Water Ecosystem Service Quality Evaluation and Value Assessment of Taihu Lake in China

Round 1

Reviewer 1 Report

The manuscript improved compared with the last version. The overall rationale and methods are coherent and robust.

My comments before publication are the following:

• The introduction still miss to a more complete discussion of ecosystem services literature.
• the manuscript presents a huge amount of tables and figures that make the reading difficult. I suggest to move some of them to supplementary materials.
• discussion section is poor. There are many findings to be discussed more in deep

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

All my comments are in the attached pdf file

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Some comments to the authors:

1. Fig.1- present the map with geographical coordinates (latitude, longitude). Indicate also the area of Suzhou, Changzhou, Wuxi, Huzhou as far you have discussed statistical data on the planting area of rice, wheat and rape in these areas. More, the value of maintaining biodiversity regards to Planting area (thousand hectares).
2. Table 1: Water quality physical and chemical index classification evaluation standard. Could you explain why it is physical index as only chemical parameters are presented. In the Discussion you refer to these chemical parameters as pollutants which more correct than physical and chemical index ; Instead of "Serial number" probably is better to use "Category" as it is also corresponds to Bad, Good, etc. ecological state.
3. Table 4: Nice approach to treat in this way the water Ecosystem services.
4. The period in question is not 2010-2018, but three years -2010, 2014, 2018. Then not clear the amount of data per year taking into account to calculate the value of WQI.
5. Line 195:  Regulate the atmosphere -Cite if there is a reference for this methods. Not clear how formulas 6-9 are applied for phytoplankton as the text declare values for aquatic plants (which are not phytoplankton). The term "Regulate the atmosphere" is not correct because here you talk for regulation of atmospheric CO2/ O2 production.
6. Fig.2, Fig.3 -simplify the captures of the figures. Chemical parameters in mg/L not clear what amount of data are used to calculated this average value. NOt clear if there are yearly, monthly.
7. Table 5- not clear the amount of data behind this average annual WQI. 
8. Table 9-not cited.
9. Table 10: Into the lake/Out of the lake: do you mean input/discharge?
10. Table 11: The value of maintaining biodiversity- Try a better way to explain this regards not the biodiversity of the lake but  total planting area and average net profit per unit area of the three crops (rice, wheat and rape).
11.  Line 663: "SPSS (software)"- make clear it is a software for statistical analysis.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors improved the manuscript according my previous comments. I have no further comments to arise. The manuscript can be accepted in the current form.

Reviewer 2 Report

Minor suggestions included in the pdf file and highlighted in pink

Comments for author File: Comments.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

General comments:

Thank you for working on this interesting paper on this important topic! Lakes are indeed understudied when it comes to ecosystem services, so it was great to see a paper focusing on this.  That said, this paper needs significant improvements before it can be considered for publication.

 

First, language needs to be extensively reviewed. If there is no team member that is able to do this, the authors must hire and external proof-reader to correct the numerous grammatical errors throughout the manuscript before it can truly be considered for publication.

 

Next, I think there authors have several misconceptions about the origin of the ecosystem service concept and language used to talk about the concept. For example, you refer to Costanza having come up with the four different ecosystem service categories which were actually developed in the Millennium Ecosystem Assessment, and not by Costanza alone. Overall, before being able to publish a paper that tries to utilize this concept, I think the team of authors needs to take a good look at the ecosystem service literature and familiarize themselves with the concept and key terminology in the field. This will really help clarify their work, and the paper should not be considered for publication before that is done.

 

In addition to this, many of the indicators used to quantify ecosystem services are not clearly explained. The reader needs access to more detail (presented concisely) about exactly which services are quantified and how they are quantified to be able to judge the quality of your work, as well as the implications of your findings.  I have provided numerous suggestions for how to improve in the below line by line comments, but major re-thinking is required before this paper can be considered for publication.

 

Next, the structure used to present the methods, results and discussion is very hard to follow.  There are results in the discussion section and methods in the results!  You need to take a look at the paper and figure out what information is really essential in the methods and results, and find a better, more streamlined way to present this information (e.g. by explaining the indicators used to quantify a service and citing the relevant data sources at the same place). Also, there is no information about how you actually made comparisons between years in your methods or results, and then suddenly in the discussion you talk about spearman correlations.  These are fine analyses to run to look at interactions between services, but they don’t tell you anything about the differences between years, and in your paper you seem to make a number of inferences not supported by your analyses, which doesn’t work. Overall, the analysis needs to be revisited and fully reconducted after you’ve ensured that the ecosystem service indicators that you use are valid. 

 

I also would like to see a much more complete discussion. You don’t relate your findings to wider implications in a meaningful way, which makes the paper stand short of what you promise you’ll do in the introduction.

 

 

Line by line comments:

Line 27 - it is grammatically incorrect to say “the ecosystem” in this sentence. Replace by “…service provided by ecosystems.”. 

Line 28 - Replace “The ecosystem” by “Ecosystems provide”

Line 29 - Same as two previous lines… you cannot use “the ecosystem” in the way you have here as it is not grammatically correct. Apply this correction throughout.

Line 32- What do you mean by “… through hydrological conditions and ecological composition.”? Do lakes really provide services through these? That doesn’t really  make sense to me!  I think what you are trying to say is that lakes provides services that are mediated by hydrological conditions and ecological composition, but I don’t even think you need this part of this sentence here.

Line 35 - there should not be a “the” before “ecosystem service”. 

Please note that at this point I am only a few sentences into the paper and realizing that language needs to be reviewed as there are already multiple grammatical mistakes.  If you feel that no one in the author team can do an adequate job reviewing language  you will have to have this paper reviewed by an external proof-reader before it can truly be considered for publication.  I will stop providing comments on language from this point onward as this isn’t the main objective of a scientific review (I want to focus on commenting on the science, not the language or writing!), and will do my best to ignore the language mistakes so I can focus on the science J.

 

Line 38 - I wouldn’t call Costanza’s assessment comprehensive.  He used land use to approximate the service provision value of the worlds different biomes, but these measures were VERY rough.  It is absolutely fine to cite Costanza’s important work, but you have oversold it here by using the term comprehensive and not highlighting caveats associated to the methods he developed using this approach.

 

Line 40 - Do you mean the monetary evaluation of an ecosystem service value?  Remember, there are many ways to quantify/attribute value to a service, so language around how that is being done needs to be clear. Although I agree that monetary valuation of services is important, I certainly wouldn’t say that monetary valuation of services is the best way to measure the “quality” of an ecosystem (which is, I believe, what you are insinuating here). 

 

Line 44- Again, are you specifically referring to monetary valuation here?  If so, specify this. Also, after stating that valuation of services in lakes are rare, I recommend saying “(but see ref 1, ref 2, ref 3)” and citing a few relevant articles. Otherwise it seems like you don’t actually know this literature very well.

 

Line 48 - What do you mean by “contribute in terms of ecology”?  To me, this doesn’t actually mean anything. Do you mean contribute in terms of the provision of ecosystem services such as access to freshwater for drinking, recreational activities, etc?  I think that the entire paper needs to be thoroughly reviewed to ensure that you are not making superfluous statements such as this one that don’t actually have meaning when you give them a good hard look.

 

Line 55- Do you have a reference to support this statement? This should be included here, otherwise it sounds like you just decided that comprehensive index methods are the most commonly used.

 

Line 59 - “…born and prospered by water” doesn’t make sense…  

 

Line 76 - Not lake Tai - correct.

 

Line 77- relationship between what two?  Not clear.

 

Line 79 - I would say “Study area” instead of “research objects”

 

Line 88 - How does the lake contribute to flood control?

 

Line 91 - Provide context about what grade V water quality is!  This will mean nothing to people that aren’t familiar with this specific rating system (which I’m guessing is a regional one)

 

Line 95 - You should describe what the data you are using is in addition to where the date is coming from in this paragraph. If that means you need to move information about data down into the methods section that is fine.

 

Line 115- this sentence is not necessary. We should be able to assume that any indicator you choose to lean on is of good quality.

 

Line 117 - Actually, the Millennium Ecosystem Assessment came up with the four ecosystem service categories you mention here, not Costanza alone... This information is incorrect.

 

Line 199- The reader needs more information about what direct use and indirect use value mean when you bring up these concepts. Please elaborate so that your reader has enough context to understand what these terms mean. Also, this is from the perspective of monetary value classification, not simply value classification. 

 

Line 120 - Who finds that “the function-based classification is more intuitive”?  You cannot simply just state this! Also, I have no idea what you mean by function-based classification here as you have not properly defined this term. 

 

Line 125 - What “various indicators”?  I definitely need this information! I also need to know how each of those indicators relate to the ecosystem services you are claiming you quantify in this study.

 

Line 131 - Is it Lake Taihu or Tai?

 

Lines 134-136 - Do you mean that the smallest “Assignement” value is the one that is used for the overall classification of water quality? What are the scores?! It is clear to me how the concentrations of TP and TN (for example) are transformed into a score, nor what the overall range of scores are and what they mean in terms of tangible water quality outcomes. I think you get to this in section 2.1.2, but the way this is written out here is confusing… I think you should find a way to combine these two sections and make them more concise.

 

Line 155- I absolultely need to know what indicators were used to quantify which services.  Also, not just service categories (i.e. “cultural services” means nothing when talking about services you quantified, I need to know what cultural services you are trying to quantify to be able to asses if the indicators you chose to use actually make sense!)  … I later see that you include this information in Table 4. Please reference that table sooner!  

 

 

Table 4 - The table is hard to read because I can’t tell what services you are saying fit into the category of provisioning, regulating, supporting and cultural services. You need to reformat the table so this is clear.  Also, the category is “provisioning services” not “supply services”, and these are “ecosystem service categories” not “service function types”.  What are you calling “evaluation indexes” appear to me to be services per say, not indexes.  What you are calling “index factors” seem to be your indicators for each of the services you assess, but I need way more information about how you quantified each of these!  For example, how did you quantify the industrial water value? There is no information about that here. I guess you used something like a market value, but I need to know where you got that market value and how you estimated it. I realize that you try to do this below in the text, but the table should give us a better idea of what you did if you want to bother including it.

 

Section 2.3 - In general, you need to specify what aspect of each ecosystem service you quantify you are quantifying (i.e. are you looking at the capacity of an ecosystem to provide a service, the flow of a service from an ecosystem to specific community members, or the demand that people have for services? Reading about these different aspects of ecosystem services in the literature (e.g. Tomscha et al. 2016, available via: https://academic.oup.com/bioscience/article/66/9/747/1753676) will help with this.

 

Section 2.3.1

• Water supply: Why not include an aspect of water quality in the quantification of this service?  Here, it seems to me as though you are only considering the quantity of water.
• Aquatic food products: Do you think that the economic value of fish that are caught and sold is the best way to quantify this service?  This is an OK (and commonly used) method, but there are other ways you could think about quantifying this service (e.g. the population size of fish)
• Shipping - OK

 

Section 2.3.2

• Atmospheric regulation: Where did you get data about oxygen release?
• Flood regulation: Is being able to store x amount of water truly an indicator of the ability to regulate floods? Shouldn’t this be more like how much water actually moves in and out of the lake each year?  I’m not sure about how other studies have calculated this, but the method needs more support for me to be convinced.
• OK (Reading this made me wonder why you provide SO much more information about the water quality data in the methods than information about the data used for the quantification of other services.)
• Surface water storage: I don’t think this service is different enough from flood regulation or water quality measurements

 

Section 2.3.3.

1. Maintain biodiversity: Biodiversity is not considered to be an ecosystem service in the Millennium Ecosystem Assessment categories, it is viewed as separate to services. Adjust language.
2. Soil conservation: I have trouble understanding how the amount of sediment deposited at the bottom of a lake is a service… To me, what you measured here is more like some sort of disserve of sediments entering the lake… Do you call this a service because the sediments that enter the lake are essential for regenerating the soil that is used to cultivate crops such as rice? Perhaps the service you should look at should be aquatic food crops instead?

 

Section 2.3.4.

• Tourism & Leisure: Why do you say that tourism and leisure was not considered in this article and then go on to explain the method that you used to quantify this service? Also, I definitely need more information about how you used price substitution of national scenic spots to calculate the value of this service in this paragraph to be able to understand how you quantified this service (and determine if that method is valid).
• Research and Education: First, specifically related to line 291, I don’t think the methods is the place for statements like “the scientific research and education value of Taihu Lake is extremely high”, so I would start by simply cutting this sentence, which actually more so belongs in a place like your discussion after you’ve shown this through your analysis. Next, the description of your measure of this service is unclear. How did you locate the amount of scientific research conducted per unit area of the assessed wetland (also, isn’t this a lake and not a wetland)? I need information about what you mean by the “value of scientific research”!

 

I am also left wondering how you compared these numerous different ecosystem services which were all quantified on different scales and using different types of units. I’m not sure if comparison was one of your objectives, but if it is, the different in units is definitely going to be a problem!

 

Section 3.1: How did you compare data between years?  This is something that you should explain in the methods. You really should have used some sort of statistical analysis (e.g. Anova for each separate service to compare values across the three assessed years).

 

Figure 2.  This figure has several big problems. First, the legend doesn’t give enough information to understand what is happening in it. What do the different panels represent? Where were these assignment values taken? Second, you didn’t label your y axes!  Next, you cannot put lines like you did between bars… Lines are used to represent regressions and it doesn’t look like you conducted a regression… This figure the next need to be completely reconstructed and your analysis needs to be clarified. The next makes it sound like you just did a qualitative analyses of results and came up with statements like “diversity index changed greatly”, but you need statistical analyses to support these types of statements!!! Note that this comment about analyses applies to your entire results section.

 

Discussion              

Line 586 - Aha!  This is where I finally understand what type of statistical analysis you did. This information does not belong in the discussion. Information about the analyses you did belongs in the methods, and the findings that you made belong in the results. Making this change will really help clarify your work.

 

Line 591- I hadn’t realized, until this point, that an objective of your work was to draw a link between changes in water quality (one of the services you assess) and other services. Making this clear in your introduction by stating the main objective of your paper (which I thought was just to quantify services) would be really helpful.

 

Table 14 - Did you scale and centre your data before looking at correlations between services? 

 

 

Reviewer 2 Report

The manuscript deals with water quality and ecosystem services assessment in a Chinese lake along three dates (2010-2014-2018). The manuscript is very well structured and is a valuable contribution for aquatic science and particularly for the relation between ecosystem quality and ecosustem services.

I have only few comments before publication:

Figure 1: the position of the study area  on the country should be represented as well.

line 225: "?? represents the annual growth rate of flood disaster loss, ??=4%". It is not clear to me what this parameter represents.

line 294: It is also not clear to me the data source of Pky

Equations 15 and 16 and related text should be moved to materials and method section

table 14: it sound a bit weird that spearman correlation between WQI and many services is 1. How is it possible? It would be also interesting to see correlation among services. Moreover, this table should be moved to results section