Integrated Spatiotemporal Analysis of Vegetation Condition in a Complex Post-Mining Area: Lignite Mine Case Study

Round 1

Reviewer 1 Report (New Reviewer)

Article written correctly. Previous works in this field have been presented, the problem and the aim of the work have been sufficient defined. The tools and methodology were explained satisfactorily. Discussion and final conclusions satisfactory.

The subject of the research - the area of ​​former lignite mining, was well-chosen from the point of view of the purpose of the research. Within a limited area, there are different landscape forms and different stages of vegetation succession. It is perfect for verifying the method proposed by the authors.

The article is almost ready for publication. In point 4 I found a record that is not clear to me. Line 752 reads: "With respect to remotely sensed data." This looks like a broken part of the sentence. This should be improved.

Author Response

Response to Reviewer 1 comments

Thank you for the detailed review of our manuscript and for the encouraging comments.

Below we present our point by point response.

 

Comment 1. Article written correctly. Previous works in this field have been presented, the problem and the aim of the work have been sufficient defined. The tools and methodology were explained satisfactorily. Discussion and final conclusions satisfactory.

Response. Thank you for the positive feedback. Please note that we have made minor changes to the Discussion and the Conclusions sections as suggested in review 3. All the changes in the manuscript have been marked in green font.

 

Comment 2. The subject of the research - the area of ​​former lignite mining, was well-chosen from the point of view of the purpose of the research. Within a limited area, there are different landscape forms and different stages of vegetation succession. It is perfect for verifying the method proposed by the authors.

Response. Thank you. The characteristics pointed out in the review have been one of the main reasons we have selected this area as a case study.

 

Comment 3.The article is almost ready for publication. In point 4 I found a record that is not clear to me. Line 752 reads: "With respect to remotely sensed data." This looks like a broken part of the sentence. This should be improved.

Response. The sentence has been corrected.

Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

This paper is an analysis of the state of vegetation recovery in the post-mining mine area, using a lignite mine in western Poland as the study area. The research methods used are valid and reflect the actual state of vegetation change in the study area better. However, there are still some works that need to be improved or further interpreted.

1. The title of the article is: “…in glaciotectonic post-mining area…”, but from the results presented in the article, the author does not explain how glaciotectonics and other tectonics are similar and different in terms of vegetation recovery, and what effects glaciotectonics have. It would be inappropriate to use this as part of the title without discussing it in detail.

2. Among the mines to be revegetated in the study area, the previous mining methods are divided into open pit mining and shaft mining. Is it possible to analyze and give a regular summary of the restoration status of the vegetation under the two different mining methods? This may be more meaningful for a case study article.

3. Vegetation restoration in the study area began around 1980, and the time series used in the article with satellite data is between 2015-2022, is this period too short a choice for the growth of vegetation?

4. The markers for embedded formulas in lines 339 and 346 of the article should be on the far right.

5. In line 400 of the article, the formula should be labeled (5), and "and" should be deleted in line 405. In addition, all formulas inserted, whether derived or quoted from others, need to be arranged in top-to-bottom order, otherwise they will be unreadable, so make sure the markers in lines 406 to 407 are correct.

Author Response

Response to Reviewer 2 comments

 

General comment. This paper is an analysis of the state of vegetation recovery in the post-mining mine area, using a lignite mine in western Poland as the study area. The research methods used are valid and reflect the actual state of vegetation change in the study area better. However, there are still some works that need to be improved or further interpreted.

Response. Thank you for the detailed review of our manuscript, for the encouraging comments and for the suggestions. Below we present our point by point response. All the changes in the manuscript have been marked in green font.

 

Comment 1. The title of the article is: “…in glaciotectonic post-mining area…”, but from the results presented in the article, the author does not explain how glaciotectonics and other tectonics are similar and different in terms of vegetation recovery, and what effects glaciotectonics have. It would be inappropriate to use this as part of the title without discussing it in detail.

Response. Indeed, using the term “glaciotectonic” in the title and in the text we have referred to the genesis of the lignite deposits and topography of the area. Thus, indirectly, glaciotectonic character of the area has an effect on the vegetation condition, e.g. through the location of the mined deposits. However, we agree with the comment. We have removed this part from the title, which now reads as “Integrated spatiotemporal analysis of vegetation condition in a complex post-mining area: lignite mine case study” to represent the combined underground and open-pit mining. We propose to add a new keyword “glaciotectonic”

 

Comment 2. Among the mines to be revegetated in the study area, the previous mining methods are divided into open pit mining and shaft mining. Is it possible to analyze and give a regular summary of the restoration status of the vegetation under the two different mining methods? This may be more meaningful for a case study article.

Response. This is a very interesting aspect of our study and characteristic of many mining sites. Actually, in the case of lignite mining in the study area we are dealing with areas of underground mining, open-pit mining and in some cases underground mining followed by open-pit mining. Sometimes these areas overlap partly. Therefore, a regular summary of the restoration status under two different mining methods would be difficult and perhaps not representative. We have made such an attempt to differentiate between vegetation cover condition changes in different post-mining zones in part 3.5 of the manuscript with examples from field examinations shown on the photos 16a to 16e.

 

Comment 3. Vegetation restoration in the study area began around 1980, and the time series used in the article with satellite data is between 2015-2022, is this period too short a choice for the growth of vegetation?

Response. It was our intention, expressed in the Introduction section, to study the condition of the vegetation thought to be in the rehabilitated phase, i.e. decades after the end of mining. As it was indicated in the Discussion section, despite the relatively short period of analysis determined by the available time series of open Sentinel-2 imagery, the proposed methodology and the results provide reliable and useful information on the general condition of vegetation, as well as identification of zones of “positive” and “negative” temporal trends of vegetation that in our opinion should be monitored further. Long-term analysis of vegetation condition based on Landsat data and aimed at the study of vegetation condition in the growth period was the subject of another publication referred to in the Discussion section, position 86 in the reference list.

 

Comment 4. The markers for embedded formulas in lines 339 and 346 of the article should be on the far right.

Response. Thank you for spotting this. The markers have been corrected.

 

Comment 5. In line 400 of the article, the formula should be labeled (5), and "and" should be deleted in line 405. In addition, all formulas inserted, whether derived or quoted from others, need to be arranged in top-to-bottom order, otherwise they will be unreadable, so make sure the markers in lines 406 to 407 are correct.

Response. Again thank you for noticing this. The numbering of formulas has been corrected

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

This paper explains the application of GIS data mining and satellite derived spectral vegetation indices in post-mining environmental research, which has certain practical application significance, and provides a new idea for detecting post-mining environmental restoration in mining areas. However, the paper has the following minor drawbacks.

1.    In the abstract section, you need a short description that highlights the innovation and importance of the research results of the paper.

2.    Figures 7 and 8 are too small, and it is recommended to redraw them to make the image more beautiful.

3.    Discussion section, it is recommended to extend the comparison of the study findings with other similar published word.

4.    The conclusion part should be more refined to make the findings and contributions of the paper clearer.

Author Response

Response to Reviewer 3 comments

 

General comment. This paper explains the application of GIS data mining and satellite derived spectral vegetation indices in post-mining environmental research, which has certain practical application significance, and provides a new idea for detecting post-mining environmental restoration in mining areas. However, the paper has the following minor drawbacks.

Response. Thank you for the positive response and for the helpful comments that have allowed us to improve the quality of our work. The proposed changes have been marked in green colour.

 

Comment 1. In the abstract section, you need a short description that highlights the innovation and importance of the research results of the paper.

Response. Thank you. We have added a sentence and modified the last part.

 

Comment 2. Figures 7 and 8 are too small, and it is recommended to redraw them to make the image more beautiful.

Response. We have increased the text size of the mentioned figures 7 and 8, as well as 6 and 9. In addition we have followed the recommendations of the Guest Editor to change the colour of the font from grey to black.

 

Comment 3. Discussion section, it is recommended to extend the comparison of the study findings with other similar published word.

Response. We have added 4 additional publications, numbered 81 and 84-86 in the revised list of sources, as well as extended the discussion.

 

Comment 4. The conclusion part should be more refined to make the findings and contributions of the paper clearer.

Response. We have refined the conclusions. Thank you.

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

This paper applies NDVI and EVI indicators for monitoring vegetation cover change related to the post-mining rehabilitation process. With the help of some analytical methods and field surveys, it concludes that the post-mining site is generally past the rehabilitation process. However, it is hard for me to capture the scientific contribution of this study.

 

And there are also some inadequacies, as follows. I suggest the paper needs a major revision.

 

The followings are some inadequacies that still need to be improved:

 

1)      The paper needs to be edited carefully. It is necessary to pay more attention to sentence structure so that the results are clearly represented to the readers.

2)      In the part of the results, the separate analysis of NDVI and EVI values in August lacks explanations.

3)      In the section of comments (lines 614 and 615), an explanation should be provided of why and how the authors found EVI being a good augmentation to NDVI and better suited for studies.

4)      The section conclusion involves both methods and results. However, all the conclusions lack relationships based on logic. I suggest this section be reorganized.

Reviewer 2 Report

The manuscript “Integrated spatiotemporal analysis of vegetation condition in a glaciotectonic post-mining area. Lignite mine case study glaciotectonic post-mining area. Lignite mine case study” examined the vegetation changes at post lignite mine area through vegetation index using different methods. The current version of manuscript has many problems in design, methodology, and writing, needs intensive revision.

 1. Design: the study mining stop operation during 1970’, since then the recovery process began, and reached stable at most location. However, this study only examined the recent years.

2.      Paper structure: some method descriptions were placed in results section. For example, 3.1.3 combinatorial temporal change detection, 3.15 Field examination.  

3.      Methodology: Because the number of cloud-free Sentinel images available is various among years (for some years from May-August, some year from June and August, or July-August), taking the mean values of NDVI or EVI from all available images as annual values is not appropriate. NDVI/EVI values change with pheonological circle, they are much different in May and August. The mean values from different years are incomparable. The good way is taking the maximum values of NDVI or EVI. In this study, using images acquired in August alone is enough, not necessary to do annually and monthly separately.

4.      Figures: legend covers the main map in many figures, not very clear caption description.

5.      Authors used different methods to analyze the vegetation condition, what are the agreements between the results and what are the disagreement? What method is more better?  

6.      English Writing: grammar mistakes, hard understand.

 Specific comments:

1.      Title: change “.” between area and Lignit to “:”, and delete the last “.”

2.      Introduction: It is too loose in literature section. You cannot just list the references (who did study) in literature review section, should summarize them and identify problems, and introduce your research objectives.

3.      Study area: Figure 1 gives readers an inaccurate message by highlighting the up right corner (Poland). Text “study area” should move down to the location of former mining area. In addition, you should add the boundary of rehabilitate area, which are your focus of analyses.

4.      Figure 2 indicate the data sources. What land cover type the white color represents? What does mean present-day (what year)

5.      Sentinel image preprocessing: It is atmospheric correction process from L1C to L2A, does not associate classification. What does mean “scene classification” in preprocessing?

6.      Figure 4: Please make a better and clear flowchart. Don’t break an entire phrase of processing name (for example, Satellite data selection) into two lines.

7.      Hot spot analysis: the equation is for vector data, it may be different for raster. By the way, how to determine the weight?

8.      Line 346: “n--total number of features and (4) and (5)”?

9.      Line 354-359: This description seems to be data standardization process, calculating z-scores and determining the significant high and low values based on the critical values (2.58 and 1.96).  Is it your method or G* calculation?

10.  Did not introduce emerging hot spot analysis.

11.  In LandTrendr, what are the input? What are the output of LandTrendr? how to interpret the results?

12.  Because the study focused on rehabilitated area, it is not necessary to compare NDVI/EVI between and entire mining are and rehabilitated area.

13.  I did not see the purpose of correlation between NDVI and EVI (Figure 6). Besides, the means of NDVI and EVI for entire study area really had no comparability. At pixel level, vegetation, the correlation between vegetation’s NDVI and EVI should be higher.

14.  Results-Section 3.1.1: this part describe the results from calculate means and CV among the study time span, did not introduced in method section.

15.  Figure 9 the colors used for different confidence levels are too close, hard to differentiate. Legends cover the boundary. What year is the map for?

16.  Line 485-487: “The cold spots NDVI patterns are more evenly distributed with the persistent, consecutive intensifying and sporadic covering types from 7.2% to 3.2% of the area”. How to interpret “evenly”?

17.  Paragraph “493-500” hard to understand.

18.  Table 6: Decimal should be “.”, not “,”. For emerging hot spot analysis, how to define “pattern types”?

19.  Figure 11: What analysis was the result came from?

20.  Result section 3.1.3 method should be introduced in Methodology section. The classification schemes are too arbitrary. How the combinatory function was conducted? between two consecutive years or taking one as base year?

21.  Using pixel numbers is not appropriate, suggest convert them to area (ex. ha).  

22.  For LandTrendr analysis, 6-7 years may be not long enough, except for abrupt change. It is more like that we conduct regression analysis, fewer samples could not produce reliable model and results.

23.  Figure 14: please indicate a-f in caption.

24.  Section 3.15 the data and method should be introduced ahead.

25.  Figure 16: where are these data came from?

26.  Comments: line 613-616: how to prove EVI is better than NDVI?

27.  Line 617-627: these messages are not supportive for choosing Sentinel data, instead of Landsat.