Landscape Dynamics of Cat Tien National Park and the Ma Da Forest Within the Dong Nai Biosphere Reserve, Socialist Republic of Vietnam

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript titled “Landscape Dynamics of Cat Tien National Park and the Ma Da Forest Within the Dong Nai Biosphere Reserve, Socialist Republic of Vietnam” is an interesting analysis of the changes in landscape structure in a protected area. The authors trace these changes on four levels: 1) EVI dynamics, 2) ESRI Land Cover and Land Cover CCI data changes, 3) landscape metrics, and 4) the human disturbance index. The results are fascinating and provide substantial data on nature protection in the region. Despite its high potential scientific value, the manuscript needs substantial improvement, as outlined in the recommendations below.

 

1. Throughout the manuscript, the authors use very general terms such as "positive trends" (lines 26,197, 379, 439, and 465) and "improvement" (lines 213 and 447). It would be better to be more specific, such as stating whether the metrics or index increased or decreased.
2. In the Results section, there are paragraphs that comment on or explain certain data based on the authors' knowledge of the studied area rather than on the results themselves. For example, lines 178–180, 194–195, 208–209, 211–212, 224–226, 233–235, 258–260, and 276–280. In my opinion, those paragraphs should be moved to Methods or Discussion sections, depending on their content..
3. The results section is organized according to the method used. It is difficult to follow because the text jumps between different data sets, analyses, and zones compared. Would a problem-oriented approach improve this section of the manuscript? First, describe the general results that apply to the entire area. Then, describe the results for the core area, followed by the buffer area and so on. This method is probably more difficult to write, but easier to read.
4. Materials and Methods. There is no clear information about the area of interest. In particular, it is unclear whether the transition area is covered by the research. This information could potentially affect the title of the manuscript.
5. The discussion is chaotic and full of statements that are unrelated to the results of the work and are often unsupported by citations from the literature. A critical comparison of results from different land cover classifications is definitely missing. Are the results of those classifications consistent? Next, present the main trends in landscape dynamics and their impact on nature protection goals.
6. Lines 186–189 and 192–195 describe EVI dynamics in the buffer zone. This is an unnecessary repetition. There is only one sentence about the core zone without a dynamic description.
7. Line 200-204. This is more of a method than a result.
8. Lines 216–220: To which area or zone does this paragraph refer?
9. Figure 5. There is a lack of explanation of what the 4 and 8 types of land cover are.
10. Figure 5: Table 3. There is no scientific rationale for presenting the same data in two different forms. This makes comparing the core and buffer zones more difficult.
11. Figure 8. The graph includes two additional years that are not described, except for 1992 and 2002.
12. Figure 8. Table 4. See Remark No. 10.
13. Lines 264–274. The data in the text does not match the data in Table 4.
14. Lines 264–268 and 269–274 provide redundant information. This redundancy should be removed from the manuscript.
15. Line 276–280: It is not a result; it is a method. Furthermore, it does not align with the description in the "Materials and Methods" section. What type of imagery was used for classification? Landsat 5 and 8? Which year? If so, why does the caption for Figure 9 refer to 2000 and 2024?
16. Line 290–292. What year does this sentence refer to? The data in the text does not match Table 5.
17. Figure 10. This figure is barely described. There is no reference to this graph in the text.
18. Table 5. For better readability, the abbreviation for each landscape metric should be explained. What is the unit for each landscape metric?
19. Table 5. Figure 10. The names of the land cover types do not match between the table and the figure.
20. Lines 296–309: Inconsistency in the names of land cover classes. There are no "disturbed forests," "herbaceous vegetation," or "build-up areas" in Table 5. The data in the text does not match the data in Table 5.
21. Lines 324–331. Where is the adjacency data presented?
22. Lines 365–371. What is the HDI value for the core and buffer zones?
23. Line 296–399. Where in the manuscript is the data on structural degradation presented?
24. Line 400–406. The authors did not study the climate conditions in tall dipterocarp forests. This paragraph is not a result of the presented study and needs to be supported by citations or related to the results of the manuscript.
25. Line 412: What do "such trees" refer to? The previous paragraph is about napalm use and forest degradation.
26. Lines 423–425: This paragraph, which concerns methodological issues, has been inserted into the discussion of anthropogenic pressure on the landscape. It does not fit and disrupts the main idea.
27. Line 426-429: This is probably true, but it must somehow be referred to the presented study.
28. Line 430-433: As above.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript makes use of a rich dataset and multiple analytical tools, and the research process is presented in detail. The topic addressed is of substantial practical significance. Nevertheless, several issues require further clarification and refinement before the paper can reach publishable quality.
1. In the abstract, the authors are encouraged to highlight the broader academic and practical value of the findings after presenting the results.
2. The introduction would benefit from a more explicit discussion of the gaps and limitations in existing studies; this would help to better position the contribution and underscore the paper’s originality.
3. The logical connection among the three stated research objectives is not clearly articulated and should be clarified to improve the overall coherence of the study.
4. The temporal coverage of the datasets appears inconsistent: EVI values were calculated for 2000–2024, while land-use types are only available for 2017–2024, and land-use change data span 1992–2022. The authors should justify or, if possible, reconcile these differences to ensure consistency.
5. The adjacency matrix referenced in the manuscript should be explicitly presented, either in the main text or as supplementary material.
6. The procedure for calculating the HDI requires a detailed description to allow replication and ensure transparency.
7.The discussion section should be expanded to compare and contrast the findings with those of prior studies, thereby highlighting both the similarities and the distinct contributions of this work.
8、Finally, the theoretical contributions of the manuscript should be explicitly summarized, to more clearly demonstrate its added value to the literature.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

It is important to mention in the summary some of the relevant data of the results obtained, in order to capture the attention of future readers.

 

It is recommended that the keywords be different from those already mentioned in the title, in order to provide more information on the lines of research of the article.

 

Include geographic coordinates in the plans, for a correct interpretation of the location of the study area.

 

It is important to include the formulas for estimating the different vegetation indices, as well as the bands used and the dates of the satellite images.

 

How were these areas determined to be concentrated areas for bamboo and palm species? Were sampling points established to validate the vegetation type classification?

 

The classification of land use and vegetation does not include the area occupied by communication routes.

 

The values ​​of this classification contrast greatly with the following period. I believe this is due to the lack of clarity or noise in the images, which could have caused a very different classification in the analysis periods.

 

Indicate the values ​​of the annual land use change rates and the deforestation rate

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The article titled “Landscape Dynamics of Cat Tien National Park and the Ma Da Forest Within the Dong Nai Biosphere Reserve, Socialist Republic of Vietnam” is well-aligned with the scope of the Journal Land. The manuscript presents a quality study; however, it requires improvements to reach its full potential.

The main issue to be addressed is a lack of specificity in key areas. Throughout the text, the authors use general terms that can create ambiguity for the reader. For example, when mentioning "remote sensing methods and Geographic Information Systems," they do not specify which techniques were employed. This ambiguity compromises the study's replicability and may diminish reader interest. Fortunately, this is an issue that can be easily resolved by the authors by adding more detail to the methodology section.

Furthermore, for the abstract and conclusion to better reflect the research's practical implications, it is crucial that the findings are translated into strategic questions to guide territorial management. The research reveals an important dichotomy: the recovery of vegetation in the core zone in contrast with the growing fragmentation and anthropogenic pressure in the buffer zone. The article would therefore be strengthened by proposing and discussing a central question: "What integrated strategies, combining land-use policies, economic incentives for local communities, and social awareness programs, can be proposed to promote sustainable development throughout the reserve, while protecting biodiversity and improving the local quality of life?" The inclusion of this strategic discussion would greatly enrich the work.

Finally, it is recommended that the methodology section be supplemented with the mathematical equations and their corresponding interpretations for the vegetation index and the other landscape metrics used.

In light of the above, my recommendation is Acceptance, conditional upon the implementation of the revisions outlined here.

 

Specific Comments

L = Line; (?) = question/doubt

L 18-19. "for evaluating ecosystem functioning and the effectiveness of natural ecosystem conservation efforts." Please improve the sentence for better flow and precision.

L 21. "... using remote sensing (?) and geographic information system methods (?)." What are these methods and information systems?

L 22-23. "... Enhanced Vegetation Index (?),..." Please add the acronym EVI. What satellite and sensor were used? How many satellite images were used? Were they annual mean images?

L 23. "... landscape metrics (?), and natural landscape..." Please list the metrics.

L 24. "... anthropogenic impacts (?) on the area." Please provide examples of these impacts.

L 24. "... The results revealed structural changes (?) in the landscapes..." What is the percentage of this change? The article is full of interesting results. Please highlight your results by adding numerical values.

L 26. "...estimates, a generally positive EVI trend was observed in both the core (?) and buffer zones (?) of..." Could you please explain what the core and buffer zones are? What happened to the agricultural lands? Please make it clear if deforestation occurred.

L 29. "... of ESRI (?) Land Cover and Land Cover CCI (?) data confirms the relative stability of land cover..." Please provide the meaning of the acronyms ESRI and CCI.

L 30. ".... while anthropogenic pressure has increased (?)..." Please state by how much it has increased.

L 32-33. "...metrics revealed the growing isolation of natural forests and the dominance of artificial plantations (?), ..." Please provide examples of artificial plantations.

L 35-36. ".... only a slight change in the average value (?) across the territory..." What is the value of this change in percentage terms?

L 36-37. "However, the coefficient of variation increased (?) significantly by, indicating a localized rise in anthropogenic pressure (?) within the buffer zone, while a reduction (?) was observed in the core zone." How much did the coefficient of variation increase? What was the increase in anthropogenic pressure? And the reduction in the core zone?

L 38. Keywords should be different from those in the title. Please change the words: landscape dynamics; fragmentation; protected areas. Suggestions: deforestation, agricultural lands, EVI, Sen’s slope, FRAGSTATS, etc.

L 49. "... and provide numerous ecological functions (Which ones?) at..." Please provide examples of ecological functions.

L 55. ".... have reported a consistent increase (By what percentage?) in forest cover over..." Please state the percentage increase in forest cover.

L 58-59. "... have had mixed effects (Which ones?) on forest rehabilitation...." Please provide examples of these mixed effects.

L 59. ".... Although forest area has increased under two national programs (Which ones?),..." Please name the programs.

L 66. "... spread of invasive species, and hunting (?)." Do you have references for this statement?

L 75. "Remote sensing (RS) methods (Which methods?) are now widely employed to study environmental processes (Which processes?)." Please provide examples.

L 76. "Landscape structure (What structure?) is frequently quantified using open-source toolkits (Which toolkits? Please list them.) designed for processing satellite data (Which satellites? For example?)."

L 77-78. "The growing availability of remote sensing resources (Which resources?), combined with advances in image analysis (For example?), has expanded the range of applications (Which applications?) for landscape-scale (What is the resolution or size of the landscape scale?) assessments." I'm sorry, but it is very important to make the text detailed and clear.

L 79-80. "These techniques (Which ones?) provide broad spatial coverage (How much?), temporal consistency (?), and access to extensive open-source datasets (For example?), enabling detailed monitoring of geoecological landscape dynamics." Regarding temporal consistency, how was temporal resolution handled? The authors also used sensors and land use products with different spatial resolutions, e.g., MODIS, TM or OLI, CCI. How were the different pixel sizes handled for the study? Please improve the explanation.

L 83. "... Vegetation Index [NDVI]) [13]..." Brackets on NDVI.

L 102-106. The authors used different periods (EVI from 2000 to 2024; CCI from 1992 to 2022; Landsat 5 and 8 from 1999–2000 and 2024–2025, respectively). Wouldn't it be better to clarify the time periods used for each purpose? Also, please specify the satellites and sensors used.

L 108. Please provide information about the climatic conditions of the study area (climate type, temperature, precipitation, etc.), topography (elevation, terrain slope), and environmental conditions (predominant vegetation types, agricultural crop types, soil type, etc.).

L 111. "... unique natural complexes (?) of the southern lowland territories..." Please provide examples of natural complexes.

L 119. Please improve Figure 1 by including geographic coordinates (Latitude and Longitude). Label the parts of the figure as a) and b). How were the transition area and buffer zone determined?

L 124. In Figure 2, which satellite does the MODIS sensor belong to (Terra or Aqua)? What does the acronym MODIS stand for?

L 126-129. Please show the formula and reference used to calculate the EVI from the MODIS sensor. Which satellite was used to calculate EVI (Terra or Aqua)? What are the data sources for the MODIS, TM, and OLI (Landsat 5 and 8) sensors? What are the spatial, temporal, radiometric, and spectral resolutions of the MODIS, TM, and OLI sensors?

L 131-132. "Remote sensing data were obtained using the Google Earth Engine (GEE) cloud (?)..." Please provide the reference or website for GEE.

L 132. ".... which provides access to an Application Programming Interface (API) (?)." What API is this? Please provide more details.

L 133-134. "...The EVI was computed using imagery from the Landsat 8 (?) archive...." This is not represented in Figure 2. There is no arrow connecting Landsat 5, 8 to EVI. Please check this.

L 134. "The Mann–Kendall trend test (?) and Sen’s slope estimator (?) were applied to MODIS time series data (?) covering the period from 2000 to 2024." Please show the formulas for the Mann–Kendall trend test and Sen’s slope estimator and their references. Explain how the test and the estimator are interpreted. What MODIS sensor data was used? Processing level? Reflectance? Which bands? EVI? It is not clear. Please improve the explanation on this. Were the MODIS sensor images used on an annual, monthly, or daily scale? Did you use a specific MODIS sensor product? Which one?

L 135. What does the Javascript code do? Please explain.

L 136. What is the version of QGIS? What is the reference for QGIS?

L 137-138. "... both publicly available monitoring datasets (?) and classifications based on original fieldwork (?) were used..." How was the field data obtained? How was the Random Forest classification used? Please provide more details about the classification. Was the classification performed in GEE or QGIS?

L 141. "...Landsat 5 and Landsat 8 imagery (?) (for the dry seasons (?) of 1999–2000 and 2024–2025)..." How many images were used? Which months constitute the dry season? What were the meteorological conditions of the dry season for the years used?

L 144. ".... a median composite (?)..." What is this composite? What is the period? 1999-2000? or 2024-2025?

L 144. "In addition to spectral bands (?)" Which spectral bands were used? Please list them.

L 145-147. "... including EVI, NDBI (Normalized Difference Built-up Index), MNDWI (Modified Normalized Difference Water Index), and BSI (Bare Soil Index)." Please provide the equations and references for the calculated indices. How do you interpret each index? For example, what are the index values for bare soil?

L 148. "... from the ALOS AW3D30 Digital Surface Model (?)..." Please cite the reference and version for the model. Explain that the spatial resolution is 30 m. Show where ALOS should be included in Figure 2.

L 156. Include a reference for Table 1.

L 157. "... was based on prior botanical research (?)..." What research was this?

L 159. "... Using FRAGSTATS 4.3 software,..." What is the reference for this software? Please provide a flowchart with the processing steps in FRAGSTATS 4.3. Show the input variables in the FRAGSTATS 4.3 software used to calculate the landscape metrics. Define the landscape metrics: Class Area (CA), Percentage of Landscape (PLAND), Number of Patches (NP), Largest Patch Index (LPI), Edge Density (ED), Mean Patch Area, and the Mean Shape Index. How can we interpret these metrics?

L 164. "...the Index of Human Disturbance (IHD) was also calculated [27,28] ..." How is the IHD interpreted?

L 165. "Hemeroby Index Values were a..." Please show the equation used to calculate the HI.

L 167. Include the reference in Table 2. Explain what the degrees of Hemeroby are. For example, what is Ahemerobic? Oligohemerobic? Mesohemerobic? β-Euhemerobic? Polyhemerobic?

L 169. "... A 1 km × 1 km fishnet grid was generated..." Why did the authors use a 1km² grid instead of 30m x 30m?

L 170. "... ArcGIS 10.8 (?) What is the reference?

L 181. Please change the color scale in Figure 3 to be continuous. Make it like Figure 4 (line 214). Please include geographic coordinates.

L 214. Can you explain what 'statistical significance' of the EVI trend means? Is it the same as the significance level?

L 221. In Figure 5, please insert titles and units of measurement on the X and Y axes. Geographic coordinates are also missing.

L 237. In Figure 6, geographic coordinates are missing. Please label the parts of the figure as a), b), and c).

L 251. In Figure 7, geographic coordinates are missing. Please label the parts of the figure as a), b), c), and d).

L 261. In Figure 8, please insert titles and units of measurement on the X and Y axes.

L 275. Please state the unit of measurement in Table 4.

L 281. Please standardize Figure 9. Insert geographic coordinates and identify the spatial scale, which should be standardized like the other figures above. Change the legend from values to classes.

L 285. Please standardize Figure 10, which is a graph similar to Figures 5 and 8. In Figure 10, insert labels for the X and Y axes and their units of measurement. The numbers on the bars are overlapping the bars.

L 295. In Table 5, please add the units of measurement for the metrics. Provide the meaning of each metric acronym. For example: CA?, etc...

L 364. Please insert geographic coordinates. Standardize the labels A and B.

L 376-406. It would be valuable to add bibliographic references to support your claims.

L 417-433. Please insert references to support your claims.

L 488. "...of values shifted significantly (?). The coefficient of variation..." Please replace the word with a similar one, for example, severely, drastically, etc.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised version of the manuscript is significantly better than the first version. However, it still contains a number of editorial errors. I managed to spot some of them, but one suggests a thorough review of the manuscript. Below is a list of comments on the text.

Line 27. “positive EVI trend was observed” - It would be better to be more specific, such as stating whether the metrics or index increased or decreased.

Line 39-41. What specific activities do the authors suggest based on the results for those zones?

Line 66-71. Such a Russian-English mixture is not acceptable in the final version.

Figure 4. The scale for the year 2020 differs from that for 2024, so direct comparison of the maps is not possible.

Table 5. MESH explanation. Why in the explanation are there 2 patches in the squared area? What about other patches?

Line 442. “broadleaf forest communities decreased from 1,117.19 km² to 1,047.34 km²”, no such value in Table 8. There are 1,118.1 and 1,048.3 instead.

Line 444. “the area classified as mosaic tree and shrub cover (>50%) with herbaceous vegetation (<50%) decreased by more than half, from 65.7 km² to 27.1 km²”.In Table 8, there are values 65.7 and 27.2. Even such small inconsistencies are not acceptable.

Table 8. “Mosaic cropland (>50%) / natural vegetation (tree, shrub, herbaceous cover) (“. I think something is missing.

Line 457-461. In fact, Table 9 presents square km, not %.

Line 468-471. As above. And note that area of water vegetation decreased from 14.3 to 8.7 which is 39%

Line 493. Please, use the same names for land cover types in the table and in the text. Are rice fields = agricultural land? If so, use one name.

Line 596- 599. The interpretation of increasing LPI is wrong. In fact, it means that the biggest patch in the landscape merges with other patches, creating one big patch. A decrease in LPI means that the largest patch was divided into at least two smaller ones. LPI is not metric related to fragmentation. On the contrary, the increase in ED and probably NP (which is not shown in the table) indicates an increase in fragmentation for both zones, although much greater in the buffer zone than in the core zone.

Line 596. Wrong table number.

Line 596, Table 6. The LSI is not explained in Table 5.

Line 605. “(up to 8,691 ha)” Please, check the real meaning of the phrase.

Author Response

Comments 1: Line 27. “positive EVI trend was observed” - It would be better to be more specific, such as stating whether the metrics or index increased or decreased.

Response 1: Corrected. Line 27

 

Comments 2: Line 39-41. What specific activities do the authors suggest based on the results for those zones?

Response 2: Added. Lines 42-43

 

Comments 3: Line 66-71. Such a Russian-English mixture is not acceptable in the final version.

Response 3: Corrected. Lines 69, 72

 

Comments 4: Figure 4. The scale for the year 2020 differs from that for 2024, so direct comparison of the maps is not possible.

Response 4: Corrected. Figure 4.

 

Comments 5: Table 5. MESH explanation. Why in the explanation are there 2 patches in the squared area? What about other patches?

Response 5: Corrected. Table 5.

 

Comments 6: Line 442. “broadleaf forest communities decreased from 1,117.19 km² to 1,047.34 km²”, no such value in Table 8. There are 1,118.1 and 1,048.3 instead.

Response 6: Corrected. Line 444

 

Comments 7: Line 444. “the area classified as mosaic tree and shrub cover (>50%) with herbaceous vegetation (<50%) decreased by more than half, from 65.7 km² to 27.1 km²”. In Table 8, there are values 65.7 and 27.2. Even such small inconsistencies are not acceptable.

Response 7: Corrected. Line 447

 

Comments 8: Table 8. “Mosaic cropland (>50%) / natural vegetation (tree, shrub, herbaceous cover) (“. I think something is missing.

Response 8: Corrected. Line 449

 

Comments 9: Line 457-461. In fact, Table 9 presents square km, not %.

Response 9: Corrected. Line 463

 

Comments 10: Line 468-471. As above. And note that area of water vegetation decreased from 14.3 to 8.7 which is 39%

Response 10: Corrected. Line 472. Line 473

 

Comments 11: Line 493. Please, use the same names for land cover types in the table and in the text. Are rice fields = agricultural land? If so, use one name.

Response 11: Corrected. Lines 495-496

 

Comments 12: Line 596- 599. The interpretation of increasing LPI is wrong. In fact, it means that the biggest patch in the landscape merges with other patches, creating one big patch. A decrease in LPI means that the largest patch was divided into at least two smaller ones. LPI is not metric related to fragmentation. On the contrary, the increase in ED and probably NP (which is not shown in the table) indicates an increase in fragmentation for both zones, although much greater in the buffer zone than in the core zone.

Response 12: Corrected. Lines 599-601

 

Comments 13: Line 596. Wrong table number.

Response 13: Corrected. Line 574

 

Comments 14: Line 596, Table 6. The LSI is not explained in Table 5.

Response 14: Added. Table 5

 

Comments 15: Line 605. “(up to 8,691 ha)” Please, check the real meaning of the phrase.

Response 15: Corrected. Line 611

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The corrections and suggestions provided for the article entitled “Landscape Dynamics of Cat Tien National Park and the Ma Da Forest Within the Dong Nai Biosphere Reserve, Socialist Republic of Vietnam” have been thoroughly addressed, resulting in a notable improvement in both the quality and clarity of the manuscript. Therefore, I am in favor of its publication.

Author Response

We extend our sincere thanks to the Reviewer for their constructive feedback, which has led to a substantial improvement in the article’s quality.