A General-Purpose Biotic Index to Measure Changes in Benthic Habitat Quality across Several Pressure Gradients

Round 1

Reviewer 1 Report

Translator      

 

Translator      

The ms is well written and clear. I add only some suggestion in the .pdf notes.

As outilned by the authors the proposed index is a new benthic index, to add to the others. I can suggest to the Authors to outline if there is the possibility to use it also in other seas and environments.

Again, seeing the great work done on all the stations proposed, my questions for using the proposed index ( and also the others) are:

Is/are the indexes suitable for a 'rapid' applications? In other word all the sampling time  and time used to analyse samples are suitable for a 'rapid' assessment of a dumping/dredging impact? The state of environment health or community impact is the ultimate response that a stakeholder has to know to start, stop or to mitigate the impact.

The Athors mentions the EU Framework directive and the Water Directive. There is also the Habitat Directive specially devoted to benthos. The above cited directives have also the target to give the stakeholder simple elements to judge the habitat health. To achieve this target the environment health is normally expressed through 5 scores/colors. I ask to the authors if it is possible to prepare a table showing a score/color comparison of the three compared methods/indexes.

All the above considerations comes from personal experience and general view about environment studies in the last 40 years. My personal view is todays,  all the impacts on the sea bottoms and sea communities should be avoided. Moreover, when impacts are known to destroy a community of great value, as in the case of maerl, coralligenous, seagrasses, corals etc the impact shoud be stopped. Todays, there are no reasons to continue absurde exploitations and sea-bottom desertifications, and science have the responsability to counteract these  impacts. The time to pay studies to Universities and Public and private bodies to mitigate with money the well-known damages to sensible marine communities is finished.

 

 

 

 

 

 

 

 

 

 

 

Comments for author File: Comments.pdf

Author Response

You can find attached our answers (in blue and italic) to the comments of the two reviewers. In order to help follow the revisions, I also join a word document using the Tracks changes tools as well as a clean version of the manuscript.

As you will see almost all the suggestions of the reviewers have been taken into account and it has been justified when it was not possible.

We hope that you will be satisfied with these changes, and I remain at your disposal should further information be needed.

Best regards

Céline Labrune, Olivier Gauthier, Anxo Conde, Jacques Grall, Mats Blomqvist, Guillaume Bernard, Régis Gallon, Jennifer Dannheim, Gert, Van Hoey and Antoine Grémare

Author Response File: Author Response.pdf

Reviewer 2 Report

This MS proposes an index based on the deviation of the macrofauna from reference conditions and presents results on 4 different case-studies. Although the subject is interesting and scientifically sound, there are some issues/potential pitfalls that should be addressed before considering publication. More specifically, I have some reservations on the way stations have been arranged along disturbance gradients as no clear and independent criteria are presented (and measured) in all cases (possibly except of the trawling case).    

 Moreover, 

1. The title is too ambitious and should be shortened.
2. In the abstract three case studies are numbered and not four
3. In the introduction, what is the point to refer on indices for fresh water
4. From ln 54-56 one may conclude that very few indices are based on benthic macrofauna and so, this biological element may be irrelevant
5. A large part of the introduction reviews previous indices but without providing details nor explain this part is useless. Better present just the two main approaches for ecological quality assessment
6. The introduction is too long; I suggest to be shortened by focusing on previous approaches on EcoQ assessment and providing the rational behind the proposed index.
7. Ln 162-171 is irrelevant for an introduction section 
8. If this work is a meta-analysis of previous data it should be clearly stated
9. I am not sure that VanVeen grab can adequately perform on maerl 
10. TDI is computed on megafuana/epifauna; so, how this index has been calculated from VavVeen macro-infauna samples?
11. Signal Detection Theory requires a criterion independent of benthic macrofauna; so, the use of an index based on macrofauna is not appropriate. Please clearly define relevant criteria; this part is very confusing.
12. Table 2. Why chi-square? In the legend a Kruskal Wallis test is mentioned.
13. Biotic indices such as AMBI have been originally develop to detect organic pollution and eutrophication; so this kind of comparison seems inappropriate
14. Reference stations and the classification of sampled stations along disturbance gradient should be independent of benthos. This is the most important to decide whether an index performs well or not. That is why biotic indices uses organic content to be tested against. I believe that the authors should clearly present their classification factors/criteria that must be independent and test their proposed index against to set boundaries.
15. The discussion is too long and verbose. I cant see the meaning to compare with biotic indices such as M-Ambi. One gets lost within this discussion that mentions many different things but without covering a case. I suggest to discard all non-necessary information and focus on their index and presented cases. 

 

Author Response

You can find attached our answers (in blue and italic) to the comments of the two reviewers. In order to help follow the revisions, I also join a word document using the Tracks changes tools as well as a clean version of the manuscript.

As you will see almost all the suggestions of the reviewers have been taken into account and it has been justified when it was not possible.

We hope that you will be satisfied with these changes, and I remain at your disposal should further information be needed.

Best regards

 

Céline Labrune, Olivier Gauthier, Anxo Conde, Jacques Grall, Mats Blomqvist, Guillaume Bernard, Régis Gallon, Jennifer Dannheim, Gert, Van Hoey and Antoine Grémare

Author Response File: Author Response.pdf