-->PONE-D-26-02051-->-->Taking Stock: Can captive species contribute to biodiversity conservation?-->-->PLOS One

Dear Dr. Lennon,

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.

Both reviewers agree that your study is valuable and robust. However, they also raise important though minor concerns that must be addressed concerning the validity of keeping captive species at zoos, and data analysis.

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Academic Editor

PLOS One

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Reviewers' comments:

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Reviewer #1: Yes

Reviewer #2: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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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: As zoological institutions continue to brand themselves as conservation organizations, I think it is a valid exercise to investigate the actual conservation value that their collections provide. Therefore I read this article with great interest. Overall the paper is clearly written, well supported by references, and its conclusions appear supported by the data they share.

It comes across as an assumption in multiple places throughout the paper (e.g. title, intro, discussion) that holding threatened/endangered species counts as helping conserve them, regardless of the other actions taken. While they do highlight some nice case studies in the UK where further conservation action is taken (e.g. reintroductions), this is not the case for the majority of threatened species held ex-situ in BIAZA institutions. It would be helpful to clarify that the contributions of zoological institutions to conservation requires more than just holding species, but actively breeding, releasing or mounting public support for conservation action, etc.

I have a few minor points of clarification that would be helpful for the authors to consider, as detailed below:

Line 86-87 A distinction might be useful here. Housing threatened species only makes conservation sense if they are used for research or breeding and release that benefits wild populations. Holding them alone does not mean any conservation action is actually taking place. And in cases where the ex-situ populations of animals are not sustainably managed, it may actually be more ethical to house non-threatened species, since removal from the wild is less likely to impact species’ status.

-I don’t dispute that covering 92% of BIAZA members should provide a good overview of the status of BIAZA collections. However, did the authors identify any biases in the institutions they weren’t able to access? For instance, if that 8% covered mostly small, regional zoos, then they might be missing out on collections of regionally important species. Alternatively if it was a random sampling that were missed, then it would be less likely to introduce biases. This extra information would be helpful for readers to assess the quality of the sample.

Table 1: the figure capture is missing a description for “DD”, which presumably is data deficient.

Line 373- The cause and effect here is hard to disentangle. Yes, a high proportion of BIAZA’s amphibian species are threatened, but might that not simple be because amphibians are more threatened globally than other species (line 89)? It does not mean these species were selected for collection planning because of their status, but could be that wild population trends have been so poor that more of the species held have become threatened over time.

Reviewer #2: The manuscript "Taking Stock: Can captive species contribute to biodiversity conservation?" addresses a relevant and debated topic in zoo biology and conservation policies. The paper is well-written, clear, and provides a novel regional perspective by assessing both species richness and population abundance within BIAZA institutions. The methodology is generally robust and effectively uses the Shannon Diversity Index to explore ex-situ population dynamics.Major/Minor Concerns (Statistical Clarification)Methodology & Analysis (Anova Assumptions): In lines 222-224, the authors state they used an ANOVA test to analyze native species population sizes across vertebrate classes because homoscedasticity was met (Lavene's test p<0.090). However, since the overarching dataset presented non-normal distribution patterns (as stated for the Mann-Whitney and Kruskal-Wallis segments), please clarify if the normality assumption was verified specifically for the native species subset to validate the use of a parametric test.ConclusionThe manuscript meets most of PLOS ONE’s publication criteria. It reports original research, adheres to ethical standards for metadata usage, and provides full data availability. Addressing the minor statistical detail regarding the ANOVA assumptions will further strengthen the manuscript.

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Reviewer #1: No

Reviewer #2: Yes:  ACACIA EDUARDA DE JESUS NASCIMENTO

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Taking Stock: Can captive species contribute to biodiversity conservation?

PONE-D-26-02051R1

Dear Dr. Lennon,

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.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Ulrike Gertrud Munderloh, Ph.D.

Academic Editor

PLOS One

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