Beyond Site-Specific Criteria: Conservation of Migratory Birds and Their Habitats from a Network Perspective

Round 1

Reviewer 1 Report

General comments

The proposed work aims to rationalize several crucial aspects and steps to create a theoretical framework necessary to design a network of areas for the protection of species that are forced to move to satisfy different ecological needs during their biological cycle.

I appreciated the work because I am convinced that, within this framework, it is essential to consider the spatial configuration of the landscape. The spatial evaluation of nodes and edges allows not only to design an effective network of protected areas but should also facilitate (at least this is the hope!) The work of policy makers, from the national to the international level, in allocating resources. usually scarcely intended for the conservation of biodiversity.

Specific comments

L.28 and following: You wrote: “….and then define ‘edges’ from the probability of movements between each pair of nodes”. The meaning of this part of the sentence is not clear to me. I believe that information of this type on connectivity is certainly objective, if based on empirical data (e.g., capture-recapture data, isotopes, genetic data, ...) and, if I'm not wrong, you are referring to migratory connectivity, between breeding and wintering areas, including stop-over sites too. Alternatively, are you also referring to possible dispersal movements? (even if this is not clear from the title).

Moreover, as a second step, I found the description of an actual connectivity "proxy" based on "a number of metrics". It is not clear to me for what purpose this step is necessary. Perhaps to find a proxy of connectivity and estimate its values (by predictive modelling?) for those sites for which no empirical data is available?

I think these concepts should be clear from reading the abstract alone.

LL.49-50: You wrote: “This can subsequently lead to population declines, and can reduce ecosystem services provided by these birds”.

I agree that ultimately the decline of some specific populations poses a problem of loss of ecosystem services. However, first I would have highlighted the negative aspect of biodiversity loss for its intrinsic value, regardless of the value it has for humans.

LL.63-65: At the end of the Introduction section I would have expected to find the specific aims of the paper and not only “…review the existing the major international conservation frameworks and propose a three-step quantitative approach.”

L.67. Section title. It is not clear from the title that this is the review declared at the end of the introduction

L.68: “this specific aspect” …which one? Starting a new paragraph, I think it would be better to be more explicit.

LL.74-76: “…and summarize their contribution by dividing the count of criteria in the corresponding category by the total number of included criteria, although certain weighing factors can also be included.” This sentence is not clear to me.

LL.77: You wrote: “Details of criteria for diversity, abundance, habitat properties and networks are given in Appendix S2.4” S4 is a list of references, not detailed criteria. In addition, to facilitate the reader, I would have expected to find the meaning of the levels of each criterion (e.g., C2, Aa, (Stage1), Sub-qualifier2.1, …) in the table footnotes.

L116: “(staging)”, is it necessary?

LL.125-130: For some criteria, in addition to the percentage, you give the number. Why not for everyone?

L.166: I found quite strange the incipit “Approach N1 defines…” without defining it before. Perhaps it would be enough to reverse the sentence. You could adopt the same structure used to describe W1.

LL.182-183: Please check. Something went wrong

L.184: The same for L.166

L.185: “Focal species” might be ambiguous. Could another term be used?

L.195: More recently even Ensemble Models;
e.g., Ratheret al 2022. Ensemble modelling enables identification of suitable sites for habitat restoration….. Ecological Engineering, 176, 106534; Dondina et al 2020. Combining ensemble models and connectivity… PLoS ONE. 15:e0229261.

LL.217-218: the last sentence of the paragraph is not clear to me.

L.220 and following: The first two sentences are not clear to me. Only after reading the third sentence the reader can understand the meaning of the paragraph. Delete or, shortening, join the first two sentences to the third.

L.286: move the abbreviation "PC" before "Approach C2". Is this acronym essential? I didn't find it in the rest of the text or in the embedded table.

Box 1: Since you used "edge" and "path", you should say what the difference is between the two terms (in case there is one. Otherwise it would be better to use the same term).

L.351: Anser albifrons in italics

L.361: Voelkl?

Author Response

Dear reviewer,

Thank you for your valuable comments. We submit the revised version of our manuscript and the response letter to your comments.

In the revised manuscript we denote how and where we have improved the text, and in the accompanying response letter we address how we have carefully considered and incorporated each general and specific remark or question raised by you.

Yours sincerely,

Yanjie Xu (also on behalf of Andy J. Green, Taej Mundkur, Ward Hagemeijer, Haitham Mossad, Herbert H. T. Prins, Willem F. de Boer)

The Helsinki Lab of Ornithology

Finnish Museum of Natural History

University of Helsinki

Finland

Email: [email protected]

Author Response File: Author Response.pdf

Reviewer 2 Report

While I am fairly familiar with the literature related to  migratory connectivity, I am not very familiar with these specific networks, and also learned much about the technical aspects of network connectivity.  Thus, while I overall think this is a valuable contribution to the literature, my ability to provide constructive criticism is based only on my general knowledge.  The writing was very clear, and I have only a few minor typographical suggestions, below.  I do think that there needs to be a stronger or clearer thesis and identification if next steps.  My main comments are somewhat general:

1. While there is some mention of sonbirds, the majority of the networks and the recommended actions seem to appear to waterbirds and their habitats.  I think perhaps the title or the introduction could better frame which groups/guilds of migratory birds apply.  I think this approach applies less well or at least differently to migratory birds that use terrestrial habitats (which are more diffuse) or rely on terrestrial habitat at the beginning or end of a longer distance flight over water.  
2. I think the clarity of the recommended actions or parameters to estimate should be made more clear through some sort of conluding paragraph.  
3. It is unclear to me the degree to which the 3-step approach would succeed unless a large majority of the nodes are known (which may be a massive sampling effort).  Is there a way to parameterize some of these measurements when a minority of nodes are known (i.e. when birds sampled at one node have a low second observation rate).  Or, should there be more discussion of how to do this, e.g. with satellite data (which is mentioned).  Maybe an example of the 3 step approach with a species/network would help.  

line 157:  understandings

line 182-183: Second bullet;

line 396-398:  here may be an opportunity to contrast waterbirds vs. terrestial before then comparing to other classes

Author Response

Dear reviewer,

Thank you for your valuable comments. We submit the revised version of our manuscript and the response letter to your comments.

In the revised manuscript we denote how and where we have improved the text, and in the accompanying response letter we address how we have carefully considered and incorporated each general and specific remark or question raised by you.

Yours sincerely,

Yanjie Xu (also on behalf of Andy J. Green, Taej Mundkur, Ward Hagemeijer, Haitham Mossad, Herbert H. T. Prins, Willem F. de Boer)

The Helsinki Lab of Ornithology

Finnish Museum of Natural History

University of Helsinki

Finland

Email: [email protected]

Author Response File: Author Response.pdf

Reviewer 3 Report

The article entitled "Beyond site-specific criteria: conservation of migratory birds and their habitats from a network perspective" establishes a new method to determinate interesting places in migration routes of birds. A very exhaustive information has been used to provide a remarked tool to validate the protection of regions used by migratory birds.

Author Response

Dear reviewer,

Thanks for your affirmation and kind words.

Yours sincerely,

Yanjie Xu (also on behalf of Andy J. Green, Taej Mundkur, Ward Hagemeijer, Haitham Mossad, Herbert H. T. Prins, Willem F. de Boer)

The Helsinki Lab of Ornithology

Finnish Museum of Natural History

University of Helsinki, Finland

Email: [email protected]