of citizens.

Zhuhai city is considered one of the China’s top ten livable cities, so I think that enhancing the quality of landscape, limiting the urban sprawl, should be a driver for a sustainable development.

In these terms I suggest to improve introduction and conclusions, especially to give the paper a greater interest in the international context of urban planning.

Taking into account the international readership of the journal should be useful to provide a generalized definition of the term ESP (ecological security pattern), also related to alternative and more general definitions in the international context.

Author Response

Reviewer #2

1. I see potential in this paper. However, readers need a more structured paper, going beyond the local case study. Readers are internationally based!

Response: Thanks for the reviewer’s comments. We have revised Introduction, Discussion and Conclusion section according to the reviewer’s comments.

In order to make the article suitable for international readers, we added literature and text in the Introduction section, and supplemented the discussion in the Conclusion section.

Introduction section (Please see line 58, 67-70, 85-88, 98-102):

“Many studies on coastal areas have confirmed the vulnerability of coastal ecosystems [10-13].

Ecological security is the ecosystem including the environment and human health, basic rights, resources, and the ability to adapt to environmental changes [21]. The ecological security pattern (ESP) refers to an ecology framework to interact ecosystems with land use, architecture, and urban design [22].

However, in the existing literature, most of the studies on building ecological security patterns (ESPs) to enhance landscape connectivity of vegetation is concentrated in areas with good ecological foundation and rarely in areas with rapid urbanization [31],

Ecosystem services are the ecological characteristics, functions, or processes that directly or indirectly contribute to human well-being [35]. Since the ecosystem supports the clarification of such services, both ecological and socio-economic aspects can be well weighed when evaluating urban areas [36].”

Conclusion section (Please see line 492-493, 498-502):

“Therefore, we believe that in the construction of coastal cities, it is essential to enhance the elasticity of the urban ecological network while limiting the urban expansion.

Our study can be used for reference by more research in the rapid urbanization of coastal areas in the world. While protecting the fragile ecosystem of coastal cities around the world, establishing ESPs based on ESV reconstruction will become an effective means with which to complete the SDGs proposed by the United Nations within a specified time.”

Taking into account the secondary impacts of ecosystem network and the social benefits of ecological corridors mentioned in your comments, we have added the text to the Discussion section. (Please see line 452-459)

“Accordingly, ecological corridors and nodes can be constructed based on local conditions. The edge of forest natural reserves, or green belts, on the coast or riverbank can serve as ecological corridors to strengthen the ecological functions of the green barriers among city groups. Ecological nodes can also be planned as parks for urban residents' recreational activities. This way, while enhancing the connectivity of the ecosystem and maintaining ecological security, it also increases the citizens wellbeing in terms of social functions. Linking the ecological network with the network of public services and mobility is expected to improve the resilience of the urban ecological network and the resulting benefits on the quality of life of citizens.”

2. Revision should carried out in order to improve introduction with a broader literature review.

Response: As advised, nine references have been newly added in the Introduction section.

Along with the newly added text are new references [10-13], [21-22], [31], [35-36]:

“10. Xu, C., Pu, L., Zhu, M., Li, J., Chen, X., Wang, X., & Xie, X. Ecological Security and Ecosystem Services in Response to Land Use Change in the Coastal Area of Jiangsu, China. Sustainability 2016, 8(8), 816. https://doi.org/10.3390/su8080816.

11. Parthasarathy, A.; Natesan, U. Coastal vulnerability assessment: A case study on erosion and coastal change along Tuticorin, Gulf of Mannar. Nat. Hazards 2015, 75, 1713–1729. https://doi.org/10.1007/s11069-014-1394-y.
12. Islam, A.M.; Mitra, D.; Dewan, A.; Akhter, S.H. Coastal multi-hazard vulnerability assessment along the Ganges deltaic coast of Bangladesh—A geospatial approach. Ocean & Coast Management 2016, 127, 1–15. https://doi.org/10.1016/j.ocecoaman.2016.03.012.
13. Hereher, M.E. Assessment of Egypt’s red sea coastal sensitivity to climate change. Environ Earth Sci 2015, 74, 2831–2843. https://doi.org/10.1007/s12665-015-4304-z.
14. Zhang, R., Pu, L., Li, J., Zhang, J., & Xu, Y. Landscape ecological security response to land use change in the tidal flat reclamation zone, China. Environmental Monitoring and Assessment 2015, 188(1). https://doi.org/10.1007/s10661-015-4999-z.
15. Su, Y., Chen, X., Liao, J., Zhang, H., Wang, C., Ye, Y., & Wang, Y. Modeling the optimal ecological security pattern for guiding the urban constructed land expansions. Urban Forestry & Urban Greening 2016, 19, 35–46. https://doi.org/10.1016/j.ufug.2016.06.013.
16. Grafius, D. R., Corstanje, R., Warren, P. H., Evans, K. L., Hancock, S., & Harris, J. A. The impact of land use/land cover scale on modelling urban ecosystem services. Landscape Ecology 2016, 31(7), 1509–1522. https://doi.org/10.1007/s10980-015-0337-7.
17. Costanza, R., de Groot, R., Braat, L., Kubiszewski, I., Fioramonti, L., Sutton, P., … Grasso, M. Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem Services 2017, 28, 1–16. https://doi.org/10.1016/j.ecoser.2017.09.008.
18. Grêt-Regamey, A., Altwegg, J., Sirén, E. A., van Strien, M. J., & Weibel, B. Integrating ecosystem services into spatial planning—A spatial decision support tool. Landscape and Urban Planning 2017, 165, 206–219. https://doi.org/10.1016/j.landurbplan.2016.05.003.”

3. Conclusion should be expanded to encompass generalized comments broadening the perspective from China to the rest of the world.

Response: Thanks for the reviewer’s comments. We have expanded our Conclusion on the representativeness and applicability of his research result, as suggested.

Suggestion applicable to the world we have added (Line 492-493):

“Therefore, we believe that in the construction of coastal cities, it is essential to enhance the elasticity of the urban ecological network while limiting the urban expansion.”

The text linking the international situation we have added (Line 498-502):

“Our study can be used for reference by more research in the rapid urbanization of coastal areas in the world. While protecting the fragile ecosystem of coastal cities around the world, establishing ESPs based on ESV reconstruction will become an effective means with which to complete the SDGs proposed by the United Nations within a specified time.”

4. Language usage should be improved throughout the text.

Response: To improve its clarity, the manuscript was proofread by professional English editor from MDPI. We hope that the quality of English writing in the revised manuscript has been improved in the current version.

5. The paper provides an interesting study of the “ecological security pattern” in the large area of Zhuhai city, negatively affected by the loss of green lands following the rapid process of urbanization. The model is strong and results are clearly exposed. The topic in the background of the paper, “how to reduce the impact of urbanization on the ecological environment”, is very relevant in the contemporary debate.

Response: We are very grateful for your comments and approval of this manuscript.

6. However, “an integrated strategy for maintaining a balance between sustainable supply of Ecological Services and urbanization” requires more general considerations that go beyond the merely ecological and environmental issue. In my opinion, what is missing in this paper is the wider meaning of the ecological services function.

Response: We appreciate it for pointing out this, and feel sorry that we did not provide enough information about this question in the last manuscript, the definition and comprehensive description of ecological services has been added to line 98-101 of the Introduction section:

“Ecosystem services are the ecological characteristics, functions, or processes that directly or indirectly contribute to human well-being [35]. Since the ecosystem supports the clarification of such services, both ecological and socio-economic aspects can be well weighed when evaluating urban areas [36].”

Along with the newly added text are new references [35]-[36]:

“35. Costanza, R., de Groot, R., Braat, L., Kubiszewski, I., Fioramonti, L., Sutton, P., … Grasso, M. Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem Services 2017, 28, 1–16. https://doi.org/10.1016/j.ecoser.2017.09.008.

36. Grêt-Regamey, A., Altwegg, J., Sirén, E. A., van Strien, M. J., & Weibel, B. Integrating ecosystem services into spatial planning—A spatial decision support tool. Landscape and Urban Planning 2017, 165, 206–219. https://doi.org/10.1016/j.landurbplan.2016.05.003.”

7. Ecological corridors are also green infrastructure into the cities, which include also a social function in terms of public spaces for citizens wellbeing; ecological nodes could also be urban parks for recreational activities. The ecological and environmental issues are strictly related to the social and cultural ones in wider meaning of “landscape”. It’s also important for urban planning to link the ecological network with the network of public services and mobility. We must consider the secondary impact of the ecological network on the quality of the landscape and the resulting benefits on the quality of life of citizens.

Response: Thanks for the reviewer’s comments. We have added text in Discussion section, as suggested. (Please see line 452-465):

“Accordingly, ecological corridors and nodes can be constructed based on local conditions. The edge of forest natural reserves, or green belts, on the coast or riverbank can serve as ecological corridors to strengthen the ecological functions of the green barriers among city groups. Ecological nodes can also be planned as parks for urban residents' recreational activities. This way, while enhancing the connectivity of the ecosystem and maintaining ecological security, it also increases the citizens wellbeing in terms of social functions. Linking the ecological network with the network of public services and mobility is expected to improve the resilience of the urban ecological network and the resulting benefits on the quality of life of citizens. The vulnerability of ecological conditions can be effectively protected by this ESP, and environmental problems such as reductions in urban green space can be effectively slowed in the study area. Instead of urban sprawl, improving the utility of the landscape through the construction of green infrastructure within the city, should be a driver for sustainable development.”

8. Zhuhai city is considered one of the China’s top ten livable cities, so I think that enhancing the quality of landscape, limiting the urban sprawl, should be a driver for a sustainable development.

Response: To address this concern, we added additional text in the Discussion and Conclusion sections to address this issue.

(Please see line 457-459, 463-465 and 492-493)

Discussion: “Linking the ecological network with the network of public services and mobility is expected to improve the resilience of the urban ecological network and the resulting benefits on the quality of life of citizens.”

“Instead of urban sprawl, improving the utility of the landscape through the construction of green infrastructure within the city, should be a driver for sustainable development.”

Conclusion: “Therefore, we believe that in the construction of coastal cities, it is essential to enhance the elasticity of the urban ecological network while limiting the urban expansion.”

9. In these terms I suggest to improve introduction and conclusions, especially to give the paper a greater interest in the international context of urban planning.

Response: Thanks for the comments, we have expanded our Introduction and Conclusion on the underpinning international context of urban planning, as suggested.

Introduction section (Please see line 58, 67-70, 85-88, 98-102):

“Many studies on coastal areas have confirmed the vulnerability of coastal ecosystems [10-13].

Ecological security is the ecosystem including the environment and human health, basic rights, resources, and the ability to adapt to environmental changes [21]. The ecological security pattern (ESP) refers to an ecology framework to interact ecosystems with land use, architecture, and urban design [22].

However, in the existing literature, most of the studies on building ecological security patterns (ESPs) to enhance landscape connectivity of vegetation is concentrated in areas with good ecological foundation and rarely in areas with rapid urbanization [31],

Ecosystem services are the ecological characteristics, functions, or processes that directly or indirectly contribute to human well-being [35]. Since the ecosystem supports the clarification of such services, both ecological and socio-economic aspects can be well weighed when evaluating urban areas [36].”

Conclusion section (Please see line 492-493, 498-502):

“Therefore, we believe that in the construction of coastal cities, it is essential to enhance the elasticity of the urban ecological network while limiting the urban expansion.

Our study can be used for reference by more research in the rapid urbanization of coastal areas in the world. While protecting the fragile ecosystem of coastal cities around the world, establishing ESPs based on ESV reconstruction will become an effective means with which to complete the SDGs proposed by the United Nations within a specified time.”

Along with the newly added text are new references [10-13], [21-22], [31], [35-36]:

“10. Xu, C., Pu, L., Zhu, M., Li, J., Chen, X., Wang, X., & Xie, X. Ecological Security and Ecosystem Services in Response to Land Use Change in the Coastal Area of Jiangsu, China. Sustainability 2016, 8(8), 816. https://doi.org/10.3390/su8080816.

11. Parthasarathy, A.; Natesan, U. Coastal vulnerability assessment: A case study on erosion and coastal change along Tuticorin, Gulf of Mannar. Nat. Hazards 2015, 75, 1713–1729. https://doi.org/10.1007/s11069-014-1394-y.
12. Islam, A.M.; Mitra, D.; Dewan, A.; Akhter, S.H. Coastal multi-hazard vulnerability assessment along the Ganges deltaic coast of Bangladesh—A geospatial approach. Ocean & Coast Management 2016, 127, 1–15. https://doi.org/10.1016/j.ocecoaman.2016.03.012.
13. Hereher, M.E. Assessment of Egypt’s red sea coastal sensitivity to climate change. Environ Earth Sci 2015, 74, 2831–2843. https://doi.org/10.1007/s12665-015-4304-z.
14. Zhang, R., Pu, L., Li, J., Zhang, J., & Xu, Y. Landscape ecological security response to land use change in the tidal flat reclamation zone, China. Environmental Monitoring and Assessment 2015, 188(1). https://doi.org/10.1007/s10661-015-4999-z.
15. Su, Y., Chen, X., Liao, J., Zhang, H., Wang, C., Ye, Y., & Wang, Y. Modeling the optimal ecological security pattern for guiding the urban constructed land expansions. Urban Forestry & Urban Greening 2016, 19, 35–46. https://doi.org/10.1016/j.ufug.2016.06.013.
16. Grafius, D. R., Corstanje, R., Warren, P. H., Evans, K. L., Hancock, S., & Harris, J. A. The impact of land use/land cover scale on modelling urban ecosystem services. Landscape Ecology 2016, 31(7), 1509–1522. https://doi.org/10.1007/s10980-015-0337-7.
17. Costanza, R., de Groot, R., Braat, L., Kubiszewski, I., Fioramonti, L., Sutton, P., … Grasso, M. Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem Services 2017, 28, 1–16. https://doi.org/10.1016/j.ecoser.2017.09.008.
18. Grêt-Regamey, A., Altwegg, J., Sirén, E. A., van Strien, M. J., & Weibel, B. Integrating ecosystem services into spatial planning—A spatial decision support tool. Landscape and Urban Planning 2017, 165, 206–219. https://doi.org/10.1016/j.landurbplan.2016.05.003.”

10. Taking into account the international readership of the journal should be useful to provide a generalized definition of the term ESP (ecological security pattern), also related to alternative and more general definitions in the international context.

Response: As advised, a generalized definition of the ecological security pattern has been added to the line 68-70 of the Introduction section:

“The ecological security pattern (ESP) refers to an ecology framework to interact ecosystems with land use, architecture, and urban design [22].”

Along with the newly added text are new references [22]:

“22. Su, Y., Chen, X., Liao, J., Zhang, H., Wang, C., Ye, Y., & Wang, Y. Modeling the optimal ecological security pattern for guiding the urban constructed land expansions. Urban Forestry & Urban Greening 2016, 19, 35–46. https://doi.org/10.1016/j.ufug.2016.06.013.”

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Authors,

The presented manuscript of establishing ecological security patterns in urbanizing areas is very interesting. The case study from Zhuhai city is innovative.

The quality of presented paper is high, the literature review and the analysis are precise.   

Only a few comments of the manuscript should be considered:

• In the Abstract (line 23) an asterisk can be found: “Getis-Ord Gi*”. It is not clear why the asterisk is present. For example, an asterisk can be found by the name of the corresponding author. Readers should be informed what meaning has the expression: “Getis-Ord Gi*” (some explanation is needed of the statistic used).
• Check the expression about the absolute value of LCDM on pages 4 and 5. The values of the LCDM model should be considered without the absolute value, otherwise it does not make sense.
• The explanation of the formula (4) is unclear. What does it mean the “type i”? Why is the “i = 1, 2, …,9”? There are nine types of ESs or nine periods? And what means the following “over many years”?
• Figure 3: it is difficult to read some of the percentages presented in the figure, especially for the period: 1999-2005.
• Page 9, lines 306 - 309: check the following: “2.56~1198.00×104 yuan/km² to 305 0.20~774.00×104 yuan/km²” and “0.52~847.40×104 yuan/km²“ and compare it with the information in Figure 4. In Figure 4 the number is not 104 yuan but 10⁴ yuan (the 4-th power).
• The authors should also inform the reads why the analysis ends in 2013. Why some more recent datasets are not presented in the manuscript.

The mentioned comments are only formal and should make the results more transparent.

Author Response

Reviewer #3

1. The presented manuscript of establishing ecological security patterns in urbanizing areas is very interesting. The case study from Zhuhai city is innovative.

The quality of presented paper is high, the literature review and the analysis are precise.  

Only a few comments of the manuscript should be considered:

Response: We are very grateful to the reviewer for his or her valuable time and the approval on this manuscript. All the comments and suggestions have been addressed now and are explained carefully in this file. And the manuscript was proofread by professional English editor from MDPI.

2. In the Abstract (line 23) an asterisk can be found: “Getis-Ord Gi*”. It is not clear why the asterisk is present. For example, an asterisk can be found by the name of the corresponding author. Readers should be informed what meaning has the expression: “Getis-Ord Gi*” (some explanation is needed of the statistic used).

Response: Getis-Ord Gi* is the name of the hot spot analysis tool in the ArcGIS software. As advised, we have added relevant reference on page 6 of the manuscript (Line 227), and explained this tool on line 23 of the Abstract.

“hot spot analysis (Getis-Ord Gi*) tool [53]”

Along with the newly added text are new references:

“53.       Tran, D. X., Pla, F., Latorre-Carmona, P., Myint, S. W., Caetano, M., & Kieu, H. V. Characterizing the relationship between land use land cover change and land surface temperature. ISPRS Journal of Photogrammetry and Remote Sensing 2017, 124, 119–132. https://doi.org/10.1016/j.isprsjprs.2017.01.001.”

3. Check the expression about the absolute value of LCDM on pages 4 and 5. The values of the LCDM model should be considered without the absolute value, otherwise it does not make sense.

Response: We thank for this careful suggestion. The symbols on both sides of this formula are square brackets, which do not mean absolute values.

4. The explanation of the formula (4) is unclear. What does it mean the “type i”? Why is the “i = 1, 2, …,9”? There are nine types of ESs or nine periods? And what means the following “over many years”?

Response: We checked this formula and decided to delete the content in the parentheses of the formula in order to avoid ambiguity and modify the explanation of the formula:

where β_i is the importance index of each ESs; i refers to the 9 services included in the ESs; v_i refers to the average change rate of the i-th ES in the study years; and is considered to be the average value of v_i throughout the study period.

5. Figure 3: it is difficult to read some of the percentages presented in the figure, especially for the period: 1999-2005.

Response: Thanks for the reviewer’s comments, and we have revised the Figure3 as follows:

6. Page 9, lines 306 - 309: check the following: “2.56~1198.00×104 yuan/km2 to 305 0.20~774.00×104 yuan/km2” and “0.52~847.40×104 yuan/km2“ and compare it with the information in Figure 4. In Figure 4 the number is not 104 yuan but 104 yuan (the 4-th power).

Response: We appreciate it for pointing out this, and feel sorry that we made a format error in the last manuscript, we have corrected it on page 9, (See lines 321-325).

“From 2005-2009, the dynamic ESV significantly decreased from 2.56~1198.00×10⁴ yuan/km² to 0.20~774.00×10⁴ yuan/km². The downtown areas of Zhuhai city, located in the middle of the Xiangzhou District, showed a gradual expansion of low-ESV areas, which was closely related to urban construction during this period.

From 2009-2013, the dynamic ESV rose slightly to 0.52~847.40×10⁴ yuan/km².”

7. The authors should also inform the reads why the analysis ends in 2013. Why some more recent datasets are not presented in the manuscript.

Response: We conducted field surveys in Zhuhai city during the study period, and the remote sensing data we used were similar in the months of these 4 years (1999, 2005, 2009, 2013). From 2013 to the present, the economic development of Zhuhai city has been steady without large-scale urbanization. At the same time, the government attach importance to protect green space through planning. In addition, we intend to compare the ESP constructed in this study with the current ESP in Zhuhai city in the next article.

We also responded to this issue in the Discussion section of the manuscript. (See line 467-470)

“Since 2013, the urbanization process of Zhuhai city has gradually slowed down, and the government has attached importance to protect green space through planning. The urban pattern of Zhuhai city has roughly formed a scale. We will compare the ESP constructed in this article with the current ESP in Zhuhai city in the later study.”

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear authors,

the manuscript has been improved significantly. Particularly, I appreciate that some comments have been added to explain the wider value of the ecological network. "Ecological nodes can also be planned as parks for urban residents' recreational activities. This way, while enhancing the connectivity of the ecosystem and maintaining ecological security, it also increases the citizens wellbeing in terms of social functions".

kind regards