Increased Genetic Diversity via Gene Flow Provides Hope for Acacia whibleyana, an Endangered Wattle Facing Extinction

Round 1

Reviewer 1 Report

Dear authors

I think it is a quite good work on how the use of several genetic analyses and softwares can be used to detect problems coming from inbreeding, outbreeding and genetic drifts, and how admixture of several population origins can boost ans enhance genetic diversity (at least in a first generation!). This work can be particularly useful for plant conservation officers and field managers and the techniques used can be exported also to other cases of endangered species where similar experiences of conservation translocations have been made. In my opinion the manuscript deserves to bee published without significant modifications.   

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper by Blyth et al. describes genome-wide genetic diversity within and among remnant stands of the endangered Acacia whibleyana which is endemic to Eyre Peninsula in South Australia. Specifically, double digest restriction-associated DNA sequencing (ddRADseq) was performed on 237 samples representing the distribution range of the species. In total only about 1800 individuals are left across all subpopulations.

All parts of the paper are very well written and appropriate state-of-the art data analyses were conducted. Most of the conclusions are justified by the data.

However, the main conclusion of low genetic diversity within species needs to be supported by additional data using comparisons with more widespread related species or species displaying similar life history traits. Are there any comparable studies on SNP variation in other Acacia species? At least, the level of within-population variation at the SNP markers should be compared with other predominantly outcrossing tree species. Ideally, a reference population of a more widespread Acacia species could have been included in the diversity assessment.

Finally, the sampling design should be described in more detail. The sample sizes for the genetic diversity assessment vary from 5 to 39 samples (Table 3). Was the sampling exhaustive for some or all stands or random within stands? Is it possible to give approximate individual numbers per stand to evaluate whether the samples analysed were representative for the stands? Please explain how the different sample sizes could have affected genetic diversity estimates.

Please address these point in the revised version. Overall, I consider the paper as a valuable contribution for the management and restoration of this endangered tree species.

Additional edits and comment are included in the pdf file.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx