The Urgent Need for River Health Biomonitoring Tools for Large Tropical Rivers in Developing Countries: Preliminary Development of a River Health Monitoring Tool for Myanmar Rivers

Round 1

Reviewer 1 Report

This manuscript addresses a topic of global importance in trying to determine the ecological health of rivers in Myanmar, South East Asia, a country where no biomonitoring tools currently exist for this purpose. The authors aim to assess which international ecological health indicators are best appropriate for Myanmar and adapt a new national index based on this information. The manuscript is broadly well written and the analyses seem appropriate given the limitations of the dataset (see below).

However, I feel the underpinning dataset is far too limited to reliably extrapolate the results and provide a comprehensive appraisals of these metrics. There are only 18 samples to interpret the data from in total, with 3 replicates per site/sampling period, which are naturally going to be highly ecologically comparable. The sampling occasions are also very close together meaning there is likely strong temporal autocorrelation in the dataset which cannot be accounted for statistically due to the size of the dataset.

The authors also chose to select sites primarily unimpacted by anthropogenic activities or ‘reference’ sites. This is a valuable step when testing or adapting ecological metrics, but the authors do not compare this against impacted sites to see whether ecological health values decline accordingly with human pressures. Therefore, I am sorry to say that I think a much more detailed dataset would be required to achieve reliable results for this topic.

Author Response

Dear Reviewer

We thank the reviewer for the nice words and the important feedback. Please see the attached document for our response.

 

Kind regards

Nyein Thandar Ko

 

Author Response File: Author Response.pdf

Reviewer 2 Report

The ms aims to evaluate three macroinvertebrate bioassessment methods to find the most suited one for the Myanmar context. The Authors compared three methods, the miniSASS (mini Stream Assessment Scoring System) developed in South Africa, The Asia Foundation method (Mongolia and Lao PDR) and The Australian Waterwatch. Unfortunately, the three methods are not explained in the text, and the web pages do not present quick information. According to the Authors, the methods are similar, because they score the macroinvertebrate families in relation to their sensitivity to pollution. To assess the three methods, they sampled 3 sites in upstream sections where the anthropogenic pressures are supposed to be low. Unfortunately, no chemical data are available to support this condition. They applied the three indexes and compared the results applying several numerical methods which need further clarification. The conclusion was that the Asia foundation was the best with several modifications to fit the Myanmar condition.

Although the ms needs major revision to document more clearly the methods, I like it essentially because the Authors decided to submit the work to a peer-reviewed journal to endorse the method they selected. Probably in many other instances, this preliminary work would be used only to compile a report for some environmental Agencies. The Authors did more, and I appreciate the effort.

I have several suggestions to improve the ms, or perhaps the work if it will be improved.

Line 101: to test the 3 methods both impacted and natural river stretches should have been selected.

Line 136: Add more details to understand how the 3 methods work

Line 153-165: it is not clear how the 3 indexes were assembled in the resemblance matrix. By applying the index to each sampling, a score was obtained, and then? What is the aim of ANOSIM? To test the difference among the rivers? Why?

Line 167: to find out which method is appropriate, the BEST routine of the Primer software was used. Please add a few general details about this analysis for people who are not users of this software. Probably it is like a Mantel test, as two matrices were used. The first one is the biota, but the second one is unclear.

Line 171: I suppose that the meaning of “the environmental Euclidean distance matrix” is the indexes distance matrixes, or nor? Very obscure.

Table 2: Is the abundance of each taxon the sum across stations and occasions in the river? Or something else?

Figure 2: Are the 3 indexes comparable? Fair class is different among indexes, so the bar plot is misleading. I think you should show 3 boxplots and univariate analysis (ANOVA) to test for differences among the 3 indexes (if comparable in numerical terms).

Figure 3 left: what data are used to calculate the resemblance matrix? The index score or the biota? ANOSIM (right) shows no differences but the vertical bar (observed metric) is missed.

Line 229: not clear how the 3 indexes were ranked. Where is this result?

Figure 4: why the correlation coefficients are negative if the relationships look positive in all the plots?

234: why the Asia Foundation Index was finally selected? What are the results that support this statement?

246: to derive sensitivity scores of taxa that are not present in the Asian index, the SIGNAL 2 was used. What is SIGNAL 2? How does it work?

Table 3: Not clear what “species” means in this table. Should it be index?

Author Response

Dear Reviewer

We thank the reviewer for the nice words and the important feedback. Please see the attached document for our response.

 

Kind regards

Nyein Thandar Ko

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors,

here some questions and comments:

In 2.1.: How did you exactly take the samples? How big was the sampled surface? From my point of view, the number of sampling sites is relatively low and critical for advanced statistics.

In 2.4: It is difficult and problematic to estimate organisms with keys from other watersheds resp. other parts of the continent. That appoach could lower the expressiveness.

In 3.2: What taxonomic groups did you estimate to species level? Table 2 only contains levels to gensu or family.

I wonder about the very low number of species and individuals in some of the samples although that are all natural rivers.

In 4: From my point of view, your results do not allow the preference for the Asia Foundation Method. For such a suggestion, the database is to small.

Best regards

 

Your reviewer

Author Response

Dear Reviewer

We thank the reviewer for the nice words and the important feedback. Please see the attached document for our response.

 

Kind regards

Nyein Thandar Ko

Author Response File: Author Response.pdf

Reviewer 4 Report

Please see attached file.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer

We thank the reviewer for the nice words and the important feedback. Please see the attached document for our response.

 

Kind regards

Nyein Thandar Ko

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Please refer to the document attached.

Comments for author File: Comments.pdf

Author Response

Thank you so much for your meaningful feedback on our paper. We are pleased we have been able to improve our explanation on the final choice for the Asia Foundation method and that the reviewer agrees on our sound basis and statistical analysis. Furthermore, the reviewer emphasizes the limitations of our dataset. We do agree with the reviewer, and we acknowledge that in our paper explicitly (see, for example, the last sentence of abstract and last two paragraphs of the paper). At the same time, we are confident that the current analysis shows the potential for biomonitoring in Myanmar. We do not claim it is the final national scale biomonitoring index, but we do say it is an important step towards this goal. Open access publication of our data, analysis and findings will spark further work on biomonitoring in Myanmar.

Sincerely,

Nyein Thandar Ko

PhD student

Delft University of Technology

The Netherlands

Author Response File: Author Response.pdf

Reviewer 2 Report

Review of the ms entitled “The urgent need for river health biomonitoring tools…” by Nyein Thandar Ko et al.

I read the ms and the supplementary materials where most of my previous questions are now answered. I’m satisfied with the clarifications provided by the Authors, now the ms describes adequately the methods and results. The two methods, Asia Foundation and The Australian Waterwatch give very similar results and both seem suitable as biomonitoring tool. However, the argumentations provided by the Authors to support the use of the Asian Foundations are fully acceptable.

Author Response

On behalf of my co-authors and me, thank you and all reviewers for this high-quality reviews and constructive suggestions. We are pleased we have been able to improve our explanation on the final choice for the Asia Foundation method.

Sincerely,

Nyein Thandar Ko

PhD student

Delft University of Technology

The Netherlands

Reviewer 3 Report

Dear authors,

thank you for the improvements! I think your contribution is ready for publication now.

 

Yours sincerely

 

Your reviewer

Author Response

On behalf of my co-authors and me, thank you and all reviewers for this high-quality reviews and constructive suggestions. We are pleased we have been able to improve our explanation on the final choice for the Asia Foundation method.

Sincerely,

Nyein Thandar Ko

PhD student

Delft University of Technology

The Netherlands

Reviewer 4 Report

I don't have time immediately for a thorough re-review; however, the revisions seem to adequately address my comments and I have no issues with publication at this point.

Author Response

On behalf of my co-authors and me, thank you and all reviewers for this high-quality reviews and constructive suggestions. We are pleased we have been able to improve our explanation on the final choice for the Asia Foundation method.

Sincerely,

Nyein Thandar Ko

PhD student

Delft University of Technology

The Netherlands