Impacts of Rapid Urban Expansion on Peri-Urban Landscapes in the Global South: Insights from Landscape Metrics in Greater Cairo

Round 1

Reviewer 1 Report

Dear Editors and Authors,

The proposed paper aims to explore the pattern and intensity of urban expansion in Greater Cairo, providing insight into the dynamics of land use/cover from 2001 to 2021. While this study is original and interesting, there are some issues that need to be addressed. Certain parts of the manuscript lack adequate depth and presentation, despite having a good methodology and clearly stated objectives. The cited references are mostly recent and relevant to the investigation conducted. Figures and tables are appropriate and easy to understand.

However, the main weakness of this manuscript lies in the presentation of results and the discussion section. There is repetition of the same results presented in different ways. Additionally, it appears that this study is based on limited numerical data. If possible, it would be beneficial to include additional data. If such data is unavailable, it would be helpful to strengthen the findings based on imagery. I suggest that the Authors combine the Results and Discussion sections into one. This would improve the presentation of their findings and enhance the discussion.

It would be beneficial to discuss how the study area has developed over the past two decades, as observed by other authors and available data, in addition to your own findings in the discussion section. Phenomena such as edge expansion, infilling patterns, and reduction of arable land could be further explored, drawing on the findings of other authors from various countries and regions. The investigated parameters (landscape metrics) are not sufficiently discussed. While mitigation strategies and policies are discussed in general manner, it would be valuable to examine how current legislation addresses issues resulting from rapid urban expansion.

Overall, the paper presents valuable findings, but it could benefit from further development. Some additional comments are given in the attached PDF file.

Kind regards

Comments for author File: Comments.pdf

Minor editing of English language required

Author Response

Thank you very much for taking the time to review this manuscript. We appreciate your thoughtful feedback. Please find the detailed responses below and the corrections highlighted in yellow color in the re-submitted PDF file.

We have carefully considered your comments and made the necessary revisions to improve the manuscript. We have combined the results and discussion sections, as suggested, and expanded upon them to provide more depth, which can be found on pages 8-14. Additionally, we have acknowledged the limitations of our study, particularly regarding the reliance on satellite imagery due to limited data availability, in the newly added section titled "3.6 Limitations and Future Research" on page 13.

Furthermore, we have delved deeper into the phenomena of edge expansion, infilling patterns, and the reduction of arable land, as requested, which is now presented on page 9. The discussion on landscape metrics has also been enhanced and can be found on pages 11 and 12. Additionally, we have addressed the current laws and legislation concerning urban expansion under the section on mitigation strategies and policies, as suggested, which is now on page 12.

Finally, we have carefully reviewed and addressed the additional comments provided in the PDF file, and the required modifications have been highlighted in yellow for your convenience. We appreciate your guidance and input throughout this process, and we believe these revisions have strengthened the manuscript significantly. Please let us know if there are any further adjustments or clarifications needed.

Reviewer 2 Report

Impacts of Rapid Urban Expansion on Peri-Urban Landscapes in the Global South: Insights from Landscape Metrics in  Greater Cairo

Review

 This paper addresses the important issue of measuring the impact of chaotic urban sprawl on peri-urban areas in the global South, using the Greater Cairo metropolitan area as a case study. It is important both as a purely urban study and in terms of its impact on landscape change and food security in the region.

The general concept of the article is clear, logically constructed, and consistently presented. The authors took satellite imagery from 2001, 2011, and 2021 and processed it with GIS using five landscape metrics.

The results of the study have scientific novelty and are clearly formulated. The level of scientific validity of the results in the article is appropriate. The conclusions presented are fully supported by the results.

The references cited are relevant, mostly relating to publications over the past five years.

In the reviewer’s opinion, it was still advisable for the authors to provide a separate paragraph on the literature review on the research topic. There are quite a few publications on peri-urbanization and spatial development in general of the suburban zone in Greater Cairo, as well as other major cities in the global South.

Accordingly, the value of the article would have been significantly increased if the "Discussion" section had included more comparisons with the works of previous authors. For the reader, it will be important to understand which of the trends in the development in Greater Cairo have been confirmed by the results obtained by the authors and which have not. Even the title of the article indicates that the results should have been presented in a broader context.

Author Response

Thank you for your insightful comments. We have made several revisions to the manuscript based on your feedback.

Firstly, we have combined the literature review with the introduction section to enhance coherence. We have addressed peri-urbanization and spatial development in Greater Cairo, as well as other major cities in the Global South, in both the introduction and results and discussion sections. These changes are highlighted in cyan for easy identification.

Furthermore, we have significantly improved the "Results and Discussion" section by including more comparisons with the works of previous authors. This addition provides a richer context for our findings and strengthens the overall analysis. Please refer to pages 8-14 for these updates.

We believe that these modifications have enhanced the clarity and depth of our manuscript, and we appreciate the opportunity to address your suggestions. Please let us know if there are any further revisions or clarifications needed.

Thank you again for your valuable feedback.

Reviewer 3 Report

The paper presents an interesting and important topic. The methods used are correct. The paper presents the study in detail. It has interesting and important findings that can need to be taken into account when preparing land management schemes. The identified loss of agricultural land and biodiversity decline can pose a serious threat to the functioning of the city. The findings are a ready-to-use evidence-base for shaping a more sustainable policies.

There is no need to modifications. The paper is well written.

Author Response

Thank you for your positive feedback on our paper. 

Reviewer 4 Report

This is an interesting article regarding the urban expansion in peri-urban areas. It mainly provides a way for planners/policymakers to find in which areas to pay attention and accordingly foster land use planning. However, in the reviewer’s opinion the article could be improved, if the authors agree, on the basis of the following observations.

- Line 38: you have deliberately written peri-urban “regions”, or you mean PUAs?

- Lines 53-54: you now use the term “peri-urban zones”, you mean something different? I believe it would be better to use one term if there are no distinctions between them.

- Lines 57-59: the loss of green spaces, changes in land use and soil sealing do not impact only peri-urban areas.

- Lines 92-94: you do not have the abbreviations you mention in your abstract.

- Lines 96-99: In your abstract you mention that this study can be useful for other similar regions worldwide, but in these lines you refer only to policymakers, planners, and environmental scientists in Greater Cairo's peri-urban area.

- Figure 1: the boundary you have is not the same of the Greater Cairo Region (as shown in the report of the World Bank [reference 41])? This boundary does not include all the urban fabric and the new towns. Also, the black area are the peri-urban areas? If that is wright there are peri-urban areas inside the metropolitan core. The report of the World Bank indicates different peri-urban areas.

- Figure 3: maybe you should choose another color instead of white for “bare land”.

- Line 214: water bodies have decreased due to urban expansion (if you know)

- Figure 5: Infilling is also depicted red in the first column.

- Line 232: you have mentioned that in line 213. Try not to be repetitive (there are other parts in the article that seems a little bit repetitive).

- Line 233: you mean Figure 6?

- Line 275: you discuss the two patterns, namely infilling and edge expansion, especially the last one (which is understandable), but you do not mention anything about the leapfrog pattern, which also has impacts and based on your finding there is a decrease between 2001-2021.

- Line 310: I believe you should specify that mitigation strategies regard urban expiation (given that mitigation is usually associated with climate change).

English language is fine, no serious issues detected. Some suggestions:

- Line 12: do you mean “measuring the impacts”?

- Line 42 and 108: use the abbreviation PUAs. 

- Lines 98-99: use the abbreviations you have set.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding corrections highlighted in green  in the re-submitted PDF.

Here are detailed responses to your comments:

- Line 38: you have deliberately written peri-urban “regions”, or you mean PUAs?

We have clarified that "peri-urban regions" refers to "peri-urban areas" (PUAs) throughout the manuscript.

- Lines 53-54: you now use the term “peri-urban zones”, you mean something different? I believe it would be better to use one term if there are no distinctions between them.

 We have unified the term to "peri-urban areas" (PUAs) consistently throughout the manuscript.

- Lines 57-59: the loss of green spaces, changes in land use and soil sealing do not impact only peri-urban areas.

We agree with this comment. Therefore, we have added one more sentence to explain that weak legislation in peri-urban areas may exacerbate these challenges. “Weak legislation in PUAs may exacerbate these challenges, allowing for unchecked development and inadequate environmental protection measures [11].”

- Lines 92-94: you do not have the abbreviations you mention in your abstract.

Abbreviations have been added to the sentence as requested.

- Lines 96-99: In your abstract you mention that this study can be useful for other similar regions worldwide, but in these lines you refer only to policymakers, planners, and environmental scientists in Greater Cairo's peri-urban area.

Thank you for your insightful comment. I have rectified the paragraph.

- Figure 1: the boundary you have is not the same of the Greater Cairo Region (as shown in the report of the World Bank [reference 41])? This boundary does not include all the urban fabric and the new towns. Also, the black area are the peri-urban areas? If that is wright there are peri-urban areas inside the metropolitan core. The report of the World Bank indicates different peri-urban areas.

Thank you for your insightful comment.  In this study, we focused only on the peri-urban areas within the boundary of Greater Cairo. The study of the World Bank was conducted in 2007 and 2008 and based on administrative boundaries which witnessed some changes. Also, we updated the peri-urban zones based on later studies by Salem et al in 2015 and 2020. Please see the updated figure and updated text on page 3. In addition, we described this issue in the limitation and future research section on page 13

- Figure 3: maybe you should choose another color instead of white for “bare land”.

The color for "bare land" has been changed to yellow for better visibility.

- Line 214: water bodies have decreased due to urban expansion (if you know)

Yes, it’s correct. I have explained that on page 8 lines 234-237.

- Figure 5: Infilling is also depicted red in the first column.

The percentage of Infilling was so little (0.03%) so the yellow color cannot be seen even if I enlarge the figure. The issue regarding the visibility of the infilling pattern has been addressed by adding the percentage beside the column.

- Line 232: you have mentioned that in line 213. Try not to be repetitive (there are other parts in the article that seems a little bit repetitive).

Thank you, the repetition has been removed. (Also, the whole text in the manuscript has been reviewed to remove any repetition).

- Line 233: you mean Figure 6?

The correct figure number has been specified as Figure 6. Thank you.

- Line 275: you discuss the two patterns, namely infilling and edge expansion, especially the last one (which is understandable), but you do not mention anything about the leapfrog pattern, which also has impacts and based on your finding there is a decrease between 2001-2021.

The leapfrog pattern has been discussed in detail, please see page 9 lines  277-281.

- Line 310: I believe you should specify that mitigation strategies regard urban expiation (given that mitigation is usually associated with climate change)

We appreciate your insightful comments and have carefully considered your suggestion regarding the clarification of mitigation strategies in the context of urban expansion within peri-urban areas. We have revised the paragraph accordingly to specify that the mitigation efforts discussed pertain specifically to managing the environmental impacts of urban expansion.

We have also made minor language edits and incorporated your suggestions for using abbreviations consistently throughout the manuscript.

Thank you once again for your valuable comments and suggestions.

Best regards,

Authors

Round 2

Reviewer 1 Report

Dear Editors and Authors,

The manuscript has been significantly improved according to the suggestions, with some minor changes still required. Comments are provided in the PDF file (marked in red). 

Kind regards

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you for your valuable suggestions and for pointing out these minor mistakes. We have carefully revised the manuscript in accordance with your comments, and the modifications have been highlighted in yellow in the attached PDF file. We sincerely appreciate the time you have taken to review our manuscript.

Best regards,

Reviewer 4 Report

The author has revised the manuscript considering the comments.

Author Response

Dear reviewer,

Thank you very much for taking the time to review this manuscript.