Macrophyte- and Macrozoobenthic-Based Assessment in Rivers: Specificity of the Response to Combined Physico-Chemical Stressors
Round 1
Reviewer 1 Report
For detailed comments and suggested changes to the manuscript, please see the pdf file
Comments for author File: 
Comments.pdf
Author Response
Thank you very much for the constructive review. Your recommendations incorporated in the pdf file of the manuscript concerning the research objective, additional information in subsection 2.2, clarification of abbreviations were performed.
Below you can find our answers to your comments.
The research objective presented is too general. Please rephrase it into a specific research hypothesis. Readers and other researchers want to know what your research question was. This is a key question and needs to be specified.
Thank you for the valuable suggestion – the paragraph was revised.
There is not the slightest need to include this kind of information in this section of the manuscript, this kind of information should be in the acknowledgments or the funding sections.
Thank you, the paragraph was deleted.
The indicated subsection needs a thorough revision concerning the clarification of the ranges of values included in the different shading classes and flow velocity. The shading scale cannot look like this. What do the shading classes shown refer to, Secchi disc visibility or PAR light measurements? Please provide an appropriate scale of values for each class. Please provide flow velocity ranges for each class, this is crucial for the merit of the manuscript.
Following your recommendation Subsection 2.2 was revised. As stated in the manuscript these parameters were determined in a semi-quantitative way using class scales, to enable a fast and easy field application. References were added (Schaumburg et al. 2004, 2006).
The number of taxa should be given in total numbers and not as a percentage in both cases for macrophytes and macrozoobenthos.
Thank you, Figure 3 was revised.
The paragraph indicated in yellow needs to be significantly shortened (about 50%), is too descriptive, and is suitable for the section in which you discuss the result obtained rather than the results.
We shortened part of the text that concerns the presence of invasive species in our study. They will be the subject of further thematic publication.
Acronyms for all given taxon names should be explained in the figure's abbreviation so that the figure is self explanatory, otherwise it will be incomprehensible to a significant audience. Please complete the legend description in the abbreviation
Thank you, the legend of Figure 4 was completed and described. A supplementary material was attached.
Please explain what HMWB abbreviation means
Heavily modified water bodies – written in full in the caption of Figure 1, then used abbreviation.
Reviewer 2 Report
Review
Paper title: Macrophyte- and macrozoobenthic-based assessment in rivers: specificity of response to combined physico-chemical stressors
The authors conducted an analysis of a data set containing information about benthic assemblages in Bulgarian rivers to relate this data to biotic and abiotic characteristics. They found that altitude was the most important factor for macrophytes and macrozoobenthos. Richness of aquatic flora positively correlated with nitrogen enrichment, while macroinvertebrates with shading and biochemical oxygen demand. Ecological status was associated with total nitrogen, phosphorous, and oxygen contents. Some revisions are required to improve the data representation and interpretation of the results.
All these reasons explain the relevance of the paper by Emilia Varadinova and co-authors submitted to "Water".
General scores.
The data presented by the authors are original and significant. The study is correctly designed and the authors used appropriate sampling methods. In general, statistical analyses are performed with good technical standards. The authors conducted careful work that may attract the attention of a wide range of specialists focused on freshwater benthic ecology.
Recommendations.
The authors cited supplementary materials but these are missing.
The authors should provide criteria for each river type. How can different river types be distinguished?
The authors cited two papers published in Bulgarian when describing the biological indices used. These papers are not available to most readers. For this reason, the authors must provide a detailed description of these indices including formulas and definitions. The same is relevant for the “ecological status”.
The authors should provide reasons for their selection of statistical methods. Why did they use RDA for species richness of macrophyte and macroinvertebrate communities and abiotic parameters and physico-chemical stressors and CCA for macrophyte species and macrozoobenthic groups and environmental factors?
Figure 2 caption. All abbreviations should be defined.
Figure 2 is of very low resolution; the font size is too small.
Figure 4 is difficult to understand because there are no explanations of abbreviations used.
The authors should explain why water temperature was not included in the analysis. They should discuss more the role of this factor in shaping the structure of benthic communities.
The discussion should be updated by relevant citations, preferably recent.
Review
Paper title: Macrophyte- and macrozoobenthic-based assessment in rivers: specificity of response to combined physico-chemical stressors
The authors conducted an analysis of a data set containing information about benthic assemblages in Bulgarian rivers to relate this data to biotic and abiotic characteristics. They found that altitude was the most important factor for macrophytes and macrozoobenthos. Richness of aquatic flora positively correlated with nitrogen enrichment, while macroinvertebrates with shading and biochemical oxygen demand. Ecological status was associated with total nitrogen, phosphorous, and oxygen contents. Some revisions are required to improve the data representation and interpretation of the results.
All these reasons explain the relevance of the paper by Emilia Varadinova and co-authors submitted to "Water".
General scores.
The data presented by the authors are original and significant. The study is correctly designed and the authors used appropriate sampling methods. In general, statistical analyses are performed with good technical standards. The authors conducted careful work that may attract the attention of a wide range of specialists focused on freshwater benthic ecology.
Recommendations.
The authors cited supplementary materials but these are missing.
The authors should provide criteria for each river type. How can different river types be distinguished?
The authors cited two papers published in Bulgarian when describing the biological indices used. These papers are not available to most readers. For this reason, the authors must provide a detailed description of these indices including formulas and definitions. The same is relevant for the “ecological status”.
The authors should provide reasons for their selection of statistical methods. Why did they use RDA for species richness of macrophyte and macroinvertebrate communities and abiotic parameters and physico-chemical stressors and CCA for macrophyte species and macrozoobenthic groups and environmental factors?
Figure 2 caption. All abbreviations should be defined.
Figure 2 is of very low resolution; the font size is too small.
Figure 4 is difficult to understand because there are no explanations of abbreviations used.
The authors should explain why water temperature was not included in the analysis. They should discuss more the role of this factor in shaping the structure of benthic communities.
The discussion should be updated by relevant citations, preferably recent.
Author Response
We would like to thank Reviewer 2 for the positive attitude and evaluation of the manuscript. Many thanks especially for the opinion that the presented manuscript may attract the attention of a wide range of specialists focused on freshwater ecology. Below you can find our answers to your questions and suggestions.
Reviewer 2
The authors conducted an analysis of a data set containing information about benthic assemblages in Bulgarian rivers to relate this data to biotic and abiotic characteristics. They found that altitude was the most important factor for macrophytes and macrozoobenthos. Richness of aquatic flora positively correlated with nitrogen enrichment, while macroinvertebrates with shading and biochemical oxygen demand. Ecological status was associated with total nitrogen, phosphorous, and oxygen contents. Some revisions are required to improve the data representation and interpretation of the results. All these reasons explain the relevance of the paper by Emilia Varadinova and co-authors submitted to "Water".
General scores. The data presented by the authors are original and significant. The study is correctly designed and the authors used appropriate sampling methods. In general, statistical analyses are performed with good technical standards. The authors conducted careful work that may attract the attention of a wide range of specialists focused on freshwater benthic ecology.
Recommendations.
The authors cited supplementary materials but these are missing.
We apologize for the inconsistency and technical mistake. Supplementary material is now attached.
The authors should provide criteria for each river type. How can different river types be distinguished?
Thanks to your comment a reference for the national river types was included: Chesmedjiev et al. (2010).
The authors cited two papers published in Bulgarian when describing the biological indices used. These papers are not available to most readers. For this reason, the authors must provide a detailed description of these indices including formulas and definitions. The same is relevant for the “ecological status”.
Thank you. We have provided formulas and descriptions for the applied indices and appropriate literature (page 6 of the manuscript).
The authors should provide reasons for their selection of statistical methods. Why did they use RDA for species richness of macrophyte and macroinvertebrate communities and abiotic parameters and physico-chemical stressors and CCA for macrophyte species and macrozoobenthic groups and environmental factors?
Thank you - We applied Detrended Correspondence Analysis (DCA), using the option “detrending-by-segment”, which allowed the gradient length of species variance along orthogonal axes to be quantified in terms of standard deviation units. Response data are compositional and have a gradient 0.6 SD for number of taxa and 0.7 SD for EQR units long. Therefore, we used linear direct analysis, suggesting modest unimodality according ter Braak & Šmilauer (2002). Both RDA and CCA were applied as direct gradient analyses. RDA was selected to test species richness in relation to abiotic parameters and stressors based on its linear response, while CCA as unimodal with the aim to explain the variation in the species composition in relation to environmental factors.
Figure 2 caption. All abbreviations should be defined.
Thank you, the legend of Figure 2 was defined.
Figure 2 is of very low resolution; the font size is too small.
Thank you, we sent separate file Figure 2.jpeg with appropriate resolution according to the journal requirements.
Figure 4 is difficult to understand because there are no explanations of abbreviations used.
Thank you, the legend of the Figure 4 was added with missing abbreviations. Supplementary material was attached.
The authors should explain why water temperature was not included in the analysis. They should discuss more the role of this factor in shaping the structure of benthic communities.
Undoubtedly, water temperature is an important factor for structuring macrozoobenthos communities. In the present study, one-time values of water temperature were measured, which are highly variable in a very short time. Therefore, we did not use the values of this factor in our analyses.
The discussion should be updated by relevant citations, preferably recent.
We have used 17 titles in the discussion, citing articles published from 2006 to the present. Of these, 9 citations are from articles published in the period 2017-2022. We added another recent reference (please see 35 of Reference).
Round 2
Reviewer 1 Report
Dear Authors,
Thank you for incorporating the improvement suggestions I indicated into the manuscript. The current version of the manuscript is much better than the previous one. I appreciate the work you have done to improve the thesis and its structure. Your research brings an extremely important aspect to research, biomonitoring and assessment of ecological status of rivers based on indices based on biological methods mainly macrophytes and macroinvertebrates.
I therefore ask you to consider the comments below.
I think that your work deserves to be published in an international scientific journal such as WATER. Your work, after applying minor changes, deserves to be published, therefore I suggest a minor revison of the manuscript.
I therefore ask you to consider the comments below.
The quality of figure number 3 is insufficient suggests splitting sections a and b into two separate figures number 3 and 4 to increase the quality and size of the figures. The font in the figures needs to be larger and more readable. Please apply my suggestions.
As with the first review of the manuscript, I do not have access to the supplementary materials, and am thus unable to verify their merit. The link to the materials provided does not work. Please ensure that the supplementary materials are available for review.
I suggest that the manuscript should be linguistically proofread by a native speaker or proofreading company. This will increase the fluency and quality of the manuscript.
Congratulations on a job well done and interesting research.
Best regards,
Reviewer
I suggest that the manuscript should be linguistically proofread by a native speaker or proofreading company. This will increase the fluency and quality of the manuscript.
Author Response
We very much appreciate the time and effort you have put into your helpful comments. Your inputs given definitely helped to improve our manuscript. Below you can find our answers to your suggestions.
The quality of figure number 3 is insufficient suggests splitting sections a and b into two separate figures number 3 and 4 to increase the quality and size of the figures. The font in the figures needs to be larger and more readable. Please apply my suggestions.
Thank you – Figure 3 (3a and 3b) was separated into Figure 3 and 4, as well as the font was increased.
As with the first review of the manuscript, I do not have access to the supplementary materials, and am thus unable to verify their merit. The link to the materials provided does not work. Please ensure that the supplementary materials are available for review.
We apologize for the lack of access to the supplementary material. It was uploaded in the first revision, we are now re-applying it in the hope that it is available.
I suggest that the manuscript should be linguistically proofread by a native speaker or proofreading company. This will increase the fluency and quality of the manuscript.
Thank you –English language and grammar were revised and we hope that these issues were solved.
Reviewer 2 Report
Second review.
The authors have considered my comments and revised the text accordingly.
Please, increase the size and font of Figure 3.
P. 7. Section 3.2. Provide the units for macrophyte abundance
Some linguistic revisions are still required.
For example:
P1. “Long-term studies provides” should be “Long-term studies provide”
P 2. “Anthropogenic stressors, like” should be “Anthropogenic stressors such as”
P 8. “The most individuals were found at site 9” should be “Most individuals were found at site 9”
P 8. “Least abundance was” should be “The lowest abundance was”
P 9. “(P= 0.01), with contribution of” should be “(P= 0.01), with contributions of”
P 12. The gradient was most strongly related with” should be The gradient was most strongly related to”
P 13. “Anthropogenic transformations of a riverbed” should be “Anthropogenic transformations of the riverbed”
Some revisions are required.
Author Response
We would like to thank again Reviewer 2 for the careful reading, thanks to which the manuscript was improved. Below you can find our answers to your questions and suggestions.
Please, increase the size and font of Figure 3.
Following the recommendation of Reviewer 1, Figure 3 (a and b) was separated into Figure 3 and 4, as well as the font was increased.
- 7. Section 3.2. Provide the units for macrophyte abundance
Thank you – the commonly used DAFOR scale (Dominant, Abundant, Frequent, Occasional, Rare) was added.
Some linguistic revisions are still required.
Thank you for your helpful recommendations – all were implemented.
