Comparing Six Vegetation Indexes between Aquatic Ecosystems Using a Multispectral Camera and a Parrot Disco-Pro Ag Drone, the ArcGIS, and the Family Error Rate: A Case Study of the Peruvian Jalca

Round 1

Reviewer 1 Report

Review of a manuscript submitted to the Water MDPI, entitled “Comparing six vegetation indexes between aquatics ecosystems using a multispectral camera and Parrot Disco-Pro Ag drone, GIS, and the Family Error Rate: a case study of the Peruvian Jalca”, by Jaris Veneros, Segundo Chavez, Manuel Oliva, Erick Arellanos, Jorge L. Maicelo, Ligia García.

 

Aquatic ecosystems are often inaccessible or logistically difficult to monitor in the field. Remote sensing provides the ability to monitor aquatic vegetation environments over large spatial areas. However, to be successful, remote sensing methods must be accurate, repeatable in time and space, and take into account the inherent spatial and environmental heterogeneity of the system.

In this study, vegetation indices were analyzed using Parrot Disco-Pro Ag and a Parrot Sequoia quad-band multispectral camera [GREEN (550 nm ± 40 nm), RED (660 nm ± 40 nm), REG (735 nm ± 10 nm) and NIR (790nm ± 40nm)] and six vegetation indices [GNDVI - Green Normalized Difference Vegetation Index, LCI - Leaf Chlorophyll Index, MCARI - Modified Chlorophyll Absorption in Reflective Index, NDRE - Normalized Difference Red Edge, NDVI - Normalized Difference Vegetation Index, SIPI2 - Structure Intensive Pigment Index 2], for four lakes of Peru's Jalca. This type of research is extremely important for assessing the condition of lakes through quality elements that are part of the ecosystem.

Overall the manuscript is not well organized and written and thus difficult to read. Nevertheless, Is an interesting paper with a clear enough purpose within its limited aims. The objective of the study has been met, and research findings have been thoroughly discussed.  The paper title match its contents, the key words and the abstract characterize the contents of the paper sufficiently, the objective of the paper formulated correctly. Chapters: 2. Materials and Methods and 3. Results and Discussion require reorganization. The assumptions formulated for the purpose have been achieved, the data contained in the tables and figures do not constitute proper, understandable documentation of the content of the work (some data - I suggest moving to the appendix or resigning from it), the discussion of the results is correct and sufficient, the literature contained in the work is sufficient and adequate to the subject of the work, correctly formulated conclusions and justified by the content and results of the work. I would support the publication of this study following a reorganization of the text. Such information as presented here can be usually only obtained with a rather high effort (really nicely accomplished by the authors) and/or are sometimes even not accessible or citable.

MINOR COMMENTS

Page 3, line 114-137 - This information should be presented in chapter 2. Materials and Methods. The purpose of the study should be clearly and legibly presented here.

Page 5, line 176-184. Figure 2/ Table 2/Table 4 - consider unnecessary

Page 6, line 184-195. 2.2.1 Flight programming - please consider if this chapter is relevant to the work presented?

Page 6, line 196-224: 2.2.2 Radiometric Calibration of the Parrot Sequoia Camera - The chapter is too broad, implying that it should be significantly shortened.  I see no justification for the presentation of Figure 4

Page 10, line 287-289: Figure 5 is unreadable

Page 12-13, line 322-333: An analysis of variance (ANOVA) I suggest to present in the form of a graph, a significant part of the information from the description is redundant

Page 13-14, line 322-374: 3.4 Tukey HSD tests - Please make the description shorter

Page 15, line 376-380 - this text fits the “introduction”, in the "discussion" it is redundant

Page 16, line 433-441 - this text fits the "conclusion", in the "discussion" it is redundant

 

After reviewing the work, I also believe that future DNA testing and calibration of AUVS and software are necessary to know the pool of microorganisms with photosynthetic activity present in each lake, and thus provide targeted high-level strategies.

Author Response

Response to Reviewer 1 Comments

Point 1: Aquatic ecosystems are often inaccessible or logistically difficult to monitor in the field. Remote sensing provides the ability to monitor aquatic vegetation environments over large spatial areas. However, to be successful, remote sensing methods must be accurate, repeatable in time and space, and take into account the inherent spatial and environmental heterogeneity of the system.

In this study, vegetation indices were analyzed using Parrot Disco-Pro Ag and a Parrot Sequoia quad-band multispectral camera [GREEN (550 nm ± 40 nm), RED (660 nm ± 40 nm), REG (735 nm ± 10 nm) and NIR (790nm ± 40nm)] and six vegetation indices [GNDVI - Green Normalized Difference Vegetation Index, LCI - Leaf Chlorophyll Index, MCARI - Modified Chlorophyll Absorption in Reflective Index, NDRE - Normalized Difference Red Edge, NDVI - Normalized Difference Vegetation Index, SIPI2 - Structure Intensive Pigment Index 2], for four lakes of Peru's Jalca. This type of research is extremely important for assessing the condition of lakes through quality elements that are part of the ecosystem.

 

Overall the manuscript is not well organized and written and thus difficult to read. Nevertheless, Is an interesting paper with a clear enough purpose within its limited aims. The objective of the study has been met, and research findings have been thoroughly discussed.  The paper title match its contents, the key words and the abstract characterize the contents of the paper sufficiently, the objective of the paper formulated correctly. Chapters: 2. Materials and Methods and 3. Results and Discussion require reorganization. The assumptions formulated for the purpose have been achieved, the data contained in the tables and figures do not constitute proper, understandable documentation of the content of the work (some data - I suggest moving to the appendix or resigning from it), the discussion of the results is correct and sufficient, the literature contained in the work is sufficient and adequate to the subject of the work, correctly formulated conclusions and justified by the content and results of the work. I would support the publication of this study following a reorganization of the text. Such information as presented here can be usually only obtained with a rather high effort (really nicely accomplished by the authors) and/or are sometimes even not accessible or citable. Such information as presented here can be usually only obtained with a rather high effort (really nicely accomplished by the authors) and/or are sometimes even not accessible or citable.

Response 1: The manuscript was reorganized for Chapters 2, Materials and Methods and 3, Results and Discussion. Also, Figure 2, Tables 2 and 4 were removed. The manuscript is now well organized and the writing has been improved.

 

Point 2: Page 3, line 114-137 - This information should be presented in chapter 2. Materials and Methods. The purpose of the study should be clearly and legibly presented here.

Response 2: Lines L114-L137 were changed to the suggested section in Chapter 2. Detailed information was added between lines 157-172 so that chapter 2 has information on the purpose of the study.

 

Point 3: Page 5, line 176-184. Figure 2/ Table 2/Table 4 - consider unnecessary

Response 3: Suggested figure and tables deleted.

 

Point 4: Page 6, line 184-195. 2.2.1 Flight programming - please consider if this chapter is relevant to the work presented?

Response 4: Yes, it is relevant. This is the first time that a fixed-wing drone has been flown in this area, because it represents a mountain ecosystem and is dangerous for take-off and landing, a landing radius for this drone was established for future research. We consider it very important also because of the cost of this equipment, a loss of this could generate problems for future researchers. Radiometric correction is also important because it can affect the quality of the images, thus our vegetation indices. All these steps make it possible for future researchers to replicate our research. Finally, we indicate how the flight programming was done as well as the estimated time of energy consumption in high elevation areas.

 

Point 5: Page 6, line 196-224: 2.2.2 Radiometric Calibration of the Parrot Sequoia Camera - The chapter is too broad, implying that it should be significantly shortened.  I see no justification for the presentation of Figure 4

Response 5: The text for the radiometric calibration part was reduced and the justification for Figure 4 is presented between lines 275-285.

 

Point 6: Page 10, line 287-289: Figure 5 is unreadable

Response 6: The quality of all images has been increased to make them more readable.

 

Point 7: Page 12-13, line 322-333: An analysis of variance (ANOVA) I suggest to present in the form of a graph, a significant part of the information from the description is redundant

Response 7: We could not find an Anova in graph form, so we left the table. Otherwise, redundant information was eliminated.

 

Point 8: Page 13-14, line 322-374: 3.4 Tukey HSD tests - Please make the description shorter

Response 8: This information was added between lines 402 and 404: This statistic was used to find means that are significantly different from each other in this case for the vegetation indices in the four lakes.

 

 

 

Point 9: Page 15, line 376-380 - this text fits the “introduction”, in the "discussion" it is redundant

Response 9: This information has been deleted because it is already in the introduction.

 

Point 10: Page 16, line 433-441 - this text fits the "conclusion", in the "discussion" it is redundant

Response 10: This information was moved to the last paragraph of the conclusions.

 

Point 11: After reviewing the work, I also believe that future DNA testing and calibration of AUVS and software are necessary to know the pool of microorganisms with photosynthetic activity present in each lake, and thus provide targeted high-level strategies.

Response 11: We have added the information that future DNA testing and calibration of AUVS and software are needed to know the set of photosynthetically active microorganisms present in each lake to provide specific high-level strategies. They are considered at 550-553.

 

 

 

 

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

In this study, the authors investigated “Comparing six vegetation indexes between aquatics ecosystems using a multispectral camera and Parrot Disco-Pro Ag drone, GIS, and the Family Error Rate: a case study of the Peruvian Jalca”. Firstly, six vegetation indexes in four lakes within the Tilacancha Private Conservation Area (PCA) in 2021 were studied. Secondly, The sensitivity and distribution of pixel values were analyzed by the multivariate statistical analysis, such as histograms, Q-Q plots. Thirdly, the results of this study were highest level of sensitivity with respect to the degree of pixels distribution in the ranges shown in the histogram according to standard deviation. The last is to detect and analyze the dynamics of biological beings with photosynthetic activity on aquatic ecosystems of the Peruvian Jalca by the six vegetation indexes.

Below I provide some comments and hopefully these comments may help the authors to improve the manuscript.

 

1. why is the six vegetation indexes? For example, using a Parrot Disco-Pro Ag fixed- wing drone and a Parrot Sequoia four-bands multispectral camera: GREEN (550nm ± 40nm), RED (660nm ± 40nm), REG (735nm ± 10nm) and NIR (790nm ± 40nm), and six vegetation indexes (GNDVI - Green Normalized Difference Vegetation Index, LCI - Leaf Chlorophyll Index, MCARI - Modified Chlorophyll Absorption in Reflective Index, NDRE - Normalized Difference Red Edge, NDVI - Normalized Difference Vegetation Index, SIPI2 - Structure Intensive Pigment Index 2),

2. the Abstract indicated the six vegetation indexes. But in introduction, the main of this study is management of data?

Moderate editing of English language required

Author Response

Response to Reviewer 2 Comments

Point 1: Aquatic ecosystems are often inaccessible or logistically difficult to monitor in the field. Remote sensing provides the ability to monitor aquatic vegetation environments over large spatial

 

In this study, the authors investigated “Comparing six vegetation indexes between aquatics ecosystems using a multispectral camera and Parrot Disco-Pro Ag drone, GIS, and the Family Error Rate: a case study of the Peruvian Jalca”. Firstly, six vegetation indexes in four lakes within the Tilacancha Private Conservation Area (PCA) in 2021 were studied. Secondly, The sensitivity and distribution of pixel values were analyzed by the multivariate statistical analysis, such as histograms, Q-Q plots. Thirdly, the results of this study were highest level of sensitivity with respect to the degree of pixels distribution in the ranges shown in the histogram according to standard deviation. The last is to detect and analyze the dynamics of biological beings with photosynthetic activity on aquatic ecosystems of the Peruvian Jalca by the six vegetation indexes.

 

Below I provide some comments and hopefully these comments may help the authors to improve the manuscript.

 

1. why is the six vegetation indexes? For example, using a Parrot Disco-Pro Ag fixed- wing drone and a Parrot Sequoia four-bands multispectral camera: GREEN (550nm ± 40nm), RED (660nm ± 40nm), REG (735nm ± 10nm) and NIR (790nm ± 40nm), and six vegetation indexes (GNDVI - Green Normalized Difference Vegetation Index, LCI - Leaf Chlorophyll Index, MCARI - Modified Chlorophyll Absorption in Reflective Index, NDRE - Normalized Difference Red Edge, NDVI - Normalized Difference Vegetation Index, SIPI2 - Structure Intensive Pigment Index 2),

 

2. the Abstract indicated the six vegetation indexes. But in introduction, the main of this study is management of data?

 

Response 1:

1.1 The use of these 6 indices is because they allow us to determine the chlorophyll content and concentration. Each index uses different wavelengths so it is important to use these 6 indices. Please see lines 116 and 122 as well as lines 289-290 (Table 3). The table indicates what each index is specifically used for.

1.2 Added between lines 116 and 122 how the use of these six indices can help to monitor water bodies and the identification of photosynthetic organisms from chlorophyll content and concentration. Also, lines 123 - 143 were moved to the materials and methods section at the suggestion of the other reviewer.

 

Point 2: Moderate editing of English language required

Response 2: English editing was done throughout the document.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The reviewed work has been revised according to the submitted suggestions

Reviewer 2 Report

 It is  revised, and accepted.

Minor editing of English language is required