Impact of Cropland Reclamation on Ecological Security in the Yangtze River Economic Belt, China

Round 1

Reviewer 1 Report

Abstract

It remains to indicate the variables used to assess the ecological security. Get worse and get better have no meaning for readers.

INTRODUCTION

• Avoid acronyms LUCC (line 33) and GDP (69) the first time it appears because readers are becoming familiar with the article's acronyms.
• The phrase of the lines 60-62 must be better explained. Authors desire to assess ecological security by focusing on the impact of the indirect ecological land loss due to cropland reclamation whose indirect impact of cropland reclamation on the ecological security remains unclear.

MATERIAL AND METHODS

• Research framework (topic) must be better explain.
• Readers would better understand the text related to ecological security evaluation (lines 129-143) if it were converted to a table.
• Variables input of ecological security evaluation must be better explained.
• Please explain: “Values in the equations are weights given to the indicators based on experts’ opinions”. Which experts?

RESULTS

• Title of figure 3 could be: Land use simulation of different scenarios in YREB in 2030.
• Title of table 2 could be: Proportions (%) of land use types and land use changes in the YREB.
• Maybe figure 4 is useless due to table 2. Y axis of figure 4 has no unit.
• Ecological security degree (figure 5) is not explained in material and methods. Which means low?
• Changes in ecological security (figure 6) is not explained in material and methods. Which means better?

DISCUSSION

• Discussion topic must follow results topic (simulation, CVOR framework, Changes in ecological security).
• Results were poorly discussed in the discussion topic. It seemed to me that the authors repeated the results.
• Why is CVOR framework superior? It is not clear.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

In this paper, CVOR framework was used to characterize the ecological security of YREB, which was measured from multiple dimensions such as ecosystem service supply, landscape pattern and vegetation status. Based on multi-scenario simulation, the impacts of different cultivated land reclamation methods on ecological security in the Yangtze River Economic Belt were evaluated. This is an important issue, because in the process of urban growth and the protection policies of basic farmland, regional ecological space is bound to be eroded, and therefore its ecological function will be affected. The research method of this paper is relatively scientific and reasonable, but the results are not detailed enough, and the discussion part is also lack of revealing the profound problems. Major revisions are recommended. Specific suggestions are as follows:

• Line 75：Should the second part be more properly called "Methodology"?
• Line139 & 142-143：Why NPP and NDVI were used for predicting Vigour and Resilience? On what basis? What aspects of the ecosystem do these two indicators reflect that can delineate V and R? It is suggested that the concepts and methods in these two parts (V and R) should be enriched and improved, because the evaluation methods in them are weaker than those in the other two parts.
• Line 224：The current rendering of the results section is too brief. It is suggested to add the separate display of evaluation results of each part of CVOR in different scenarios, which may be more conducive to understanding the details of ecological security in different scenarios and areas, rather than only showing the final comprehensive results.
• Line 259：The discussion part is relatively simple on the whole, and is more about the problems directly illustrated by the results and the confirmation of existing relevant researches. However, there is no further revelation of deeper problems and solutions, and the discussion of limitations is also lacking. Suggest deepening the discussion section.For example, the article mentioned that "the CVOR framework is superior in evaluating ecological security at a grid level to other approaches". How is its superiority reflected and how does it make up for the deficiency of other methods? What are the specific situations suitable for applying this method? A conclusion alone does not constitute a valid discussion.
• Lines 267-269：Why were the above ecosystem services selected as representatives of ecosystem functions in the Yangtze River Economic Belt region? The selection criteria of ecosystem services should be explained in the method section to further improve the scientific nature and rigor of research methods.
• Lines 286-289：This is a simple repetition of the method of use, not a discussion of the interpretation of the results of different scenarios
• Lines 291-296：It is necessary to point out the limitation. Because the change of ecological land is affected by many factors, cultivated land reclamation is only one of them.Only emphasizing and simulating the impact of cultivated land reclamation on ecosystem function can indeed highlight its role, but it cannot guarantee that the change of ecological security comes entirely from cultivated land reclamation, because it is impossible to control variables or exclude the influence of other factors. Therefore, this limitation should be added to explain: 1) How the conclusions of this paper are not affected by this limitation; 2) Further research should be conducted on how to break through this limitation.
• Line 298：Most of this discussion only illustrates one point: urbanization and cultivated land changes have a negative impact on ecological security, which has been proved by many studies.However, this study did not make more findings on this basis, nor did it carry out more discussions in the study area of Yangtze River Economic Belt. The suggestion of "optimize landscape structure to improve ecological security" is also very general. Overall, this discussion is not very illuminating.
• Lines335-338：This is an interesting finding: it indicates that the improvement of ecological security lies in the maximization of the common value of ecosystem function and structure, rather than the enhancement of one aspect alone. Unfortunately, there is no in-depth discussion in this paper on how the increase of vegetation coverage has a negative impact on ecological security by affecting landscape heterogeneity and connectivity, resulting in more potentially valuable information being ignored.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Authors complied with the suggested modifications. However, the degree of ecological security has not yet been adequately qualified/described. The phrase that was included about ecological safety is still insufficient for a better understanding of the results. How do variables behave within ecological safety categories?

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and suggestions:

The author basically revised and replied to the suggestions and questions raised in the last round, especially in the improvement of methodology and depth of discussion. On this basis, there are still the following two problems to be solved:

First of all, the author mentioned in the reply that the reason why the results of each scenario were not presented separately was that the evaluation results of each scenario were similar to each other, especially SC2 and SC3. Then what is the reason for this similarity? Is it related to the reason that the setting of the scenarios is not reasonable enough? And how similar are the comprehensive results among the three scenarios based on the similar individual results, and why? It may not be presented separately in the results section, but the underlying reasons mentioned above are expected to be seen in the discussion.

Secondly, I did not find the importance of selected ecosystem services to the study area mentioned by the author in the reply in line 160 of this version. The line numbers of the most recently submitted version of the manuscript does not appear to correspond to the line numbers mentioned by the authors in the reply, which is also present in the response to other questions.

In addition, professional language services are recommended to improve overall language expression.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx