Grazing Exclusion Affects Alpine Meadow Plants’ Root Morphological Traits and Reduces Their Cold Resistance on the Qinghai–Tibetan Plateau

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Generally fine but the methods are not robust enough. Lots of clarity missing.

Specific comments:

Intro

No hypotheses included

Methods

Need more info on grazing: what kind of animals? How many animals? AUMs? Timing of grazing (generally).

What made a plant dominant? How much cover did it need? Or frequency?

How far were the subplots from one another? How far were they from fence lines or water?

Why were only 4 replicates used?

Were 4-7 root samples taken per species? Per species per plot? Total?

Samples were taken in two different years, were these samples pooled? I now see (now that I am up to the results) that this was not the case. So.. was it 4-7 samples taken per year? Also, clarify why samples were taken in two different years. Why is there an expectation that time might have an effect, particularly after grazing has been stopped for ten years already.

Provide a citation for the three point sampling method of the soil.

The table is not clear without lines. Include a line to separate the species from the two treatments. Also, the family column is confusing.. does this mean that no grasses were found in the FG treatment?

If you want to compare root traits and col resistance depending on treatment then why would you include any species that were not found in both treatments?

Why was a PCA used rather than an NMDS, for example?

Need way more information on how things that were measured connect to col resistance.

A whole host of soil characteristics were measured (e.g. pH, SOM, etc). Why? From the results, I see why they were measured but this needs to be better explained in the methods. But also, correlations were made between soil characteristics and root traits/col resistance but there was no description of how the soil characteristics differed between treatments? This needs to be included.

Results

Usually when significant differences are indicated (e.g. soil temp), the stats associated with that outcome is included.

Strange to say that a ‘trait’ increased (e.g. line 192)

Author Response

Comments 1: Intro No hypotheses included

Response 1: Thanks for the comments. We have added the hypotheses in the introduction. " This change can be found in line 95-96 of the revised manuscript.

 

Comments 2: Need more info on grazing: what kind of animals? How many animals? AUMs? Timing of grazing (generally).

Response 2: Thanks for the comments. We have added the grazing intensity in line129.

 

Comments 3: What made a plant dominant? How much cover did it need? Or frequency?

Response 3: Thank you for pointing this out. We selected the dominant plants based on frequency and height. We have added frequency and height in Table 1.

 

Comments 4: How far were the subplots from one another? How far were they from fence lines or water?

Response 4: Thanks for the comments. We have added some location information of subplots in line 137-138.

 

Comments 5: Why were only 4 replicates used?

Response 5: Thanks for the comments. Generally, the repetition is three times. We adopt four times to better ensure the data accuracy

 

Comments 6: Were 4-7 root samples taken per species? Per species per plot? Total?

Response 6: Thanks for the comments. It is 4-7 root samples taken per species in GE and FG.

 

Comments 7: Samples were taken in two different years, were these samples pooled? I now see (now that I am up to the results) that this was not the case. So.. was it 4-7 samples taken per year? Also, clarify why samples were taken in two different years. Why is there an expectation that time might have an effect, particularly after grazing has been stopped for ten years already.

Response 7: Thanks for the comments. Every year, we collect 4 to 7 samples from each plant. The two-year sample collection is to enrich the results of a single year

 

Comments 8: Provide a citation for the three point sampling method of the soil.

Response 8: Thanks for the comments. Three point sampling method of the soil is a wrong statement. We have modified three point sampling method to five point sampling method in line 145, and reference 36 was cited.

 

Comments 9: The table is not clear without lines. Include a line to separate the species from the two treatments. Also, the family column is confusing. does this mean that no grasses were found in the FG treatment?

Response 9: Thanks for the reviewer's suggestion. We have modified Table 1. Combined with the opinion of another reviewer, we have changed "family" to "group", and "non-Gramineae" represents that the the plant is not a Gramineae plant.

 

Comments 10: If you want to compare root traits and col resistance depending on treatment then why would you include any species that were not found in both treatments?

Response 10: Thanks for the comments. Because the dominant plants in the two treatments are different, comparing only the same plants will ignore the impact of community changes under different treatments.

 

Comments 11: Why was a PCA used rather than an NMDS, for example?

Response 11: Thanks for the comments. The reason why we use PCA is to determine the root economic type spectrum adopted by plants under flocking and grazing treatment based on the distance of the points. NMDS focuses more on reflecting the ranking relationship of the values in the distance matrix and is not very suitable for determining the root economic type spectrum.

 

Comments 12: Need way more information on how things that were measured connect to cold resistance.

Response 12: We agree with this comment. We have added the association between the measured indicators and cold resistance in lines 155-166.

 

Comments 13: A whole host of soil characteristics were measured (e.g. pH, SOM, etc). Why? From the results, I see why they were measured but this needs to be better explained in the methods. But also, correlations were made between soil characteristics and root traits/col resistance but there was no description of how the soil characteristics differed between treatments? This needs to be included.

Response 13: Thanks for the comments. We have added the reasons for studying soil properties in lines 171-172 of the method. And in 3.1, the differences in soil properties under different treatments have been added

 

Comments 14: Usually when significant differences are indicated (e.g. soil temp), the stats associated with that outcome is included.

Response 14: Thanks for the reviewer's suggestion. We have revised ‘significant differences’ to ‘differences’ in 3.1.

 

Comments 15: Strange to say that a ‘trait’ increased (e.g. line 192)

Response 15: Thanks for pointing out the error. We have deleted the ‘trait’.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors measured some root parameters and plant enzyme activities in ungrazed and grazed plots to assess how grazing affected plant root dynamics and cold resistance. There are many drawbacks in this paper. 

First, the abstract did not include the results of enzyme analyses. Lines 11- 18 should be condensed into one or two sentences. 

Second, the questions to be addressed have not been well formulated. The authors did not introduce the latest development in this research area and which aspects are less understood.   How did your research bridge the knowledge gaps?

Third, The sampling protocols were not clearly described. It is unclear which parts of plants, roots or aboveground parted, were sampled for enzyme analyses. Did you assess the relative contributions of each studied species to the total in terms of biomass, coverage or numbers of individuals? This is a big concern as grazing could change plant composition. Such a change could affect the cold resistance values as different plant species have different cold resistance. 

In results section, the correlation analyses did not show the number of samples. 

In 3.1 it is really hard for readers to believe that grazing significantly changed the temperature as temperatures in grazing plots were not always higher in certain months. 

 

Comments on the Quality of English Language

The English needs extensive editing.

Author Response

Comments 1: First, the abstract did not include the results of enzyme analyses. Lines 11- 18 should be condensed into one or two sentences.

Response 1: Thank you for your suggestion. We have revised the abstract.

 

Comments 2: Second, the questions to be addressed have not been well formulated. The authors did not introduce the latest development in this research area and which aspects are less understood. How did your research bridge the knowledge gaps?

Response 2: Thanks for the comments. We have added the hypotheses in the introduction. " This change can be found in line 95-96 of the revised manuscript.

 

 

Comments 3: Third, The sampling protocols were not clearly described. It is unclear which parts of plants, roots or aboveground parted, were sampled for enzyme analyses. Did you assess the relative contributions of each studied species to the total in terms of biomass, coverage or numbers of individuals? This is a big concern as grazing could change plant composition. Such a change could affect the cold resistance values as different plant species have different cold resistance.

Response 3: Thanks for the comments. Combined with the opinions of other reviewers, we have added specific sampling schemes in 2.3.

 

Comments 4: In results section, the correlation analyses did not show the number of samples.

Response 4: Thanks for the comments. We have added the number of samples in line 316.

 

Comments 5: In 3.1 it is really hard for readers to believe that grazing significantly changed the temperature as temperatures in grazing plots were not always higher in certain months.

Response 5: Thank you for pointing this out. We have revised ‘significant differences’ to ‘differences’ in 3.1.

Reviewer 3 Report

Comments and Suggestions for Authors

The subject of this paper is interesting and important. Authors applied a broad spectrum of methods and obtained some interesting data. But now the design of research is not clearly described.

1. The results should be given separately for each species which is dominant in both types of plots (e.g., Carex muliensis, Kobresia pygmaea, Saussurea pulchra).
2. There are some contradictions in the description of the results. Therefore, the conclusions look to be not well-founded.
3. Experimental plots are not spatially independent, so conclusions are not well proved.
4. It should use more worldwide articles on the impact of grazing on plants.

Other comments are in attached file.

Comments for author File: Comments.pdf

Author Response

Comments 1: The results should be given separately for each species which is dominant in both types of plots (e.g., Carex muliensis, Kobresia pygmaea, Saussurea pulchra).

Response 1: Thank you for your suggestion. This study only focuses on the results under different treatments and only compares the same species, ignoring the dominant plants in grazing rejection.

 

Comments 2: There are some contradictions in the description of the results. Therefore, the conclusions look to be not well-founded.

Response 2: Thanks for the comments. We have made corrections for the mistakes.

 

Comments 3: Experimental plots are not spatially independent, so conclusions are not well proved.

Response 3: Thanks for the reviewer's comments. The fence was set up in 2013 around the experimental plot using galvanized steel wire. After then, the grazing-exclusion grassland was completely enclosed. So GE and FG are completely isolated. We have supplemented the relevant content in lines 125-126.

 

Comments 4: It should use more worldwide articles on the impact of grazing on plants.

Response 4: Thank you for your suggestion. Since the research area of this thesis is the eastern edge of the Qinghai-Tibetan Plateau, we have has cited the literature from regions with relatively similar natural conditions as much as possible.

 

Comments 5: Please specify studied type of ecosystems (or the region) in the title.

Response 5: Thanks for the comments. We have revised the title.

 

Comments 6: Do not italicise author names.

Response 6: Thanks for the comments. We have modified in the revised manuscript.

 

 

Comments 7: I think that photo is needless.

Response 7: Thanks for the comments. We have deleted the picture in Figure 1.

 

Comments 8: What species of animals graze on plots? What is the frequency of grazing?

Response 8: Thanks for the comments. We selected the dominant plants based on frequency and height. We have added frequency and height in Table 1.

 

Comments 9: What means this abbreviation?

Response 9: Thanks for the comments. This is the product model of moisture and temperature probes.

 

Comments 10: How are these points related to four 1 m * 1 m plots?

Response 10: Thanks for the comments. These points are around the sampling points. We have added the position to line 133.

 

Comments 11: How were dominant plants identified? What measure of their abundance was used? group, non family

Response 11: Thank you for pointing this out. We have modified Table 1.

 

Comments 12: What about leafs? How many specimens or stems of each species were surveyed?

Response 12: Thanks for the comments. We have added the specific weights of the collected leaves and roots in lines 140-141.

 

Comments 13: Please specify a number of observations in any part of the manuscripts.

Response 13: Thanks for the comments. We have pointed out in line 232 that one-way analysis of variance was used.

 

Comments 14: Figure 2 shows that monthly temperatures for grazing and grazing-exclusion sites are very similar. Why is so a big annual difference? Figure 2 shows very close values. It contradicts to the first sentence of the paragraph. From figure 2 I conclude that this is right, and the first sentence is wrong.

Response 14: Thanks to the reviewer for pointing out the error. We have modified the result of 3.1.

 

Comments 15: There as an axis for soil moisture is first, please rearrange the elements of the legend. Pleasure add the unit of measure.

Response 15: Thanks for the comments. We have revised Figure 2.

 

Comments 16: I think that these are not functional, but morphological traits.

Response 16: Thanks for the comments. We have modified to morphological traits.

 

Comments 17: What means a-h letters? What species of plant was studied? a b c?What means a-d letters?

Response 17: Thank you for pointing this out. We have added the note in the revised manuscript.

 

Comments 18: Species or specimens? I suggest that results for different species should be given separately.

Response 18: Thanks for the comments. It is species. Principal component analysis was to analyze and extract the principal components of all species together to facilitate the calculation of the D values in Table 3. The D values of different species have been given respectively in Table 3.

 

Comments 19: I didn't find Table 4 in the manuscript.

Response 19: Thank you for pointing this out. We have added Table 4 in the revised manuscript.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

good accommodations of reviewer comments

Author Response

Thank you for your comments.

Reviewer 2 Report

Comments and Suggestions for Authors

This is the second submission of the manuscript. The authors tried to address my previous concerns on the inadequate presentation of their results and  methods. However, the modifications did not make the paper meet the requirements of publishing. 

1. The abstract is lack of cohesions, particularly the question raised in the first part.
2. The research objectives are to assess how grazing-exclusion affects root traits and plant cold resistance. For these reasons, differences in temperature and soil water contents are not the focuses. 
3. There are many redundant information, like 127-128, 207-209, 233-234. Lines 155-181 should be condensed 3-5 sentences. 
4. It is unclear the differences in cold resistance between grazing and grazing exclusion plots  are caused by changes in plant species composition or eco-physiological adaptation within the same species. Please analyze it. 

Comments on the Quality of English Language

The manuscript should be edited by a professional English editor before resubmission 

Author Response

Comments 1:The abstract is lack of cohesions, particularly the question raised in the first part.

Response 1: Thank you for your comments. In response to the questions you raised, we have revised the Introduction.

Comments 2: The research objectives are to assess how grazing-exclusion affects root traits and plant cold resistance. For these reasons, differences in temperature and soil water contents are not the focuses.

Response 2: Thank you for your suggestion. The temperature and moisture content are indeed not the key focus. The aim of analyzing the differences in soil temperature and humidity between grazing exclusion and grazing is to verify that there are differences in soil conditions under these two condition, in order to better conduct further analysis.

Comments 3: There are many redundant information, like 127-128, 207-209, 233-234. Lines 155-181 should be condensed 3-5 sentences.

Response 3: Thank you for pointing this out. We have modified these sentences.

Comments 4: It is unclear the differences in cold resistance between grazing and grazing exclusion plots are caused by changes in plant species composition or eco-physiological adaptation within the same species. Please analyze it.

Response 4: Thank you for your comments. The reasons for the differences in cold resistance were not clearly pointed out in the article. However, the ranking of different plants’ cold resistance in Table 3 indicates that the differences in cold resistance between grazing and prohibited grazing plots are caused by changes in the composition of plant species rather than ecological and physiological adaptations within the same plant species. We have explained this conclusion to lines 385-389.

Comments 5: The manuscript should be edited by a professional English editor before resubmission.

Response 5: Thank you for your suggestion. The manuscript have edited by a professional English editor.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript was significantly improved. There are some comments in the attached file. 

Comments for author File: Comments.pdf

Author Response

Comments 1: or morphological? or "morphological", as in the caption?

Response 1: Thank you for your suggestion. We have made modifications to this.

Comments 2: It may be useful to add the Qinghai-Tibetan Plateau

Response 2: Thank you for your suggestion. We have made modifications to the title.

Comments 3: It duplicates the previous sentence.

Response 3: Thank you for your comments. We have deleted the duplicate sentences.

Comments 4: Please write full names of substances.

Response 4: Thank you for your suggestion. We have added the full name of SOD, POD and CAT.

Comments 5: Keywords mainly coincide with the title. Can you give more concrete and informative keywords?

Response 5: Thank you for your comments. We have modified the keywords.

Comments 6: Please describe how did you measure the frequency of plants

Response 6: Thank you for your comments. We have added the frequency measurement method on lines 206-209

Comments 7: from each of 1*1 m plots or from each of GE and FG plots?

Response 7: Thank you for your comments. To answer your questions. it is from each of the GE and FG plots. We have added an explanation to the manuscript

Comments 8: Please specify the unit of measure.

Response 8: Thank you for your comments. The unit of height is centimeters. We have added this unit to Table 1.

Comments 9: Do not italicise author names.

Response 9: Thank you for your comments. We have modified the revised manuscript.

Comments 10: Please specify the number of samples and what is a sample (plant species per plot per year or no?)

Response 10: Thank you for your comments. We have indicated the number of samples and what is a sample on lines 393-395.

Comments 11: 6 species, two species in two environmental conditions.

Response 11: Thank you for pointing this out. We have modified it.

Comments 12: The asterisk or the underlining?

Response 12: Thank you for your comments. To answer your questions, it is the asterisk. We have made revisions to the manuscript.

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

Great improvements have been made in English, data analyses and presentation of results and discussion. 

Some parts like lines 371-372 need to be edited to make it clear. 

The conclusion is still too long. Please make it concise. 

Author Response

Comments 1: Some parts like lines 371-372 need to be edited to make it clear.

Response 1: Thank you for your comments. We have edited it in the manuscript.

Comments 2: The conclusion is still too long. Please make it concise.

Response 2: Thank you for your suggestion. We have modified conclusion.