Wild Plant Habitat Characterization in the Last Two Decades in the Nile Delta Coastal Region of Egypt

Round 1

Reviewer 1 Report

The manuscript explains dominance of species in Nile delta coastal region of Egypt for 37 selected vegetation stands. Soil analysis was also done in these stands to establish relationship between the dominance of species and soil parameters. Land use map for two-time steps (1999 and 2019) was prepared to assess changes in land use types and NDVI, NDSI and NDMI values of the habitat. The MS needs to explain few things boldly, such as why this study is important, whether the selected stands represent agriculture or forest or mixed classes, significance of LULC and NDVI/NDSI/NDMI analysis with reference to vegetation, etc. Methodology section require a major revision. The specific comments that need to be addressed are indicated below.

Minor concerns:

1. The title can simply be written as “Wild plant habitat characterisation in the last two decades at the Nile delta coastal region of Egypt”.
2. Line 23: “wild plant habitat” can be replaced with more clear explanation.
3. Line 32: replace “on the vegetation” with “influencing vegetation”
4. Line 32: replace “loss of bare lands” with “coverage of bare lands”
5. Line 35: replace “loss of” with “occupancy of”
6. Line 77: replace “RST” with “RS” and delete “Technology”
7. Line 83: “plant communities-environment interactions” is a big term and such analysis require much more consideration and evaluation. So better replace this word with “habitat characteristics”
8. Line 87/88: Information on location of threatened wild plant habitats are not presented in this study thus this statement needs to be deleted.
9. Line 129: “Several field trips”. Please provide how many filed trips were done.
10. Line 137: replace “important value” with “importance value”
11. Table 2: in the heading of 5^th column, mention (IVI ± SD)
12. Table 3 caption: delete “the” before “vegetation”
13. Figure 3: In the caption, please mention what does the numbers on each dot within figure panel represent?
14. Figure 5: Match the colour of “bare land class” for LULC maps and Bar chart.
15. Figure 6: It is really difficult to distinguish “moderate vegetation” with “dense vegetation”, may please use different colour that distinguish each.

Major concerns:

16. Describe more precisely about the study area to indicate whether vegetation represent forest, agriculture, or both. From MS it is not clear what kind of region this Nile delta coastal area represent, for which the study has been done.
17. Line 112: why only 37 stands were evaluated. Provide justification.
18. Line 113: provide justification for opting 20 x 20 m sampling size.
19. Line 130: How the randomisation for selecting 37 stands were performed needs to be elaborated.
20. Line 132: How authors justify using 3 quadrats of size 10 m each?
21. Line 133: What kind of enumeration was done using visual interpretation. Please elaborate. How vegetation density and cover was evaluated visually and what kind of scales were used to represent vegetation density and cover. While calculating Importance Value (IV) how this visual interpretation was used for allocating numerical values?

Comments for author File: Comments.pdf

Author Response

Dear Respected Reviewer

            According to the your valuable comments, we have revised the manuscript “Vegetation Composition and Changes of Habitats Distribution in the Last Two Decades at the Nile Delta Coastal Region” with ID agriculture-1510267.

            In the revised version we changed the title according to the reviewer request as follows: “Wild plant habitat characterization in the last two decades at the Nile delta coastal region of Egypt”. Additionally, In the revised version, we have changed the text, providing answers to all the enumerated points. Please, find attached the reviewer’s comments with our point-by-point responses and the revised manuscript with changes highlighted in blue color. Thank you for your valuable comments that allowed us to improve the manuscript greatly

Sincerely,

Yasser A. El-Amier and co-authors

RESPONSES TO REVIEWERS

Reviewer #1

The manuscript explains dominance of species in Nile delta coastal region of Egypt for 37 selected vegetation stands. Soil analysis was also done in these stands to establish relationship between the dominance of species and soil parameters. Land use map for two-time steps (1999 and 2019) was prepared to assess changes in land use types and NDVI, NDSI and NDMI values of the habitat. The MS needs to explain few things boldly, such as why this study is important, whether the selected stands represent agriculture or forest or mixed classes, significance of LULC and NDVI/NDSI/NDMI analysis with reference to vegetation, etc. Methodology section require a major revision. The specific comments that need to be addressed are indicated below. The specific comments that need to be addressed are indicated below.

Response:

• Thank you for your time and efforts in the revision of our manuscript and for your comments that will modify our manuscript greatly.
• The present paper focused on wild plant habitats of the Northern Coastal Nile Delta of Egypt considering plant composition and spatial/temporal changes that occurred in the investigated area with the aid of space-borne multispectral Landsat images. To accurately map the natural resources and anthropogenic activities of a certain area, there is a need to extract land use/ cover maps and relevant spectral indices (e.g. NDSI, NDVI, and NDMI). NDVI is an index that helps to assess vegetation cover density and to discriminate the changes in sparse natural vegetation and crops. NDSI is an index specific for mapping the land affected by salinization problems while the NDMI can monitor the changes in soil moisture that occurred due to changes induced by natural and anthropogenic factors.
• The area of study represents one of the mixed land-use regions and is one of the pioneering regions in regard to government projects such as urbanization and industrialization. Regular monitoring and assessment of the investigated area are important to assess the environmental changes as a result of the construction of the newly developed city named “New Mansoura”. Monitoring the impact of such projects on the wild plant habitats is important to assess positive or negative impacts that might occur as a result of these anthropogenic activities. Further, plant composition and relevant importance are one of the main objectives of the present study which magnifies the benefits from the naturally grown plants and helps to conserve these habitats.

Minor concerns:

Comment: The title can simply be written as “Wild plant habitat characterisation in the last two decades at the Nile delta coastal region of Egypt”.

Response: We agree with your modification. The title was changed to “Wild plant habitat characterization in the last two decades at the Nile delta coastal region of Egypt”

Comment: Line 23: “wild plant habitat” can be replaced with more clear explanation.

Response: The sentence was corrected as follows: “Thirty-seven stands were spatially identified and studied to represent the different habitats of the wild plants in the Deltaic Mediterranean coastline region”.

Comment: Line 32: replace “on the vegetation” with “influencing vegetation”.

Response: Done. Corrected.

Comment: Line 32: replace “loss of bare lands” with “coverage of bare lands”

Response:   Done. Corrected.

Comment: Line 35: replace “loss of” with “occupancy of”

Response:   Done. Corrected.

Comment: Line 77: replace “RST” with “RS” and delete “Technology”

Response:  Done. Corrected.

Comment: Line 83: “plant communities-environment interactions” is a big term and such analysis require much more consideration and evaluation. So better replace this word with “habitat characteristics”

Response: Done. Corrected.

Comment: Line 87/88: Information on location of threatened wild plant habitats are not presented in this study thus this statement needs to be deleted.

Response: OK, deleted.

Comment: Line 129: “Several field trips”. Please provide how many filed trips were done.

Response:  we carried out 6 field trips during the period 19th March – 5th May 2019

Comment: Line 137: replace “important value” with “importance value”

Response: Done. Replaced.

Comment: Table 2: in the heading of 5^th column, mention (IVI ± SD)

Response:   Done

Comment: Table 3 caption: delete “the” before “vegetation”

Response:   Done. Deleted.

Comment: Figure 3: In the caption, please mention what does the numbers on each dot within figure panel represent?

Response: This point was clarified in the revised cersion of the manuscript as flollows: “The stands were numbered from 1 to 37 and represented by “●”.

Comment: Figure 5: Match the colour of “bare land class” for LULC maps and Bar chart.

Response: Done

Comment: Figure 6: It is really difficult to distinguish “moderate vegetation” with “dense vegetation”, may please use different colour that distinguish each.

Response: Thanks for your comment. These colors were derived from thr Arch Software Program. Also, the dense vegetation patched is very small compared to the moderate, therefore, they need more focusing by eyes to distinguish.

Major concerns:

Comment: Describe more precisely about the study area to indicate whether vegetation represent forest, agriculture, or both. From MS it is not clear what kind of region this Nile delta coastal area represent, for which the study has been done.

Response: The area of study represents one of the mixed land-use regions and is one of the pioneering regions in regard to government projects such as urbanization and industrialization. It’s located along the Mediterranean Sea at the Middle of the Egyptian Nile delta. The areas require regular monitoring to assess the environmental changes as a result of the development in Dakahlia governorate.

Comment: Line 112: why only 37 stands were evaluated. Provide justification.

Response: we make stands that coverd all different habitats within the study area.

Comment: Line 113: provide justification for opting 20 x 20 m sampling size.

Response: Sorry for this mistake. The stand area is not definite, while within each stand we make three quadrates with an area of 10 × 10.

Comment: Line 130: How the randomisation for selecting 37 stands were performed needs to be elaborated.

Response: we selected the species location according to the vegetation patches distribution.

Comment: Line 132: How authors justify using 3 quadrats of size 10 m each?

Response: Sorry for this mistake. Actually, we make three quadrates within each stand, where the area of each quadrate was 10 × 10. This area of the quadrate was determined according to the measurements of the minimal area. In the revised version of the manuscript, we adjusted this point properly.

Comment: Line 133: What kind of enumeration was done using visual interpretation. Please elaborate. How vegetation density and cover was evaluated visually and what kind of scales were used to represent vegetation density and cover. While calculating Importance Value (IV) how this visual interpretation was used for allocating numerical values?

Response: Quantitive assessment of land cover changes was achieved based on the maximum likelihood supervised classification of two multitemporal Landsat images dated 1999 and 2019. Likewise, the vegetation density was qualitatively and quantitatively assessed using calibrated reflectance images using ENVI 5.3 software. The obtained maps were assessed to monitor the changes in land cover and vegetation density in the investigated habitats.

Author Response File: Author Response.pdf

Reviewer 2 Report

Brief summary

This interesting study deals with the vegetation composition and changes of habitats distribution the last two decades at the Nile Delta Coastal Region. In total 57 species, belonging to 51 genera and 20 families were recorded, while after TWINSPAN classification 4 vegetation groups ware identified. The Canonical Correspondence Analysis (CCA) revealed that electrical conductivity, cations, organic carbon, porosity, chlorides, and bicarbonates are the most effective soil variables on the vegetation. Furthermore, the results of the spectral analysis indicated an annual loss of bare lands (3.56 km2) strongly related with the annual increase of vegetation (1.91 km2), water 33 bodies (1.22 km2), and urban areas (0.43 km2) as it is also evaluated by NDVI throughout the period 1999-2019.

However, the submitted manuscript needs a major revision. I have listed major and minor concerns below.

Comments

1. In Figure 1 it is useful to add north arrow on the maps.
2. The Coordinates of the Supplementary Table 1 (Table S1) are not the same as the coordinates used in the Figure 1. You should present the coordinates using a uniform coordinate system.
3. In the Supplementary Table 2 and 3 (Table S2, S3) different terms (Chorotypes and Floristic categories) are used in order to describe the chorology of the plant species. You should avoid to use different terms because this may confuse the reader. Use the same term throughout the manuscript and the Supplementary Material.
4. In Table 1 “NDMI ˂ -1)” should be replaced by “NDMI ˂ 0.1”
5. Line 61: Replace “plants” by “plant species”. Use the same term throughout the manuscript and the Supplementary Material
6. Line 62: Delete “Coastal belt” and write “Coastal zone”
7. Line 104: Delete “comparable” and write “similar”
8. Line 124: Replace “because” by “because of”
9. Line 206: Add dot after bloom
10. Line 209: Delete “and represent” and write “representing”
11. Line 212: Delete “as well as effective dispersal of their diaspores by wind” and write “as well as their effective dispersal of seeds or spores by the wind”
12.  Lines 213-215: Rewrite the sentences as follows “Plant species which belong to the Poaceae have some characteristics that allow them to tolerate grazing pressure and drought, and even profit from it. They developed a dense surface root system that allowed them to absorb moisture from the soil effectively”
13. Line 222: Delete “presence range of 50-25%” and write “presence ranges from 50-25%”
14. Line 239: Delete “The Saharo-Arabian belt” and write “The Saharo-Arabian zone”
15. Line 249: Delete “categories” and write “groups or units”. Use the same term throughout the manuscript
16. Lines 257 - 259: Rewrite the sentences as follows “Figure 2. TWINSPAN dendrogram of 37 stands based on the important value of plant species. The first three letters of both the genus and species names are an abbreviation of the Indicator species names”
17. Line 267: Delete “comprise” and write “consist of”
18. Line 274: Rewrite the sentences as follows “Table 3. Soil physical and chemical analysis of the four identified vegetation groups (I-IV) of the study area.”
19. Line 279: Please check and correct the value of C. polygnoides (IV= 23.14). In the Table 2 the value of C. polygnoides is IV=8.91.
20. Line 284: Delete “comprise” and write “consist of”. In addition, check and correct the value of C. polygnoides (IV= 38.20). In the Table 2 the value of C. polygnoides is IV=16.07.
21. Line 289: Delete “comprise” and write “consist of”
22. Line 317: Use the term “The plant species diversity” instead of “The plant diversity”
23. Lines 317-323: It is necessary to add a Table with the correlation of the examined variables with the first two CCA axis. In addition, data such as eigenvalues of the ordination axis should be mentioned (see bibliography e.g. Zotos et al., 2021; Triantafyllidis et al., 2020).
24. Lines 334-353: Rewrite these two (2) paragraphs describing the correlations of plant species with soil variables more accurately and clearly.
25. Lines 368-374: Rewrite the sentences as follows “A clear decrease in the most dominant class was observed: Bare land class decreased from 222.47 Km² (77.02 %) in 1999 to 151.18 Km² (52.34%) in 2019. The second dominant class is the water bodies occupying an area of 35.85 77Km² (12.41%) and 60.24 Km² (20.86 %) in the years 1999 and 2019, respectively. In addition, the vegetation class increased by 21.86 Km² (7.57 %) in 1999 to 60.11 Km² (20.81%) in 2019. The urban class was found in the last position, presenting however an increase of 8.65 Km² (3.00 %) to 17.29 Km² (5.99 %) between the years 1999 and 2019, as shown in Figure 5.”
26. Lines 397-401: Rewrite the sentence as follows “The application of the NDVI was necessary to differentiate the vegetation classes and to detect the change the last two decades in the wild plant habitats that are included in the sparse vegetation which showed the highest increase from 21.23 Km² in 1999 to 77.44 Km² in 2019 with annual increase detected by 2.81 km².”
27. Lines 412-414: Rewrite the sentence as follows “Moreover, this spread may be threatened in the future by urban crawling, which consequently changes the soil character, turning the habitat to be unfavorable for the flourishment of the wild plants.”
28. Lines 458-460: Rewrite the sentence as follows “Moreover, this could be an indicator of the reason why most of the wild plants presented in the wild habitats in the coastal region of Dakahlia Governorate are not adaptive to high salinity.”

Author Response

Dear Respected Reviewer

            According to the your valable comments, we have revised the manuscript “Vegetation Composition and Changes of Habitats Distribution in the Last Two Decades at the Nile Delta Coastal Region” with ID agriculture-1510267.

            In the revised version we changed the title according to the reviewer request as follows: “Wild plant habitat characterization in the last two decades at the Nile delta coastal region of Egypt”. Additionally, In the revised version, we have changed the text, providing answers to all the enumerated points. Please, find attached the reviewer’s comments with our point-by-point responses and the revised manuscript with changes highlighted in blue color. Thank you for your valuable comments that allowed us to improve the manuscript greatly

Sincerely,

Yasser A. El-Amier and co-authors

RESPONSES TO REVIEWERS

Reviewer #2

This interesting study deals with the vegetation composition and changes of habitats distribution the last two decades at the Nile Delta Coastal Region. In total 57 species, belonging to 51 genera and 20 families were recorded, while after TWINSPAN classification 4 vegetation groups ware identified. The Canonical Correspondence Analysis (CCA) revealed that electrical conductivity, cations, organic carbon, porosity, chlorides, and bicarbonates are the most effective soil variables on the vegetation. Furthermore, the results of the spectral analysis indicated an annual loss of bare lands (3.56 km²) strongly related with the annual increase of vegetation (1.91 km²), water 33 bodies (1.22 km²), and urban areas (0.43 km²) as it is also evaluated by NDVI throughout the period 1999-2019.

However, the submitted manuscript needs a major revision. I have listed major and minor concerns below.

Response: Thank you for your time and efforts in the revision of our manuscript and for your comments that will modify our manuscript greatly. In the revised version we take consideration for all raised comments, suggestions and corrections.

 Comment: In Figure 1 it is useful to add north arrow on the maps.

Response:  The north aroow was added in the modified version.

Comment: The Coordinates of the Supplementary Table 1 (Table S1) are not the same as the coordinates used in the Figure 1. You should present the coordinates using a uniform coordinate system.

Response: The coordinates form were unified either within the manuscript and the supplementary materials.

Comment: In the Supplementary Table 2 and 3 (Table S2, S3) different terms (Chorotypes and Floristic categories) are used in order to describe the chorology of the plant species. You should avoid to use different terms because this may confuse the reader. Use the same term throughout the manuscript and the Supplementary Material.

Response: In the revised version we unify the term as “Chorotypes”.

Comment: In Table 1 “NDMI ˂ -1)” should be replaced by “NDMI ˂ 0.1”

Response: Done. Corrected.

Comment: Line 61: Replace “plants” by “plant species”. Use the same term throughout the manuscript and the Supplementary Material

Response: Done. Changed.

Comment: Line 62: Delete “Coastal belt” and write “Coastal zone”

Response: Done. Deleted.

Comment: Line 104: Delete “comparable” and write “similar”

Response:  Done

Comment: Line 124: Replace “because” by “because of”

Response:  Done. Replaced.

Comment: Line 206: Add dot after bloom

Response: Done.

Comment: Line 212: Delete “as well as effective dispersal of their diaspores by wind” and write “as well as their effective dispersal of seeds or spores by the wind”

Response:  Done. The sentence was deleted in the revised version of the manuscript.

Comment:  Lines 213-215: Rewrite the sentences as follows “Plant species which belong to the Poaceae have some characteristics that allow them to tolerate grazing pressure and drought, and even profit from it. They developed a dense surface root system that allowed them to absorb moisture from the soil effectively”

Response: Done. Corrected as provided.

Comment: Line 222: Delete “presence range of 50-25%” and write “presence ranges from 50-25%”

Response: Done. Deleted.

Comment: Line 239: Delete “The Saharo-Arabian belt” and write “The Saharo-Arabian zone”

Response:  Done. Deleted.

Comment: Line 249: Delete “categories” and write “groups or units”. Use the same term throughout the manuscript

Response:  Done. Deleted.

Comment: Lines 257 - 259: Rewrite the sentences as follows “Figure 2. TWINSPAN dendrogram of 37 stands based on the important value of plant species. The first three letters of both the genus and species names are an abbreviation of the Indicator species names”

Response:  Thanks for your correction. Done. Corrected as provided.

Comment: Line 267: Delete “comprise” and write “consist of”

Response:  Done. Corrected.

Comment: Line 274: Rewrite the sentences as follows “Table 3. Soil physical and chemical analysis of the four identified vegetation groups (I-IV) of the study area.”

Response: Done. Corected as provided.

Comment: Line 279: Please check and correct the value of C. polygnoides (IV= 23.14). In the Table 2 the value of C. polygnoides is IV=8.91.

Response: Sorry for this mistake. The value of C. polygnoides (IV= 23.14) is corrected, and correct in Table 2.

Comment: Line 284: Delete “comprise” and write “consist of”. In addition, check and correct the value of C. polygnoides (IV= 38.20). In the Table 2 the value of C. polygnoides is IV=16.07.

Response: Sorry for this mistake. The value of C. polygnoides (IV= 38.20) is corrected in the Table 2.

Comment: Line 289: Delete “comprise” and write “consist of”

Response: Done. Corrected.

Comment: Line 317: Use the term “The plant species diversity” instead of “The plant diversity”

Response:  Done. Corrected.

Comment: Lines 317-323: It is necessary to add a Table with the correlation of the examined variables with the first two CCA axis. In addition, data such as eigenvalues of the ordination axis should be mentioned (see bibliography e.g. Zotos et al., 2021; Triantafyllidis et al., 2020).

Response: The table of the biplot scores were provided in the revised version as Table S5, which also include the eigenvalue, % variance, cumulative %.

Comment: Lines 334-353: Rewrite these two (2) paragraphs describing the correlations of plant species with soil variables more accurately and clearly.

Response: The sentence was rewritten properly in the revised version of the manuscriptas follows: “In the upper right side of the CCA diagram, Calligonum polygnoides (co-dominant species in community II and dominant in community III) showed a close correlation to soil cations (calcium, potassium, magnesium, and sodium), potassium adsorption ratio, and sand. On the other hand, the Arthrocnemum macrostachyum (dominant species of community IV), S. divaricatus (dominant species of community IV), and Senecio glaucus were plotted in the lower-right side of the CCA diagram, where they showed a correlation to organic matter content. Also, on the same side, the Lotus spicatus, Lotus halophilus, and Tamarix nilotica showed a close correlation to bicarbonates and calcium carbonate content (Figure 4).

            On the upper-left side of the CCA biplot, Mesembryanthemum crystallinum, Malva parviflora, Zygophyllum aegyptium (dominant in community II), and Echinopus spinosus (dominant in the community I) showed a correlation to salinity and clay content. While on the lower-left side, the Brassica tournefortii, Mesembryanthemum nodiflorum, and Cakile maritima were closely correlated to the water-holding capacity, pH, porosity, chloride, and sulphate.”

Comment: Lines 368-374: Rewrite the sentences as follows “A clear decrease in the most dominant class was observed: Bare land class decreased from 222.47 Km² (77.02 %) in 1999 to 151.18 Km² (52.34%) in 2019. The second dominant class is the water bodies occupying an area of 35.85 77Km² (12.41%) and 60.24 Km² (20.86 %) in the years 1999 and 2019, respectively. In addition, the vegetation class increased by 21.86 Km² (7.57 %) in 1999 to 60.11 Km² (20.81%) in 2019. The urban class was found in the last position, presenting however an increase of 8.65 Km² (3.00 %) to 17.29 Km² (5.99 %) between the years 1999 and 2019, as shown in Figure 5.”

Response: Thanks for your correction. The sentences was rewtitten as provided.

Comment: Lines 397-401: Rewrite the sentence as follows “The application of the NDVI was necessary to differentiate the vegetation classes and to detect the change the last two decades in the wild plant habitats that are included in the sparse vegetation which showed the highest increase from 21.23 Km² in 1999 to 77.44 Km² in 2019 with annual increase detected by 2.81 km².”

Response: Thanks for your correction. Corrected as provided.

Comment: Lines 412-414: Rewrite the sentence as follows “Moreover, this spread may be threatened in the future by urban crawling, which consequently changes the soil character, turning the habitat to be unfavorable for the flourishment of the wild plants.”

Response: Thanks for your correction. Corrected as provided.

Comment: Lines 458-460: Rewrite the sentence as follows “Moreover, this could be an indicator of the reason why most of the wild plants presented in the wild habitats in the coastal region of Dakahlia Governorate are not adaptive to high salinity.”

Response: Thanks for your correction. Corrected as provided.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The revised MS has been improved.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

After your latest revise, the submitted manuscript is significantly improved . Please find my comments (according to the agriculture-1510267-peer-review-v2.pdf file that is attached) below:

1. Line 104: Delete “similarto”and write “similar to”
2. Line 265: Delete “consist of4 stands” and write “consist of 4 stands”
3. Line 406: Please delete one of the two dots.
4. In Figure 4: Delete “HCO3, CACO3 and SO4”and write “HCO₃, CACO₃ and SO₄”

Author Response

Please see the attachment

Author Response File: Author Response.pdf