Multitemporal Analysis of Tree Cover, Fragmentation, Connectivity, and Climate in Coastal Watersheds of Oaxaca, Mexico

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Description of the article

This research article describes a study combining remote sensing and ecology. Various ecological indices were used in the quantification of the landscape-scale changes in the vegetation cover in watersheds in Mexico.

General comments

Two climate parameters were studied and changes were shown. During the study period, there is anthropogenic climate change as well as microclimatic effects caused by the changes in forest landscape. It may be better to discuss the relative importance of these two forcings.

The description of the forest communities can be enriched. A change in forest cover may carry broad meanings. In the study, it was found that the forest cover first increased, then decreased. Other than the change in the area, the ecological functions also worth discussing.

Specific comments

Abstract

Line 18

The data source can be provided and briefly described.

Line 22 to 24

The authors can mention the periods during which vegetation connectivity showed particular improvements.

Line 24 to 26

Vegetation and climate interact with each other. Plants can modify their surrounding microclimate, e.g. evapotranspirative moisture and shading-induced cooling. Have the authors found any interactions in the watersheds?

Introduction

Line 32 to 44

It may be better to briefly describe the pressure faced by the vegetation. Natural and anthropogeneic pressure may create substantial changes in vegetation systems on a landscape scale.

Line 51 to 57

Some background knowledge is required here. It is suggested that the authors can find quantitative evidence of the effects of climate on vegetation and discuss it here.

Line 58

Maybe the term "a critical dilemma" can be removed from this sentence.

Line 69

Can an English translation of the term "ejido" be provided in brackets?

Materials and Methods

Line 85

Please provide the area size of Hydrological Region 21.

Line 85

Again, the English meaning of the location "Costa de Oaxaca" can be provided in brackets.

Line 98 to 100

In these forest ecosystems, what are the dominant vegetation species?

Line 109

In Table 1, citation should be provided for Simpson's Diversity Index (SIDI) and Probability of Connectivity Index (PCI).

Results

Line 213 to 214

The accuracy and the Kappa statistics of the models indicated a high degree of accuracy. It is worth sharing the reasons for keeping this high accuracy.

Line 231 to 232

Although the forest coverage between year 1979 to 2010 increased, decrease has been recorded in the two most recent periods. In the past, the increase was recorded over a 30-year period. However, in just 13 years, decrease was recorded. How would the authors project the future trends based on the reasons fuelling the recent changes?

Line 270 to 292

Vegetation has played a role in modifying the climate of the study location. However, the effect of anthropogeneic climate change may also modify the recorded change in climate. Maybe the authors need to acknowledge such effect.

Discussion

Line 310 to 312

There is a theory saying that some vegetation prefers a warmer environment because it can increase their photosynthetic efficiency. To what extent can this theory be applied to the Hydrological Region 21?

Line 325 to 329

Deforestation can reverse previous improvements in the forest landscape. Are there any policies arresting the rate of deforestation?

Conclusion

I have no critical comment on this section.

Author Response

Revisor 1

_____________________________ General comments____________________________

Two climate parameters were studied and changes were shown. During the study period, there is anthropogenic climate change as well as microclimatic effects caused by the changes in forest landscape. It may be better to discuss the relative importance of these two forcings.

Autor response [AR]

Thank you for this observation. We agree that both global (anthropogenic) and local (microclimatic) drivers are relevant when interpreting climate trends. However, our dataset does not include field-level microclimatic measurements. Therefore, rather than analyzing their relative contributions quantitatively, we have incorporated a new paragraph in the Limitations section (L. 464-473) to acknowledge the possible interaction between these two scales of influence. This paragraph also points to the need for future research with finer spatial and temporal resolution to disentangle the role of microclimate better.

The description of the forest communities can be enriched. A change in forest cover may carry a broad meaning. In the study, it was found that the forest cover first increased, then decreased. Other than the change in the area, the ecological functions are also worth discussing.

[AR]

We appreciate this suggestion. We agree that changes in forest cover entail not only spatial shifts but also ecological consequences. While our study primarily assessed forest cover in terms of area and structural metrics, we recognize the importance of discussing potential functional implications. To address this, we have added a paragraph in the limitations section (L. 474-483) acknowledging the constraints of our approach and the challenges associated with evaluating functional changes in forest ecosystems. Specifically, we explain that the lack of historical ecological data and limited official records on deforestation patterns in Mexico restricts the ability to assess changes in forest function over time. We also emphasize the need for future studies that integrate field-based ecological indicators to complement remote sensing analyses.

_____________________________ Specific comments____________________________

Abstract

Line 18 The data source can be provided and briefly described..

[AR]

2. 18-19 Thanks for the suggestion. In this new version, we added the data source of the image satellite that you suggested; however, due to that, in the 2.2 Section of Land use and vegetation, there is a description of this image satellite.

Line 22 to 24 The authors can mention the periods during which vegetation connectivity showed particular improvements.

[AR]

1. 22-27 We added the periods to be clearer that during the period 1979–2010, there was a slight increase in forest cover, and in the period 2010–2023, a loss of forest cover was observed. We also added that in the period evaluated, 1979-2023, the main results.

Line 24 to 26 Vegetation and climate interact with each other. Plants can modify their surrounding microclimate, e.g. evapotranspirative moisture and shading-induced cooling. Have the authors found any interactions in the watersheds?

[AR]

We appreciate the reviewer’s observation regarding potential vegetation–climate interactions. While such microclimatic feedbacks are well supported in the literature, our study was not designed to directly detect or quantify them within the watersheds. Given the landscape-scale focus of our analysis and the use of regional climatological datasets, it was not feasible to capture microclimatic feedbacks associated with vegetation dynamics. However, we acknowledge the relevance of these processes and have added a paragraph to the limitations section (L. 464-473) where we discuss the potential interplay between forest structure and local climate regulation, and emphasize the need for future studies that incorporate fine-resolution ecological and climatic data.

Introduction

Line 32 to 44 It may be better to briefly describe the pressure faced by the vegetation. Natural and anthropogeneic pressure may create substantial changes in vegetation systems on a landscape scale.

[AR]

As suggested, we enriched the Introduction by adding a paragraph (L. 48–64) that outlines the main pressures driving vegetation change. This includes both external drivers, such as climate change and land-use change, and internal drivers like population growth, tourism, and agricultural expansion. We also briefly discuss how these pressures have led to ecosystem degradation and reduced ecosystem services, while recognizing that forest recovery processes, driven by policy shifts or conservation programs, can sometimes reverse these trends. This contextual framing supports a better understanding of the landscape dynamics analyzed in the study.

Line 51 to 57 Some background knowledge is required here. It is suggested that the authors can find quantitative evidence of the effects of climate on vegetation and discuss it here.

[AR]

We added quantitative evidence (Lines 76–86) showing that both human activities and climate variability contribute to vegetation change, citing studies where anthropogenic factors accounted for up to 85% of observed changes, and climate between 38% and 64%, depending on the region. This provides a clearer context for the pressures affecting vegetation dynamics.

Line 58 Maybe the term "a critical dilemma" can be removed from this sentence.

[AR]

1. 86 We revised the sentence and removed the phrase “a critical dilemma.” to “This creates a knowledge gap”.

Line 69 Can an English translation of the term "ejido" be provided in brackets?

[AR]

1. 100-102 We have now included an explanation of the term communal and ejido in brackets to clarify its meaning for international readers.

Materials and Methods

Line 85 Please provide the area size of Hydrological Region 21.

[AR]

The area size of Hydrological Region 21 has now been added in line 122 of the revised manuscript. Additionally, the macrolocalization in Figure 1 has been updated to include the boundaries of Hydrological Region 21 to improve geographic context and visualization.

Line 85 Again, the English meaning of the location "Costa de Oaxaca" can be provided in brackets.

[AR]

Thank you for the suggestion. In the revised manuscript (L. 117-123), we now clarify that “Costa de Oaxaca” refers to a hydrological region. Additionally, we have included a brief explanation of what a hydrological region is in the context of Mexico, noting that these are delineated by the National Water Commission (CONAGUA) based on watershed boundaries and are used as planning units for water resource management.

Line 98 to 100 In these forest ecosystems, what are the dominant vegetation species?

[AR]

L.140-143 We have specified the main ecosystem types present in the study area

Line 109 In Table 1, citation should be provided for Simpson's Diversity Index (SIDI) and Probability of Connectivity Index (PC).

[AR]

We have added the corresponding references for the landscape indices in the revised manuscript

Results

Line 213 to 214. The accuracy and the Kappa statistics of the models indicated a high degree of accuracy. It is worth sharing the reasons for keeping this high accuracy.

[AR]

L.262-268 We have expanded the text in the revised manuscript to explain the reasons behind the high accuracy and Kappa values obtained. We note that this performance is mainly due to the simplicity of the classification scheme, which considered only two categories (tree cover vs. non-tree cover), thus reducing class confusion, and to the strong spectral contrast between these covers, since woody vegetation exhibits distinct reflectance patterns that facilitate discrimination in remote sensing analyses.

Line 231 to 232 Although the forest coverage between year 1979 to 2010 increased, decrease has been recorded in the two most recent periods. In the past, the increase was recorded over a 30-year period. However, in just 13 years, decrease was recorded. How would the authors project the future trends based on the reasons fuelling the recent changes?

[AR]

Projecting future forest trajectories was not part of the original objectives of our study; however, we agree that it is an important issue to acknowledge. For this reason, we have added a note in the Limitations section (L. 491-498), where we explain that anticipating such dynamics would require specific modeling approaches and the integration of socioeconomic variables to support land-use planning and decision-making.

Line 270 to 292 Vegetation has played a role in modifying the climate of the study location. However, the effect of anthropogeneic climate change may also modify the recorded change in climate. Maybe the authors need to acknowledge such effect.

[AR]

1. 342-355 In the revised manuscript, we now acknowledge that while vegetation can provide climatic benefits through processes such as carbon sequestration and microclimate regulation, these effects are not immutable. This addition clarifies that vegetation–climate interactions are highly context-dependent and vulnerable to broader climate trends.

Discussion

Line 310 to 312 There is a theory saying that some vegetation prefers a warmer environment because it can increase their photosynthetic efficiency. To what extent can this theory be applied to the Hydrological Region 21?

[AR]

This is an interesting point. Indeed, photosynthetic performance varies by plant type, as temperature is a decisive factor influenced by different mechanisms in C₃, C₄, and CAM species. However, we did not evaluate species-level physiological processes in our study, since our objectives were focused on landscape-scale forest cover and climate trends, and it would be too speculative to draw such conclusions from our data, as this was beyond the scope of the research.

Line 325 to 329 Deforestation can reverse previous improvements in the forest landscape. Are there any policies arresting the rate of deforestation?

[AR]

1. 393-399 This aspect is addressed; we describe the policies and community initiatives that have sought to mitigate deforestation in the study area. Specifically, we explain the implementation of federal programs such as Payments for Environmental Services (PES), the designation of Protected Natural Areas (PNAs), and the role of communal and ejidal governance in forest management. In addition, we highlight restoration projects with native species promoted by international foundations and local municipalities. Together, these initiatives illustrate the multi-level strategies that have been applied to contain deforestation, although their effectiveness has been uneven.

Conclusion

I have no critical comment on this section.

[AR]

Thanks for the positive comment

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The title is informative and clear.

Abstract: what does "socio-ecological" diversity mean?

Line 29: add on the annual level (after 219 mm)

Figure 1: symbol for elevation is barely visible. Change it

Line 107: tree cover refers to the layer of high trees or high trees and shrubs? What percentage of area should be covered by trees to be labeled as "tree cover". There are different definitions, so please do explain, and cite the source.

Line 115: Corona or CORINE?

Line 117: Do you have a permission/licence of using ArcMap 10.8?

Line 141: What is a source for this formula?

Line 170: Again, source/citation for the formula used.

Figure 3: with corresponding facets is hardy visible. Have you considered to create a map with the starting state (1979) and end of the analysis (2023) in terms of overlaping these two maps. So you can have these two seperately next to each other, and then the third which will show the diffrences for each of three categories analysed. If the there is an increase (of for example forest cover) these dots can be in green, if there is no change -yellow, and decrease can be in red. For each of three elements/categories, you can use different shades of green, yellow and red. The existing maps are not informative enough, in terms of detecting where the changes have occured.

Subchapter 4.2 raises many new questions and is not effectively linked with the rest of the paper.

Line 399: What are the exact socioeconomic drivers you are reffering to? Can you name them, and also mention them in the text before the discussion.

Conclusion: the conclusion is overwhelmed with exact numbers and data related to the case study area. Could make this more concise and straigtforward? Also, can you make a more general comments on fragmentation and connectivity of tree cover, especially in the tropics. 

Author Response

Revisor 2

_____________________________ Specific comments____________________________

Title

The title is informative and clear.

Autor response [AR]

            Thanks for the positive comment

Abstract

What does "socio-ecological" diversity mean?

[AR]

We agree that the term “socio-ecological diversity” may be ambiguous without further clarification. We intended highlight both the rich biodiversity of the region and the variety of human land-use practices, livelihoods, and governance systems that shape the landscape. To improve clarity, we have revised the expression to “biological and socio-economic diversity” in the abstract (L. 18).

Line 29: add on the annual level (after 219 mm)

[AR]

Thank you for the suggestion. We have added the phrase “annualy” to improve clarity and specificity.

Figure 1: symbol for elevation is barely visible. Change it

[AR]

Thank you for the observation. The symbology of elevation in Figure 1 has been improved in the revised version to ensure greater visibility and readability.

Line 107: tree cover refers to the layer of high trees or high trees and shrubs? What percentage of area should be covered by trees to be labeled as "tree cover". There are different definitions, so please do explain, and cite the source.

[AR]

1. 153-157 Thank you for the observation. We have clarified this point in the Methods section, where we specify the land use and vegetation types that were considered as tree cover and non-tree cover for the analysis, following the official classification system. This ensures consistency in the definition and interpretation of both categories.

Line 115: Corona or CORINE?

[AR]

We used Corona image, Corona satellite program  (https://cmr.earthdata.nasa.gov/search/concepts/C1220566377-USGS_LTA.html) represents one of the earliest sources of high-resolution remote sensing data, originally developed as part of the first generation of U.S. photographic intelligence satellites between 1960 and 1972. Although initially restricted to intelligence purposes, these data were later declassified and made available to the scientific community. Since then, Corona imagery has provided a unique historical baseline, allowing researchers to examine long-term environmental change, land-use and land-cover dynamics, as well as landscape transformations that predate the advent of modern Earth observation programs.

Line 117: Do you have a permission/licence of using ArcMap 10.8?

[AR]

Yes, we have A valid institutional license for the use of ArcMap 10.8 is held through the Universidad Autónoma Metropolitana, under subscription ID 8240543280

Line 141: What is a source for this formula?

[AR]

L.188 Thank you for the comment. In the revised manuscript we have added the corresponding source for this formula: Puyravaud J-P (2003) Standardizing the calculation of the annual rate of deforestation. Forest Ecology and Management 177:593–596.

Line 170: Again, source/citation for the formula used.

[AR]

1. 217 Thank you for the comment. In the revised manuscript we have added the corresponding source for this formula: Saura S, Pascual-Hortal L (2007) A new habitat availability index to integrate connectivity in landscape conser-vation planning: Comparison with existing indices and application to a case study. Landsc Urban Plan 83:91–103

Figure 3: with corresponding facets is hardy visible. Have you considered to create a map with the starting state (1979) and end of the analysis (2023) in terms of overlaping these two maps. So you can have these two seperately next to each other, and then the third which will show the diffrences for each of three categories analysed. If the there is an increase (of for example forest cover) these dots can be in green, if there is no change -yellow, and decrease can be in red. For each of three elements/categories, you can use different shades of green, yellow and red. The existing maps are not informative enough, in terms of detecting where the changes have occured.

[AR]

Thank you for this valuable suggestion. We improved Figure 3 by prioritizing the visualization of spatial changes between 1979 and 2023. We applied a color scheme (blue for increases, white for stability, and red for decreases) to highlight gains, losses, and areas without change, which makes the patterns and location of changes more evident and easier to interpret.

Subchapter 4.2 raises many new questions and is not effectively linked with the rest of the paper.

[AR]

Thank you for pointing this out. The presence of the question mark in Subchapter 4.2 (L. 36) was a drafting error. In the revised manuscript this has been corrected (L. 430), and the section has been edited to ensure consistency and clearer linkage with the rest of the paper.

Line 399: What are the exact socioeconomic drivers you are reffering to? Can you name them, and also mention them in the text before the discussion.

[AR]

1. 48-64 Thank you for the observation.We now explicitly list the socioeconomic drivers referred to in the discussion. These include population growth, economic expansion, industrial development, agricultural and livestock activities, the expansion of the agricultural frontier, and the growing demand for tourism. We also note that certain factors such as land abandonment, policy shifts, and conservation programs (e.g., PES) have contributed to processes of forest recovery.

Conclusion: the conclusion is overwhelmed with exact numbers and data related to the case study area. Could make this more concise and straigtforward? Also, can you make a more general comments on fragmentation and connectivity of tree cover, especially in the tropics. 

[AR]

L. 500-509 In the revised manuscript we have simplified the Conclusion by reducing the amount of numerical detail and presenting the findings in a more concise manner. The section now emphasizes that, although forest cover and landscape connectivity in the coastal watersheds of Oaxaca have improved over the last four decades, these gains coexist with sustained climatic deterioration, highlighting a decoupling between structural recovery and environmental 

Author Response File: Author Response.docx