PONE-D-21-19581

Trophic niche overlap between coyotes and gray foxes in a temperate forest in Durango, Mexico

PLOS ONE

Dear Dr. Valenzuela-Galván,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

The manuscript is well written and the data presented are valuable. However, several parts can be improved following the reviewers' suggestions (see also the attached file). Particular care must be given to the introduction and conclusion (discuss mechanisms allowing niche overlap and coexistence) and the methods (more details on the transects and fecal collection). 

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PLOS ONE

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Reviewers' comments:

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: No

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This manuscript provides a simple, straightforward examination of dietary niche overlap between sympatric coyotes and gray foxes. As the authors point out, there is a lack of data examining the partitioning of these two ecologically similar and highly overlapping carnivores. I believe the authors’ research provides valuable information on the dietary niches of these two species. However, I also note a number of points that could be addressed to strengthen the manuscript.

1. The introduction could benefit from a bit more thoughtful expansion. The authors state that high trophic overlap for ecologically similar species is rare (line 45), but I might disagree. There are many sympatric generalist species, including carnivores (such as foxes, coyotes and bobcats), that can have high trophic overlap but coexist through mechanisms such as fine-scale spatial and/or temporal partitioning. In fact, the authors mention a study where coyotes and gray foxes can be found to have high dietary overlap (line 55). I believe it would strengthen the introduction to discuss the mechanisms which allow sympatric species with overlapping trophic niches to have stable coexistence. The authors mention that trophic niche segregation may allow stable coexistence (line 64), but what about circumstances (such as the findings in this manuscript) where trophic niche overlap is high but coexistence still appears to occur?

2. The transition from the broad introduction to the authors’ specific research seems a bit abrupt. Further discussion on how the reasoning and application of this research may be prudent.

3. In the Sample Collection and Identification section, a few points may benefit from clarification which could improve future design replication:

a. How were transects allocated with respect to vegetation type? What was the length(s) of each transect?

b. This is quite minor, but it feels inappropriate to say all feces were removed from the study area (line 99). Instead, “all feces were removed from the transects” might be more appropriate.

c. Were there any other sympatric carnivores that could be mis-identified as grey fox or coyote (e.g. Mephitidae species or other Vulpes species)? Especially if so, were all other scats cleared from transects during each survey?

4. Although the authors mention sampling transects in each vegetation type, and that coyote food item consumption may vary by habitat type (line 276), vegetation type is not included in any analysis or discussion. The authors find high dietary overlap, but do not discuss any other mechanisms which may facilitate stable coexistence. Examining the spatial overlap (site based or vegetation type based) of both species occurrences and dietary items may further illuminate the mechanisms which allow for sympatry of these two species. While this is briefly mentioned as a potential mechanism (lines 325 – 326), the authors likely have the necessary data to examine a spatial component as well (location and vegetation association of scat samples) to improve their findings.

5. The authors do a good job of thoroughly reviewing the findings in the discussion, but could strengthen their conclusions with greater connections back to the introduction. The authors do not relate back to their prediction in the introduction (lines 73 – 77), and I believe this would be important especially because the authors found high and not low trophic niche overlap. Due to these findings, further discussion on if/how stable coexistence may be occurring could be beneficial. The final conclusion in the discussion feels a bit lacking and leaves the reader wondering how these findings are applicable and where researchers/managers might benefit and move forward.

6. The authors have generally written a nice manuscript, but it could be improved with some editing to correct grammar and improve sentence flow. A few examples are:

a. Lines 33 – 35: the first “difference” would read better as “differences” ; “these different body sizes canid species” perhaps instead could be “these different sized canid species”

b. Line 47 and 59: what is “them” referencing ?

c. Line 55: “its distribution the overlap of its diets” – what is “its” referencing?

d. Lines 61 – 65 and lines 73 - 77: these sentences are a bit hard to work through and could be improved with grammatical changes and/or being broken into two sentences.

Reviewer #2: The subject is interesting. However, it lacks many details of the methodology in the collection of samples. It is important to have information on the period with which the transects traveled, if in all the collections they traveled the same transects. This is due to the fact that generalist and opportunistic species such as the coyote and the gray fox can vary their diet in reduced time and space. On the other hand, the morphological characterization of the excrements would be convenient to strengthen it with some chemical or molecular technique; because its morphology is similar and the probability of error is high. On the other hand, it is important to include complementary material with the characteristics of the hair of the identified species because several are similar.

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Reviewer #1: No

Reviewer #2: Yes: octavio monroy-vilchis

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Attachments

Attachment

Submitted filename: PONE-D-21-19581.pdf

PONE-D-21-19581R1Trophic niche overlap between coyotes and gray foxes in a temperate forest in Durango, Mexico PLOS ONE

Dear Dr. Valenzuela-Galván,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

The authors adequately addressed all the reviewers' comments. However, I agree with Rev 1 in that readability of the manuscript must be improved, and English grammar and structure thoroughly checked and revised. Once these issues are addressed, I will be happy to accept the manuscript. Some minor changes are suggested below (please revise the entire manuscript for other typos or errors).

Please submit your revised manuscript by Nov 22 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Nicoletta Righini, PhD

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments (if provided):

Some minor revisions:

L. 16: Resource partitioning, and especially dietary partitioning, is …..

L. 18: Mexico – without accent

L. 18: Better put ‘in Mexico’ after ‘widely distributed’

L. 20: HAVE not been

L. 40- understanding the ways in which species partition these resources

L. 46- IT is relatively common…

L. 61- ..THEIR coexistence..

L. 68- THESE canids

l. 70 – HAVE not been thoroughly studied

L. 77- a mechanism partly explaining

L. 127- We CHOSE

L. 128-131: ‘spp.’ must not be italicized, only the name of the genus goes in italics, e.g. Pinus spp.

L. 132- formal collection of FECAL samples

L. 134- however THEY all produce..

L. 135- careful to IDENTIFY feces

L. 138: IN the vicinity of the collection site (delete ‘DE’)

L. 145: Please rephrase (season considered and considered…)

L. 145: we assigned feces TO any..

L. 146- feces collected IN a particular season WERE representative…

L: 147: IN that period of the year.

L. 148-49: In THE laboratory….and washed THEM with water

L. 160: trough THEIR guarding hairs

L. 167: the overall and SEASONAL representation

L. 170: the percentage of feces that CONTAINS…and although IT DOES not necessarily…

L. 185: Mexico without accent

L. 190 : and that they DID NOT HAVE any issues in LETTING us do…

L. 194: FECAL samples

L. 201: we EXPLORED

L. 337: detected in coyote’s feces likely represent carrion…

L. 340: COINCIDE with the feeding patternS

L. 373-374- IN the area…..differences we found IN trophic diversity

L. 378: However, the relevance of each….

L. 379: IN the coyote’s than IN the gray fox diet

L. 379: Delete ‘and’ at the beginning of the sentence

L. 395: FECAL samples

L. 398-399: shouldn’t this be ‘ defecate several hours LATER..’? (not ‘before’)

L. 399: IN a different habitat type

L. 399- However, differences among habitats in the success…

L. 401: in accordance WITH our findings

L. 410 – FOR a better understanding

L. 411: can help minimize

L. 415: IN this Natural Protected Area

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

********** 

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

********** 

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

********** 

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

********** 

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors thoughtfully addressed the initial review comments. My only minor comment is that the manuscript requires a final proof-read to eliminate any typos and improve readability through correcting some grammar and sentence structure. A few examples from the Introduction, but not a thorough list, are below:

• Line 46: what is the subject of “is relatively common” ?

• Line 54 – 57: This sentence is a bit difficult to understand

• Line 57: “this kind” should be changed to “these kind” to match the plural of “interactions”

o Also on line 62: “this questions” should be changed to “these questions”

• Line 62: “choose” should be “chose”

• Line 63: there should not be a comma after “species”

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If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

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Trophic niche overlap between coyotes and gray foxes in a temperate forest in Durango, Mexico

PONE-D-21-19581R2

Dear Dr. Valenzuela-Galván,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Nicoletta Righini, PhD

Academic Editor

PLOS ONE