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I am satisfied with the changes that you have made to the text and am proposing that the manuscript be accepted for publication in PeerJ. Thank you for your contribution.
[# PeerJ Staff Note - this decision was reviewed and approved by Xavier Pochon, a PeerJ Section Editor covering this Section #]
I have received comments back on your resubmission and a number of minor adjustments need to be taken into account.
Please note the comments of the reviewer about making changes that were not included in the response letter. For this round, please ensure that you take all of the comments into consideration and include them in a new version of the manuscript and in your response letter.
The manuscript evaluates the response of coral communities in southwestern Madagascar (Mahafaly seascape) to the fourth global mass coral bleaching event in 2024. The topic is highly relevant and timely, and the manuscript has considerably improved from the previous version, enhancing the overall quality of the article.
The abstract is much better structured, and the authors made effective use of the word limit allowed by PeerJ. The Material and Methods section is now much clearer, although one statistical test mentioned in the Results is not described here. The Results remain somewhat verbose but are now more fluid, and the authors have done a fine job polishing the Discussion.
A final note is that, although I noticed some changes in the manuscript in line with my previous review, the authors did not include the alterations performed based on my suggestions in the rebuttal letter. As a result, I had to re-review the entire paper to check whether my earlier suggestions had been incorporated, which required considerable time. In the future, I strongly encourage the authors to address all the suggestions by all the reviewers in the future rebuttal/response letter.
Given the improvement in this revised version, I now recommend that the manuscript be accepted for publication in PeerJ. I only have a few minor suggestions that the authors can see below.
Minor comments:
L1-3: I personally do not like overly extensive titles. I suggest that the authors either remove the initial sentence before the ‘:’ or highlight the reefs as potential refugia. For example, the title could be something like “Reefs of the Mahafaly Seascape, SW Madagascar, as potential climate refugia following the 2024 global coral bleaching event”.
L19-46: The abstract must be only one paragraph.
L22: Marine heatwaves are only one of the causes of coral bleaching and are not the main reason that caused the bleaching you are reporting here. Please rewrite.
L35-38: I do not see the relevance of the sites' names in this context, as most readers are not familiar with the sites in Madagascar. The main information is the difference between the north and south sites. Please remove the names of the sites here and focus on the north/south differences.
L39-40: If the reason these species are more sensitive is due to their morphology, please make it clear, as you are comparing them to other types of coral forms.
L48-49: Keywords must be different from those present in the title, and three of the seven presented are in both of them.
L66: Remove the ellipsis and add at least another example, please.
L81: Add ‘the’ before ‘global’.
L85: Cyanobacteria, without the ‘l’
L94: Exhibit, without ‘s’.
L98: This is instead of ‘these are’ and ‘changes’ in the plural.
L90-93: This sentence is not clear. Please rephrase it.
L117: Remove the point before the references.
L127: Change to ‘This study aims…’
L152: Please change to ‘who focus…’
L164: Remove the comma after corals and Millepora.
L166: Remove the comma after stations.
L168: Add ‘of’ after depth.
L172-178: I understood that the severity categories were based on the work mentioned, but the codes C1-C6 are from the Coral Health Chart or from McClanahan 2004? If it is from the CHC, it needs to be explained in the sampling text.
L183: Add a comma after ‘category’.
L199: Change less to fewer.
L221: Remove the point after Ambohibola.
L224: There is an extra point.
L228: Thermal stress should not be capitalized.
L229: Add ‘the’ before interpretation.
L231: Add ‘the’ before corrected.
L263: Change both ‘to’ to ‘and’.
L276-277: The authors did not mention the chi-square test in the materials and methods
L281-282: See comment above. Also, is it the strongest or a stronger? Additionally, add ‘the’ before health.
L284: Table 3 does not follow a clear order. Please put the table in a sequence that makes sense. It could be by alphabetical order, from the genus with the largest abundance, or the worst BRI.
L292: Add ‘the’ before thermal.
L375: Remove the ellipsis.
L387: Change to also shown.
L397: Change to “the reef sites’ responses…”
L406: Comma before both.
L407 and L414: Pacific should be capitalized.
L421: Increase ‘in’ severity.
L442: Fish not fishes.
L448-451: Please add references that both discuss the pros and cons of this approach to restore reefs and add a couple of sentences on these positive and negative sides.
L450: “Like those in Itampolo…”
L463: ‘of reef habitats’.
L481: Relatively, not relative.
L483: ‘for recovery’.
no comment
no comment
I have received comments back on your revised manuscript from one reviewer. I am in complete agreement with the reviewer that DHW must be included in the analysis and not just added as an appendix. Also please ensure you either follow the suggestion to not use logged data in the ANOVA or provide a compelling reason as to to why.
ok
ok
ok
It's not often that I push back on a response to referees but I'm afraid I'm going to here. I mentioned twice that DHW needs to be included in the analysis but the authors have simply added the data in an appendix so that someone else could do it. I didn't find the rationale for not doing it compelling.
My other commment about how to approach the analysis and not use logged data with ANOVA was accepted but not carried out. This isn't really adequate. There's no good reason not to do this.
So much as though I still like this paper, I feel the authors really ought to implement the recommendations or provide a more compelling reason why they cannot. This is particularly relevant for the use of DHW.
Two expert reviewers have evaluated your manuscript and their comments can be seen below. The data set is useful and relevant given the mass bleaching event occurring globally.
However, as you can see there are many important suggestions that have been made by both reviewers to improve the manuscript. Please pay particular attention to the comments about the methods made by both reviewers. This will potentially affect the results, discussion and conclusions.
As you prepare your revised manuscript, please ensure that you attend to all of the comments by the reviewers and that you clearly indicate where you have made the modificaitons related to each comment. This will ensure that the process of evaluation of the revised version is efficient.
**PeerJ Staff Note:** Please ensure that all review, editorial, and staff comments are addressed in a response letter and that any edits or clarifications mentioned in the letter are also inserted into the revised manuscript where appropriate.
The manuscript evaluates the response of coral communities in southwestern Madagascar (Mahafaly seascape) to the fourth global mass coral bleaching event in 2024. This is a highly relevant and timely topic, and the manuscript is generally well-structured and written, aside from a few grammatical issues that need attention. However, a critical detail in the Methods section raises concerns that could potentially affect the analysis, results, and conclusions of the study.
The Abstract is underdeveloped and needs to be rewritten. The authors provide little to no context for their study and fail to describe the methodology used to reach their conclusions. PeerJ allows up to 500 words for the abstract, yet the current version contains only 187. The authors should take advantage of this limit to produce a more complete, informative abstract that includes the background, objectives, methodology, main findings, and implications of the study. The Introduction is well-structured and informative, though slightly long.
The Methods section needs the most attention. The description of the indices used is unclear and potentially inaccurate. The main concern is that, when describing one of the indexes used in the study, the formula presented differs from the original, in which the authors divide by six instead of five, as in McClanahan (2004). This discrepancy is not explained. If it was miswritten, it can be easily corrected; however, if the authors applied a miscalculated formula throughout their analysis, the data must be reanalyzed, and all related figures and interpretations revised.
Additionally, the sections lack an explanation of how the sites were chosen. It is unclear whether the sites are similar in key ecological and environmental aspects or if they represent a gradient of conditions and human use. Consequently, because they were treated individually in the results and discussion, it seems that they are completely different, which is not clear. The only factor mentioned in the Discussion is the distance of all reefs to a city (Toliara), which, according to the authors, “reduces anthropogenic influences […] compared to reefs that are closer”, but no other characteristics are described.
The Results are dense and primarily descriptive. The authors focus heavily on comparisons between sites, but without adequately introducing the particularities of those sites in the Methods, these comparisons become difficult to interpret. The Discussion is extremely long, while being redundant in some parts but discussing aspects not pertaining directly to the results obtained. Therefore, it would benefit from a reduction.
Given the comments and the suggestions below, I cannot recommend the manuscript for publication in its current form. However, I believe the study could represent a valuable contribution to the understanding of the impact of the fourth mass bleaching event. I hope the authors view these comments and suggestions as an opportunity to enhance their work, allowing a revised version to meet the standards for publication in PeerJ.
no comment
no comment
Minor comments
L1-2: Please add a reference to Madagascar in the title as not all readers are familiar with the Mahafaly seascape.
L20-34: Since PeerJ accepts up to 500 words, I believe the authors could improve the abstract. First, contextualize your research before presenting your goal. The methods applied were not mentioned. As mentioned in the title, the readers are not necessarily familiar with Madagascar. Instead of just giving the name of the sites, describe them: are the “select sites” closer to the coast, or closer to urban areas? In the next sentence, the authors grouped the species in categories (e.g. thermally sensitive taxa) so the same must be done to the sites. Also, change 4th to fourth.
L30–32: Speculative statements not supported by data should be removed.
L36: “Mahafaly seascape” is already in the title. Change for another keyword such as “climate change”.
L43: Not entirely true, as reef ecosystems can also include other biogenic reefs and rocky and artificial reefs. Rephrase considering that or make it clear you are talking about coral reefs, not all reef ecosystems.
L45-47: All organisms (humans included) are exposed to environmental change. Please rephrase for clarity.
L51: Coral bleaching is not a “physiological stress” itself. While ocean warming is, the bleaching is a response to it.
L51-53: Replace “zooxanthellae” with Symbiodiniaceae and rephrase to acknowledge that organisms other than cnidarians can bleach.
L54: Please check this information as I did not find this value (i.e. up to 95%) in the article cited and correct the term “supply” to “supplies”
L57-59: Please add a supporting reference for this affirmation.
L63: This information is incorrect as the World Meteorological Organization (WMO) has pointed out that 2024 is the warmest year on record, based on the datasets of several agencies worldwide.
L65: Remove “predicting”.
L71: Use plural (“events”).
L78-79: What does “weedy” mean in this context? Is this an adjective describing corals? Please clarify.
L80-81: Rewrite this sentence as it is confusing.
L83: Remove the unnecessary “that”.
L102: As the focus is on the fourth global bleaching event, refer to bleaching events by order (e.g., third global event) instead of year ranges.
L109: Clarify what is meant by “managed” Is a “managed” area a type of protected area? If so, no work has ever assessed bleaching with protected areas in Madagascar? But make it clear if you are talking about LMMAs, as mentioned in L113, or other managed areas.
L129: Please add the shape of the Tsimanampesotse - Nosy Ve - Androka Biosphere Reserve also to figures 1A-B and a “Madagascar” label to the right panel.
L137-139: Rewrite as the use of the verb is incorrect.
L139: Add the full name before the abbreviation as this is the first time mentioning LMMA.
L150: The correct is “design”.
L153: Change “including” for “and” as the phrasing makes it look like Millepora is also a scleractinian coral.
L156: Remove “the”.
L57: “At” each site.
L162: Make the red square a little darker or use only a solid border to ease the visualization.
L178-186: Please better describe the equation, explaining the categories and what are the numbers before each category (are they weights to each category?). See the example in the article cited (McClanahan 2004). Why use a different name (i.e. Bleaching Response Index versus Bleaching Index by the original author)? Did the authors mean to reference Szereday et al. (2024) instead? Additionally, explain why divide by 6 and not by 5 as both indexes did. If the formula was the same from any of the two articles, either the equation (which I hope is the case) or all the results (and consequently their interpretation, if divided by 6) are incorrect. Also, why summing all the data for all the species but not showing for each species as both articles cited did? The authors are aware that minority (or dominant) taxa can impact the results of those indexes (L193-194)
L185: Please present the BRI to each species/genus, maybe as supplementary material, so the data can be comparable in the future. See McClanahan (2004) figure 3.
L186-194: The reference to the BSI is missing (or misplaced).
L207: Add information if it is a 3-way ANOVA or other type of ANOVA.
L211: ‘Taken’ instead of “taking”.
L212: “Tukey’s” instead of “Tukey”.
L213: Paid “to” not “for”.
L219: The correct name is Student's t-test
L231: The “any” is misplaced and the sentence does not make sense. Please rewrite.
L238: So, the authors did have the data for each group. This is not clear in the methods as I mentioned before. Please consider creating a figure with the data of Table 3 as it will ease the interpretations for the reader. The same is valid for Table 4, in which “colonies” is miswritten and only the word “Reef” in the first column should be capitalized.
L241: Use “remained” instead of “remain”.
L249: Change “by” to “from” and rewrite it as “during the event”.
L254: Did the authors mean “no difference”?
L264: The correct word is “concerning”.
L287-289: This sentence is redundant as states the same as the previous one. Please remove.
L291-292: If the authors are referencing “several studies”, please cite those studies, not just one.
L293: Since this is a new section, add the full name before presenting an abbreviation (i.e. SWIO).
L296-299: I am assuming that the genera described are more resistant to bleaching but it should be made clear by the authors so the reader can understand if the pattern is constated (or contrasted) by the results. Also, if the results support this, change the word constated to “corroborated” or other similar, to avoid confusion.
L304: Use plural “events”.
L307-309: This is the type of information I expected to see in L296-299. Consider presenting this information previously.
L315-319: If the authors did not investigate or do not have information on the symbionts of the species studied in the area, this sentence is not relevant and should be removed.
L332: Define LMMA on first use in each section.
L340-346: The authors could group the information based on events as the descriptions are too long.
L351-354: Add citation for this information.
L362: Change “reefs that are closer” to “closer reefs”.
L396: Use either “another region” or “other regions”
Figures and tables legend: Add information regarding Madagascar to each one of the legends as they need to be extremely descriptive and not all readers are familiar with the Mahafaly seascape or the sites sampled. Also, do not use abbreviations without describing them (e.g. LMMA in Table 1 legend).
OK
OK
ok
I think this is a useful dataset as we need to know about minor as well as major bleaching events. My comments are intended to help the authors extract greater value from the study and increase it's usefulness globally as well as locally.
1. It's really important to include a measure of max thermal stress at each site. Please use DHW. That way the results can be compared to other locations - see NOAA website and extract the relevant data
2. Some of your results are given with too much precision. For example only give a % to 1 decimal place maximum.
3. The use of log transform is not really ideal these days. It will strongly limit the variability in your data and reduce your power of detection of trends. I would urge you to choose a different approach, such as using a glmer with binomial distributions and sites as random effects. Moreover, for the assessment of sensitivity of genera (or groupings of genera) you could treat location as a nested random effect also. Include DHW as a predictor. The package glmmTMB handles all this in R. You convert your cover or percentage data to integers between 0-100 to run such analyses.
4. I'd like to see a more explicit attempt to relate the BRI to DHW across sites.
5. I would be careful inferring that management doesn't have much impact on bleaching responses. Many of the previous studies looking for an effect of MPAs on bleaching are unable to resolve this question (see Mumby et al 2021 Conservation Letters). Having said that, the main effect of MPAs would be in supporting reef recovery and your data don't have enough time post-disturbance to quantify that (and there wasn't much mortality anyway).
6. Careful also in your introduction. Yes phase shifts are common after bleaching but not necessarily to macroalgae - this is very region specific. See Roff and Mumby 2012 TREE for more discussion on that.
Good luck, it's a valuable dataset.
Peter Mumby
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