Analysis of the Evolution of Mangrove Landscape Patterns and Their Drivers in Hainan Island from 2000 to 2020
Round 1
Reviewer 1 Report
The main take-home message from the study ‘Analysis of the Evolution of Mangrove Landscape Patterns and their Drivers in Hainan Island from 2000 to 2020.’ is that the area under mangrove coverage increased in Hainan Island between 2000 and 2020, with similarly increased shape complexity, patch fragmentation, and increased richness. Also, the high correlation between annual temperature and mangrove decline and patch fragmentation implies important systematic associations. The work is well structured considering the set objectives, research design, and reporting of findings and Discussion and could be of broader relevance to mangrove conservational efforts in Hainan.
Comments for author File: 
Comments.pdf
Author Response
Response to Reviewer1 Comments
Dear Reviewer:
We highly appreciate the reviewer for the insightful comments and criticism, which have helped us improve both the content and the presentation of our work. We believe that the revised version of our paper addresses all concerns by the referees in detail. The paper also carried out a new grammar and language proofreading service. The changes are highlighted within the manuscript. Please see below, in red, respond to reviewers ' focused comments and concerns point by point.
Point 1. Line : 14-24 Abstract:This is too wordy. Summarize into a more concise sentence
Response 1: We sincerely appreciate the reviewer’s question. Modified to: (1) The total mangrove landscape area of Hainan Island between 2000 and 2020 showed a trend of first decreasing and then increasing. In the past 20 years, the mangrove area has increased by 1315.75 ha, with an annual change rate of 65.79 ha/a. (2) From 2000 to 2020, the mangroves in Hainan Island were characterized by increased fragmentation, increased heterogeneity, decreased connectivity, and increased richness, and tended to be balanced. (3) Natural factors such as the annual average temperature in the study area were the main factors driving the large-scale reduction of mangroves and the deepening of landscape fragmentation, followed by human factors, and the impact of macro-policies cannot be ignored.
Point 2. Line : 40-42 This is an ambiguous statement, please revise
Response 2: Thanks for your suggestion. This paragraph was intended to outline the overexploitation and unreasonable use of coastal wetlands, such as land reclamation, port construction, and water conservancy facilities, which will have a certain impact on the growth and distribution of mangroves, but it is too detailed and therefore deleted from the revised draft.
Point 3. Line : 93-94 also, revise the sentence "therefore, the scope of this study is to investigate the changes and reasons of mangrove landscape pattern in Hainan Island in a long time scale. " to fit a literature review format, i.e., a gap identified, and in need of more studies, and not your study's aim.
Response 3: Thank you for your valuable comments. This part has been modified to: Therefore, it is necessary to explore the changes in mangrove landscape patterns and their causes on Hainan Island.
Point 4. Line : 112-115 Revise for more clarity. Consider using shorter sentences.
Response 4: Thanks for your careful check. This part has been modified to: In the middle of Hainan Island, high terrain surrounded by low terrain has formed a number of large and small rivers, showing the characteristics of a radial water system.
Point 5. Line : 120 Figure 1:redo this figure to map the study area within the geographical location in China, and the sea. Probably as an inset.
Response 5: We sincerely appreciate the reviewer’s suggestion. Figure 1 has been modified to :
Point 6. Line : 123-125 Include a first sentence here showing what you used 'Sentinel-2' data for ..., before the descriptive sentences
Response 6: Thanks for your suggestion. Add the first sentence as required: In this study, we selected Sentinel-2 data as a data source for the comparison of the accuracy of multiple machine learning approaches.
Point 7. Line : 125-127 Why compare with 'Landsat-8 '? Table 1 lists two other datasets, Landsat 5 and 7.
Response 7: Thank you for your valuable comments. This is the author 's thinking is not comprehensive, has been revised as : Compared with Landsat data, Sentinel-2 data have a resolution of 10 m in the B2 (B), B3 (G), B4 (R), and B8 (NIR) bands and 20 m in the remaining bands, whereas Landsat data have a resolution of 30 m.
Point 8. Line : 131-133 Revise to be unambiguous.
Response 8: Thanks for your careful check. This part has been modified to: We selected remote sensing images from the months of May–September, and selected a study area that was cloud-free or with cloud coverage of less than 5% to prevent misclassifications and omissions due to cloud interference, so that we could obtain accurate mangrove information.
Point 9. Line : 168-169 Why are Machine learning algorithms such as support vector machine not fully applicable to the extraction of mangroves in Hainan Island?
Response 9: Thanks for your suggestion. This part is the author 's inaccurate expression. The original intention is that there are now conventional algorithms such as support vector machines to extract the area of mangroves. Now it is necessary to determine the best algorithm for extracting the area of mangroves in Hainan Island, so it is necessary to increase the comparison of other algorithms. Has been changed to : To determine the best machine-learning algorithm for extracting mangrove areas in Hainan Island, a comparative study of Catboost, XGBoost, and AdaBoost, representing new machine learning algorithms and models,was conducted.
Point 10. Line : 165 There no reason to list and describe each of the algorithms. Revise this part to collapse all subsections under 4.1 Machine-learning algorithms, highlighting what is most relevant (to your study) of each algorithm. For instance: you can do this by summarizing the background performance baselines of each algorithm and the relevant references
Response 10: Thank you for your valuable comments. This part has been modified to:
4.1.1. CatBoost
The traditional gradient enhancement process for sample gradient calculation depends on the sample's own CatBoost results, which effectively avoids the prediction offset and reduces overfitting. In terms of its parameter settings, Cat Boost sets iterations = 200, depth = 8, and learning rate = 0.05.
4.1.2. XGBoost
XGBoost is a fast implementation of Gradient Boosting algorithm, which can make full use of multi-core CPUs for parallel computation, while improving the algorithm to improve overall accuracy. The basic idea of the XGBoost algorithm is to first establish a base classifier/regressor and gradually add a new classifier / regressor. In this study, XGBoost algorithm parameters eta = 0.3, max_depth = 6, gamma = 0 and Colsample_by = 1.
4.1.3. AdaBoost
AdaBoost is an iterative algorithm of the boosting type. The final result is obtained via the weighted averaging of the learners. In this study, the number of base estimators was 150, the learning rate was 0.05, and the loss function was linear.
4.1.4. Random forest (RF)
Random forest is an ensemble learning algorithm based on decision trees, which combines multiple decision trees via the use of a bagging model. In this study, we set the number of trees (n_estimators) to 150, the maximum number of features (max_features) to the square root of the number of features, and the maximum depth (max_depth) to 16.
4.1.5. Support Vector Machine (SVM)
A support Vector Machine is a classical machine learning algorithm theory proposed by Corinna Cortes and Vladimir Vapnik in the 1990s. In this study, the parameter settings were Degree = 3, Cost = 10, and Gamma = 0.3.
Point 11. Line : 261-262 include a sentence to clarify why you chose these variables 'to quantify the drivers of change in the mangrove landscape patterns '
Response 11: Thanks for your careful check. Add the reasons for choosing these criteria before the selected indicators: referring to the relevant studies and considering collectability of indicator data, we selected eight indicators—including population, gross regional product, gross fishery product, and mean annual temperature—based on the relevant studies.
Point 12. Line : 296 Subdivision based on what criteria? Also, list the 11 areas (names) into which the Hainan Island Mangrove Forest can be subdivided into, at the end of this statement
Response 12: Thank you for your valuable comments. The 11 study areas subdivided by mangroves in Hainan Island are divided according to geographical location. The 11 areas(names) are : Dongzhai Harbor, Xinying Mangrove, Qinglan Harbor, Danzhou Bay, Huachang Bay, Wanquan river estuary, Sibi Bay, Wanning Xiaohai, South Sanya, Xincun Harbor and Li 'an Harbor, Changhua river estuary.
Point 13. Line : 297-298 No, you should present your findings first, and then speculate what might explain them, not the other way round.
Response 13: Thanks for your careful check. This part has been modified as : The area of mangroves in Dongzhai Harbor did not change much in 20-year period because Dongzhai Harbor is China 's first mangrove nature reserve, the government and related agencies are aggressively protecting it.
Point 14. Line : 330 this figure does not properly convey your message. Revise to replace the radial bar chart with grouped bar plots
Response 14: Thanks for your suggestion. Figure 4 has been modified to :
Point 15. Line : 331 It is not evident, nor previously mentioned, what 'type level' means. Revise.
Response 15: Thank you for your valuable comments. This part has been modified to: Added description in Section 5.3, the characterization of landscape pattern types and levels was achieved using MPS, COHESION and FRAC. The indexes used for the characterization of landscape patterns and levels were NP, PD, LSI, SHEI, SHDI. When analyzing the characteristics of mangroves at different levels, assessing their types and landscapes, it is helpful to explore the various factors affecting the landscape patterns and change processes of mangroves and the mechanisms influencing them, thus revealing the reasons for the changes in mangrove areas.
Point 16. Line : 429-433 Revise to make clear. Tip: use concise sentences.
Response 16: Thanks for your careful check. This part has been modified to: Rapid economic development can appropriately increase the protection and restoration of mangroves, but at the same time, human activities can continue to encroach on the living spaces of mangroves, resulting in the degradation of mangroves.
Point 17. Line : 458-462 This is difficult to understand. Revise to make clear.
Response 17: Thanks for your suggestion. This part has been modified to: Anthropogenic factors directly affected the changes in mangrove areas on Hainan Island, so it was identified as the main cause of mangrove degradation on Hainan Island on a small time-scale, whereas natural factors had a stronger influence on mangrove landscape pattern on Hainan Island than man-made factors on a large time-scale.
Point 18. Line : 467-468 It was merely a plan which was first to be implemented. It had not 'perfectly met the realistic needs ' yet! Revise for clarity
Response 18: Thank you for your valuable comments. This part has been modified to: which were later revised in 2004 and 2011 to meet the practical needs of Hainan mangrove ecological protection and restoration, but there have not been effectively implemented.
Point 19. Line : 492-498 these are comparisons which can be similar without being accurate or correct. Rewrite for a better discussion tone
Response 19: Thanks for your careful check. This part has been modified to: This pronounced convergence is evidence of the high accuracy and reliability of the data reflecting the mangrove forest coverage areas of Hainan Island as identified and extracted in this study. However, Hainan Island’s mangrove area in the same years as measured by Peiqiang Wu, Xiaoyu Li, and Wuxia Wang were not similar, perhaps due to the dissimilarity of the visual interpretation standards and the differences in image precision, which could have led to the differences in the data classification result and the dissimilarities in terms of mangrove recognition and extraction precision.
Point 20. Line : 538-544 This paragraph is unclear. Please revise to use clear concise sentences. Break up the sentences.
Response 20: Thanks for your careful check. This part has been modified to: The results showed that among the driving factors of mangrove landscape pattern changes on Hainan Island, the driving force of natural factors was stronger than that of human factors, which was similar to the conclusions of a study by Jia Mingming, but contradicted Li Xiaoyu's conclusion that population density was an important reason for mangrove degradation. Daniel's study suggested that rising temperatures may lead to faster growth and reproduction among mangroves, which respond more directly to precipitation.
Point 21. Line : 573-575 revise to be better understandable
Response 21: Thanks for your suggestion. This part has been modified to: In this paper, based on the use of Aentinel-2A data, five machine-learning algorithms were used to identify and extract data on the mangrove areas of Dongzhai Port, and we determined that the most suitable algorithm for extracting the mangrove area data of Hainan Island was the XGBoost algorithm.
Point 22. Line : 584-589 Make concise
Response 22: Thank you for your valuable comments. This part has been modified to: The total mangrove landscape area of Hainan Island between 2000 and 2020 showed a trend of first decreasing and then increasing. In the past 20 years, the mangrove area has increased by 1315.75 ha with an annual change rate of 65.79 ha/a.
We look forward to hearing from you regarding our submission. We would be glad to respond to any further questions and comments that you may have.
Sincerely,
Authors
27th December, 2022
Reviewer 2 Report
Dear Authors,
The manuscript is very interesting, it analyzed the Evolution of Mangrove Landscape Patterns and their Drivers on Hainan Island from 2000 to 2020. In general, although the manuscript is well written, it should be sent to proofreading services for grammar and language.
There are some more corrections in the manuscript:
Line 111-117 : The sentences were too long.
Line 117 : What were the annual sunshine hours (???)
Line 117-118 : In 2020, Hainan Island’s regional GDP was 553.239 billion yuan, an increase of 3.5% over 2019 at constant prices à is it related to the paragraph?
Line 131-132 : the main time à Is there any other time? Please describe it
Line 135 : Please relate Table 1 with the text
Line 237-238 : the abbreviation is not match
Line 276 : Please relate Table 4 with the text
Line 281 & 315: Please prepare a better, proper, and clear map (Figures 2 and 3)
Line 343-375 : where are the real data? please relate to tabel/figure
Line 390-408 and 419-41 : where are the number come from?
Please revise the manuscript.
Thank you.
Comments for author File: Comments.pdf
Author Response
Response to Reviewer 2 Comments
Dear Reviewer:
We highly appreciate the reviewer for the insightful comments and criticism, which have helped us improve both the content and the presentation of our work. We believe that the revised version of our paper addresses all concerns by the referees in detail. The paper also carried out a new grammar and language proofreading service. The changes are highlighted within the manuscript. Please see below, in red, for a point-by-point response to the reviewer’s comments and concerns.
Point 1. Line 111-117 : The sentences were too long. Line 117 : What were the annual sunshine hours (???)
Response 1: We sincerely appreciate the reviewer’s question. It has been deleted and amended to the following: At the same time, there is sufficient precipitation in Hainan Island and it has a circular distribution: the average annual precipitation is 1640 mm. In the middle of Hainan Island, high terrain surrounded by low terrain has formed a number of large and small rivers, showing the characteristics of a radial water system. Hainan Island has a tropical monsoon oceanic climate, with an average annual temperature of 22.5–25.6°C and 1780–600 annual sunshine hours.
Point 2. Line 117-118 : In 2020, Hainan Island’s regional GDP was 553.239 billion yuan, an increase of 3.5% over 2019 at constant prices à is it related to the paragraph?
Response 2: Thanks for your suggestion. Overview of study area originally intended to provide a comprehensive introduction to Hainan Island in terms of climate, economy and other aspects, but the changes in mangrove area and landscape pattern in Hainan Island were less affected by economic changes, so delete this part of the document in the modified version.
Point 3. Line 131-132 : the main time à Is there any other time? Please describe it
Response 3: Thanks for the references and suggestions, your comments coincide with the reviewer 1, remote sensing images are collected from May to September, due to misrepresentation, so delete ' main'.
Point 4. Line 135 : Please relate Table 1 with the text
Response 4: We apologize for causing you doubts. Table 1 contains specific information on the five remote sensing images used in the study, with ' Remote sensing image information is shown in Table 1.' added to the revised version, relate Table 1 with the text.
Point 5. Line 237-238 : the abbreviation is not match
Response 5: We apologize for causing you doubts. In this study, the mean patch area (MPS), number of patches (NP), patch density (PD), and landscape shape index (LSI) were used to characterize individual units of the landscape.
Point 6. Line 276 : Please relate Table 4 with the text
Response 6: We apologize for causing you doubts. At the beginning of 5.1, a description is added, 'Five machine-learning algorithms were used to extract mangrove vegetation information from DongZhai Harbor, and their user-accuracy and production-accuracy values are presented in Table 4', relate Table 4 with the text.
Point 7. Line 281 & 315 : Please prepare a better, proper, and clear map (Figures 2 and 3)
Response 7: We apologize for causing you doubts. Figures 2 and 3 have been replaced with clearer figures in the revised draft.
Point 8. Line 343-375 : where are the real data? please relate to tabel/figure
Response 8: We apologize for causing you doubts. This part of the data is represented in the form of a grouped bar chart in Figure 4.
Figure 4. Landscape pattern index map of mangroves on Hainan Island
Point 9. Line 390-408 and 419-41 : where are the number come from?
Response 9: We apologize for causing you doubts. This part of the data is represented in Figure 5.
Figure 5. Gray correlations between relevant indicators and the landscape pattern indexes of mangroves on Hainan Island.
We look forward to hearing from you regarding our submission. We would be glad to respond to any further questions and comments that you may have.
Sincerely,
Authors
27th December, 2022
Author Response File: 
Author Response.docx
Round 2
Reviewer 1 Report
I am impressed with the authors’ efforts to revise the manuscript following the first review round. The work has been much improved.
I have inserted a few exemplary comments in the PDF that they should consider to revise the work further. In addition,
There remain some poor sentence structure and typos. The authors should carefully re-read the full text to improve overall clarity and logic.
Some in-text citations are not correctly formatted. To improve the paper's readability, the authors should carefully consider the correct formatting of the in-text citations when they are inseparable parts of sentences vs. when they are not.
Comments for author File: Comments.pdf
Author Response
Response to Reviewer1 Comments
Dear Reviewer:
We highly appreciate the reviewer for the insightful comments and criticism, which have helped us improve both the content and the presentation of our work. We believe that the revised version of our paper addresses all concerns by the referees in detail. The changes are highlighted within the manuscript. Please see below, in red, respond to reviewers ' focused comments and concerns point by point.
Point 1. Line : 10 Insert the locality indicator of Dongzhai Harbor
i.e., Dongzhai Harbor, northeast Hainan Province, China.
Response 1: Thanks for your suggestion. 'Dongzhai Harbor ' has been modified to ' Dongzhai Harbor, northeast Hainan Province, China'.
Point 2. Line : 18 it is not clear what 'tended to be balanced ' here means.
Response 2: We sincerely appreciate the reviewer’s question. SHDI showed a continuous growth trend during the years, while SHDI increased, indicating that the proportion of each landscape type tends to be equilibrated. This part has been modified to: while proportion of each landscape type tends to be equilibrated.
Point 3. Line : 48 Correctly format this citation
Your referencing style implies the citation 'Lorenzo' should also have the citation number when it is an inseparable part of the sentence, e.g., 'Lorenzo [0]'
Response 3: Thanks for your careful check. Some authors such as Lorenzo, Madhuri R, are referenced or mentioned as part of the article, the reference format has been modified to Lorenzo [10], Madhuri R [29], and the other reference format is not standardized modified.
Point 4. Line : 50 revise to include the dataset you're referring to here, e.g., 'various remote sensing datasets'
Response 4: Thank you for your valuable comments. This part has been modified to: Numerous studies has applied high resolution remote sensing and unmanned aerial vehicle dataset to extract mangrove-related parameters from different regions via different classification techniques.
Point 5. Line : 104-105 add the value of this 'highest elevation' after center.
Response 5: We sincerely appreciate the reviewer’s suggestion. This part has been modified to: The highest elevation of Wuzhi Mountain in the middle is 1867 meters, which is the center of the whole island.
We look forward to hearing from you regarding our submission. We would be glad to respond to any further questions and comments that you may have.
Sincerely,
Authors
30th December, 2022
Author Response File: Author Response.pdf
