Ecosystem Service Relationships, Drivers, and Regulation Strategies in a Degraded Alpine Shrub Meadow on the Northeastern Qinghai-Tibetan Plateau
Round 1
Reviewer 1 Report
In this study, "Ecosystem service relationships, drivers and regulation strategies in degraded grasslands of the northeastern Qinghai-Tibetan Plateau", the authors analyze the effect of grassland degradation on soil water retention and forage supply as well as the relationship between these two ecosystem services. They measured above ground biomass in reference to that of undegradated areas and analyzed soil samples for their field capacity and related characteristics (e.g. porosity) as well their content of organic carbon, nitrogen, phosphorus, and potassium. These analyses were conducted at 4 different sites in the Haibei Tibetan Autonomous Prefecture located on the Qinghai Tibetan Plateau. The 4 sites represent different levels of use by local herders. This study bears valuable ecological information necessary for the development of sustainable modes of land use and ecological monitoring in general. To my knowledge, the authors used state of the art, standardized methods which render their findings comparable to similar studies. A fact that adds to its general value for ecological studies. Data analysis also was conducted carefully and presented comprehensively. I do however, need to raise some concerns about the overall quality. First of all, I am sorry to say that the language is in need of some editing as some of the sentences are misleading or even incomprehensive. I have some comments on that later but the manuscript needs an extensive language editing. Aside from that I have two major concerns: 1. A lack of clear definitions and thorough separation of the used terminology: In the title as well as in the introduction the authors mention and describe "grasslands" while the analyzed sites are always referred to as "shrublands". It is crucial to provide definitions for the two vegetation types and clarify their similarities and differences. Furthermore, the study focuses on ecological services and mentions different types e.g. "regulating", "supporting", and (later on in the ms) "provisioning" without providing a definition for each of them. For the sake of the discussion it is imperative to clearly define these types and provide examples as they are discussed to work in a trade-off relationship. In the introduction there are topic is brought up very early, including examples, but they need to be clearly distinguished and explained. 2. From what I understand the forage support (i.e. the biomass consumed by live-stock) is the defining factor of the different levels of degradation. Thus, the two things are inseparable and cannot be treated as independent neither in the analysis nor in the discussion. E.g. in line 327ff: "Our study found that degradation has led to an increase in forage supply service in alpine shrub meadow, but also a decrease in water retention service, so that the two showed a trade-off relationship, and the degree of trade-off tended to decrease and then increase with degradation." the degradation has indeed not led to an increase in forage supply but is defined by it. While it does not render any findings less important or interesting, it needs to be discussed differently. Please rephrase the discussion in a way that does not treat these two factors independently or, alternatively, please elaborate why I am wrong in that point.
A list of minor comments with respective lines:
l34: "They" instead of "It"
l45: language should be improved, sentences are repetitive.
l46: "fuelwood" consistency, since you used that term before
Introduction general: You use both singular and plural of "grassland". I would recommend to use plural only.
l50: "limits" instead of "limit"
l50: How does it limit the coordinated and sustainable ecological and economic development?
l63-68: Consider splitting up that long sentence and please explain the last statement (...making the relationship between human and natural ecosystems contra dictionary and unbalanced.)
l84: "Secondly" instead of "Second"
l84-88: Is that meant to be a general category like in the previous sentence or specific to QTP? Sentence is hard to understand
l90-93: Please rephrase, sentence not clear
l107: What does "site scale" refer to?
l111-118: That is a nice overview of what was conducted and it is well phrased too. Just wanted to mention that.
l126: It is the first occurrence of a species name therefor I will mention it here but not again: species names have to be in italics. Please correct throughout the ms
Figure 1: Very helpful overview, can you provide an in-between zoom to better visualize where in the north east of the QTP the region is located?
l137: Please implement all the "Note"s into the respective figure legends.
l149ff: Please elaborate in more detail how you collected the data at the different "plots". Also, for better readability I suggest to first explain the sample collection methods and afterwards choice of sites and replications.
l162: Elaborate the difference between disturbed and undisturbed soil samples; are the cm values referring to depth? Please add that information
l170: provide reasoning for the service selection. "regulating service" instead of "regulating services"
l174: The first "actual" can be removed, second one could be replaced by "effective"
l177: "indirect" can be removed, a proxy always is indirect
l179ff: Was the long-term grazing excluded site protected from all grazers or just from livestock? Are there any other grazers that might have had access to that area?
l188: M1 does not make any sense to me in the current description. Why would you take the first measurement after oven-dry the sample, when you later on oven-dry it again? Is there a mistake in the temperature?
l198: Where did you get the particle density from?
l262: "was found" is doubled in this sentence.
table 2: A table with just one entry seems unnecessary, put the value in the running text.
figure 4: How come the axes are ranged from 0 to 1 each? Forage supply, regarding to your methods, is the difference between theoretical maximum and the observed above ground biomass. So that can easily be normalized
to values between 0 and 1. What about the water retention? In the methods you claim to use field capacity to represent water retention. How come you also have values between 0 and 1? Please elaborate in the methods
section for forage supply and water retention how exactly you calculated these numbers for figure 4.
l286: R2 is 0.484 in the graph (also "2" should be superscript)
l296: there is nothing like "relatively significant"
l330-334: please consider splitting this sentence. Also, "some studies" are mentioned but only one is cited.
l351: "...maximum reduction in SOC stocks up to 43%" unclear! Does it mean that the SOC is reduced by up to 43%?
l355ff: In this paragraph I am missing a general discussion of the potential mechanisms leading to the decrease in water retention. Is it due to faster evaporation caused by direct sunlight/decreased foliage cover? Is SOC crucial for soil water storage? The causalities are not discussed.
l405: Water retention and forage supply are the only two services analyzed by this study. Are there other studies that support your statement of these two dominating the mentioned trade-off relationship?
Conclusion general: The conclusion reads like a summary. It should be boiled down to key findings and the authors interpretation of those.
Author Response
Response to Reviewer 1 Comments
Point 1: In this study, "Ecosystem service relationships, drivers and regulation strategies in degraded grasslands of the northeastern Qinghai-Tibetan Plateau", the authors analyze the effect of grassland degradation on soil water retention and forage supply as well as the relationship between these two ecosystem services. They measured above ground biomass in reference to that of undegradated areas and analyzed soil samples for their field capacity and related characteristics (e.g. porosity) as well their content of organic carbon, nitrogen, phosphorus, and potassium. These analyses were conducted at 4 different sites in the Haibei Tibetan Autonomous Prefecture located on the Qinghai Tibetan Plateau. The 4 sites represent different levels of use by local herders.
This study bears valuable ecological information necessary for the development of sustainable modes of land use and ecological monitoring in general. To my knowledge, the authors used state of the art, standardized methods which render their findings comparable to similar studies. A fact that adds to its general value for ecological studies. Data analysis also was conducted carefully and presented comprehensively.
I do however, need to raise some concerns about the overall quality.
First of all, I am sorry to say that the language is in need of some editing as some of the sentences are misleading or even incomprehensive. I have some comments on that later but the manuscript needs an extensive language editing.
Response 1: We enlisted the help of native English writers to revise and polish the paper.
Aside from that I have two major concerns:
Point 2: A lack of clear definitions and thorough separation of the used terminology: In the title as well as in the introduction the authors mention and describe "grasslands" while the analyzed sites are always referred to as "shrublands". It is crucial to provide definitions for the two vegetation types and clarify their similarities and differences.
Response 2: In this study, we consider alpine shrub meadows as a type of grassland and focus more on their utilization, namely grazing. We have modified the title of the paper from "grassland" to "alpine shrub meadow" to better align with the research topic. In addition, we have extensively revised the introduction and added an explanation of alpine shrub meadows. Please see lines 108-116.
Point 3: Furthermore, the study focuses on ecological services and mentions different types e.g. "regulating", "supporting", and (later on in the ms) "provisioning" without providing a definition for each of them. For the sake of the discussion, it is imperative to clearly define these types and provide examples as they are discussed to work in a trade-off relationship. In the introduction there are topic is brought up very early, including examples, but they need to be clearly distinguished and explained.
Response 3: We explain the definition of ecosystem services at the beginning of the introduction, as well as the four main types it includes and their examples, see L 44-47.
Point 4: From what I understand the forage support (i.e. the biomass consumed by live-stock) is the defining factor of the different levels of degradation. Thus, the two things are inseparable and cannot be treated as independent neither in the analysis nor in the discussion. E.g. in line 327ff: "Our study found that degradation has led to an increase in forage supply service in alpine shrub meadow, but also a decrease in water retention service, so that the two showed a trade-off relationship, and the degree of trade-off tended to decrease and then increase with degradation." the degradation has indeed not led to an increase in forage supply but is defined by it. While it does not render any findings less important or interesting, it needs to be discussed differently. Please rephrase the discussion in a way that does not treat these two factors independently or, alternatively, please elaborate why I am wrong in that point.
Response 4: We have modified such statements, i.e. as you mentioned, to include degradation and forage supply as two separate factors. Please see L 459-461.
A list of minor comments with respective lines:
Point 5: l34: "They" instead of "It"
Response 5: It has been revised in accordance with your comments.
Point 6: l45: language should be improved, sentences are repetitive.
Response 6: We have rewritten the sentence.
Point 7: l46: "fuelwood" consistency, since you used that term before
Response 7: It has been amended in accordance with your comments, please see L 56.
Point 8: Introduction general: You use both singular and plural of "grassland". I would recommend to use plural only.
Response 8: In line with your comments, we use the plural form of grassland consistently in the introduction section.
Point 9: l50: "limits" instead of "limit"
Response 9: It has been replaced in accordance with your comments.
Point 10: l50: How does it limit the coordinated and sustainable ecological and economic development?
Response 10: The meaning conveyed here is ambiguous, so we have rewritten the relevant content. The intended meaning is that the degradation of grasslands has led to a decline in a series of ecosystem services, including carbon storage, nutrient supply, and biodiversity, and it also affects their ability to provide provisioning services, such as food, to humans. Furthermore, it exacerbates the inherent conflict between ecological and productive functions in grassland ecosystems, further disturbing this delicate balance.
Point 11: l63-68: Consider splitting up that long sentence and please explain the last statement (...making the relationship between human and natural ecosystems contra dictionary and unbalanced.)
Response 11: We have rewritten the introduction to remove this passage and added content on alpine shrub meadows, see L108-116.
Point 12: l84: "Secondly" instead of "Second"
Response 12: We have made replacements based on your comments.
Point 13: l84-88: Is that meant to be a general category like in the previous sentence or specific to QTP? Sentence is hard to understand
Response 13: We have rewritten this sentence to make it easier to read, see L153-155.
Point 14: l90-93: Please rephrase, sentence not clear
Response 14: We have rewritten this sentence to make it easier to read, see L176-182.
Point 15: l107: What does "site scale" refer to?
Response 15: We have revised the expressions, please see L182-183.
Point 16: l111-118: That is a nice overview of what was conducted and it is well phrased too. Just wanted to mention that.
Response 16: Thank you for your comments.
Point 17: l126: It is the first occurrence of a species name therefor I will mention it here but not again: species names have to be in italics. Please correct throughout the ms
Response 17: Thank you for the reminder that we have revised the canonical formatting of species names throughout the paper.
Point 18: Figure 1: Very helpful overview, can you provide an in-between zoom to better visualize where in the north east of the QTP the region is located?
Response 18: We have modified Fig. 1 as per your request, please see Fig. 1.
Point 19: l137: Please implement all the "Note"s into the respective figure legends.
Response 19: Based on your comments, we have modified Fig2, Fig3, Fig4 and Fig6.
Point 20: l149ff: Please elaborate in more detail how you collected the data at the different "plots". Also, for better readability I suggest to first explain the sample collection methods and afterwards choice of sites and replications.
Response 20: Plots were incorrectly stated, what we were trying to convey was that 3 points were randomly selected for sample collection out of 4 degraded sites, and the samples were replicated 3 times. We have amended the relevant text, please see L252-269. Following your suggestion, we have revised the order of description, i.e. explaining the method of sample acquisition first, then the selection of sample sites and the number of sampling replicates, see L252-269.
Point 21: l162: Elaborate the difference between disturbed and undisturbed soil samples; are the cm values referring to depth? Please add that information
Response 21: In soil science, a disturbed soil sample is one that has been altered from its natural state by physical manipulation or exposure to external factors such as heat or pressure. Examples of disturbed soil samples include soil that has been sieved, mixed, homogenized, or subjected to high temperatures during drying or sterilization.
In contrast, a non-disturbed soil sample is one that has been carefully extracted or collected from the field and preserved in a way that maintains its natural structure and composition. Non-disturbed soil samples are often collected using specialized tools such as soil cores, which allow for the collection of intact soil columns without disrupting their structure.
cm is the soil depth, to which we have added information, see L263.
Point 22: l170: provide reasoning for the service selection. "regulating service" instead of "regulating services"
Response 22: The reasons for choosing these two services are described in 2.3, see L278-282. The comment has been followed by replacing "regulating services" with "regulating service"
Point 23: l174: The first "actual" can be removed, second one could be replaced by "effective"
Response 23: It has been amended in accordance with your comments, please see L286.
Point 24: l177: "indirect" can be removed, a proxy always is indirect
Response 24: Removed 'indirect' as per your comment
Point 25: l179ff: Was the long-term grazing excluded site protected from all grazers or just from livestock? Are there any other grazers that might have had access to that area?
Response 25: The grazing exclusion here is the exclusion of all herbivores, as fences have been erected to make all large mammals inaccessible.
Point 26: l188: M1 does not make any sense to me in the current description. Why would you take the first measurement after oven-dry the sample, when you later on oven-dry it again? Is there a mistake in the temperature?
Response 26: There was an error in the writing here and we are very sorry. We have reworked the formula as well as the text, please see L300-315.
Point 27: l198: Where did you get the particle density from?
Response 27: Reference values for soil particle density are obtained from datasets published by the field stations in which the study area is located, to which we have added citations, see L315.
Point 28: l262: "was found" is doubled in this sentence.
Response 28: We have removed duplicate expressions, see L388.
Point 29: Table 2: A table with just one entry seems unnecessary, put the value in the running text.
Response 29: We have deleted Table 2 and added the information to the text, see L389.
Point 30: Figure 4: How come the axes are ranged from 0 to 1 each? Forage supply, regarding to your methods, is the difference between theoretical maximum and the observed above ground biomass. So that can easily be normalized to values between 0 and 1. What about the water retention? In the methods you claim to use field capacity to represent water retention. How come you also have values between 0 and 1? Please elaborate in the methods section for forage supply and water retention how exactly you calculated these numbers for figure 4.
Response 30: Here the two services are expressed not in terms of actual service quantities, but rather in terms of standardized relative ecosystem services, as detailed in 2.4.2. In addition, we have modified the title of Figure 4, see L408.
Point 31: l286: R2 is 0.484 in the graph (also "2" should be superscript)
Response 31: Thank you for your reminder, we have revised the numbers and formatting, please see L414.
Point 32: l296: there is nothing like "relatively significant" 没有什么 "相对显著 "的说法
Response 32: We have removed relatively，see L424.
Point 33: l330-334: please consider splitting this sentence. Also, "some studies" are mentioned but only one is cited.
Response 33: We have rewritten the passage, see L464-465.
Point 34: l351: "...maximum reduction in SOC stocks up to 43%" unclear! Does it mean that the SOC is reduced by up to 43%?
Response 34: Here we intended to say exactly what you understand it to mean. We have modified the original sentence to make the meaning clearer, please see L487.
Point 35: l355ff: In this paragraph I am missing a general discussion of the potential mechanisms leading to the decrease in water retention. Is it due to faster evaporation caused by direct sunlight/decreased foliage cover? Is SOC crucial for soil water storage? The causalities are not discussed.
Response 35: In response to your comments, we have added to the discussion on the mechanisms of decline in water retention and the reasons for the correlation between SOC and water retention, see L496-505 and L531-536.
Point 36: l405: Water retention and forage supply are the only two services analyzed by this study. Are there other studies that support your statement of these two dominating the mentioned trade-off relationship?
Response 36: There is a problem with the presentation here and we have rewritten the section, please see L559-571.
Point 37: Conclusion general: The conclusion reads like a summary. It should be boiled down to key findings and the authors interpretation of those.
Response 37: In the light of your comments, we have rewritten our conclusions, please see L559-571.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper presented a study of ecosystem services in Tibetan rangeland. Two ecosystem services were assessed and compared along a gradient of degradation.
My main concern is about the forage supply estimation. Generally, the ecosystem service of forage provision is the standing biomass. I understood that in this case the authors try to evaluate the intake. However, the authors use a ungrazed area as a reference (I did not understand if the reference was the same for all the sites or it was specific to each site. The ungrazed plot could be put in the map. The authors suggest to the difference between the two dry mass is only due to the grazing intake. However, the difference could be due to other factors (degradation and so one). The hypothesis that site with low standing biomass means higher forage intake and so service is not in my opinion necessarily true. I would like some analysis with the standing biomass to be able to compare.
My second concern is about the description of the Statistic analysis, The authors must explain more the different use of analysis and the question that the analysis answers. For example the use of root mean square error and constraint line extraction must be clearer.
Author Response
Response to Reviewer 2 Comments
Point 1: The paper presented a study of ecosystem services in Tibetan rangeland. Two ecosystem services were assessed and compared along a gradient of degradation. My main concern is about the forage supply estimation. Generally, the ecosystem service of forage provision is the standing biomass. I understood that in this case the authors try to evaluate the intake. However, the authors use a ungrazed area as a reference (I did not understand if the reference was the same for all the sites or it was specific to each site. The ungrazed plot could be put in the map. The authors suggest to the difference between the two dry mass is only due to the grazing intake. However, the difference could be due to other factors (degradation and so one). The hypothesis that site with low standing biomass means higher forage intake and so service is not in my opinion necessarily true. I would like some analysis with the standing biomass to be able to compare.
Response 1: Only one grazing exclusion site was used as a reference for above-ground biomass in an ungrazed state for the whole area, considering the small size of the study area (6.5 km2) and the homogeneous nature of the vegetation and soil and the flat topography. We have placed the ungrazed sample plots in Figure 1.
We approximated the forage supply service by using the intake of livestock because it was difficult to obtain accurate data. Instead, we used the difference between the theoretical maximum above-ground biomass and the existing above-ground biomass as an estimate. Although there could be other factors affecting the biomass, such as climate, soil, and vegetation, we believe that grazing by livestock is the primary reason for the differences in biomass. The degraded sites we studied are located close to each other and have similar environmental conditions, making it easier to attribute the differences to grazing.
Point 2: My second concern is about the description of the Statistic analysis, The authors must explain more the different use of analysis and the question that the analysis answers. For example, the use of root mean square error and constraint line extraction must be clearer.
Response 2: We have added a description of the details and uses of statistical methods, see L345-348 and 355-357.
Author Response File: Author Response.docx
Reviewer 3 Report
Your paper presents (391) an in-depth (but still superficial) analysis of the relationship between forage supply and water retention services in degraded alpine shrub meadows, in particular, to explore the constraint relationship between the two, with the aim to (420) provide an important reference for reconciling the contradiction between grassland conservation and development on the Qinghai-Tibetan Plateau and establishing sustainable use of grassland ecosystems....
The theme of grassland degradation is old, well known, and widespread worldwide, as well as their causes and related solutions that cannot or do not want to be adopted either by decision-makers (77-79) nor by the peoples who exploit those pastures until they become unusable (63-70).
In my opinion, it would have been more useful and interesting to focus the study on correlation between the grazing intensity, in term of number of grazing animals and type of grazing management (and therefore the anthropic pressure), and the level of degradation of the meadows to achieve the goal (421).
Author Response
Response to Reviewer 3 Comments
Point 1: Your paper presents (391) an in-depth (but still superficial) analysis of the relationship between forage supply and water retention services in degraded alpine shrub meadows, in particular, to explore the constraint relationship between the two, with the aim to (420) provide an important reference for reconciling the contradiction between grassland conservation and development on the Qinghai-Tibetan Plateau and establishing sustainable use of grassland ecosystems....
The theme of grassland degradation is old, well known, and widespread worldwide, as well as their causes and related solutions that cannot or do not want to be adopted either by decision-makers (77-79) nor by the peoples who exploit those pastures until they become unusable (63-70).
In my opinion, it would have been more useful and interesting to focus the study on correlation between the grazing intensity, in term of number of grazing animals and type of grazing management (and therefore the anthropic pressure), and the level of degradation of the meadows to achieve the goal (421).
Response 1: Thank you for your comment, but that would be a great departure from the subject of this study, but we will consider adopting this perspective as you mentioned in future studies.
Author Response File: Author Response.docx
Reviewer 4 Report
The results and discussion part are very strong. The articles can go for publishing.
Author Response
Response to Reviewer 4 Comments
Point 1: The results and discussion part are very strong. The articles can go for publishing.
Response 1: Thank you for your comments.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors have incorporated substantial changes into the manuscript addressing all my original comments. I do not see any further issues that need to be addressed and recommend to publish the article in the current form.
Comments for author File: 
Comments.pdf
Reviewer 3 Report
Dear Authors,
As already stated, I don't trust that (89) "Understanding these relationships can help decision-makers to manage potential conflicts between services effectively", nor that (91-94) "Research on ecosystem service relationships in grasslands through remote sensing data and models, or correlation analysis and spatial overlay analysis" can help to resolve the problems that, in my opinion, are due to the already knowed (97) "grazing intensities, and land management practices", being in your QTP (106) "in recent years, ….. nearly 90% of grasslands on the plateau have been degraded to some extent due to climate change and human activities" and (115) "the increasing intensity of grazing have led to the degradation of alpine shrub meadows", with (117) "still insufficient attention to this phenomenon".
For these reasons, (157) "identifying the underlying constraints that affect the relationships between ecosystem services"; nor (202) "provide a better understanding of the complex relationships between ecosystem services in alpine shrub meadow ecosystems and to identify the factors that can be used to manage these relationships", aren't useful, in my opinion, in enhance knowledge to solve the problems of (180) "land management practices and grazing intensity", that are worldwide well knowed (and unresolved, for cited reasons); as also listed in your manuscript (226-231), (242-243), (373-376), (414-416), (472-476), (482-487), (489-490), (497-505), (531-541).
In this sense, I consider the methods applied to be inconsistent with the aims of your research, as in (548).
However, I appreciate your engage in analysis of the issue and, also for your cited intentions for next studies, I can consider the paper publishable in this form.
