The article is interesting and could make an important contribution to the field, but unfortunately in its current form the manuscript lacks research depth, visible by the lack of discussions and poor conclusions, and requires a strong development of these sections, which are also too descriptive, and lack the analytical touch required to emphasize the contribution of the study to the theoretical advancement of the field. In general, the manuscript presents too many results, without a clear indication of their contribution to the advancement of the field. Moreover, the article lacks the international exposure required for publication in an international journal. Detailed comments are provided for each section of manuscript.

The introduction does not justify the publication of the article in an international journal. The literature review is focused on China rather than on the research issue investigated in the study (vulnerability of species and influence of water level intervals). It looks that the issue addressed by the article is of local interest and does not justify the publication of the article in an international journal; a local journal would be more appropriate. The publication in an international journal would be justified by a significant advancement to the field, such as a conceptual or methodological gap, regardless of the spatial limits of the case study investigated.

Figure 1 shows the inability of authors to write up research. This is an article for an international journal, and not a report for the national authorities. The authors should present a map showing the location of the study area in an international context, making visible the neighboring countries with their names, so that a Brazilian researcher could understand it too.

The most important section of a research article, the Discussions, meant to emphasize the importance of research, justifying its publication, is insufficiently developed. The introduction identifies the research gaps filled in by the current research, but the discussions do not reveal how the results fill in this gap. Normally, the discussions must include (A) the significance of results - what do they say, in scientific terms; (B) the inner validation of results, against the study goals or hypotheses; (C) the external validation of results, against those of similar studies from other countries, identified in the literature; (D) the importance of the results, meaning their contribution (conceptual or methodological) to the theoretical advancement of the field; (E) a summary of the study limitations and directions for overcoming them in the future research. Out of all these, only the significance of results is presented; the other parts need to be developed too. Conclusions are not sufficiently broad in scope, and lack research depth, pertaining only to the case study and being in fact just a summary of the main findings. Conclusions are meant to deliver a scientific message, far away beyond the case study, to the entire scientific community, making a clear contribution to the theoretical (conceptual or methodological) development of the field. It is recommended to develop the conclusions, and to separate them from the discussions, although the Guidelines allow for it. In any case, the results are not properly exploited to reveal their broader significance.

The abstract looks like a shopping list, focusing on the case study only, and not on the broader implications of research and only on what has been done, without the slightest indication on why it has been done, and what knowledge gap is actually being filled in. The abstract is supposed to deliver ideas, and not useless figures. It needs to be rewritten entirely, and shift the focus from the case study (China) to the research issue investigated in the study (vulnerability of species and influence of water level intervals).

The authors have provided a response to my comments written in a clearer and more straightforward way than the article itself. I suggest them to insert their response, reproduced below, in the article, because it would provide the reader a better key to understanding the article than the current phrasing. Their best place is in the beginning of the discussions.

First, Poyang Lake wetland in China is an internationally important wetland and the largest bird conservation area in the world, which provides important habitats for millions of wintering water bird species worldwide. More specifically, it is the largest wintering destination for the Siberian crane worldwide, which is one of the most endangered species in the world. Thus, the study of the Siberian crane habitats in Poyang Lake wetland is of great importance to both China and the world. Second, this article focused on evaluating the habitat vulnerability of wintering migratory birds within more precise water level intervals and quantifying the influences of water level change. Therefore, at the beginning of the Introduction section, we highlighted the importance of the service function of Poyang Lake wetland ecosystem as the habitats for Siberian cranes, and then elaborated the reason why the habitat availability of cranes is highly dependent on hydrological conditions in Poyang Lake wetland. We believe that this study provided a novel perspective in evaluating the habitat vulnerability of wintering migratory birds within precise water level intervals and quantifying the influence of water level change on the habitat vulnerability in a typical wetland, which can be considered to fill a conceptual gap to the field. Moreover, the proposed approaches can be easily extended to identify the suitable habitats of other wintering birds in other typical wetlands, to evaluate the corresponding habitat vulnerability, and to quantify the response to water level change, which can be considered to fill a methodological gap.