Successional Pathways of Riparian Vegetation Following Weir Gate Operations: Insights from the Geumgang River, South Korea

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Brief Summary of the Article: The researchers investigated the succession of riparian vegetation in the Geumgang River, South Korea, in response to the operation of dam gate structures. To achieve this, they used remote sensing imagery (NDVI and NDWI) along with field surveys. Changes in vegetation were determined based on the elapsed exposure time. The results indicate that the exposure of sandbars, caused by variations in water levels, directly influenced vegetation colonization and succession. Three main succession trajectories were identified.

 

General Comments:

Dear authors, I congratulate you on the research conducted, which significantly highlights the impact of anthropogenic actions on the ecology of a habitat. The article presents solid results and addresses an important topic for the formulation of public policies and the development of more effective strategies for the management and conservation of natural resources. However, some additional analyses and a deeper discussion could further enhance the quality of the study. I highlight these suggestions in detail in the specific comments.

 

Specific Comments:

 

Supplementary Table 1 was essential for understanding the temporal events. However, it would be ideal if readers could grasp this understanding directly from the article. A possible alternative would be to include a figure in the form of a timeline, illustrating the year the work was created, the periods of partial and complete openings, the periods of field visits, and the acquisition of satellite images. It is up to the authors to assess whether this addition is relevant. 

Figure 4 is excellent. However, I suggest including a graph that shows the total area (ha) of each class (water, sandbar by partial opening, etc.) over the different time periods and areas analyzed. 

Land use and land cover maps for each period evaluated, along with quantification of the size of these classes, would help to understand the behavior of the classes and their succession. This would allow for the calculation of transition rates between different classes (e.g., how many hectares of shrubland turned into riparian forest?). If possible, this analysis would add a lot to the article. 

Figure 5 – A more detailed explanation of the figure elements is recommended, including the meaning of the sizes, colors, and other visual representations. Although the statistical approach used is robust, the explanation could be made more accessible to readers without expertise in ecological statistics. 

Discussion – The authors should consider reflecting on the possible limitations of the methodology used, such as the resolution difference between the Landsat 5 and Sentinel-2 images, among other aspects. Additionally, a better discussion on the use of remote sensing is suggested, presenting results from other studies that used these techniques, highlighting their implications, and correlating them with what was found in this research. 

Conclusion – It is recommended to avoid methodological explanations in this section, as they have already been detailed earlier. The conclusion should focus on the results and their implications. The authors should summarize the three successional pathways identified and their impact on environmental management, as well as suggest future research based on the existing gaps.

Author Response

1. Summary
Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions in the re-submitted files.

2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Yes	Thank you for your evaluation.
Is the research design appropriate?	Can be improved	In accordance with your suggestion, we have systematically described the research design.
Are the methods adequately described?	Yes	Thank you for your good evaluation
Are the results clearly presented?	Can be improved	We have revised the manuscript in accordance with your comments.
Are the conclusions supported by the results?	Yes	Thank you for your good evaluation

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: Dear authors, I congratulate you on the research conducted, which significantly highlights the impact of anthropogenic actions on the ecology of a habitat. The article presents solid results and addresses an important topic for the formulation of public policies and the development of more effective strategies for the management and conservation of natural resources. However, some additional analyses and a deeper discussion could further enhance the quality of the study. I highlight these suggestions in detail in the specific comments.

Response 1: Thank you for your positive feedback on the manuscript.

Comments 2: Supplementary Table 1 was essential for understanding the temporal events. However, it would be ideal if readers could grasp this understanding directly from the article. A possible alternative would be to include a figure in the form of a timeline, illustrating the year the work was created, the periods of partial and complete openings, the periods of field visits, and the acquisition of satellite images. It is up to the authors to assess whether this addition is relevant.
Response 2: We appreciate your valuable advice which will contribute to enhancing the reader's understanding of our research. To facilitate comprehension of the research process in its entirety, a comprehensive table has been incorporated into the manuscript. The new table meticulously details timelines of the construction and operation of the weirs, as well as the schedules of satellite imagery and field investigations (Please refer to Table 1 on line 201).

Comments 3: Figure 4 is excellent. However, I suggest including a graph that shows the total area (ha) of each class (water, sandbar by partial opening, etc.) over the different time periods and areas analyzed.

Response 3: We appreciate the suggestion. To provide a clearer understanding of the temporal and spatial changes, we have added a new table presenting the total area of each class over different time periods and regions. This ensures detailed data accessibility while maintaining the clarity of Figure 4 (Please refer to Table 2 on line 394).

Comments 4: Land use and land cover maps for each period evaluated, along with quantification of the size of these classes, would help to understand the behavior of the classes and their succession. This would allow for the calculation of transition rates between different classes (e.g., how many hectares of shrubland turned into riparian forest?). If possible, this analysis would add a lot to the article.

Response 4: Thank you for your suggestions for further in-depth research. We were not able to track the change in area of the transitional stage of vegetation succession across the entire study area because our study of the successional process was not conducted at the entire site level, but rather at a limited plot level. We captured and analyzed successional trends through plot-level surveys, as shown in Figures 6 and 7. However, we acknowledge that quantifying successional changes in terms of area and calculating transition rates between different classes would further enhance the study. While mapping land cover change is a valuable approach, it requires a consistent classification system across all time periods, as well as high-resolution data that accurately captures both spatial and temporal vegetation dynamics. Given the limitations of available remotely sensed data, particularly the differences in spatial resolution between Landsat 5 and Sentinel-2, such an approach could introduce classification uncertainties. In addition, vegetation succession is influenced by microhabitat conditions that may not be fully captured at a broader scale. Instead, our study focused on direct ecological observations at the plot level, which allowed us to analyze vegetation structure, species composition, and successional trajectories in greater detail. Nevertheless, we recognize the potential value of land cover transition analysis to complement our findings and suggest that future studies incorporate high-resolution satellite imagery or field-based habitat mapping to quantify successional change at larger spatial scales. We have included a discussion of these methodological limitations and future research directions (see lines 567-587).

Comments 5: Figure 5 – A more detailed explanation of the figure elements is recommended, including the meaning of the sizes, colors, and other visual representations. Although the statistical approach used is robust, the explanation could be made more accessible to readers without expertise in ecological statistics.

Response 5: We agree with the reviewer's suggestion and have revised the description in the title of Figure 5 to provide a clearer explanation of the elements of the figure, including the meaning of the colors and the clustering process (see the title of Figure 5 on lines 432-439).

Comments 6: Discussion – The authors should consider reflecting on the possible limitations of the methodology used, such as the resolution difference between the Landsat 5 and Sentinel-2 images, among other aspects. Additionally, a better discussion on the use of remote sensing is suggested, presenting results from other studies that used these techniques, highlighting their implications, and correlating them with what was found in this research.

Response 6: Thank you for your suggestion. We have extensively revised the Discussion section to emphasize the originality and significance of our study, while at the same time ensuring objectivity by addressing the limitations of our study (see the revised Discussion section, lines 567-587).

Comments 7: Conclusion – It is recommended to avoid methodological explanations in this section, as they have already been detailed earlier. The conclusion should focus on the results and their implications. The authors should summarize the three successional pathways identified and their impact on environmental management, as well as suggest future research based on the existing gaps.

Response 7: Thank you for your review. We have also made comprehensive revisions to the conclusion section to avoid redundancy and further emphasize the significance of our study (refer to the revised Conclusion section, lines 589-606).

4. Response to Comments on the Quality of English Language

Point 1: Quality of English Language

(x) The English is fine and does not require any improvement.

Response 1: Thank you for your evaluation.

5. Additional clarifications

Nothing

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript assesses the successional changes in riparian vegetation caused by the construction and operation of large weirs along the Geumgang River in South Korea. By using multi-year remote sensing data and field surveys, it investigates how sandbar exposure duration and vegetation colonization time vary due to weir operations. The research seeks to classify vegetation communities, identify successional pathways, and highlight the role of hydrogeomorphic conditions in shaping riparian vegetation dynamicsm, hence as guidance adaptive river management strategies for sustainable river restoration. A first suggestion is to avoid numbering of paragraphs, because it seems more an habit of a report than a research paper.

Generally, the introduction discusses previous research on river management, weir impacts, and vegetation succession. However, it does not explicitly highlight what is unknown or insufficiently studied, and there is excessive repetition about the effects of weirs and human interventions on riparian ecosystems.
The authors are invited to clearly stating the research questions would strengthen the focus of the introduction.

Second, while remote sensing and field surveys are mentioned as complementary tools, the rationale for their combined use is weak. It would be beneficial to explain why integrating these methods provides a novel or superior approach compared to past studies.

Regarding the methodology, the study does not explicitly explain why these specific sections were chosen and how representative they are of the entire Geumgang River system, and mainly focuses on changes after weir construction without presenting detailed pre-weir conditions. This limits the ability to determine the true extent of hydrological and ecological impacts. Besides, the survey sections are located around the weirs, but other parts of the river may exhibit different ecological responses. It is unclear whether the study controls for natural variations in river morphology and hydrology.

Importantly, the threshold values used for NDVI and NDWI classification are not justified. Without validation using ground truth data, the accuracy of classification remains uncertain.

A section that is quite problematic is the result section. It suffers from excessive length (normal results section are around 800-1000 words), and redundancy, making it difficult for readers to extract key findings efficiently. Many details are repeated, particularly in discussions about the exposure of sandbars and the formation of vegetation, which could be condensed for clarity. The organization of information lacks fluidity, with weak transitions between discussions on geomorphological changes, vegetation classification, and vegetation dynamics. The explanation of sandbar exposure times is particularly fragmented, spread across multiple sentences rather than presented in a cohesive manner. Another issue is the overuse of numerical values without sufficient context, making the text overwhelming. A high concentration of hectare values, timeframes, and percentages detracts from readability, and a more effective approach would be to summarize this information in a table rather than listing every detail within the text. Similarly, figure and table referencing could be improved. The results section describes Figure 4 at length, but the explanation is unnecessarily wordy. Tables are mentioned but are not clearly integrated with the findings, reducing their effectiveness in conveying information. The classification of vegetation communities also contains unnecessary technical jargon, which could be simplified to enhance accessibility. While scientific names and indicator species are useful in specialized contexts, not all clusters require detailed descriptions. Instead, summarizing key communities would make this section more digestible for a broader audience.

The discussion also contains excessive repetition and redundancy. The organization of ideas lacks coherence, with weak transitions between key topics. Discussions on geomorphological changes, vegetation succession, and methodological approaches are interwoven without clear separation, making it difficult for readers to follow the logical flow of arguments. Another major flaw is the overuse of technical jargon and complex sentence structures, which may hinder accessibility for a broader audience. While scientific terminology is necessary, excessive use of Latin plant names and intricate descriptions of succession pathways could be streamlined. The discussion also lacks a critical evaluation of its findings in relation to broader ecological contexts or previous studies. While some references are included, there is limited discussion on how the results compare with similar research or what implications they hold for river management and restoration efforts beyond the specific case of the Geumgang River. A more explicit discussion on the broader applicability of these findings would strengthen the section.

Finally, while remote sensing is highlighted as an effective tool for tracking vegetation succession, the discussion does not adequately address its limitations. Potential sources of error, uncertainties in satellite image interpretation, or the need for ground validation should be acknowledged to provide a more balanced perspective on the methodology.

Minor issues:

The dimensions of vegetation plots vary, making direct comparisons challenging. Additionally, the exclusion of anthropogenically disturbed plots may bias results, as disturbance is an integral factor in riparian ecology. The study also assumes that tree age directly corresponds to the elapsed exposure time.

The study applies clustering methods for vegetation classification, but there is no indication of validation techniques (e.g., cross-validation or comparison with expert classification).

Comments on the Quality of English Language

The english quality is good.

Author Response

1. Summary
Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions in the re-submitted files.

2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Can be improved	The manuscript was revised in response to the reviewer's comments.
Is the research design appropriate?	Can be improved	In accordance with your suggestion, we have systematically described the research design.
Are the methods adequately described?	Can be improved	We have revised the method according to your point out.
Are the results clearly presented?	Can be improved	We have revised the manuscript in accordance with your comments.
Are the conclusions supported by the results?	Can be improved	We have revised our conclusions based on your evaluation.

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: A first suggestion is to avoid numbering of paragraphs, because it seems more an habit of a report than a research paper.

Response 1: Thank you for your suggestion. We have removed paragraph numbering and improved the flow between sentences to enhance readability and coherence (for example, please refer to lines 285-307).

Comments 2: Generally, the introduction discusses previous research on river management, weir impacts, and vegetation succession. However, it does not explicitly highlight what is unknown or insufficiently studied, and there is excessive repetition about the effects of weirs and human interventions on riparian ecosystems.
The authors are invited to clearly stating the research questions would strengthen the focus of the introduction.

Response 2: We appreciate your suggestion. We have revised the introduction to summarize the effects of weirs and human interventions and to state clearly the research questions by strengthening the analysis of previous studies (see the revised Introduction section, lines 40-126).

Comments 3: Second, while remote sensing and field surveys are mentioned as complementary tools, the rationale for their combined use is weak. It would be beneficial to explain why integrating these methods provides a novel or superior approach compared to past studies.

Response 3: Additionally, we have emphasized the necessity of integrating remote sensing and field surveys to highlight the strengths of this study (see the revised Introduction section, 58-85).

Comments 4: Regarding the methodology, the study does not explicitly explain why these specific sections were chosen and how representative they are of the entire Geumgang River system, and mainly focuses on changes after weir construction without presenting detailed pre-weir conditions. This limits the ability to determine the true extent of hydrological and ecological impacts. Besides, the survey sections are located around the weirs, but other parts of the river may exhibit different ecological responses. It is unclear whether the study controls for natural variations in river morphology and hydrology.

Response 4: Thank you for your suggestion. We have strengthened the explanation of the rationale behind site selection and categorized the hydrological characteristics of each section to highlight the validity of our study areas (see lines 162-173).

Comments 5: Importantly, the threshold values used for NDVI and NDWI classification are not justified. Without validation using ground truth data, the accuracy of classification remains uncertain.

Response 5: We agree with your perspective. Field survey results confirm that, at the plot level, our classification approach achieved near-perfect accuracy. Additionally, this method has been partially applied to the Geumgang River, demonstrating an accuracy of over 96% at the landscape scale. We have emphasized the methodological explanation and provided relevant references to support this claim (see lines 271-276). However, we acknowledge that additional validation would have strengthened the study’s applicability when transitioning from point-based assessments to broader area-wide analyses. This remains a limitation of our research. To address this, we have reinforced the explanation in the methodology section and explicitly acknowledged this limitation in the discussion to enhance objectivity (see lines 567-587).

Comments 6: A section that is quite problematic is the result section. It suffers from excessive length (normal results section are around 800-1000 words), and redundancy, making it difficult for readers to extract key findings efficiently. Many details are repeated, particularly in discussions about the exposure of sandbars and the formation of vegetation, which could be condensed for clarity.

Response 6: Thank you for your suggestion. We have carefully revised the results section to reduce redundancy and streamline content. The descriptions of sandbar exposure and vegetation formation have been summarized while maintaining key details to ensure clarity. We believe these modifications improve readability and allow readers to extract key findings more efficiently (see the revised Results section, lines 367-388,  398-429,  454-474, and 487-498).

Comments 7: The organization of information lacks fluidity, with weak transitions between discussions on geomorphological changes, vegetation classification, and vegetation dynamics. The explanation of sandbar exposure times is particularly fragmented, spread across multiple sentences rather than presented in a cohesive manner.

Response 7: We appreciate your feedback regarding the structure of the results section. To improve coherence, we have enhanced transitions between sections and reorganized the discussion on sandbar exposure time. Instead of fragmented descriptions, the explanation has been consolidated into a more structured format that better connects geomorphological changes with vegetation responses (see the revised Results section).

Comments 8: Another issue is the overuse of numerical values without sufficient context, making the text overwhelming. A high concentration of hectare values, timeframes, and percentages detracts from readability, and a more effective approach would be to summarize this information in a table rather than listing every detail within the text.

Response 8: Thank you for highlighting this issue. We have reduced the excessive listing of numerical values in the text. This restructuring improves readability and allows for a clearer presentation of results while still maintaining important quantitative details (refer to the revised Results section).

Comments 9: Similarly, figure and table referencing could be improved. The results section describes Figure 4 at length, but the explanation is unnecessarily wordy. Tables are mentioned but are not clearly integrated with the findings, reducing their effectiveness in conveying information. The classification of vegetation communities also contains unnecessary technical jargon, which could be simplified to enhance accessibility. While scientific names and indicator species are useful in specialized contexts, not all clusters require detailed descriptions. Instead, summarizing key communities would make this section more digestible for a broader audience.

Response 9: We appreciate your detailed feedback. To improve clarity, we have revised figure and table references, ensuring they are more directly integrated with the findings. The description of Figure 4 has been condensed to avoid unnecessary repetition. Additionally, we have simplified the language in the vegetation classification section by reducing excessive technical jargon while maintaining scientific accuracy. Key plant communities are now summarized more concisely to enhance accessibility for a broader audience (refer to the revised Results section).

Comments 10: The discussion also contains excessive repetition and redundancy. The organization of ideas lacks coherence, with weak transitions between key topics. Discussions on geomorphological changes, vegetation succession, and methodological approaches are interwoven without clear separation, making it difficult for readers to follow the logical flow of arguments.

Response 10: Thank you for your insightful feedback. To improve the coherence and readability of the discussion section, we have reorganized it into distinct thematic areas: (1) geomorphological changes, (2) vegetation succession, and (3) methodological considerations. This restructuring allows for a clearer logical flow, making it easier for readers to follow our key findings and their implications. Additionally, redundant descriptions have been removed to ensure conciseness while preserving essential information (refer to the revised Discussion section, lines 510-587).

Comments 11: Another major flaw is the overuse of technical jargon and complex sentence structures, which may hinder accessibility for a broader audience. While scientific terminology is necessary, excessive use of Latin plant names and intricate descriptions of succession pathways could be streamlined.

Response 11: We appreciate your concern regarding accessibility. In response, we have simplified overly technical language and minimized the excessive use of Latin plant names, particularly in sections discussing succession pathways. While retaining scientific rigor, we have focused on presenting key concepts in a more concise and reader-friendly manner. This ensures that the discussion remains informative and accessible to a broader audience without unnecessary complexity (see lines 547-566).

Comments 12: The discussion also lacks a critical evaluation of its findings in relation to broader ecological contexts or previous studies. While some references are included, there is limited discussion on how the results compare with similar research or what implications they hold for river management and restoration efforts beyond the specific case of the Geumgang River. A more explicit discussion on the broader applicability of these findings would strengthen the section.

Response 12: Thank you for your suggestion. We have expanded the discussion to provide a more explicit comparison between our findings and those of previous studies. We now highlight how our research aligns with or differs from existing work on riparian succession and river management. Furthermore, we discuss the broader implications of our results, emphasizing their relevance for riverine ecosystem restoration efforts beyond the Geumgang River, particularly in managed rivers with weirs and dam-influenced hydrology. These additions strengthen the discussion's applicability to a wider ecological and management context (see lines 524-546).

Comments 13: Finally, while remote sensing is highlighted as an effective tool for tracking vegetation succession, the discussion does not adequately address its limitations. Potential sources of error, uncertainties in satellite image interpretation, or the need for ground validation should be acknowledged to provide a more balanced perspective on the methodology.

Response 13: We acknowledge the importance of addressing the limitations of remote sensing-based analysis. In response, we have expanded the discussion to explicitly highlight potential sources of error, including uncertainties in satellite image interpretation, classification inaccuracies, and spatial resolution discrepancies between different sensors. We also emphasize the need for additional ground validation to enhance classification accuracy and provide a more balanced assessment of our methodology. These additions ensure a more comprehensive and objective discussion of the strengths and limitations of our approach (see the lines 567-587).

Comments 14: The dimensions of vegetation plots vary, making direct comparisons challenging.

Response 14: The variation in vegetation plot sizes reflects an ecological approach to obtaining consistent samples while accommodating diverse plant community structures. This method follows standard ecological survey methodologies, and we have provided relevant references to support this approach (see the lines 236-241).

Comments 15: Additionally, the exclusion of anthropogenically disturbed plots may bias results, as disturbance is an integral factor in riparian ecology.

Response 15: The "disturbed plots" excluded from this study refer specifically to areas that have been fully transformed into recreational parks where leisure and outdoor activities occur. These plots are located in regions with minimal hydrological influence and are primarily composed of ornamental vegetation rather than natural riparian species. We have incorporated this explanation into the methodology section to clarify the rationale behind their exclusion (see the line 233-236).

Comments 16: The study also assumes that tree age directly corresponds to the elapsed exposure time.

Response 16: The exposure timing of sandbars was determined based on weir operation records and remote sensing. The age of the trees measured on-site was mainly used as verification data for the estimated exposure period of the sandbar. However, in floodplains that have not been disturbed for a long period of time, there is no satellite imagery, so the exposure period was considered to be the age of the trees. While tree age does not represent the exact moment of initial plant establishment, field observations indicate that young trees often appear on recently exposed sandbars, with their ages aligning closely with exposure duration. This suggests that the approach is suitable for analyzing successional trends.

Comments 17: The study applies clustering methods for vegetation classification, but there is no indication of validation techniques (e.g., cross-validation or comparison with expert classification).

Response 17: This study is based on extensive vegetation field surveys. Although no classification method can achieve perfect clustering, the identified vegetation types exhibit clear ecological characteristics and indicator species, supporting the reliability of the classification. Additionally, a common challenge in statistical vegetation classification is that rare communities may be overlooked. To mitigate this limitation, we employed silhouette-based non-hierarchical clustering to optimize classification accuracy. We have strengthened the methodological explanation to highlight these considerations (see the lines 329-333).

 

4. Response to Comments on the Quality of English Language

Point 1: Quality of English Language

Comment: The english quality is good.

Response 1: Thank you for your evaluation.

5. Additional clarifications

Nothing

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

Congratulations on the excellent revision work. The article is now more objective, with fewer repetitions, and the text flows in a clearer and more cohesive manner. I believe this version will make it easier for readers to understand the content.

The inclusion of the table with the area of the classes was a valuable addition, enriching the presented analysis. Furthermore, the conclusion is more concise and aligned with the obtained results, without redundancies in the description of the methodology used.

There is just one point I suggest adding: a paragraph discussing the impacts of human activities on this type of environment. It would be interesting to include references to studies that analyze how dam construction and other interventions that alter the natural flow of water influence vegetation. These studies may be based on remote sensing or other approaches. This suggestion aligns with my previous request regarding the presentation of results from other works in the earlier rounds of revision.

Once again, I congratulate the authors on their excellent work.

Author Response

Comments 1: Congratulations on the excellent revision work. The article is now more objective, with fewer repetitions, and the text flows in a clearer and more cohesive manner. I believe this version will make it easier for readers to understand the content. The inclusion of the table with the area of the classes was a valuable addition, enriching the presented analysis. Furthermore, the conclusion is more concise and aligned with the obtained results, without redundancies in the description of the methodology used.

Response 1: Thank you for your positive feedback on the revised manuscript.

Comments 2: There is just one point I suggest adding: a paragraph discussing the impacts of human activities on this type of environment. It would be interesting to include references to studies that analyze how dam construction and other interventions that alter the natural flow of water influence vegetation. These studies may be based on remote sensing or other approaches. This suggestion aligns with my previous request regarding the presentation of results from other works in the earlier rounds of revision.

Response 2: Thank you for your valuable review. We agree with this comment. We have described the impacts of dams and weirs on river ecosystems and ecological restoration efforts to reduce these impacts, and cited the literature on this (please see lines 516-525)

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have undertaken a thoughtful revision of the manuscript in response to the previous suggestions. They streamlined the introduction and reworked to clearly define the research questions and to integrate previous studies in a manner that emphasizes the novel combination of remote sensing and field surveys. This approach not only provides a clearer picture of the research gap but also underlines the added value of the chosen methodology.

In the methodology section, the authors have clarified the rationale behind the selection of study sites and detailed the categorization of hydrological characteristics. They have also justified the use of NDVI and NDWI thresholds by presenting field survey validations while openly acknowledging the limitations inherent in scaling point-based validations to larger landscape assessments. Maybe the inclusion of more recent work, especially on new sentences proposed in the manuscript, while directly targeting inland waters, could better justify their rationale and increase the rechability of the study.

The results section has been significantly revised to eliminate redundancy and excessive technical details. The revised narrative now summarizes key quantitative findings more effectively by integrating them into tables and concise descriptions, which allows readers to grasp the main outcomes without getting overwhelmed by numerical details. 

Finally, the discussion has been restructured to clearly separate distinct thematic areas, such as geomorphological changes, vegetation succession, and methodological insights. This reorganization, along with a simplification of overly technical language and the minimization of excessive scientific jargon, has enhanced both clarity and accessibility. The authors have also expanded on the broader ecological implications of their findings, drawing comparisons with previous studies and addressing the limitations of remote sensing tools, including potential errors and the necessity for further ground validation.

Minor suggestions:

In the Introduction, the sentence “The identification of diverse plant communities and environmental conditions, which are challenging to discern through remote sensing in floodplains, can be enhanced by detailed field surveys.” Although the concept is broadly accepted, adding a reference (or a couple) from studies that explicitly compare the resolution or limitations of remote sensing versus field survey data would reinforce this claim. For example, citing recent work that documents the complementary nature of field data in complex riparian environments would be useful. Likewise, in the Introduction, the statement “Since the 1960s, river improvement projects in South Korea have focused on flood control and water resource management…” would be strengthened by including historical or governmental reports that review the evolution of river management practices in South Korea (e.g., doi: https://doi.org/10.3390/w9090717).

Please add a reference after in the sentence "The images employed the red and near-infrared (NIR) bands of Landsat 5 and the NIR and shortwave infrared (SWIR) bands of Sentinel‑2. All bands were resampled to a 10×10 m resolution, and the images were subsequently utilized to calculate the normalized difference vegetation index (NDVI) and the normalized difference water index (NDWI) [40‑41]." with focus on targeting multi‐sensor data fusion approach for calculating NDVI and NDWI, which is already supported by recent advancements in remote sensing of inland waters (e,g, doi: https://doi.org/10.3390/rs11242967; https://doi.org/10.1016/j.jag.2024.104283).

In the discussion, the sentence “Field-based studies facilitate a more profound ecological understanding by analyzing vegetation at the community and species levels, offering a more detailed understanding of succession dynamics.” could be bolstered by adding a reference that demonstrates the advantages or higher resolution of field-based data over remote sensing when assessing species-level dynamics (e.g., doi:  https://doi.org/10.1002/1099-1646(200011/12)16:6<543::AID-RRR590>3.0.CO;2-N).

Author Response

Comments 1: The authors have undertaken a thoughtful revision of the manuscript in response to the previous suggestions. They streamlined the introduction and reworked to clearly define the research questions and to integrate previous studies in a manner that emphasizes the novel combination of remote sensing and field surveys. This approach not only provides a clearer picture of the research gap but also underlines the added value of the chosen methodology.

In the methodology section, the authors have clarified the rationale behind the selection of study sites and detailed the categorization of hydrological characteristics. They have also justified the use of NDVI and NDWI thresholds by presenting field survey validations while openly acknowledging the limitations inherent in scaling point-based validations to larger landscape assessments. Maybe the inclusion of more recent work, especially on new sentences proposed in the manuscript, while directly targeting inland waters, could better justify their rationale and increase the rechability of the study.

The results section has been significantly revised to eliminate redundancy and excessive technical details. The revised narrative now summarizes key quantitative findings more effectively by integrating them into tables and concise descriptions, which allows readers to grasp the main outcomes without getting overwhelmed by numerical details. 

Finally, the discussion has been restructured to clearly separate distinct thematic areas, such as geomorphological changes, vegetation succession, and methodological insights. This reorganization, along with a simplification of overly technical language and the minimization of excessive scientific jargon, has enhanced both clarity and accessibility. The authors have also expanded on the broader ecological implications of their findings, drawing comparisons with previous studies and addressing the limitations of remote sensing tools, including potential errors and the necessity for further ground validation.

Response 1: Thank you for your positive feedback on our revision.

Comments 2: In the Introduction, the sentence “The identification of diverse plant communities and environmental conditions, which are challenging to discern through remote sensing in floodplains, can be enhanced by detailed field surveys.” Although the concept is broadly accepted, adding a reference (or a couple) from studies that explicitly compare the resolution or limitations of remote sensing versus field survey data would reinforce this claim. For example, citing recent work that documents the complementary nature of field data in complex riparian environments would be useful. Likewise, in the Introduction, the statement “Since the 1960s, river improvement projects in South Korea have focused on flood control and water resource management…” would be strengthened by including historical or governmental reports that review the evolution of river management practices in South Korea (e.g., doi: https://doi.org/10.3390/w9090717).

Response 2: Thank you for your comments. We have added supporting references (please see lines 81-83 and 86-88)

Comments 3: Please add a reference after in the sentence "The images employed the red and near-infrared (NIR) bands of Landsat 5 and the NIR and shortwave infrared (SWIR) bands of Sentinel‑2. All bands were resampled to a 10×10 m resolution, and the images were subsequently utilized to calculate the normalized difference vegetation index (NDVI) and the normalized difference water index (NDWI) [40‑41]." with focus on targeting multi‐sensor data fusion approach for calculating NDVI and NDWI, which is already supported by recent advancements in remote sensing of inland waters (e,g, doi: https://doi.org/10.3390/rs11242967; https://doi.org/10.1016/j.jag.2024.104283).

Response 3: Thank you for your suggestion. We have improved the wording and added supporting references based on your comments (please see lines 272-276).

Comments 4: In the discussion, the sentence “Field-based studies facilitate a more profound ecological understanding by analyzing vegetation at the community and species levels, offering a more detailed understanding of succession dynamics.” could be bolstered by adding a reference that demonstrates the advantages or higher resolution of field-based data over remote sensing when assessing species-level dynamics (e.g., doi:  https://doi.org/10.1002/1099-1646(200011/12)16:6<543::AID-RRR590>3.0.CO;2-N).

Response 4: Thank you for your valuable comments. We have added supporting references (please see lines 552-554).