The Impacts of Land Use Changes on Water Yield and Water Conservation Services in Zhangjiakou, Beijing’s Upstream Watershed, China

Round 1

Reviewer 1 Report

Thank you for the opportunity to review the manuscript titled " The Impacts of Land Use Changes on Water-related Ecosystem Services in Zhangjiakou, Beijing’s Upstream Watershed, China". The authors have employed the InVEST and LUCC models for a comprehensive analysis of the impact of land use changes and climate scenarios on water yield and conservation. The manuscript is well-structured, the methods employed are sound, and the results have significant policy implications. However, I have identified several areas that need further elaboration:

¾    Introduction is a bit lengthy. Please divide this into two parts, the first one focusing on the introduction of the issues, while the second focusing on theoretical aspects and positioning the article in the existing scholarly debate. The Introductions should end with a statement of research gap, the particular objectives, and finally the novelty of the study. In this regard, I would suggest including the following recent and relevant papers in the study:

https://doi.org/10.1016/j.scitotenv.2019.02.266

https://doi.org/10.1007/s11356-022-24736-5

¾    Authors need to strengthen the model validation to enhance the reliability of the study. It's important to clearly demonstrate the accuracy of the InVEST model when juxtaposed with observed data in the study area.

¾    It was expected that authors would provide a more comprehensive discourse on the uncertainties and assumptions related to the InVEST model and the input data. To this end, authors need to provide a more complete understanding of the study's limitations.

¾    Please incorporate in the model/results the potential changes in climate while considering future scenarios of land use. Given the significant impact of climate change on water yield and conservation, including these factors will be valuable.

¾    While the authors mention the impact of the "Grain for Green" project on land use change, the paper will benefit from a clear analysis of how these policy and management factors were incorporated into the study.

¾    The authors can strengthen the manuscript by comparing the findings from the Zhangjiakou region with other similar semi-arid regions. This will help to understand whether the patterns observed are unique to the study area or common in similar environments.

¾    More contextual details about the study area, particularly socio-economic factors that might influence land use decisions and thus impact water yield and conservation, will add to the richness of the paper.

¾    I noticed several typographical and punctuation errors in the manuscript. I would recommend a thorough proofreading of the paper before submitting a revised version.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The study interesting and very important in terms of understanding the impacts of land use change on water resources and the services obtained from it. My concern is why the authors could not carry out land cover analysis instead of using the available land cover data as the scale at which the study is conducted and the land cover/use data was generated vary. However, still using the available data is not a problem but at least the authors have to explain this.

Temporally, I am concerned why they studied only in 2 years (1990 and 2020). What about the years in between?

Fig. 3(a): it is difficult to see the lines as they have the same color with the respective class background

For me there is a confusion in the concept of water related ecosystem services. What are water related services? Those could be availability, amount, quality, etc. I do not also see water related benefits properly addressed. May be the authors have addressed water availability and it is not sufficient to talk about water related ecosystem services. I am not also convinced with the terminology "water related ecosystem services" as water in terms of availability, quality etc is considered as one ecosystem service. Hence, I would suggest the authors to modify the title. The big concept of ecosystem service should be removed from the title and the manuscript body. It can focus on the impact of land cover/use change on water availability

 

Why in Fig. 2, there are two years 1990 and 2020 and in Fig 8, there are 4 more years included. I think the other years after 1990 and before 2020 are not addressed in relation to their impact on water availability. So what is the relevance to have them in the ms.

The language is ok for the general readers

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

General comments:

1. The study is clear, not really innovative, just the area of application is interesting. The objectives are limited and this research could have a greater reach if the suggestions are implemented. Regarding improvements, the text could benefit from clearer paragraph organization and better flow between sentences. Some sentences are unnecessarily long and could be divided into two or more.

 

2. Additionally, the text could benefit from a more critical analysis of the limitations of InVEST model and its application in estimating WESs. The validation of the results should be strengthened.

 

3. Finally, the text could provide more information about the relative contribution of climate change and human activities to the spatial and temporal changes of WESs is not analyzed.

 

Specific Comments:

1. Abstract: what do you mean "Capital Two Zones itself"?

2. Introduction: Overall, the introduction provides a clear background and rationale for the study of WESs. One suggestion to improve the introduction would be to provide a more concise and focused problem statement or research question, which can help readers to better understand the specific objective of the study. Formulate a hypothesis as well.

3. Study area, data and methods: Some points that could be improved in this section of your article include:

(1) Detailed description of the study area: Although the text provides basic information about the study area, it is important to provide more details about its location, geographical and ecological characteristics, as well as the human activities that occur in the area. Additional information could be added on the soil, vegetation and land use types.

(2) Greater precision in data sources: The text describes the types of data used in the study area, but could be more precise regarding their spatial resolutions.

(3) Trend analysis: Theil-Sen median trend analysis and Mann-Kendall test are two robust non-parametric methods. A combination of the two methods can effectively reflect the trend of WESs and improve the accuracy and reliability of the results.

(4) Data preprocessing and validation: The authors have not mentioned any data preprocessing techniques such as normalization, resampling, imputation, or outlier treatment. These techniques can be used to standardize the data, handle missing values, and identify and treat outliers before applying statistical techniques. Additionally, there is no validation of simulated WESs.

4. Results: Consider conducting further analysis to identify the factors that may be contributing to the observed changes in WESs.

5. Discussion: Some suggestions for improving the discussion include:

(1) The discussion can be better structured with topics or subtopics to facilitate reading and understanding of the results and their implications.

(2) Another suggestion would be to include more information on the practical implications of the results found.

(3) It would also be interesting to mention possible limitations of the study and suggestions for future research.

(4) Additionally, the authors do not provide a detailed discussion of the uncertainties associated with their predictions or the potential sources of error in their model.

6. Conclusion: Conclusion section is like result or finding section. Therefore, this section should indicate some recommendations that will be made as a result of the study, limitations found in the study's design or methodological approaches used; and situations such as what innovations can be directed to future studies if they are made.

The English in this text can be further improved by a native-speaker. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors have carefully revised the paper. I have no further comments.