Elementome of Endemic Dolomitic Flora: Pterocephalus spathulatus (Lag.) Coult

Round 1

Reviewer 1 Report

Dear Editors,

Dear Authors,

I found the manuscript entitled "Elementome of endemic dolomitic flora: Pterocephalus spathulatus (Lag.) Coult." a very interesting one, with a novel chemical-ecological approach, well written and attractive for potential readers of the journal Land.

Therefore, I suggest to accept this manuscript in its present form.

Author Response

Dear Reviewer,

thank you very much for your excellent review. It is a pleasure for us to have such a positive feedback. However, the text has been carefully revised to improve the English style and to adjust it to the suggestions and comments of the other two reviewers.

We thank you for your kind words and invite you to come back to review the new version of the manuscript.

Reviewer 2 Report

Dear authors,

you have an interesting idea and a manuscript, but in my opinion it cannot be accepted for publication (i.e. it received the “grade of major revision”) before you rewrite it according to my remarks. This is especially true of the design of the botanical part of the experiment.

My biggest objection (which caused the “major revision” decision) to this manuscript relates to the following:

1. One of the focuses listed in lines 194, 195: „…to assess its potential value as a bioindicator species for heavy metals (or at least to have some clue, or to find other species with potential phytoremediation utility among the dolomiticolous flora)“. This statement raised two questions for me: a) which other species and how will you relate the results for Pterocephalus spathulatus to these other species - I do not see this clarification in the methods. Namely, your idea is in that case in collision with the view that „… differences in elementome among species are a function of taxonomy and phylogenetic distance, sympatry (the bioelemental compositions should differ more among coexisting than among non-coexisting species to avoid competitive pressure), and homeostasis with a continuum between high homeostasis / low plasticity and low homeostasis / high plasticity…“ (Peñuelas et al. 2019: Ecology: https://0-doi-org.brum.beds.ac.uk/10.1002/ecy.2652). The same then applies to the conclusion, lines 562-564. A re-examination of scientific hypotheses is, of course, to be expected, but it must be substantiated, both experimentally and theoretically. This leads me to the second question:
2. b) how does the choice of the endemic species spathulatus fit into this relationship with other dolomite species?
3. The paragraph 2.1. should be named „Study area and sampling“. Namely, since you are working with an endemic species that is rare in the world, I guess for research, and especially for sampling in which you will “destroy” it, you need the permission of the relevant national institutions. This is not visible from your manuscript and should be clearly stated (usually under acknowledgment). In this paragraph, it should be stated how many specimens of the endemic plant were sampled at which locality and where the VOUCHERS are deposited (this is very important!). This is also directly related to the paragraph 2.3. - how was the experimental design prepared for the analysis of leaves, I guess for each locality separately, how many samples, what was the amount of analyzed leaf tissue…? But that is not stated anywhere ...
4. The paragraph 2.5. „ spathulatus plant communities“ inaccurately and insufficiently describes the design of this part of the research, and I see a potential copyright issue. Namely, a group (RNM-344) whose, apparently previously published (or at least recorded) vegetation data used in this study, was mentioned. It is not stated exactly which group and data it is? If these data are taken from other researchers / publication / database etc., they should be cited and the data used should be made visible through supplementary material (if not available through some other reference).

Notes to be taken into account but not crucial for the "major revision" decision:

1. There can be no abbreviations in Keywords without clarification!
2. The Introduction is a little too extensive, I felt like I was reading a review article. Therefore, I would like to ask the authors to shorten the Introduction to the most necessary information on the topic.
3. The Figure 1. is mentioned in the text after it is presented in the paper. Additional note: the images included in Figure 1 are lovely, but not all of them are necessary for the introductory part of the manuscript. One image of Pterocephalus and one of the habitat would be sufficient. For example, Convolvulus in this “story” doesn’t really matter, does it? But, I leave this part of the “decision” to the journal’s editor(s).
4. It would be desirable for your country samples to be referenced according to the World Reference Base for Soil Resources (WRB).
5. Line 183. According to the Plants of the world Online valid author names for the genus are: Pterocephalus ex Adans.
6. The Acknowledgement is stated in such a way that some sources of funding are repeated, without concrete thanks to them?
7. Data Availability Statement (VERY IMPORTANT) are missing (related to my remarks on vouchers and vegetation data).

Author Response

Dear revisor,

Thank you so much for the extensive review of our manuscript and for the suggestions and comments, which have undoubtedly helped to considerably improve the final result of the text.

If you allow us, we will respond to your indications on your recommendations to the editors in order to resolve them point by point.

you have an interesting idea and a manuscript, but in my opinion it cannot be accepted for publication (i.e. it received the “grade of major revision”) before you rewrite it according to my remarks. This is especially true of the design of the botanical part of the experiment.

• Thank you very much for your kind consideration. Having reread the manuscript, we have realised that there is information regarding the botanical survey that is missing from the draft. All the co-authors of the article are members of the RNM344 research group at the University of Almeria, except A.O-U., who is a recent graduate student of the Biotechnology degree. The RNM344 research group is made up of researchers from the Chair of Botany and the area of Plant Physiology at the UAL. To remedy this information deficiency, we have rewritten the relevant parts of the text and supplementary material has been appended.

My biggest objection (which caused the “major revision” decision) to this manuscript relates to the following:

One of the focuses listed in lines 194, 195: „…to assess its potential value as a bioindicator species for heavy metals (or at least to have some clue, or to find other species with potential phytoremediation utility among the dolomiticolous flora)“. This statement raised two questions for me: a) which other species and how will you relate the results for Pterocephalus spathulatus to these other species - I do not see this clarification in the methods.

• In order to clarity this aspect we have deleted the part of sentence “or to find other species with” (line 200). This mistake comes from a wider consideration of the study of other plant species living on dolomitic submits from the same point of view, such as Convolvulus boissieri, Rothmaeleria granatensis, Santolina elegans…, which shares this habitat with Pterocephalus spathulatus in the Betic Ranges, and probably the study of their nutritional strategies could shed light both on their bio-indicator capacity, and also on the reasons for the high diversity, rarity and plant richness of dolomitic plant communities.

Namely, your idea is in that case in collision with the view that „… differences in elementome among species are a function of taxonomy and phylogenetic distance, sympatry (the bioelemental compositions should differ more among coexisting than among non-coexisting species to avoid competitive pressure), and homeostasis with a continuum between high homeostasis / low plasticity and low homeostasis / high plasticity…“ (Peñuelas et al. 2019: Ecology: https://0-doi-org.brum.beds.ac.uk/10.1002/ecy.2652). The same then applies to the conclusion, lines 562-564. A re-examination of scientific hypotheses is, of course, to be expected, but it must be substantiated, both experimentally and theoretically.

• Lines 201 – 202. The scientific hypothesis has been restated, both in relation to the potential bioindicator aspect, and the explanation for the high rarity and richness of these plant communities.

The ideas in Lines 572 – 574 have been rewritten as well: “This fact could predict the existence of other species in the plant community with bioindicator or even phytoremediation potential for other elements, since the elemental compositions should differ more among coexisting species to avoid competitive pressure”

This leads me to the second question:

1. b) how does the choice of the endemic species spathulatus fit into this relationship with other dolomite species?

• Pterocephalus spathulatus has been chosen as a species of high significance in the dolomite communities of the Betic Ranges (Mota et al., 1993). From the point of view of these plant communities there are associations of characteristic species that make up this type of exclusive vegetation and in which adaptations to the extreme xericity they face living in high mountain dolomite ecosystems can be identified. We have assumed that these adaptations would not only be possible in terms of their biotype, phenology, life cycle, seed dispersal, longevity... but could also occur in the case of a nutritional adaptation to life on dolomitic substrates, and this in turn would justify the high rate of endemicity and plant richness, as these are areas where speciation has been enhanced (the isolation of the high mountain is coupled with the high specificity of the substrates and extreme xericity) and could lead us to the hypothesis that perhaps these species, or some of them share physiological behaviours that allow them to thrive in this habitat, including the ability to tolerate, accumulate or excrete elements from these soils.

The paragraph 2.1. should be named “Study area and sampling“.

Namely, since you are working with an endemic species that is rare in the world, I guess for research, and especially for sampling in which you will “destroy” it, you need the permission of the relevant national institutions. This is not visible from your manuscript and should be clearly stated (usually under acknowledgment).

• Absolutely agree. Permission for the collection of the plant material was granted in the framework of the state project CGL2007-63563/BOS funded by the Spanish Ministry of Science and Innovation. For each sampling, permission was requested from the Consejería de Medioambiente de la Junta de Andalucía. In the event that the plant population was located within a protected Natural Area, express permission was requested from the Natural Park authority, and on several occasions, we were accompanied by technical personnel from the natural area. We have included this idea at the sentence in lines 221-222 in order to explain accurately the process. Thank you very much for this point.

In this paragraph, it should be stated how many specimens of the endemic plant were sampled at which locality and where the VOUCHERS are deposited (this is very important!).

• So grateful for the observation. In lines 221-224 we have included this information.

This is also directly related to the paragraph 2.3. - how was the experimental design prepared for the analysis of leaves, I guess for each locality separately, how many samples, what was the amount of analyzed leaf tissue…? But that is not stated anywhere ...

• Thank you so much for this correction. In lines 265-266 the procedure has been explained.

The paragraph 2.5. „ spathulatus plant communities“ inaccurately and insufficiently describes the design of this part of the research, and I see a potential copyright issue. Namely, a group (RNM-344) whose, apparently previously published (or at least recorded) vegetation data used in this study, was mentioned. It is not stated exactly which group and data it is? If these data are taken from other researchers / publication / database etc., they should be cited and the data used should be made visible through supplementary material (if not available through some other reference).

• The paragraph, lines 292-294, has been rewritten to clarify that all information has been generated by the authors of the text. In addition, the inventories have been attached as Supplementary Material.

Notes to be taken into account but not crucial for the "major revision" decision:

There can be no abbreviations in Keywords without clarification!

• Abbreviations has been deleted in keywords section. Thank you very much for this appreciation.

The Introduction is a little too extensive, I felt like I was reading a review article. Therefore, I would like to ask the authors to shorten the Introduction to the most necessary information on the topic.

• Some paragraphs from the introduction section have been reduced. However, we think that a deep explanation of the peculiar dolomitic habitat is necessary.

The Figure 1. is mentioned in the text after it is presented in the paper. Additional note: the images included in Figure 1 are lovely, but not all of them are necessary for the introductory part of the manuscript. One image of Pterocephalus and one of the habitat would be sufficient. For example, Convolvulus in this “story” doesn’t really matter, does it? But, I leave this part of the “decision” to the journal’s editor(s).

• Figure 1 has been placed properly. Thank you very much for the aesthetic valuation of the image’s quality. We would prefer to conserve all of the in the final version of the manuscript, in order to offer a wider vision of the dolomitic habitats in the high mountain of the Betic Ranges. Nevertheless, we also want to leave this part of the “decision” to the journal’s editor(s), as the referee indicates.

It would be desirable for your country samples to be referenced according to the World Reference Base for Soil Resources (WRB).

• Thank you for this interesting suggestion. According to the World Reference Base for Soil Resources (WRB) the sampled soils are classified as Dolomitic Regosols (do), which principal qualifier would be (do)=Dolomitic (having dolomitic material throughout between 20 and 100 cm from the soil surface or between 20 cm and continuous rock, technic hard material or a cemented or indurated layer, whichever is shallower). We have included this data in lines 272-275.

Line 183. According to the Plants of the world Online valid author names for the genus are: Pterocephalus ex Adans.

• Thank you so much for this correction.

The Acknowledgement is stated in such a way that some sources of funding are repeated, without concrete thanks to them?

• Funding and Acknowledgements have been written in order not to repeat sources.

Data Availability Statement (VERY IMPORTANT) are missing (related to my remarks on vouchers and vegetation data).

• We have included the Data Availability Statement. In addition, a supplementary section with the vegetation data has been included.

Author Response File: Author Response.pdf

Reviewer 3 Report

The article “Elementome of endemic dolomitic flora: Pterocephalus spathulatus (Lag.) Coult.” relates the nutritional quality of the soil with vascular tissue samples of Pterocephalus spathulatus. The theme is of high scientific interest and can be replicated in other territories. Overall, the article is well structured and presents quite complete information, so I consider this article to be suitable for publication in the journal Land. However, I suggest improving some aspects.

The authors adequately developed the Introduction, presenting the problems and correctly defining the objectives.

The methodology is adequate, however, the quality of the legend in Figure 3 must be improved, in order to allow a better reading. Does the entire caption need to present the information in italics?

In the Results topic, the text is enlightening and does not raise doubts for the reader, however, in Figures 4-6 I suggest that the letters in the graphics do not overlap with the bars, in order to improve reading.

The Discussion is well developed and the data presented is correctly compared with other articles.

Conclusions are based on the results obtained, presenting objective ideas that are very relevant to the scientific community.

The authors are to be congratulated for the results obtained in this work.

Author Response

Dear Reviewer,

thank you very much for your excellent review. It is a pleasure for us to have such a positive feedback. 

In order to improve the aspects that the referee suggested we have carefully revised he draft to improve the English style and to adjust it to the comments.

The quality of the legend in Figure 3 has been improved, in order to allow a better reading. The information is presented now in regular style.

As well Figures 4-6 have been changed to clarify the labels in the graphics. Now they do not overlap with the bars, so the reading is clearer.

We would like to thank the reviewer for his suggestions, which have helped to clarify key aspects of the manuscript and have considerably improved its quality.

Round 2

Reviewer 2 Report

Dear Authors,

thanks for appreciating most of my comments and explaining the comments which were “critical”. I see you even corrected some parts I didn't comment on, well done for that too.

Therefore, in this form the manuscript is acceptable for publication and I congratulate you on interesting work.

Best wishes for the future work!