Effects of Habitat Change on the Wintering Waterbird Community in China’s Largest Freshwater Lake

Round 1

Reviewer 1 Report

General comments:

The paper entitled “Effects of habitat change on the wintering waterbird community in China’s largest freshwater lake” has been reviewed and evaluated for publish. The authors make great effort to compare the wetland and the waterbird community. However, I find the results may be un-robust and biased because the authors compared only the data for 2007 and 2019 without further information to see the long-term changes. I suggest adding data for more years between 2007 and 2019 could help to examine the trend. Almost all the relationships are statistically insignificant. This would be very difficult to make conclusion. I think an updated analysis is needed. Is the format to cite references in the text correct? The authors need to check and confirm this. Specific comments are provided below for authors improving the paper.

 

Specific comments:

1. Introduction

Because the waterbird species is important to the Poyang Lake wetland, I would suggest that the authors may include relevant studies on the waterbird community. This helps the understanding of the waterbird ecology in wetland as the background information.

 

Last paragraph: we first compared waterbird diversity and habitat area in 2007 and 2019…

Explain why you select the year 2007 and 2019 for comparison.

 

2. Methods

2.1. Study area

We studied 16 sub-lakes…

It would be easy to follow by summarizing this paragraph using tables that lists the names, area, and other information.

 

Figure 1. Study area showing the 16 sub-lakes in Poyang Lake wetland…

Please explain why the 16 sub-lakes in Poyang Lake wetland were selected for analysis.

 

2.2. Waterbird survey…

Again please explain why you select the year 2007 and 2019 for comparison. Is there any change during the period?

 

Each ecological group comprised 50, 100, and 200 individuals…

Explain the ecological group in more detail. How are the numbers 50, 100, 200 selected? Are there any studies to support this approach?

 

We calculated waterbird diversity, including richness, abundance, Shan-non–Wiener index (SHDI), Pielou index (E), and Simpson’s index (D)…

We used independent samples t-tests in SPSS 22.0 to test the significance of inter-annual differences…

Citations are needed for the equations. Why did you use “t-test” to compare the inter-annual differences? They are all index values.

 

Table 1. Species and total abundance…

Maybe the waterbird community shifts to the other areas that are not covered or surveyed in Figure 1.

 

3. Results

3.1. Changes in species richness, abundance, and diversity indices between periods

Species richness (T=2.37, df=30, p=0.024) and the SHDI (T=2.32, df=30, p=0.027) were significantly higher in 2007 than in 2019…

Indicate where I can see the results for species richness and the SHDI values? Figure 2 shows the changes in the richness, abundance, and so on only.

 

3.3. Relationship between change in habitat area and change in waterbird diversity

Summarize this paragraph using tables. As you can see almost all the relationships are statistically insignificant except for two. This is hard to make conclusion given insignificant outcomes like this.

 

Figure 4. Relationships of change…

I don’t see any description relating to Figure 4 in the text.

 

4. Discussion

These findings were not consistent with the results of Wang et al. (2019); the smaller size of our study area might explain these inconsistencies.

So this implies that results from this study may be biased. Need to think about this.

 

At most of the sites, the area of deep water bodies increased, and the area of shallow water bodies and mudflats decreased.

However, most of the relationships are statistically insignificant. This would be difficult to conclude based on the results of this analysis.

 

Poyang Lake has experienced several extreme climatic events over the last few decades, and this has altered the area and structure of habitat…

So you may find the consequences of altering the area and structure of habitat. I suggest the authors focusing their study on this issue.

English language is fine. Minor editing may be required.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The MS reports the results of long-term waterbird monitoring data and Landsat remote sensing data to quantify the relationship between habitat variation and waterbird biodiversity at the community and foraging guild levels in Poyang Lake. The use of long-term data is interesting and allows us to investigate the change in the bird community over the years.

Although this, there are some points to address before the MS can be considered for publication. Please find the specific comments in the pdf file attached. 

It is not clear why only data starting from 2007 were used even if data are available from 1999 (see section 2.1). The authors should add some details to explain this. 

2.1. Study area: This part is confusing and it is not clear the use of numbering (1 and 2) after the citation of Changhu Lake. Please revise.

In general, there is a problem with the format used to provide references that are not in line with the journal guidelines. Authors should carefully revise all in line with the authors' guidelines.

Table 1 (not supplementary but only Table 1) should be revised by adding some reference about the criteria used to list the threatened species: IUCN? global? local? 

In Table 2: instead of the ''number'' of species, maybe the name of the species could also be provided.

Results: the results of ANOVA could be summarized in a table instead to repeat the values in the text.

 Figure 2: consider dividing this figure into different figures (according to the categories). İt is too long and dispersive.

The references used in the whole MS are too local. I suggest enriching the discussion by adding some ''global studies'' not related to the local contest.

Conclusions should be revised by adding some sentences to suggest the application of the same methodology also in other areas and to underline the importance of the study on a global scale

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Please see associated .pdf file.

Line numbers were not present in draft, please consider in future.

A weakness of this submission is the lack of integration with wider studies beyond China. How can your work help others, how do your results reflect other patterns in Asia?

Additionally, why only two years of survey data? Were surveys not available from other periods? Are your results part of wider trends, or were these just "up/down" years in relative variation?

 

Comments for author File: Comments.pdf

Minor editing of English language required.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

All the issues highlighted in the previous version were solved and the revised MS is now clear and well structured. The English was also revised and improved. The MS can be accepted for publication in this form.