When Theory Meets Practice: Balancing Genetic Diversity and Behaviour When Choosing Founders for a Recently Reintroduced Bison (Bison bison) Herd in Banff National Park, Canada
Round 1
Reviewer 1 Report
In this study, the authors report on the genetic diversity and structure of a recently reintroduced bison population in a Canadian national park. The text is well-written, succinct, and materials and methods described in sufficient detail.
However, using only 10 microsatellite markers in such a small population is unlikely to produce any population structure in the data – therefore the results are not surprising. The analysis should have been conducted with either more microsatellites or SNPs, or by including data from previous studies. I strongly encourage the authors to go back to their data and conduct additional analyses using other Bayesian clustering methods as well as other techniques. Running the data through Structure is the bare minimum and there surely is much more information that they could get out of their samples. As the study currently stands, there is very little value and novelty.
What is also missing is a thorough discussion on how their study fits within the context of previous research – not only on bison but also on other large herbivores and on reintroduction programs and their outcomes.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
In this manuscript, Wilson et al. describe the procedure they conducted to select plains bison for reintroduction to an unoccupied area of their historic range in Banff National Park (Canada). They mainly used genetic criteria for the selection of individuals and assessed the consequences of these criteria on the genetic composition of the reintroduced herd. The authors made a valuable effort by considering both genetic measurements, as well as health and safety of the animals as criteria to select the best set of founders. Moreover, they used interesting strategies to capture as much genetic diversity as possible from the source population.
However, there are drawbacks that can prevent the publication of the manuscript in Diversity journal. Firstly, there are no relevant scientific questions addressed in the work. In the manuscript, the authors described the methodology they used to choose the founders and the genetic consequences of this methodology. Choosing unrelated founders with unique or rare alleles is expected to increase genetic diversity measures such as the allelic richness and the expected heterozygosity in the founding population. Considering the title and the objective of the work (“determined the effectiveness of these techniques in ensuring…”), the reader might expect a research article that uses statistical procedures to compare different techniques and determine their effectiveness in maximizing the genetic diversity of the reintroduced population.
Second, the procedure of choosing founders is not clearly explained. The description of the procedure for choosing founders is a main issue in the manuscript. However, the lack of information and imprecisions in the procedure makes it impossible to repeat the work. I point out some missing information and some imprecisions:
Material and Methods section:
How was determined the age of individuals?
How was determined the pregnancy status?
Were the 25 candidate funders the only individuals that complete the age, sex and pregnancy criteria? In case there were more individuals in the group of captured animals (N=70), what criteria were used to select the founding candidates?
Why were 12 females and 4 males recommended as founders?
Information about the 50 microsatellite microsatellite markers for maternity assignments is insufficient.
Results section:
If the ranking of individuals was stablished only using the MAF criterium (see females 443 and 424 in Table 2), why did the authors determine unique or rare alleles?
The threshold to categorize a pair of individuals as closely related seems to be 0.5. Is there a reason to use this threshold?
In Table 2, female 453 was categorized as a used founder. However, in the main text the authors wrote that this female was removed.
Why did females 435 and 437 were removed from the group of used founders?
Why did male 420 was used as a founder instead of male 445? Note that male 445 had higher ranking and the male 420 was closely related to the used 425 female.
Finally, there is a decision that did not follow the argumentation provided in the Introduction and Material and Methods sections. I agree with this decision, but it makes the article less publishable. The authors rightly put health and security criteria before genetic criteria to select founders. However, this decision was not related to the objectives of the manuscript. I don’t mean that the decision was erroneous, but it deserves a refocus of the manuscript. Moreover, because of this untreated argument, a premise of the work was changed: the number of founder males was established in 6 instead of the recommended 4. As the authors discussed, the increase of the number of founding males might have positive consequences on the viability of the reintroduced populations. I’m not sure the reasons for the recommended number of founding males, but this was a premise in the work and this premise was broken by reasons that were not related to the issues treated in the manuscript.
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
Inclusion of pregnant females may considerably improve the genetic variety of tiny founder populations, according to the manuscript's description of the genetic diversity in bison (Bison bison bison). Although the adult reintroduced herd had fewer alleles and observed heterozygosity than the larger source herd, anticipated heterozygosity was greater, perhaps as a consequence of favouring animals with uncommon alleles.
To evaluate the genetic diversity in the source population, 58 individuals (33 from Elk Island NP, 33 from each possible founder) had their tail hair samples taken.
Results and analysis are sufficient; however, the sample size is insufficient to draw firm conclusions and make recommendations.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Dear authors, thank you for your revised version. I am satisfied with your responses and edits.
Author Response
Thank you for all of your work reviewing the manuscript. We’re glad you think it has been improved.
Author Response File: Author Response.docx
Reviewer 2 Report
In this new version of the manuscript, Wilson et al. carried out improvements in relation to the previous version. They provided more information on the methodology and corrected inaccuracies. They have also changed the focus to consider the behavioral aspects of their results. I agree with the authors that the application of existing techniques to real world situation is a valuable contribution to the scientific literature. The positive contributions of reviewer 1 and Academic Editor, as well as the possibility of resubmission provided by the Editorial Office, made me to reconsider my recommendation.
My overall recommendation has changed to Major revision, but there is a relevant consideration that the authors should address. Despite the improvements conducted, there is a comment that was not solved. The authors should provide methodological for the work to be repeatable. They focus their results and discussion on the genetic perspective. However, there was a relevant result that determined the final set of founders: the aggressive social interactions. For the work to be repeatable, the authors should address the following issues:
Method.
11) Describe the behavioral variable that was used to measure aggressive social interactions.
22) Describe the methodology to quantify this behavioral variable.
33) Design an index to objectively select the founders. This index should incorporate genetic and behavioral variables.
Results.
44) Show the results of the behavioral variable for each individual or for each pair of individuals. This information might be included in tables 1 and 2, or in a new table.
55) Show the result of the selection index for each individual.
The addressing of these issues would significantly improve the presentation of results and favor the repeatability of the work. Furthermore, it might help the authors detect inaccuracies and readers follow the results. For instance, after mi previous comments and the authors’ responses I can’t find the reasons why the female 437 and the male 445 were not used as founders.
Minor comment.
There are sentences and paragraphs that should be moved to the Methods section. For instance: L181-184, L243-245 or 285-292.
Author Response
Reviewer 2:
In this new version of the manuscript, Wilson et al. carried out improvements in relation to the previous version. They provided more information on the methodology and corrected inaccuracies. They have also changed the focus to consider the behavioral aspects of their results. I agree with the authors that the application of existing techniques to real world situation is a valuable contribution to the scientific literature. The positive contributions of reviewer 1 and Academic Editor, as well as the possibility of resubmission provided by the Editorial Office, made me to reconsider my recommendation.
My overall recommendation has changed to Major revision, but there is a relevant consideration that the authors should address. Despite the improvements conducted, there is a comment that was not solved. The authors should provide methodological for the work to be repeatable. They focus their results and discussion on the genetic perspective. However, there was a relevant result that determined the final set of founders: the aggressive social interactions. For the work to be repeatable, the authors should address the following issues:
Method.
1) Describe the behavioral variable that was used to measure aggressive social interactions.
Thank you for all of your suggestions. We appreciate all of the time you have put into your review.
This has been added to the Methods section, lines 143-158.
2) Describe the methodology to quantify this behavioral variable.
This has been added to the Methods section, lines 143-158.
3) Design an index to objectively select the founders. This index should incorporate genetic and behavioral variables.
We included a behavioral (stress) score that the reader can balance against the more scientifically measured genetic variables (Tables 1 and 2). A combined index incorporating both was not possible, as concerning behavior always trumped genetic variables. While we would have liked to be able to place more weight on the genetic variables, ultimately cramming a panting, perpetually chased and stressed bison into a container with its pursuers was not an option.
Results.
4) Show the results of the behavioral variable for each individual or for each pair of individuals. This information might be included in tables 1 and 2, or in a new table.
Addressed in new column within Tables 1 and 2.
5) Show the result of the selection index for each individual.
This has been added to Tables 1 and 2, and the iterative approach used to choose founders based on behavioural characteristics is described in 263-279
The addressing of these issues would significantly improve the presentation of results and favor the repeatability of the work. Furthermore, it might help the authors detect inaccuracies and readers follow the results. For instance, after mi previous comments and the authors’ responses I can’t find the reasons why the female 437 and the male 445 were not used as founders.
We agree these changes improve the MS, and thank the reviewer for the recommendation. Reasons for excluding those animals from the founders (behavior) are now more apparent in both Tables 1 and 2 and the associated text in lines 263-279.
Minor comment.
There are sentences and paragraphs that should be moved to the Methods section. For instance: L181-184, L243-245 or 285-292.
Thank you for the suggestions. L181-184 and 285-292 have been moved to the Methods section. The brief L243-245 section has not been moved, as we do not discuss effective population size until after we mention that the sex ratio had to be modified and we felt this flow was better. Hopefully this is acceptable to you.
Round 3
Reviewer 2 Report
In this new version of the manuscript, the authors significantly improved the presentation of their results. The behavioral methodology is now described, and the results of aggressive social interaction have been incorporated in tables 1 and 2. The authors have also clarified the criteria they used to select or reject each individual as founder.
Minor comments.
1) L178-179. “This led not only led to…”. I don't feel qualified to judge about the English language and style, but authors might revise this sentence.
2) Authors should only include in the Results section the results they obtained. Explanations about a genetic measurement (L209) or the effective population size (L350) were not results of the study. Authors should revise the Results section and confirm that they are only including results.
Author Response
In this new version of the manuscript, the authors significantly improved the presentation of their results. The behavioral methodology is now described, and the results of aggressive social interaction have been incorporated in tables 1 and 2. The authors have also clarified the criteria they used to select or reject each individual as founder.
Thank you, we’re glad that you feel the manuscript has been improved.
Minor comments.
- L178-179. “This led not only led to…”. I don't feel qualified to judge about the English language and style, but authors might revise this sentence.
You are correct, and thank you for pointing it out. The text has been changed to, “This not only led…” (L152 in the latest version).
- Authors should only include in the Results section the results they obtained. Explanations about a genetic measurement (L209) or the effective population size (L350) were not results of the study. Authors should revise the Results section and confirm that they are only including results.
As the reviewer suggested, the MAF description has been moved from the Results section to the Materials and Methods (L123-126). The Ne description has been moved from the Results section to the Materials and Methods section (L156-164). It does not appear that there are any other parts of the Results section that need to be moved to a different part of the article.
