Assessing the Vegetation Dynamics and Its Influencing Factors in Central Asia from 2001 to 2020

Round 1

Reviewer 1 Report

The article presents the results of a serious comprehensive study of the influence of climatic factors and human activity on the spatial and temporal development of vegetation in Central Asia. Based on various climate data and human activity data, this study explores the driving factors behind vegetation spatial heterogeneity and vegetation changes using geographic detectors and correlation analysis. Partial research findings demonstrate a certain degree of rationality. At the same time. the authors rightly note in conclusion that in addition to climatic factors vegetation is influenced by many other factors, as well as combinations of various factors, which is the subject of future research.

Building upon existing research on vegetation changes in Central Asia, this article analyzes the vegetation variations in the region over the past two decades, which helps reveal the spatial-temporal patterns of vegetation changes in Central Asia. The content of this study is of great urgency and significance for the restoration of the deteriorating ecological environment in Central Asia. In addition, the abstract outlines the main content of the article and the results obtained. Other sections are also made in accordance with the requirements.

However, the article still has several aspects that need improvement.

(1) The study attempts to explore the reasons behind vegetation spatial heterogeneity and vegetation changes concerning human activities and climate variations. However, the author's understanding of the causal logic behind vegetation spatial heterogeneity contains errors. The Normalized Difference Vegetation Index (NDVI) reflects vegetation types in remote sensing data, so land cover types cannot be considered as the cause of spatial heterogeneity in NDVI. Vegetation, as a natural environmental element, follows certain zonal patterns (such as latitudinal zonality, longitudinal zonality, and altitudinal zonality). The research needs to reveal the dominant factors contributing to vegetation spatial heterogeneity in the Central Asian region, particularly the impact of human activities on vegetation spatial heterogeneity.

(2) The study analyzed the correlation between various climate factors and vegetation changes in the Central Asian region and obtained intriguing conclusions. However, there are several climate elements in the CRU dataset and Terraclimate dataset that the research did not utilize, with evapotranspiration playing a significant role in the vegetation changes in Central Asia.

(3) The Introduction section provides additional literature on the causes of vegetation spatial heterogeneity and vegetation changes in Central Asia.

(4) Figure 1 need to add the spatial locations of the terrain types mentioned in the article, such as the Karakum and Kyzylkum Deserts, Ustyurt Plateau, etc., to help readers better understand the results of the study.

(5) In the Data Source section, the study requires the addition of information regarding the acquisition time of various datasets, including MODIS data, Gridded climate data, land cover dataset, anthropogenic factors, etc. Additionally, it should detail the standardized spatial and temporal resolution processes, including the different data discretization procedures.

(6) Methods section: At line 175, add the case for slope=0;At line 205, add the case for r=0.

(7) Figure 4 needs to be supplemented with a legend indicating the proportions of different vegetation change types (e.g., Slightly decrease: 66.4%), and the method for classifying different vegetation change types (e.g., Dramatically increase: slope > 0.2; Slightly increase: 0.2 > slope > 0). Additionally, Figure 4 should add the overlay classification maps depicting the spatial distribution of different vegetation change areas for the first phase (2001-2010) and the second phase (2010-2020), For example, the spatial distribution map of the regions where the vegetation change showed significant growth in the first stage (2001-2010), and the regions where the vegetation change showed a significant increase in the second stage (2010-2020).

（8）In the section titled "3.3 Relative contributions of natural and anthropogenic factors to spatial and temporal dynamics of vegetation," it is essential to clarify the temporal scale of the analysis. Specifically, it should be specified whether the results were obtained using annual data (e.g., NDVI, precipitation) or data analyzed specifically for the growing season. Furthermore, to understand the reasons behind the temporal changes in Central Asian vegetation, the study should consider providing a more detailed analysis at the pixel level. This approach will be more conducive to revealing the patterns of vegetation changes in the region. Alternatively, the study can analyze the causes of temporal changes in Central Asian vegetation based on the four vegetation change categories derived from the spatial distribution of NDVI changes from 2001 to 2020 (Figure 4).

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The article is interesting and could make an important contribution to the field, but unfortunately in its current form the manuscript lacks research depth, visible by a focus on the case study rather than the research issue, proved by poor discussions and conclusions, and, in general, focuses more on the case study than on its broader significance and contribution of findings to the theoretical advancement of the field. Thus, the manuscript requires a strong development of these sections. Detailed comments are provided for each section of manuscript.
The discussions need to address whether the research goals (lines 98-104) were reached, and what the implications of reaching them (or not) are for the field. Conclusions are insufficiently developed and are not real conclusions, but only a summary of main findings.
Conclusions are meant to deliver a scientific message, far away beyond the case study, to the entire scientific community, making a clear contribution to the theoretical (conceptual or methodological) development of the field. Conclusions must be developed beyond the case study.
The abstract looks like a shopping list, focusing on the case study only, and not on the broader implications of research and only on what has been done, with little indications on why it has been done, and what knowledge gap is actually being filled in. The abstract is supposed to deliver ideas, and not state the research steps in brief and provide useless figures instead of their significance. It needs to be rewritten shifting the focus from the case study to the research issue investigated in the study (assessing the vegetation dynamics and its drivers).

There are numerous basic deviations from a correct English language making the manuscript hard to read, such as an inconsistent use of capitalization (see only the section headers - line 41 vs. line 107), measurement units not using properly sub/superscripts. The authors need to seek for the assistance of a native speaker or specialized proofreading services.

Author Response

Please see the attachment!

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear Sirs,

your manuscript, well written, is detailed in the description of parameters used to find correlations between NDVI and various factors, but you did not mention that P values of NDVI trends in Figure 3 are all not statistically significant, being higher than 0.05, and this is not fine for scientific soundness of your investigation, at least as concerns NDVI values during time. Temporal trends indeed are visible, but are not sufficiently robust. Besides, you did not report computer softwares you used to perform data processing, a useful information for result repeatibility.

Anyway, the research design is commendable, and I would like you could integrate NDVI data to confer soundness to NDVI temporal trends.

I suggest publication after major revision, best regards

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Dear Authors,

Here is my review of your manuscript with some suggested improvements:

Figures:

Figure 1: The labeling of the elevation as -156 meters is incorrect. Please check and correct the actual elevation in meters above sea level (m.a.s.l.). Providing context about the location and topography of the study area would help orient the reader.

Figure 3: The temporal trend shown could be strengthened by generating the figure in R script for clearer visualization of patterns over time. Adding more detailed description of the trends and any key findings would make this figure more informative.

Figure 8: The current description is unclear. Please rewrite to adequately explain what is being shown and any insights gleaned from the relationship between NDVI and climate factors over time.

Text:

On page 14 (line 469), the phrase "with its variability exhibiting a negative correlation with the interannual variability of NDVI" is nonsensical. Please rewrite for clarity. Precisely what is being correlated and what are the key results/insights here?

Overall, the manuscript would benefit from proofreading to correct any technical or grammatical errors. Strengthening the visualizations and text descriptions of findings for key figures will help attract reader interest. Please let me know if you have any other questions!

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper has corrected the existing problems. But please check if the spatial resolution of the land use data (MCD12Q1) is 0.05° or 500m? In addition, the authors are requested to supplement the download time of the paper data.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

My comments were fully addressed and the manuscript can be published.

Author Response

Thank you for your feedback. We're pleased to hear that your comments have been fully addressed.

Reviewer 3 Report

Dear Sirs,

considering your kind Authors' reply, I have added a couple of comments to the last version of the manuscript, to which I refer you.

I recommend publication after a minor revision, best regards

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx