Biodiversity in the Cueva del Viento Lava Tube System (Tenerife, Canary Islands)

Round 1

Reviewer 1 Report

The Cueva del Viento and Cueva de Felipe Reventón lava tubes located in Tenerife, Canary Islands, are the volcanic caves with the greatest troglobiont diversity in the world and among the longest volcanic caves in the world. Despite this, the information related to these caves is dispersed and incomplete. The authors present a clear manuscript about this complex of lava tubes, integrating available and new information: (i) geological data from the island relevant to the formation of these caves, (ii) their most outstanding internal geomorphological structures, (iii) analysis of the environmental parameters relevant to animal communities, (iv) an updated list of the troglobiont species and their adaptations, (v) palaeontological data, and (vi) conservation status of these tubes.

I find the manuscript well structured, with an interesting compilation on these two important volcanic tubes of the Canary Islands, world-renowned for their dimensions and biological and geomorphological importance. The English appears to be adequate, but I prefer this be assessed by the editor or other referees, since my English level does not warrant a reliable opinion. Many citations are old in terms of year, but I have verified that there are no recent articles on these caves and the topic discussed, so all citations are appropriate and I have not identified inappropriate self-citations.

The sections on Geology and Geomorphology of this cave system are really interesting and probably will be for other experts in subterranean biology. They are topics I am barely familiar with, while they are important to understand the distribution and dynamics of the populations of their subterranean fauna. In general, I consider the article will not only be of interest to the scientific world, but also to local administrations because it is an important source of information about these volcanic tubes, since they are under a process of continuous technical evaluation in order to protect and conserve them.

I find this manuscript to be a good contribution to Diversity in its Special Issue focusing on Hotspots of Subterranean Biodiversity. However, I suggest some minor changes and corrections that may improve the article. Three of them are explained below, but the rest are less important and I indicate them directly in the pdf:

1. Some confusion arises from terms used to refer to the caves or to the aggregation of several caves. The authors sometimes use Cueva del Viento to refer to all the caves in the area (see name printed in figure 2), other times they use Viento-Sobrado cave, Viento-Sobrado cave system, etc. I consider it is convenient to use only the term Viento-Sobrado cave to refer to all the connected caves that constitute this system (Breveritas (Viento), Belén, Piquetes, Sobrado, Ingleses), thus defining it as soon as possible in the text and using only this term throughout the ms to refer to such aggregation of different connected caves. I recommend referring to the Felipe Reventón cave as such (as the authors do), and avoid using the term Cueva del Viento complex to refer to the set Cueva del Viento-Sobrado plus Felipe Reventón cave. Regarding the latter, to avoid confusion and clarify the concepts, it is preferable to put "Cueva del Viento-Sobrado and Cueva de Felipe Reventón" whenever necessary, instead of "Cueva del Viento complex".

Once this is clarified, I recommend unifying the nomenclatural criteria for these caves, since throughout the text each of them are named in different ways, which can cause some confusion. I found these different names:

- Cueva del Viento-Sobrado / Viento-Sobrado cave / Viento-Sobrado

- Cueva de Felipe Reventón / Felipe Reventón / Felipe Reventón cave

At the beginning of the article, Cueva de Viento-Sobrado and Cueva de Felipe Reventón are the names almost always used, and in the second half of the article only Viento-Sobrado and Felipe Reventón are practically the terms always used… at least put “cave” behind the name of the cave.

Other different option to avoid this problem with the names of caves could be that authors consider since the beginning of the article all the caves of this area (Cueva Viento-Sobrado and Cueva Felipe Reventón) as the same cave called Cueva del Viento complex. In this case, authors have to assume that although Cueva Viento-Sobrado and Cueva Felipe Reventón are not connected by a section of tube, this lack of connection is probably not a problem for the movements of the subterranean fauna between the two caves, as already they mentioned in the text.

2. I find it unnecessary to put both figures 1 and 2, as together some data is redundant. I recommend using only figure 2 because is more informative and clear. It would be even more informative if the authors put the colours of the different sections as in figure 1, and also better in a landscape format with a larger size to clearly see the morphological details of the caves.

3. Table 1 summarises the eight richest caves in troglobionts. It seems that authors have updated the information of a previous table and now the Canarian caves have higher values of the number of troglobionts, but caves have not been rearranged based on new information about their number. With the new information, Felipe Reventón cave would be the richest cave, and Viento-Sobrado cave would be the second one together with the Postojna-Planina system. Based on these new values, the information in the Introduction section relative to the position of the Canarian caves based on their richness in troglobionts should also be reviewed, since the authors say that Felipe Reventón and Viento-Sobrado caves have the second and fourth position respectively.

Other minor revisions are indicated in the pdf of the manuscript,

Comments for author File: Comments.pdf

Author Response

Dear Reviewer

1.- We have assigned the following names to the caves, and used them always in the text:

Cueva de Felipe Reventón

Cueva del Viento with the particular names of its main parts or galleries. We have abandoned the term Viento-Sobrado because Sobrado is only one of the five main parts of Cueva del Viento proper.

Cueva del Viento System when referring to both caves together. We preferred “System” to “complex”. Therefore, we have followed your second option. Actually, we have changed the title: Biodiversity in the Cueva del Viento lava tube system (Tenerife, Canary Islands).

2.- In Figure 1 we have eliminated the orthophoto (wou were right, the survey was not well contrasted with the orthphoto), and included instead another composition with a mapo f the archipelago and a map of Tenerife with the location of Cueva del Viento System and the Pico Viejo volcano that produced the lava flows.

3.- After request of the editors of our article, we have deleted Table 1 because they  are going to include a similar one with new data.

We have followed most of the small corrections you had suggested for the manuscript. Most of them are commented in our new versión of your PDF.

Thank you for your comments, that have substantially improved our manuscript.

Pedro Oromí and Sergio Socorro

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

After minor corrections and additions, I warmly recommend the manuscript for publication in the journal Diversity as the paper is of utmost importance as an overview of the most important sites for diversity in volcanic caves.

All technical corrections and comments were added directly in the pdf document of the manuscript (figure captions, text corrections,...).

All the very best,
 
Reviewer

Comments for author File: Comments.pdf

Author Response

Dear Reviewer

We have followed almost any change and correction that you suggested, all of them corrected in the pdf you sent as well as in the final draft.

We have changed Figure 1 (which was not very clear) by a mapo f the archipelago and a map of Tenerife with location of the caves and the Pico Viejo volcano that produced the lava flows.

We have added to the Figure 3 red and white arrows indicating lava stalactites and roots, respectively.

Lines 270-271, new text: In various passages of Ingleses one can see how the hot flows through the tube “corroded from the inside” the solidified lava in the pahoehoe flow on the surface that had formed the roof of the tube.

The former Table 2 (now Table 1: the ditors suggested to delete the old Table 1): In my original table the names had no word partition, this was done by the journal. I have ammended this but I don't know if the journal will respect it. After request of the editors, I have added the dates of description of the species.

Lines 429-430. We don’t agree with the changes you suggest, because Oromia hephaestos des not occur neither in the MSS nor in La Gomera.

Line 442, new text: Detritivores are more varied than root-feedin species.

We have followed all your other suggestions, which have been very useful to improve the English, and the manuscript as a whole.

Thank you

Pedro Oromí and Sergio Socorro

Author Response File: Author Response.docx

Reviewer 3 Report

Dear authors,

thank you for this quite comprehensive overview of two fascinating lava tube caves. Given the wide scope of the article, I have to admit that I was only able to comprehensively review the biospeleological / faunistic aspects; and added a few general remarks.

Please find my detailed comments in the attached PDF file. Furthermore, I herewith want to highlight a few points which I especially want to ask for a careful revision:

1) although the article is aimed for getting published in the special issue on "hotspots of subterranean biodiversity", the current title alone does not explain the intention of the manuscript. Imagine a reader who is searching for articles and simply reading this title. It would be thus great to refine the title further

2) the overall language is quite technical. If the aim is to address a highly specialised audience (which is difficult given the so many topics) this would be ok, otherwise, the average reader will not understand several of the terms used. Please re-word some passages for improved readability.

3) it is especially important to refer and cite the biospeleological concept for cave-dwelling in your manuscript. Troglobionts are treated differently by different authors. Also "cave-dwelling taxa" often can involve also subtroglophiles and eutroglophiles, not only (eu)troglobionts. Sometimes MSS-dwelling taxa might be included, sometimes not...

So it is really important to state and refer to the concept you are applying, and checking if comparisons are based on troglobiont numbers inferred from the same concept.

4) you should also take care that the numbers listed in table 1 for "troglobionts" are referring always to the same concept.

5) more specific question to table 1: why are both lava tubes treated as two separate caves of apparently the same system (at least for cave-dwelling invertebrate taxa, not yet for humans), whereas Postojna-Planina is listed as a single?

6) is there an overview of subtroglophile and eutroglophile species occurring in the caves? It would be interesting to add to the table of troglobionts, as they are also important parts of the subterranean biodiversity. Especially when the special issue topic is about subterranean biodiversity. Here, not only troglobionts but cave-dwelling taxa (obligate or facultative, or temporary) are important to indicate in my opinion.

Otherwise, I very much like especially the images shown. They give a good and comprehensive overview of characteristic taxa.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer

We have followed most of the detailed comments of the PDF you attached. We have noted the corrections and short comments therein, as well as in the final draft. Concerning your special points:

1.- We have changed the title: Biodiversity in the Cueva del Viento lava tube system (Tenerife, Canary Islands).

2.- We have reworded some technical passages, and especially some technical terms.

3.- We have differentiated the concept “life forms” and “lifestyle” in order to explain which species are included in our troglobiont list and comments, according to Deharveng & Bedos (2018, page 115), and we have include a definition of each term the first time they are used in the text. Evenmore, we have included in the list of Table 1 (formerly Table2, because the old Table 1 has been deleted after request of the editors) a column with the particular life form of each troglobitic species (troglomorphic, hypogeomorphic, edaphomorphic). On the recommendation of the editors, we have used troglobiont as a noun, and troglobiotic as an adjective.

4.- The former table 1 has been deleted.

5.- We have considered Viento and Felipe Reventón as a single lava tube system, both in the title and in general comments in the text referring to both caves together. However, we have used the names of each cave when we refer to peculiarities of each one, and they are still separated in the species list.

6.- We have not listed the subtroglophile and eutroglophile species, but we have defined these tems and applied to annotated species, and added some more to the text.

Your comments and corrections have been very useful to improve the English, and the manuscript as a whole. Thanks so much.

Pedro Oromí and Sergio Socorro

Author Response File: Author Response.docx