Evaluation of Macrophyte Community Dynamics (2015–2020) in Southern Lake Garda (Italy) from Sentinel-2 Data

Round 1

Reviewer 1 Report

This paper addresses the Evaluation of macrophyte community in southern Lake Garda (Italy) from Sentinel-2 data. However, there are several statements given without rationale or with misunderstandings.

[Abstract] What is the objective of this paper, the author should highlight in this section. Moreover, the result finding is not discussed here.

[Introduction] We noticed the author discussed the transformation of macrophyte in terms of actual data. Are you doing any future prediction? The contribution of the research is not discussed in this section. We strongly recommend the author to include contributions.

[Related Work] We are unable to find any related work section here, we recommend the author to include recent year papers in this section and formulate the problem statement.

[Proposed Model] The material and method is discussed well.

[Result and discussion] Comparative analysis (sentinel and airborne) is explained well.

Line: 194 - “Remote Sensing Reflectances (Rrs)” or “Remote Sensing Reflectances (Rsr)”

Author Response

[Abstract] What is the objective of this paper, the author should highlight in this section. Moreover, the result finding is not discussed here.

• Answer: Thanks for this useful comment. The various objectives of the paper and the results were also discussed in the abstract.

[Introduction] We noticed the author discussed the transformation of macrophyte in terms of actual data. Are you doing any future prediction? The contribution of the research is not discussed in this section. We strongly recommend the author to include contributions.

• Answer: Thanks for this comment. We added a sentence to discuss the contribution of the present study in the wider research field on macrophyte function.

 [Related Work] We are unable to find any related work section here, we recommend the author to include recent year papers in this section and formulate the problem statement.

• Answer: Thanks for this comment. We added a paragraph to better contextualize our work in the international context od related works. See lines 122-135.

Line: 194 - “Remote Sensing Reflectances (Rrs)” or “Remote Sensing Reflectances (Rsr)”

• Answer: The correct acronym is Rrs.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript handles with Evaluation of macrophyte community dynamics (2015-2020) in southern Lake Garda (Italy), although I have some questions.

 

The document is generally well written, in which, it is well explained the objectives and methods. But on other hand, some conclusions like herbivore population increase or decrease. I can't understand how it was obtained and what kind of animals they were.

 As well as the association of not using the lake with the increase in macrophyte. Because the year the have a greater increase was in 2017.

Author Response

Thanks for this comment, we have clarified in the text that we are referring to birds monitored in winter (line 456, table 5) and also clarified it in the methods (lines 306-308) and we have now also listed the top 3 herbivorous birds to make things clearer. We have closer linked the increase in macrophytes in 2017 to the decline in herbivorous birds that year in the text (line 464).

Author Response File: Author Response.pdf

Reviewer 3 Report

The topic is suitable for “Applied Science”, should be interesting to a broad audience. The research method used is sound and the presented results are reasonable.  I recommend it for publish after the following comments and suggestions

1. The importance of the selected Lake Garda should be more emphasized in introduction section to make this research more interesting for a broader audience.
2. The materials and method used in the study need a brief summary to be clearer.
3. The importance of the research area needs more expended discussion.
4. It is suggested to add the lat and lon coordinates to the image in Figure 1 for readers to better understand the geo location of the studied area.  Please give explanations for each small picture in Figure 1.
5. Please do proofreading and gramma check.

Author Response

The importance of the selected Lake Garda should be more emphasized in introduction section to make this research more interesting for a broader audience.

• Answer: Thanks for raising this important point. As suggested, we have included a sentence (lines 100-107) that emphasizes the importance of Lake Garda and of the Sirmione Peninsula in the Introduction.

The materials and method used in the study need a brief summary to be clearer.

• Answer: Thank you for your comment. Sentinel-2 image processing is explained in detail in section 2.2. Here is a brief summary of the various steps:
  1. download of S2 Level 1 images (not atmospherically corrected). All images were chosen without clouds and cloud-shadows, without sun-glint and other radiometric noise;
  2. resampling of all bands at the same spatial resolution (10 m);
  3. resize of images on the study area (Sirmione Peninsula);
  4. conversion of Top of Atmosphere (TOA) reflectances into TOA radiances, through the SNAP tool "ReflectanceToRadianceOp" for allowing the atmospheric correction to be performed;
  5. obtaining metadata needed for atmospheric correction: AOD₅₅₀, sun zenith angle, sun azimuth angle, sensor zenith angle and sensor azimuth angle;
  6. atmospheric correction through 6SV software;
  7. obtaining the Remote Sensing Reflectances (Rrs) dividing by π;
  8. creation of the mask (see Fig.1) through ENVI software;
  9. Rrs products were used as input for the BOMBER bio-optical model for estimating the substrate coverage (three class: sand (b0), rock (b1) and rooted macrophytes (b2));
  10. union of classes b1 and b0 to obtain products characterized by two main classes: bare sediment (BS) and rooted macrophytes (RM);
  11. the main class RM was partitioned into two subclasses: dense macrophytes (D_RM) and sparse macrophytes (S_RM).
  12. the maps obtained through BOMBER were merged in average maps representative of the season of each year (2015-2020).

If any steps are unclear, I will be glad to edit the text to make it clearer.

The importance of the research area needs more expended discussion.

• Answer: As for your first comment, we have added a sentence that describes the importance, especially for the tourism sector, of the Sirmione Peninsula (lines 100-107 and 195-196).

It is suggested to add the Lat and Lon coordinates to the image in Figure 1 for readers to better understand the geo location of the studied area.  Please give explanations for each small picture in Figure 1.

• Answer: We agree and we modified Figure 1 as suggested. In addition, we have modified the caption of Figure 1 to make it clearer.

Please do proofreading and gramma check.

• Answer: Done.

 

Author Response File: Author Response.pdf