Effect of plateau pika presence on the ecosystem services of alpine meadows
- 1Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, P. R. China
- 2Academy of Animal and Veterinary Sciences, Qinghai University (Qinghai Academy of Animal and Veterinary Sciences), Xining, China
- 1Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, P. R. China
- 2Academy of Animal and Veterinary Sciences, Qinghai University (Qinghai Academy of Animal and Veterinary Sciences), Xining, China
Abstract. The activity of small mammalian herbivores influences grassland ecosystem services in arid and semi-arid regions. This study took plateau pika (Ochotona curzoniae) as example animal to investigate the effect of small mammalian herbivores on meadow ecosystem services in alpine regions. In this study, a home-range scale was used measure the forage availability, water conservation, carbon sequestration and soil nutrient maintenance services (total nitrogen, phosphorus, and potassium) of topsoil layer; and a quadrat scale was used to assess the biodiversity conservation service of alpine meadows. This study showed that plateau pika presence led to lower forage availability and water conservation services, and led to higher biodiversity conservation, carbon sequestration, soil nitrogen and phosphorus maintenance services of meadow ecosystem, whereas it had no impact on soil potassium maintenance service of meadow ecosystem in alpine regions. This study further found that the forage availability, biodiversity conservation, and soil nutrient maintenance services of meadow ecosystem in alpine regions firstly increased, and later decreased as the disturbance intensity of plateau pikas increased, whereas the water conservation service tended to decrease with the increasing disturbance intensity of plateau pikas. These results not only present a possible pattern of plateau pikas influencing the ecosystem services of meadow ecosystem in alpine regions, and consummate the small mammalian herbivores in relation to grassland ecosystem services.
Yingying Chen et al.
Status: final response (author comments only)
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RC1: 'Comment on bg-2021-313', Xiaojun Yu, 09 Feb 2022
This manuscript describes the effect of plateau pika presence on the ecosystem services of alpine meadow. In general, the experimental design is sound and results are convincing. In my opinion, its topic is of interest.
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AC1: 'Reply on RC1', Zheng Gang Guo, 09 Feb 2022
We appreciate for your time on our manuscript . It is really a very high opinion of this article. In addition, we did not find the specific comments in review system. If you have specific comments on our manuscript, please tell us, we will appreciate to revise the manuscript. Thank you again. Best wishes.
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AC1: 'Reply on RC1', Zheng Gang Guo, 09 Feb 2022
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RC2: 'Comment on bg-2021-313', Shixiong Li, 10 Feb 2022
Small mammalian herbivores often create extensive disturbance on grasslands, and might affect the ecosystem services of grassland ecosystem. This study uses plateau pika as an example herbivore to investigate the effect of disturbance by small mammalian herbivores and its disturbance intensity on ecosystem services of alpine meadows on the Qinghai-Tibetan Plateau. This study finds that the presence of plateau pikas and its disturbance intensity have different effect on ecosystem services of alpine meadows when the indicators, which are used to estimate the ecosystem services of alpine meadows, are various. These findings can improve the understanding of small mammalian herbivores in relation to grassland ecosystem services. The experimental design is sound and results are striking. In my opinion, its topic is of interest to its audience of our journal. I suggest that the manuscript can be published after some minor corrections.
General comments:
The plateau pika had been introduced in introduction sector and Field survey design sector. It had better move the description of plateau pikas in Field survey design sector to introduction.
The confidence intervals are required to represent in the Figure 2.
Some specific comments:
Line 41: Please add the Latin name of prairie dogs when it first appeared.
Line 44: What is the Latin name of European rabbit.
Line 141: The same alpine meadow is not good words. It may be alpine meadow with same dominant plant.
Line 190-194: The quantity of samples in each plot with or without plateau pika is better to expressed consistently with Arabic numerals?
Line 190-194: 5 soil samples in each plot were mixed into composite sample to measure carbon and nutrient concentrations, or each of 5 soil samples was used to measure carbon and nutrient concentrations. Please clarify it.
Line 255: Please move “Differences were considered significant at p < 0.05.” into the analysis of “LMM” in paragraph 2 of Data analysis sector.
Line 302: a quadrat scales?
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AC2: 'Reply on RC2', Zheng Gang Guo, 16 Feb 2022
Small mammalian herbivores often create extensive disturbance on grasslands, and might affect the ecosystem services of grassland ecosystem. This study uses plateau pika as an example herbivore to investigate the effect of disturbance by small mammalian herbivores and its disturbance intensity on ecosystem services of alpine meadows on the Qinghai-Tibetan Plateau. This study finds that the presence of plateau pikas and its disturbance intensity have different effect on ecosystem services of alpine meadows when the indicators, which are used to estimate the ecosystem services of alpine meadows, are various. These findings can improve the understanding of small mammalian herbivores in relation to grassland ecosystem services. The experimental design is sound and results are striking. In my opinion, its topic is of interest to its audience of our journal. I suggest that the manuscript can be published after some minor corrections.
Response: Thank you for your positive comments, and we have revised the manuscript carefully according your advices.
General comments:
- The plateau pika had been introduced in introduction sector and Field survey design sector. It had better move the description of plateau pikas in Field survey design sector to introduction.
Response: Good comment. We have moved the description of plateau pikas in Field survey design sector to introduction sector.
- The confidence intervals are required to represent in the Figure 2.
Response: Thank you for your comment. We have added the confidence intervals in the Figure 2.
Some specific comments:
- Line 41: Please add the Latin name of prairie dogs when it first appeared.
Response: Thanks for your advice. We have added the Latin name of prairie dogs when it first appeared (Line 41).
Line 44: What is the Latin name of European rabbit.
Response: Thank you for your suggestion. We have added the Latin name of prairie dogs when it first appeared (Line 44).
Line 141: The same alpine meadow is not good words. It may be alpine meadow with same dominant plant.
Response: Thanks for your comment. We have revised “the same alpine meadow” into “the alpine meadow with same dominant plant”.
Line 190-194: The quantity of samples in each plot with or without plateau pika is better to expressed consistently with Arabic numerals?
Response: Thank you for your advice. We have revised the quantity of samples in each plot with or without plateau pika with Arabic numerals.
Line 190-194: 5 soil samples in each plot were mixed into composite sample to measure carbon and nutrient concentrations, or each of 5 soil samples was used to measure carbon and nutrient concentrations. Please clarify it.
Response: Good question! In this study, we collected one soil sample from one subplot. 5 samples in each plot from 5 subplots were individually measured. The average value of five soil samples in one plot was considered as the representative data of that plot. We had clarified it in manuscript.
Line 255: Please move “Differences were considered significant at p < 0.05.” into the analysis of “LMM” in paragraph 2 of Data analysis sector.
Response: Thank you for your suggestion. We have moved “Differences were considered significant at p < 0.05.” into the analysis of “LMM” in paragraph 2 of Data analysis sector (Line 249).
Line 302: a quadrat scales?
Response: Thanks for your suggestion. We have revised “a quadrat scales” into “the quadrat scales”.
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AC2: 'Reply on RC2', Zheng Gang Guo, 16 Feb 2022
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RC3: 'Comment on bg-2021-313', Xiaojun Yu, 10 Feb 2022
I suggest that the manuscript can be published after a little correction.
- "this study" appeared in the abstract four times. It is necessary to further polish the language.
- For references in scientific hypothesis, please check whether there is the necessity of citation. So, it is suggested to summarize the existing research in the research progress. Then put forward scientific hypothesis.
- P96-97,“Plateau pikas can live in various habitats with different soil types, topographies, and microclimates.” This sentence lacks qualified region.
- What is the grazing situation of the experimental site and how to eliminate the impact of grazing intensity on the grassland.
- ABED (active burrow entrance densities), when is the investigation period?
- In Fig.1, the presence of plateau pika, What pika density are based on?
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AC3: 'Reply on RC3', Zheng Gang Guo, 16 Feb 2022
I suggest that the manuscript can be published after a little correction.
Response: We thanked you for your positive comments, and we have revised the manuscript carefully according your advices.
- "this study" appeared in the abstract four times. It is necessary to further polish the language.
Response: Thank you for your advice. We have polished the language in the abstract.
- For references in scientific hypothesis, please check whether there is the necessity of citation. So, it is suggested to summarize the existing research in the research progress. Then put forward scientific hypothesis.
Response: Exactly, we had summarized the existing research progress in front paragraphs of introduction. It is unnecessary to cite the references in hypothesis, and it seems redundant. To make the hypothesis more scientific, we have deleted the references in the hypothesis according to your opinion.
- P96-97 “Plateau pikas can live in various habitats with different soil types, topographies, and microclimates.” This sentence lacks qualified region.
Response: Thanks for your suggestion. We have added the qualified region “on the Qinghai-Tibetan Plateau” in this sentence (Line 97).
- What is the grazing situation of the experimental site and how to eliminate the impact of grazing intensity on the grassland.
Response: Thanks for your comment. This study used a stratified random and paired design to discover the general effect of plateau pika disturbance on ecosystem services of alpine meadows. In experimental design, each paired plot shared the same grazing intensity during the cold season, however, 50 paired plots consisted of different yak grazing intensity, and this can permit the general pattern relating to the effect of plateau pika disturbance on alpine meadow ecosystem services. We have supplemented this information into “Field survey design” sector.
- ABED (active burrow entrance densities), when is the investigation period?
Response: Thanks for your comment. The ABED (active burrow entrance densities) was measured in the process of field sampling. As described in field sampling, this study firstly measured the density of active burrow entrance, and then measured the area of bare soil patches, collected vegetation and soil samples.
- In Fig.1, the presence of plateau pika, What pika density are based on?
Response: Thanks for your comment. Fig.1 shows that plateau pika density is a qualitative description, which is to present the difference in ecosystem services of alpine meadows between the presence of plateau pikas and the absence of plateau pikas. Fig.2 shows that the changeable trends of each ecosystem service of alpine meadows as the disturbance intensity of plateau pikas increased. In Fig.1, 50 disturbed plots with different plateau pika densities (it ranged from 83 to 1384 entrances ha-1) was considered as a whole to compare with the 50 undisturbed plots. We supplement some sentences to clarify this research approach in data analysis sector.
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EC1: 'Comment on bg-2021-313', Paul Stoy, 28 Feb 2022
I am in receipt of an additional review from an expert Referee, pasted below. When preparing a response, please include a response to these insightful comments, which follow.
Overall, I am very excited to see the authors addressing this topic in this system. I especially appreciated the authors integrating a number of measures into their suite of response variables; that should be done more frequently! On the other hand, some of the methods either need to be clarified or better justified, because the current description comes across as potentially biased. Furthermore, I don’t understand why the authors make things (for me, at least) more complex and difficult to understand – instead of simply naming the particular response variable, they have created monikers such as “biodiversity conservation service” that obfuscate meaning and make reading harder. Also, as noted below, I’m not sure that I agree with the authors’ assertion of a threshold, simply because a quadratic relationship exists. Isn’t that the default assumption of niche dynamics and (more relatedly) the Intermediate Disturbance Hypothesis? I don’t see where the bare vs. the vegetated plots in the pika-occupied areas is discussed in the main text. Also, some of the Discussion seems like a pretty strong over-simplification of how to contextualize the study’s results with the broader literature. Also, given that all of the sampling occurred in 1 month of 1 year, and that the entire sampled area spanned 0.1225 km2, it would seem appropriate for the authors to acknowledge with a caveat or two the limitations of this spatio-temporal domain. I realize that the sampling scales of biogeochemistry investigations are much more limited than that of animal ecologists, but note that you’re investigating the dynamics of both soils and animal behaviors.
Larger, more-important topics that are of greatest concern to the robustness of the study and its conclusions:
Line 27 – If this is true, consider adding “linearly”, immediately after “decrease”. Later on in the sentence, note that nowhere in the abstract have you defined what “disturbance” or “disturbance intensity” is, specifically. This 2nd point remains true on line 54 through at least 66, in the Introduction. It appears again on line 152. What is the “disturbance”? Needs to be defined.
Line 32-33 and 70-71 – It’s not clear what “provisioning, regulating, supporting” refer to: each needs to be in reference to something else. E.g., provisioning WHAT?, regulating WHAT?, supporting WHAT?
Line 49-51 – This sentence needs to be re-phrased; its meaning is not clear, and there are several studies (in just 1 species of pika [Ochotona princeps], alone) that show how American pikas are ecosystem engineers, alterers of vegetation composition, a keystone species, etc. These include Aho et al. (1998), several papers by Denise Dearing at the University of Utah (see her thesis: https://www.proquest.com/docview/304226940?pq-origsite=gscholar&fromopenview=true), Dearing (1996: Oecologia), Hall and Chalfoun (2019; J. Animal Ecology), Jakopak et al. (2017, J. Mammalogy), among others. Also, it would be important for the authors to cite one or more papers that have noted specifically that the plateau pika is a keystone species. This will help ensure the objectivity and lack of bias in the research, rather than it appearing that plateau pikas are nothing more than a “pest” (see N. Fan, W. Zhou, W. Wei, Q. Wang, and Y. Jiang. 1999. chapter 13. Rodent Pest Management in the Qinghai-Tibet Alpine Meadow Ecosystem. 20 pages.). This lack of clarity here is pivotal, because this is where you’re really setting up the goal of the manuscript and why it will be an important contribution.
Lines 85-93 – I very much like that you have laid out your hypotheses and cited one or more studies that found a certain result. However, unless the reader goes and reads all five of those papers, it’s not clear whatsoever why those predictions are being made, nor by which processes or mechanisms those results were created. It would be helpful if you provided concise descriptions of those.
Lines 103-105 – Excellent that you provide the reader some overview of conditions at the site. However, it would be much, much more informative, and relevant to your study objectives and interpretation of your results, if you were to provide understanding of how much of the annual precipitation falls as snow (either % or amount during the warm season, and % or amount as snow during cold season), and what the temperatures are in the warm and cold seasons. Pikas generally do not respond to any annual-average measure.
Lines 114-115 – I’m not sure what it means that “… many plant species are found until late summer.”
Line 116 – It’s not a “census”; it’s a “sample” or a “survey”.
Line 116-118 – Yak grazing appears that it could be a confounding influence, here. Given that effects in low-productivity systems such as this are likely to have ecological memory (or legacy effects), this sentence does not make sense logically to me.
- 119 – “only a small burrowing herbivore” … what does this mean? It’s not important?
Section 2.2 – You might give just a little more background on the life-history strategy of plateau pikas here, as most readers of the journal will not know the relevant details. E.g., typical body mass, does sexual dimorphism exist?, are they generalist herbivores or if not, what do they eat?, are they burrowers themselves, or do they conscript burrows made by other species?, how deep do their burrows go?, do they hibernate?, etc. May only need to be an extra 2-4 sentences, but this will help the reader immensely.
- 123 – When you say “diffusion”, do you mean “dispersal”? If so, is this natal dispersal, or adult dispersal? If the process is gradual, does the ability to find reference (unused) sites depend on the timing of your sampling?
- 133-134 – I don’t understand this sentence at all; the text after the comma is exactly the same as the start of the sentence.
- 134-135 – To make the study repeatable, we need to know what that distance was specifically that you used.
- 152 – Depending on what “disturbance” means, this assumption may or may not hold true. I would be surprised if it did NOT hold for amount of biomass within a certain distance of the burrow entrance (if the species is a central-place forager), but as noted earlier in the MS, some ecosystem properties are not affected while others are even promoted by the presence of pikas.
- 156-160 – The reader does not have enough detail to know what you are doing, to assign causality by plateau pikas. Rather than assume that the reader will just trust your method, you need to provide clear information that both makes the method repeatable, and convinces the reader that you accounted for this in a robust, defensible manner.
- 163-164 – It seems that if you are only moving the quadrats slightly in the pika-occupied sites (but not in the non-pika-occupied sites), you are biasing the sampling and results. Either clarify or justify this approach. By not having any sites be randomly selected, it causes concern in the reader and in my mind as well. Furthermore, in reading the rest of the main body of the text, I’m not seeing any reference to the comparisons of bare vs. vegetated plots within the plateau pika area
- 164-165 – What is the purpose of the paired bare patch vs. the vegetated patch? The reader has no idea about why you are doing this?
- 172 – Species richness is simply a tally of the species present in a given area; you mention “their numbers”, which leads me to think that you also measured abundance, so that you could quantify measures like evenness and Hill series.
- 173 – “palatable” and “unpalatable” to which species? Obviously, palatability depends upon the herbivore that one is considering.
- 192 – You need to connect this back to your sampling approach. Consider adding “Because pika-absent sites did not include sampling at bare areas, only” before the start of the “Five soil samples…” sentence.
- 200-201 – What does “artificially removed” mean? I think that you may mean “manually picked out”…?
- 202-203 – This sentence is nonsensical, as written – passing soil through a sieve does not allow one to estimate any of these concentrations.
- 203-206 – Please specify which technique is associated with which concentration – e.g., Kjeldahl procedure measures total N concentration.
- 216-218 – Yes, but how do you measure the area of a shape that is irregular? Need more details on how you measured areal extent.
- 219-220 – How close to reality was this consideration? Depending on how far from actual truth it is, this assertion worries me.
- 225-229 – You cannot assume that your reader is going to read all 3 of these papers. You need to provide the key details, here, to convince the reader that you’re doing this robustly.
- 241 – Is the presence vs. absence of plateau pikas considered your “fixed effect” ?
- 243 – This is a VERY long sentence. Consider ending the first sentence in the middle of line 247. Also, the phrase from middle of line 247 to 251 is not written correctly – you’re not performing a regression analysis between (nor among) all of the response variables.
- 255 – Given the tens to hundreds of different analyses that you’re performing across this study, please provide a justification of why you are not correcting for experiment-wise error rates (e.g., Bonferroni stepwise correction). That is, if you perform 100 tests, you will likely have 5 tests that will be “statistically significant”, even when there is no pattern nor biological effect whatsoever, just by chance alone.
- 259-269 – Consider simply reporting the results of what you found, as opposed to giving everything another name for each predictor. However, what you’ve done makes things more complicated, in my view, because you’ve lumped several response variables into classes of responses (such as “provisioning services”).
- 280-283 – I think that it would be preferable to comment on the fit of the linear vs. the quadratic relationship to the data. Also, does a bell-shaped curve unequivocally indicate a “clear threshold for disturbance”? I’m not sure that it does … what about the Intermediate Disturbance Hypothesis as an alternative explanation for the pattern?
- 322 – Although I appreciate the desire to connect plateau pika activity to positive provision of ecosystem services, using terms like “in relation to the forage availability service of grassland ecosystems” makes it confusing for the reader to understand what is really going on in the text. Also, the logic of lines 321-325 is not at all clear to me … what are you saying is the mechanism causing this context-dependence?, i.e., why are the responses different in the two classes of regions?
- 326-335 – I am very impressed that you are trying to contextualize your results amidst some studies from the existing literature, but you are really undercutting the value of these comparisons by virtue of how high-level, superficial, or simplistic that they are. E.g., why are the results consistent with the one study, but not the other? What are the magnitudes of the effects?
- 349-350 – This sentence makes no sense, given that you define “biodiversity conservation [service]” as species richness of plants.
- 364-365 – I am not demanding that you do that for this study, but quite a lot of your interpretation (e.g., see lines 394-397) rests on the assumption that number of active burrows serves as an accurate index for disturbance intensity. It sure would be nice (and, for me, more empirically compelling) to correlate number of active burrows with number of pika-hours spent foraging aboveground, on one or a small number of days throughout the season. The latter would be a much more direct measurement of one process (i.e., forage consumption) that can lead to some of the changes that you are suggesting are imposed by pikas.
Lines 389-394 – As mentioned above, this sentence feels like a pretty strong over-simplification of the dynamics of herbivory, given how few studies the authors are citing across the paper, compared to the plethora of studies on the topics listed in this sentence that exist. None of the numerous review articles published over several decades is cited, and the authors are reporting nothing more than directionality.
Lines 407-409 – The existence of a quadratic relationship to disturbance intensity does not necessarily indicate an existence of a threshold. Much previous ecological literature has been produced on the topic of thresholds; consider consulting it.
Issues that compromise the clarity, readability, and breadth of audience of the article:
Line 15 – “pika” is singular; either say “pikas” or “the plateau pika” (also on line 52, 53, 62, 151, etc.). Also, “an example” of what? Maybe instead say “a model organism” or “a focal organism”.
Line 17 – “forage availability”: does this mean forage available to pikas, livestock, or other herbivores?
Throughout Abstract and entire MS – Using three or more nouns in a row is called “freight-train wording”. Its usage makes it very difficult for the reader to divine which noun(s) are acting as adjectives, and which one(s) are acting as a noun. For greater clarity, you need to either 1) hyphenate the nouns that are acting as adjectives, or, preferably, 2) use prepositions to clarify the relationships among the nouns. For example, at this point in the MS, I have no idea what “soil nutrient maintenance services”, “soil potassium maintenance service”, or “forage availability service” (line 44) is. I recommend the authors implement these clarifying changes, throughout the MS.
Line 23 – Change “, whereas it …” to “. In contrast, it …”
Line 30 – “richen” should be “richening”, to be parallel with “influencing”; I will stop identifying this type of grammatical error here. The MS will be markedly improved and clearer, when all such issues are resolved.
Line 80 – “land-use” should be “patterns of habitat use” or simply “habitat use”; the former refers most commonly to how humans use landscapes for anthropogenic activities. Not sure what “the scales” means, on line 81.
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AC4: 'Reply on EC1', Zheng Gang Guo, 30 May 2022
Dear Editor
Thank you for your patience with our manuscript numbered “BG-2021-313”. Based on the further comments from the reviewer and editor, we have revised the manuscript carefully again. We found that these questions and comments are valuable to improving the quality of this manuscript. Here, we submit both a clean and a track changed versions of manuscript to “Biogeosciences”.
The responses to the reviewer’ comments are following:
Chen and others explore the role of pika presence at different densities to ecosystem services. The manuscript makes a few interesting points but could be strengthened by focusing more on fundamental ecological theory.
- I wasn't entirely sure how it was identified that pikas caused some bare patches and not others, for example if the bare patches were caused by past pika activity. Therefore it was unclear to me how controls were used to test the objectives.
Answer: this is a common comment we met. The soil bare patches caused by plateau pikas is easily to identify because one soil bare patch caused by pika is paired with a visible burrow entrance (Pang et al. Geoderma, 2021, 115098). Other soil bare patches are not paired with visible burrow entrance.
The soil bare patches caused by past plateau pika activities can be divided into two types. Some can be gradually restored, and others are still be bare.
In this field survey, we firstly identified the soil bare patches caused by plateau pikas though the paired visible burrow entrance. And then, we continued to identify whether these soil patches are bare. If bare, we divided them into soil bare patches caused by pika; if not bare, we did not divide them into soil bare patches caused by plateau pikas. We supplemented this information into 2.3 Field sampling.
- 'plateau pika presence' in the title is a bit smoother (and section 3.1).
Answer: Thanks for your comment. We have revised “plateau pika presence' into “the presence of plateau pikas” in the title and section 3.1.
- 17: 'ecological service of' can be deleted here because it's mentioned below. Honestly the word 'ecological service' needs to only be stated once or maybe twice in the abstract; it's continued usage is redundant. Also in the main text. A previous reviewer may have recommended this but it needn’t be repeated so much.
Answer: Great comment. According to you this comment, we have only stated once in the abstract, and the other have been deleted in the revision manuscript.
- The abstract doesn't contain any qualitative values and it would be of greater use to the reader if it did. 'Possible pattern' is also speculative, you can say what the pikas did in your study.
Answer: Thank you for your comment. We have revised the abstract and result sectors, in which some qualitative values are added into manuscript. This study showed that the forage available to livestock and water conservation were 19.74% and 15.86% lower in the presence of plateau pikas than in their absence, while biodiversity conservation, carbon sequestration, soil nitrogen, and phosphorus maintenance were 14.58%, 29.15%, 9.97% and 8.89% higher in the presence of plateau pikas than in their absence.
In addition, we have deleted possible, which confirmed that the findings of this study present a pattern of plateau pikas influencing the ecosystem services of meadow ecosystems in alpine regions.
- 62: 'with averaging' isn't correct usage. A few minor usage changes throughout the manuscript would make for an improvement, using an automated grammar checker will probably catch almost all instances. (see also 66 'with average' and numerous other instances, e.g. line 137 'can turn green until July'. "don't turn green until July"?).
Answer: Thank you for your suggestion. Based on your comment, we have revised “with averaging” into “with an average weight of”; We have revised “with average” into “with an average length and depth of”; we have revised “can turn green until July” into “don't turn green until July”. In addition, we have used an automated grammar checker to make for an improvement throughout the manuscript.
- 192: use 'W' if it is the shape of a W. I wasn't sure if it meant "West".
Answer: Thank you for your comment. We have revised “a W pattern” into “ the shape of a W pattern”.
- Figure 1: why does it go 'a' then 'b' for some bars and 'b' then 'a' for others?
Answer: This is a statistical expression. Lower case represents a significant difference between the absence and presence of pika in Figure 1. Generally, bars with “a” represent the bigger value, and bars with “b” represent the smaller value.
- 2: this looks like the famous "Intermediate disturbance hypothesis" in some cases. (There’s even a wikipedia page for it: https://en.wikipedia.org/wiki/Intermediate_disturbance_hypothesis). A little bit of pika activity is good but too much and they take over. De-emphasizing the comparisons against rabbits and prairie dogs and thinking more about ecological principles could structure the Discussion more and add references, which are a bit lacking. In other words, if you expand the interesting discussion beginning line 457 a bit and focus on fundamental theory in addition to these nice examples of intermediate disturbances, the Discussion could be further improved. (This paragraph is also too long; breaking it up would help the reader.)
Answer: Thanks for your comment. At the beginning line 457 in former revision (line 455 in present revision), we firstly focus on the Intermediate disturbance hypothesis. We looked up some literatures (Dial and Roughgarden, Ecology, 1998, 79(4), 1412-1424; Gao and Carmel, Oikos, 2020) to refer the methods that introduce the fundamental theory. The revision discussion is as follows:
This study also shows that the disturbance intensity of plateau pikas also affects the forage available to livestock, biodiversity conservation, water conservation, carbon sequestration, and soil total nitrogen and phosphorus maintenance. As found in plant-species richness and aboveground plant productivity (Dial and Roughgarden, 1998; Gao and Carmel, 2020), the response of plant-species richness and palatable plant biomass to the disturbance intensity of plateau pikas follow the pattern for the intermediate disturbance hypothesis in this study. In addition, the soil organic carbon stock, soil total nitrogen and phosphorus stocks at home-range scale also support the intermediate disturbance hypothesis. However, the top soil water storage does not conform the intermediate disturbance hypothesis.
At lower disturbance intensity, stronger competition of dominant sedges often restrains the grass to grow well (Pang and Guo, 2018) and the rare plants to coexist (Wang et al., 2012), which leads the forage available to livestock and biodiversity conservation of alpine meadows to be maintained at a low level. Although the presence of plateau pikas can increase the input of soil organic matter, this increase is low (Pang and Guo, 2017; Pang et al., 2020b), which enables the soil organic carbon sequestration and soil nitrogen and phosphorus maintenance of alpine meadows to maintain a relatively low level.
At intermediate disturbance intensity, the activities of plateau pikas improve the growth potential of grass plants (Wang et al., 2012), and increase the input of organic matter, soil total nitrogen (Li et al., 2014), organic carbon accumulation (Yu et al., 2017b), which contributes to higher the biodiversity conservation, forage available to livestock, carbon sequestration, soil total nitrogen and phosphorus maintenance services.
At higher disturbance intensity of plateau pikas, frequent bioturbation can enable all species to be at risk of going extinct (Dial and Roughgarden, 1998). Low soil water content in alpine meadows (Liu et al., 2013) only sustains the xerophytes and mesophytes, most of which are unpalatable (Pang and Guo, 2018). This contributes to relatively lower forage available to livestock and biodiversity conservation. Low vegetation biomass decreases the input resources of soil organic matter (Sun et al., 2015; Pang and Guo, 2017), contributing to a decrease in the soil organic carbon sequestration and soil nitrogen and phosphorus maintenance of alpine meadows.
Additionally, the linearly negative relationship between the water conservation of alpine meadow and disturbance intensity of plateau pikas is ascribed to evaporation and more water infiltration on bare soil patches, as the amount of water evaporation and infiltration tends to increase as the area of bare soil increases (Liu et al., 2013).
The manuscript has been revised carefully and strictly according to your comments. We hope our modification and explanation is clear enough, however, if there is still any question, please do not hesitate to contact us.
Yours sincerely
Ying Ying Chen, Huan Yang, Gen Sheng Bao, Xiao Pan Pang, Zheng Gang Guo*
First author: Ying Ying Chen, Email: chenyy2019@lzu.edu.cn
Corresponding authors: Zheng Gang Guo, E-mail: guozhg@lzu.edu.cn
Yingying Chen et al.
Yingying Chen et al.
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