Analysis of Vegetation Dynamics and Driving Mechanisms on the Qinghai-Tibet Plateau in the Context of Climate Change

Round 1

Reviewer 1 Report (New Reviewer)

The article conducted an analysis of vegetation dynamics and driving mechanisms on the Qinghai-Tibetan Plateau in the context of climate change. It is interesting and deserved to be published. However, there are some minor to be focused on the paper.

The introduction was not completed.

1.       Different vegetation types are influenced by different hydrothermal conditions, such as alpine meadows by temperature and alpine grasslands influenced by a combination of precipitation and temperature. And alpine shrublands were also regulated by climate factors (Nie et al., 2018).

Nie et al (2018)., Aboveground biomass of the alpine shrub ecosystems in Three-River Source Region of the Tibetan Plateau. Journal of Mountain Science.

2.       In addition to the influence of natural factors, man-made activities also affect vegetation changes, such as intensive human activities, road construction, and ecological planning. The grazing also affect control vegetation changes (Nie et al., 2023).

Nie et al (2023) Different responses of soil element contents and their stoichiometry (C: N: P) to different grazing intensity on the Tibetan Plateau shrublands. Frontiers in Environmental Science.

3.       Forest soils can store large amounts of water and can release it over a longer period to avoid direct climatic impacts on vegetation. Meanwhile, grasslands are more vulnerable to climate change (Nie et al., 2023) and man-made activities [59].

Nie et al.(2023) Storage and controlling factors of soil organic carbon in alpine wetlands and meadow across the Tibetan Plateau. European Journal of Soil Science.

It is ok.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

An article of little scientific value. All analyzes were based on NDVI values. It index informs about the increase in the density of the vegetation cover, but it does not have to go hand in hand with a real improvement in the conditions for the growth of vegetation in individual ecosystems. Large areas can be artificially forested, while valuable open ecosystems (meadows, steppes) are being destroyed. Open areas, poor in vegetation, can represent valuable ecosystems, and excessive succession of forest vegetation can be unfavorable for them. The increase in afforestation may also result from the introduced ban on deforestation on the Qinghai-Tibet Plateau. The presented analyzes have not been supported by any field research and do not illustrate changes related to the dynamics of vegetation in terms of  plant ecology. Writing about the evolution of plants over a period of 21 years is a big abuse on the part of the authors of the article.

Author Response

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Reviewer 3 Report (New Reviewer)

For the Qinghai-plateau vegetation dynamics with NDVI-evaluation and their drivers are analysed for 2000-2020. Geodetector model was used to analyse the driving forces. Climate and human factors are well described, influencing change of NDVI. In rows 86-92 give references, that linear regression analysis with modeling had problems in detection the drivers. Aims are ok.

In Tab. 1 main factors are listened and illustrated with Fig. 2. Theil-sen and Mann-Kendall tests were done for trend analysis and Tab. 3 gives the criterias to evaluate vegetation changes. Explanatory power of variables was analysed with Geodetector Model - will be good to explain a little more the differences between use fo Geodetector Model and multiple regression analysis?

Results are clear described with Fig. 4-6.  Row 262-267 "high vegetation" - what is this? use scientific names-vegetation types (see Fig. 2).  In 3.1.1 describe more NDVI-change for the most important vegetation types - not only total as in Fig. 4. In 3.2.1 driving factors well described; in Fig. 9  X13 (veg.type) has a higher explanatory value - why?  In 3.2.1 give some concrete examples for driver effects. 3.3.1 is good. See Fig. 11 - there are autocorrelations for variables (e.g. humid zone X2 + X6) - How is this problem solved, because main driver should be statistically independent.

4. Discussion - is very general: in 4.1 past 21 years vegetation growth because of protection projects - but not described in results? Also show in results where climatic variables mainly contribute to increase NDVI as basis for diiscussion. Why northern and western parts show degradation? contradiction to rows 487-498? Mixed forests more sustainable - why?

Rows 522-525 some conclusions are trivial as vegetation growth with precipitation. Discuss more which zones/vegtation types are more sensitive to CC and human impact? In 4.3 missing the influence of interannual variance of P, sunshine, evaporation on NDVI-changes. That arid areas are more sensitive to P-changes not new- but not shown in the paper. How T-increase and therefore evaporation influence NDVI-development? Explain more the advantages of Geodetector model for your results.

 

Author Response

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Round 2

Reviewer 2 Report (New Reviewer)

Thank you for the corrections and additions made. I still believe that this type of research (based on the NDVI index) can only play an auxiliary/supporting role in the assessment of changes taking place within the vegetation. Nevertheless, I consider the Authors' attempt to explain these difficult relationships to be valuable and worth publishing.

Author Response

Dear Reviewer 2:

Thanks for your letter and we are grateful to reviewer 2 for his insightful review comments. We are confident that we will try our best to revise and further improved the quality of the manuscript based on the reviewers' comments. Thank you again for your evaluation of our research. We value the feedback you provide and will work hard to improve our work in the future.

Kind regards,

Yinghui Chang

E-mail address: [email protected]

Corresponding author: Chuncheng Yang

E-mail address: [email protected]

Reviewer 3 Report (New Reviewer)

comments in reference to authors responses reviewer 3:

(1) references for limitations of linear regression added

(2) advantages of Geodetector model now clear

(3) questions are answered well

(4) In 4.1 protection projects now better explained; why northern and western part have degradation and why MF´s are sustainable NOT explained

(5) row 567 "water sourced from natural ET..." ?  wrong - ET is a consumer of water (soil water) and not a source - please correct

more explanations for the response of vegetation types to driving forces not done - still not clear or discussed the relationsship between human impacts and climate factors on NDVI-development!

Author Response

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Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

I have received the manuscript titled "WATER-2473826: Analysis of vegetation dynamics and driving mechanisms on the Qinghai-Tibet Plateau in the context of climate change." The manuscript employs the Normalized Difference Vegetation Index (NDVI) to analyze the spatial-temporal distribution and consistency of dynamic trends in the vegetation of the Tibetan Plateau from 2000 to 2020. Additionally, it investigates the independent contributions and interactions of natural and anthropogenic factors on vegetation changes at multiple scales. However, I struggled to identify novel insights, and the abstract seems to lack a clear articulation of the research significance.

The English quality of this article is worrying, with too many long sentences that are very difficult to understand

Reviewer 2 Report

Review Report for Author(s) of manuscript 2473826 “ Analysis of vegetation dynamics and driving mechanisms on 2 the Qinghai-Tibet Plateau in the context of climate change.”

The objective of the paper is to analyze the trends and driving mechanisms of vegetation changes in the Qinghai-Tibet Plateau from 2000 to 2020 using the normalized difference vegetation index (NDVI) and investigate the independent contributions and interactions of factors of natural and man-made activities on vegetation changes at multiple scales through the Geodetector model. The study aims to understand the intrinsic mechanisms of vegetation changes on the plateau and provide a reference for ecological conservation and further prediction and assessment of vegetation ecosystem stability.

Despite the significance of the topic at hand for the Qinghai-Tibet Plateau region, the authors still need to adequately address the contribution of their research in comparison to prior studies. Additionally, they need to effectively convey the importance of their research objectives. The authors must devote more effort toward defining and clarifying their research objectives and the relevance of the methodology used.  As it stands, the research does not yet meet the necessary criteria for publication.

 

Major Comments/questions

The English composition of the manuscript poses a considerable challenge to its readability. The authors are advised to take corrective measures to mitigate this issue. Specifically, it is recommended to rephrase repetitive statements to improve the clarity of the paper's objectives and goals, as observed in the Introduction and other sections.

 

In the "Methods" section, the authors should explain why they have chosen to use Theil-Sen trend analysis, Mann-Kendall significance test, Hurst index, and R/S analysis in relation to the TB region. Merely stating that these methods are commonly used is inadequate. The complexity of the vegetation evolution requires a more detailed explanation of the methods' relevance and the selection of relevant explanatory variables in the TB region to accurately evaluate the study's results.

 

Specific comments/questions:

Line 21: the word “showed” is repeated twice. Please review and update/rewrite the sentence.

Line 22: replace the word “rete” with “rate”

Line 47-50: When you write that "high-altitude regions are more sensitive to climate change, .." what are you comparing them to? The same goes for when you write about how "vegetation on the Qinghai-Tibetan Plateau (TP) is more sensitive to climate change…." The word "more" implies a comparison with something else. I recommend rewriting this to make it easier for the reader to understand.

Lines 56-58: Please provide a citation.

Lines 68-69: What do you mean by “Long time Series NDVI…….”?

Line 135-138: Since there is a dedicated section for processing, it would make sense to move this information to that section.

 

Lines 140 -145. This paper needs to be self-sufficient and not solely depend on citing other papers' methodologies. It is necessary to provide a clear explanation of how the index system was developed based on the TP region rather than referring readers to other sources.

Line 180 : From the beginning of the paper, it was made clear that NDVI is used to evaluate changes in vegetation. Therefore, it is not necessary to write "change in vegetation NDVI." It would be better to simply use "change in vegetation" as the use of NDVI is already implied.

 

The manuscript contains a lot of typos. While I have pointed out some, I suggest that the authors conduct a more comprehensive review of the paper to correct them..

 

Comments for author File: Comments.pdf

The English composition of the manuscript poses a considerable challenge to its readability. The authors are advised to take corrective measures to mitigate this issue. Specifically, it is recommended to rephrase repetitive statements to improve the clarity of the paper's objectives and goals, as observed in the Introduction and other sections

Reviewer 3 Report

The manuscript focuses on the Analysis of vegetation dynamics and driving mechanisms on the Qinghai-Tibet Plateau in the context of climate change The authors should consider the following points:

1. The section of introduction need to be rewritten from.At present, the introduction is very illogical and unclear, and Research progress not enough, leading to the scientific problems of the preface are not very clear。

2. The study area description needs to added the content. At present, the description is very confusing,the Study area description is too fragmented and confusing.

3. 3.2.2. Spatial and temporal evolution characteristics of vegetation NDVI needs to be rewritten.

4. The authors should summarize the data source in an independent sub-section.

5. There are many factors that affect the changes in vegetation factors, such as altitude, accumulated temperature, soil nutrients, etc. However, many of these factors currently selected by the author are crucial. Please describe clearly in the manuscript why these factors were chosen

6. It is too simple to discuss the relationship between the model and the impact. It is suggested to discuss in different points.More comparisons with previous studies of the spatiotemporal dynamics of Vegetation related research in the same area need to be added.

7. There are too many conclusions, which need to be summarized and simplified again.Especially for this part- Implications and limitations, it is recommended to merge

8. The texts in the whole manuscript are redundant and should remarkably condensed.

9. The legends in Figures 2 and 6 are not very clear, it is recommended to modify them.The font in Figure 9 is too small.

10. The basic data in Table 1 should be supplemented to the supplementary material.

11. Line405-408 These sentences are not clear.

12. Line535-539 These sentences are not clear.