Roots, Litter, and Seasonal Drought Together Inhibit Plant Growth in the Herbaceous Layer in a Subtropical Moist Forest of Southwestern China
Round 1
Reviewer 1 Report
The study investigated the impact of plant roots, forest litter, and seasonal drought on the diversity and abundance of plants, seedlings' height, and yearly primary production in the herbaceous layer near the forest's ground. The authors try to link the work with global change. They assume that control treatment (i.e., plants not receiving watering) in summer is a drought treatment! This not mimicking global change as the plants of the study site are adapted to such a climate. Mimicking the global change could be in a control area where you reduce the amount of the annual rainfall in plots more than others. Global change could be mimicked under natural habitat if that area received lower rainfalls for 2-3 years than the long-term annual average rainfall. The manuscript is written in proper language.
Introduction
The authors should strongly justify why they assessed forest litter and plant roots. Which roots were used, understory or overstory plants' roots?
Materials and Methods
The total monthly precipitation during the study period should be provided.
It would be good if the physical and chemical properties of the soils of the study sites were provided.
When forest litter exclusion, the litter leachates from the surrounding areas could also inhibit the growth of the understory plants. How they controlled for that?
It would be great if the authors assessed the relationship between the litter thickness and the number of plants; this might provide a better estimate of the impact of the litter.
Define which months received extra summer water.
How were roots and litter inclusion done? Have you removed the roots? If yes, Is this means you removed the whole plants to remove the roots?
The treatment subplots were 1 m x 1 m; how the subplots were vertically excavated down to the soil parent material (around 1.5 m) in such a small area without affecting the soil structure of the surrounding subplots..
Results
In tables 1 and 2, Many species are repeated. Keep the genus name in full once and then the initials for the repetition. Also, no need to add the species authors every time. Maybe once!
Figures:
There are too much descriptions in the legends. No need to repeat the long description of the treatments in each figure. For example, in fig. 6, you stated the description as follows: CR+L+: the treatment with plant roots and forest litter inclusion, CR+L-: the treatment with plant roots inclusion but forest litter exclusion, CR-L+: the treatment with plant roots exclusion but forest litter inclusion, and CR-L-: the treatment with plant roots and forest litter exclusion in control plots; and WR+L+: the treatment with plant roots and forest litter inclusion, WR+L-: the treatment with plant roots inclusion but forest litter exclusion, WR-410 L+: the treatment with plant roots exclusion but forest litter inclusion, and WR-L-: the treatment with plant roots and forest litter exclusion in watered plots). Instead, mention the meaning of CR, WR, L+, and L-. In addition, the filling of the bars is present on the graph; no need to state, "Data of yearly primary production of plant seedlings in control and watered plots are illustrated by the blank and dark grey columns, respectively". Do the same for all graphs.
In Table 3: Add the values of the mixed linear model, then put *, **, and *** for significant values at <0.05, <0.01, and <0.001, respectively. Insignificant values (>0.05) with nothing.
Discussion:
The discussion is general; make it directed more to the recorded species in this study.
Another assumption for the greater diversity and productivity in the watered plants than the control could be attributed to the plot disturbance. The water enhances the seedings' emergence in such disturbed subplots. Also, water can leach the allelochemicals from the litter of the watered plots away, giving a higher chance for seedling emergence. Elaborate more about this!
Defining the level of root competition between the different species is important. The root niche of every species should be described; e.g., which species have roots at the same level (i.e., competing with each other), and which at different levels (i.e., minimum competition)? Use such data in interpreting the results.
The authors stated that "Forest litter on the top of fiberglass screens was swept away in time for unblocking natural sunlight and through fall, all seeds on each fiberglass screen were collected and evenly returned to the corresponding subplot". Such a process exposed seeds to light. In fact, many of the large-seeded forest plants germinate mainly in darkness. However, removing the litter will reduce their germination and enhance the germination of small-seeded plants that require light. You can elaborate on this issue to interpret which species increased in the different treatments.
More discussion is needed on the positive responses of specific species to certain treatments; for example, Nephrolepis cordifolia is associated more with litter removal. Why? Besides, Nephrolepis cordifolia is associated more with control than watered plots.
There is a misunderstanding for seed germination. Seeds can emerge from under the litter, especially those with medium or larger sizes. Therefore, litter is not always a barrier to seed germination
Author Response
Dear reviewer and editor,
We sincerely appreciate your time and effort in reviewing and commenting our manuscript entitled “Roots, litter and seasonal drought together inhibit plant growth in the herbaceous layer in a subtropical moist forest of southwestern China”. We found that the suggestions and comments are highly constructive for improving our manuscript. Thank you very much for that. In response, we have thoroughly revised our manuscript according to the reviewer’s suggestions and comments. Here, we explain our responses to the reviewer’s suggestions and comments point-by-point below.
Point 1: The authors try to link the work with global change. They assume that control treatment (i.e., plants not receiving watering) in summer is a drought treatment! This not mimicking global change as the plants of the study site are adapted to such a climate. Mimicking the global change could be in a control area where you reduce the amount of the annual rainfall in plots more than others. Global change could be mimicked under natural habitat if that area received lower rainfalls for 2-3 years than the long-term annual average rainfall.
Response 1: Good comments! This might be because our unclear expressions in our manuscript. We revised our hypothesis and cited four publications to afford it. Our explanation is here: we did not assume that control treatment in summer is a drought treatment; we keep their natural status of all treatments in control plot, and irrigated quantificationally in watered plot during dry season for eliminating the negative effects of seasonal drought on the five dependent variables of plant seedlings. We investigated the negative effects of seasonal drought through this irrigation method after comparing to the five dependent variables in control plot.
Point 2: Introduction: The authors should strongly justify why they assessed forest litter and plant roots. Which roots were used, understory or overstory plants' roots?
Response 2: Good suggestion! (1) We revised the first paragraph and added some information about forest litter and plant roots to justify why we assessed them. Please see L66-74; (2) We used all the stronger root systems of overstory woody plants and analyzed their function in inhibiting seedling growth in the herbaceous layer. We excavated deeper than 1.5m soil profiles for preventing stronger root systems from extending into the subplot. Please see L209-212.
Point 3: Materials and Methods：The total monthly precipitation during the study period should be provided.
Response 3: Good suggestion! We provided the precipitation and evaporation in 2021. Please see l161-162.
Point 4: Materials and Methods：It would be good if the physical and chemical properties of the soils of the study sites were provided.
Response 4: Good suggestion! We provided the physiochemical properties of the soils in our study sites, please see L177-182.
Point 5: Materials and Methods：When forest litter exclusion, the litter leachates from the surrounding areas could also inhibit the growth of the understory plants. How they controlled for that?
Response 5: Good question! For control the litter leachates from the surrounding areas, we did: (1) we vertically excavated down to the soil parent material and insulated subplot soils from outside by galvanized steel sheets with 1mm thick; (2) the galvanized steel sheets were higher about 10cm than ground surface for excluding forest litter and their leachates around the subplots; and (3) we weekly cleaned forest litter around the subplots for excluding their leachates.
Point 6: Materials and Methods: It would be great if the authors assessed the relationship between the litter thickness and the number of plants; this might provide a better estimate of the impact of the litter.
Response 6: Good suggestion! We assessed the relationship between the litter thickness and the number of plants in the “Discussion” section. Please see L417-419 and Figure 8.
Point 7: Materials and Methods: Define which months received extra summer water.
Response 7: Good suggestion! We defined the range of month received extra summer water. Please see L230.
Point 8: Materials and Methods: How were roots and litter inclusion done? Have you removed the roots? If yes, Is this means you removed the whole plants to remove the roots?
Response 8: Good question! (1) we just left the plant roots and forest litter in their natural status without any disturbance to keep roots and litter inclusion; (2) to keep the original state of soil profiles to the greatest extent, we only removed all the plant roots along the perimeter of soil profiles which diameters were > 1 cm; and (3) we only removed the woody roots with diameters > 1 cm and all herbaceous individuals in the 1m × 1m subplots, without removing the woody trees.
Point 9: Materials and Methods: The treatment subplots were 1 m x 1 m; how the subplots were vertically excavated down to the soil parent material (around 1.5 m) in such a small area without affecting the soil structure of the surrounding subplots.
Response 9: Good question! All people stood out the 1m × 1m subplots when we excavated the soil profiles without diturbing the subplots; the distance between two subplots was more than 10m, that means we had enough space to excavate soil profile without disturbing surrounding subplots.
Point 10: Results: In tables 1 and 2, Many species are repeated. Keep the genus name in full once and then the initials for the repetition. Also, no need to add the species authors every time. Maybe once!
Response 10: Good suggestion! We revised Table 1 and 2 as reviser’s suggestion.
Point 11: Results: Figures: There are too much descriptions in the legends. No need to repeat the long description of the treatments in each figure. For example, in fig. 6, you stated the description as follows: CR+L+: the treatment with plant roots and forest litter inclusion, CR+L-: the treatment with plant roots inclusion but forest litter exclusion, CR-L+: the treatment with plant roots exclusion but forest litter inclusion, and CR-L-: the treatment with plant roots and forest litter exclusion in control plots; and WR+L+: the treatment with plant roots and forest litter inclusion, WR+L-: the treatment with plant roots inclusion but forest litter exclusion, WR-410 L+: the treatment with plant roots exclusion but forest litter inclusion, and WR-L-: the treatment with plant roots and forest litter exclusion in watered plots). Instead, mention the meaning of CR, WR, L+, and L-. In addition, the filling of the bars is present on the graph; no need to state, "Data of yearly primary production of plant seedlings in control and watered plots are illustrated by the blank and dark grey columns, respectively". Do the same for all graphs.
Response 11: Good question! We revised all the legends of figures and tables.
Point 12: Results: In Table 3: Add the values of the mixed linear model, then put *, **, and *** for significant values at <0.05, <0.01, and <0.001, respectively. Insignificant values (>0.05) with nothing.
Response 12: Good suggestion! We revised the Table 3 as reviser’s suggestion.
Point 13: Discussion: The discussion is general; make it directed more to the recorded species in this study.
Response 13: Good suggestion! We revised all parts of “Discussion” section, shortened the first paragraph, merged two paragraphs into one, and made them more specific for this study.
Point 14: Discussion: Another assumption for the greater diversity and productivity in the watered plants than the control could be attributed to the plot disturbance. The water enhances the seedings' emergence in such disturbed subplots. Also, water can leach the allelochemicals from the litter of the watered plots away, giving a higher chance for seedling emergence. Elaborate more about this!
Response 14: Good suggestion! We add more information about leaves’ leachates in the last part of “Discussion”, i.e., 4.4. Synergistic Effect of Plant Roots, Forest litter and Seasonal Drought on Plant Diversity and Seedling Growth in the Herbaceous Layer. Please see L497-512.
Point 15: Discussion: Defining the level of root competition between the different species is important. The root niche of every species should be described; e.g., which species have roots at the same level (i.e., competing with each other), and which at different levels (i.e., minimum competition)? Use such data in interpreting the results.
Response 15: Good suggestion! We collected all plant seedlings in the herbaceous layer to weighed for determining their dry biomass without collect their root weight specially. We added some root information about competition between woody species and seedlings. Please see L430-435.
Point 16: Discussion: The authors stated that "Forest litter on the top of fiberglass screens was swept away in time for unblocking natural sunlight and through fall, all seeds on each fiberglass screen were collected and evenly returned to the corresponding subplot". Such a process exposed seeds to light. In fact, many of the large-seeded forest plants germinate mainly in darkness. However, removing the litter will reduce their germination and enhance the germination of small-seeded plants that require light. You can elaborate on this issue to interpret which species increased in the different treatments.
Response 16: Good suggestion! We elaborated this information in the “Discussion” section. Please see L398-403.
Point 17: Discussion: More discussion is needed on the positive responses of specific species to certain treatments; for example, Nephrolepis cordifolia is associated more with litter removal. Why? Besides, Nephrolepis cordifolia is associated more with control than watered plots.
Response 17: Good suggestion! We added these information in the “Discussion” section, please see L452-457 and L499-513.
Point 18: Discussion: There is a misunderstanding for seed germination. Seeds can emerge from under the litter, especially those with medium or larger sizes. Therefore, litter is not always a barrier to seed germination.
Response 18: Good suggestion! We clarified this issue in the first part of “Discussion” section. Please see L436-444.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Title
What do you mean by ‘seasonal drought’? The inhibition is in all the species of the herbaceous layer or just some of them?
Abstract
L17: Why do you say that studies on the herbaceous layer are ‘rare’? In your country or worldwide? I doubt that nobody has studied the herbaceous layer. Please be more realistic.
L18: By ‘environmental factors’ you understand roots and litter? Please clarify.
L22: My surmise is that you have a split-plot design which have two errors. Please see comments later on the text.
L27: How was the seedling density before the experiment was set-up? How was the seed bank? It is important to clarify the previous state of the study site.
L31-32: Where in your study can I see data about soil moisture and nutrient status? I think this is out of the scope of your work because you do not analyze those variables.
L32-33: What do you understand by ‘seedling establishment’? How did you measure it?
L34: The word ‘may’ is not appropriate for a conclusion. Conclusions must be clear and unquestionable. Similar to that with soil moisture and nutrition status, you cannot talk about plant physiological responses and forest evolution here because you do not evaluate those factors. Conclusions are about the objectives of your work. Please rewrite from L31 to L35.
Keywords
Please remove or replace all those words already mentioned in the title.
Introduction
L65-77: This paragraph seems excessive for a work devoted to the herbaceous layer. Consider shortening or removing.
L81: How can I be sure that works on herbaceous layer are ‘rare’? What type of studies of the herbaceous layer are rare? Ecological, physiological, evolutive studies? This phrase is quite provocative and authors must clarify if this lack of studies is at the worldwide level or only at the local level. If the latter, then the study answer a local question.
L85: Please provide an appropriate rationale for using roots and litter as explanatory variables of the herbaceous layer.
L89: Please provide references for all those variables affecting the herbaceous layer.
L91-93: This sentence makes no sense to me. Besides it seems contradictory because in your analyses you separated the main effects of controlled drought from roots and litter. According to your title and hypothesis, you should focus on the interaction (what you call synergistic effects) among factors.
L105: Can you briefly explain why drought results in ‘massive litter deposition’?
L112: What do you mean with seasonal drought? And what is the opposite concept? Permanent drought perhaps?
L121-135: What is the contribution of this paragraph? Drought affects forests ecosystems worldwide and I see no point on highlighting your particular ecosystem. This seems ‘too local’ for an international audience. Consider removing.
L135-136: But, what is the justification of studying the herbaceous layer? Is it only because in your region there are few studies on this topic or is it because there is a global research question that remains unanswered? What would be that question? Please clarify.
L145-146: But in your work you do not compare adults versus seedlings or juveniles, neither you assessed competition ability for nutrients and water. Please consider rewriting your hypothesis.
L147: By ‘physically isolates’ you mean that seeds do not reach the soil and do no germinate?
L148-153: What is the difference between objectives 1 and 2? My surmise is they are similar. To ‘investigate’ the effects of roots, litter and drought on the herbaceous layer you need to ‘analyze’ the interaction among those factors.
Material and Methods
L203-205: What was the abundance of these species in your plots before the experiment? It is important to characterize the previous conditions in order to isolate possible effects of the previous status of the soil and vegetation before the study begins.
L215-216: This is clearly a split-plot design. Please be aware that split-plot designs have two errors. One associated to the main plot and one associated to the subplot. This usually changes the significance of effects compared to a randomized block design.
L218: And what are the results of this population census? I am confused with the previous status of your plots.
L222-223: What was the water content in the unwatered plot? Did the soil profile receive water to supply water demands on summer? Depending on the type of soil, they can hold water during winter that can be used by plants on spring-summer. I do not think that your unwatered plots were ‘completely dry’ during your experiment. Please clarify.
L228: What happened with the aboveground biomass (the shoot)? Did you cut it and leave only roots? What was the roots density in your treatments? Was it similar or some treatments had more roots density than others? Do you have adult trees within your plots?
L234-241: Please provide a picture or drawing for a better understanding.
L251: How did you measure water content? Do you have records for the unwatered plots?
L252-255: Please provide a better explanation.
L260: Then you have an ANOVA with Repeated Measures instead of a common ANOVA. Am I right? If so, please declare it in the corresponding section.
L260-263: I am lost here. Did you cut only the shoot and leave the roots depending on the treatment. Please clarify because here you say that ‘all seedlings were removed’.
L273: Why non-parametric analyses? Why not a generalized linear model for non- normal variables (i.e., counting) with a poisson distribution, and an ANOVA with Repeated Measures for continuous variables (height)? Please provide a rebuttal if you do not agree.
L271-274: What is the purpose of analyzing the main effects of irrigation separated from the effects of roots and litter? I see no much point on this and is one of the reasons of my rejection. Your hypothesis is about the interaction among factors and not on the independent effects of factors.
L282-290: I do not understand this analysis. You are basically doing the same of the first analysis i.e., comparing the main effects of irrigation.
Results
Please ‘interpret’ your results. Do not be ‘redundant’. Most of the information provided in the text is easily seen in figures. You must interpret what one can not see in figures.
L295: Here and in the complete paragraph: what do you mean by 4.3/m2 species? Did you mean that you found 4.3 species in a square meter? If so, please write properly.
L303: What do you mean by ‘different composition’?
L326: I wonder how you analyzed ‘maximum height’. For example, say that you have 10 plants with an average height of 40 cm and one of these 10 plants measures 100 cm. Is 100 cm your maximum height? If so, how did you average it and run ANOVAs with one data?
L356: Is ‘primary production’ similar to ‘dry biomass’? You basically dried your samples and determined the resultant mass after been dried in the oven. Net primary production (NPP) is the amount of biomass or carbon produced by primary producers per unit area and time, obtained by subtracting plant respiratory costs (Rp) from gross primary productivity (GPP) or total photosynthesis. Please use an appropriate term.
L386-Table 3: I see that all main effects and interactions were significant at p < 0.05. Just curious because it is hard to find significant triple interactions when you have so many factors (3 factors in your case) with few replicates (3 in your case). It is important that you analyze your data with the proper model. In your case I think you should try to use a split-plot design to see if triple interactions (water + root + litter) still remain significant. It is possible that triple (even double) interactions disappear. If triple interactions are all highly significant then you accept your hypothesis which is great.
L392: Is this the same that the triple interactions of your Table 3? My surmise is yes. If so, then why conducting a different analysis to communicate the same results. Please clarify what is the purpose of your 3 different statistical analyses of subheading 2.4.
Figure 6: I see that in your panels you use ‘sum, average, and maximum’? Why was that? The caption of the figure is not clear. What is the rationale here? Clarify.
Discussion
L418-437: OK, but this seems more than a minireview on forest litter than discussing your results with the existing literature. Please consider shortening or merging with your results. In addition, why you discuss the effects of litter separated from roots and drought. Again, you should focus on the triple interaction (if still exists after re-running your analyses).
L438-447: This paragraph seems quite unbalanced with the previous paragraph. I suggest merging them trying to explain the rationale of your results and not simply saying what you observed in the field.
L448: Similar to subheading 4.1. Why you separate the discussion of the factors under study? You should focus on discussing the interaction among factors.
L448-466: This paragraph is too generalist. Please discuss and connect based on your ecosystem and your species trying to provide possible mechanisms.
L467-469: This are ‘Results’. Do not repeat it again.
L469-477: Please provide appropriate references for this 4 reasons on your ecosystem and at least in your species or similar species. You do not measure any of these variables so you must provide an appropriate rationale. Which secondary metabolites?
L477: Which mechanisms are you referring here? The 4 reasons abovementioned or the presence of secondary metabolites?
L479: Here you are referring to the interaction between roots and litter (R+L+) but your subheading is only about roots. Why?
L494-499: This is obvious and repetitive. Please provide an explanation or possible mechanisms operating here.
L499-507: This explanation is too basic. If you are talking about different species, you should at least provide some information about their ecological requirements and compare it with environmental conditions at your study site.
L510-522: This paragraph seems not adequate for your study. It is too general. Please be specific in discussing your ecosystems and your species.
L522: ‘It is believed’ is not a happy sentence. Provide evidence.
L525-528: There is no contribution of this paragraph to the discussion of your work. Please consider removing it.
L538-540. Why ‘apparent’? You reported significant effects of roots, litter and drought in Table 3. This is a fact.
L542: An what is this supposed ‘dominant role’? I was expecting an explanation and not simply say that factors under study ‘plays a dominant role’?
L544-553: Basically, this is a repetition of your results. You are not providing a proper discussion.
Conclusions
L555: I think it is not appropriate to start this section with ‘In summary’.
L568-560: This is a repetition of what you have already said in the first paragraph.
L562: Replace ‘in collaboration’ with’ in combination’.
L563-565: This is not a conclusion of your study. It is a simple declaration of next steps.
L565-569: This paragraph seems more appropriated for the Discussion section.
L569-570: As I was expecting that you clarify some possible mechanisms here, I think that your work must be probably considered as a short communication after major revisions.
Author Response
Dear reviewer and editor,
We sincerely appreciate your time and effort in reviewing and commenting our manuscript entitled “Roots, litter and seasonal drought together inhibit plant growth in the herbaceous layer in a subtropical moist forest of southwestern China”. You gave us many suggestions and comments, which was obviously that you read and ponder over our manuscript word by word. It is extremely constructive and helpful for improving our manuscript. Thank you very very much for that. In response, we have thoroughly revised our manuscript according to the reviewer’s suggestions and comments. Here, we explain our responses to the reviewer’s suggestions and comments point-by-point below.
Point 1: Title: What do you mean by ‘seasonal drought’? The inhibition is in all the species of the herbaceous layer or just some of them?
Response 1: Good question! (1) One year in the region of this study could be divided into dry season and wet season according to the precipitation and temperature. Drought event that threatens plants’ germination and growth usually occurs in the mid- and late every dry season, which results “seasonal drought” . We explained this in the fourth paragraph of “Introduction” section and the second paragraph of “Materials and Methods-2.1. study sites”. (2) The inhibition that was investigated in this study included all grasses, ferns, and one-year seedlings of woody species of the herbaceous.
Point 2: Abstract: L17: Why do you say that studies on the herbaceous layer are ‘rare’? In your country or worldwide? I doubt that nobody has studied the herbaceous layer. Please be more realistic.
Response 2: Good question! We revised “rare compared to” to “less than”. Please see L17.
Point 3: Abstract: L18: By ‘environmental factors’ you understand roots and litter? Please clarify.
Response 3: Good suggestion! We clarify it in the parentheses following the words “environmental factors”. Please see L19.
Point 4: Abstract: L22: My surmise is that you have a split-plot design which have two errors. Please see comments later on the text.
Response 4: Yes, it is a split-plot design. We have already considered the two errors during we analyzed the data. Brilliant!!!
Point 5: Abstract: L27: How was the seedling density before the experiment was set-up? How was the seed bank? It is important to clarify the previous state of the study site.
Response 5: Good question! (1) the forest in this study is a mature forest, canopy and shrub species are dense, and there covers thick floormss on the ground surface. There is rare grasses, ferns and one-year seedlings of woody species on the forest ground surface, which could be showed clearly in the Figure 1B. Occasionally one or two small grasses or ferns in the subplot were removed before starting this study. (2) We could see some seeds of Schima wallichii and Quercus franchetii when we swept away litterfall, but we did not investigate the seed bank in this study.
Point 6: Abstract: L31-32: Where in your study can I see data about soil moisture and nutrient status? I think this is out of the scope of your work because you do not analyze those variables.
Response 6: Good question! We revised this sentence to delete the undetermined data.
Point 7: Abstract: L32-33: What do you understand by ‘seedling establishment’? How did you measure it?
Response 7: “Seedling establishment” represents “seed germinates and seedling survives”, which is measured by plant species richness and individuals (Figure 3a and b).
Point 8: Abstract: L34: The word ‘may’ is not appropriate for a conclusion. Conclusions must be clear and unquestionable. Similar to that with soil moisture and nutrition status, you cannot talk about plant physiological responses and forest evolution here because you do not evaluate those factors. Conclusions are about the objectives of your work. Please rewrite from L31 to L35.
Response 8: Good suggestion! We rewrite it as “Our study demonstrates how plant roots, forest litter and seasonal drought synergistically regulate seedling establishment and growth of the herbaceous layer in tropical and subtropical forest understory. This synergistic regulation changes plant physiological responses and forest evolution through controlling plant diversity and individual richness of herbaceous layer in the context of the sustained global climate change.” Please see L32-36.
Point 9: Keywords: Please remove or replace all those words already mentioned in the title.
Response 9: Good suggestion! We have already replaces all those words already mentioned in the title. Please see L 37-38.
Point 10: Introduction: L65-77: This paragraph seems excessive for a work devoted to the herbaceous layer. Consider shortening or removing.
Response 10: Good suggestion! We remove it and rearrange the references.
Point 11: Introduction: L81: How can I be sure that works on herbaceous layer are ‘rare’? What type of studies of the herbaceous layer are rare? Ecological, physiological, evolutive studies? This phrase is quite provocative and authors must clarify if this lack of studies is at the worldwide level or only at the local level. If the latter, then the study answer a local question.
Response 11: Good question! We have already replaced “rare compared to” by “less than”. Please see L57.
Point 12: Introduction: L85: Please provide an appropriate rationale for using roots and litter as explanatory variables of the herbaceous layer.
Response 12: Good suggestion! We added information to explain why we chose plant roots and forest litter as our research content and added references to affort it, as “Plant roots control seedling diversity and individual growth in the herbaceous layer through interacting with soil microbial population, activating soil mineral nutrients, and secreting various exudates; forest litter regulates seed germination and seedling establishment through obstructing light and temperature as well as water, releasing various nutrients, and secreting various exudates. Which mechanism of them plays a dominant role in impacting herbaceous layer in forests? It should depend on the biotic and abiotic conditions in different forest ecosystems. ” Please see L66-72.
Point 13: Introduction: L89: Please provide references for all those variables affecting the herbaceous layer.
Response 13: Good suggestion! We added references for all those variables affecting the herbaceous layer. Please see L63.
Point 14: Introduction: L91-93: This sentence makes no sense to me. Besides it seems contradictory because in your analyses you separated the main effects of controlled drought from roots and litter. According to your title and hypothesis, you should focus on the interaction (what you call synergistic effects) among factors.
Response 14: Good suggestion! We deleted this sentence.
Point 15: Introduction: L105: Can you briefly explain why drought results in ‘massive litter deposition’?
Response 15: Good question! We briefly explain why drought results in “massive litter deposition” in the parentheses as “trees defoliate because of severe water stress for reducing water losses through leaf transpiration and surviving the drought event”. Please see L86-87.
Point 16: Introduction: L112: What do you mean with seasonal drought? And what is the opposite concept? Permanent drought perhaps?
Response 16: Good question! One year in the region of this study could be divided into dry season and wet season according to the precipitation and temperature. Drought event that threatens plants’ germination and growth usually occurs in the mid- and late every dry season, which results “seasonal drought”. Seasonal drought is regularity and predictability because it occurs almost in every dry season; Its opposite concept is the one- to several-year extreme drought disturbance with unregularity and unpredictability characteristics because of global climate change, it is different to permanent drought that means water stress always threaten plant’ survival, such as in the desert ecosystem.
Point 17: Introduction: L121-135: What is the contribution of this paragraph? Drought affects forests ecosystems worldwide and I see no point on highlighting your particular ecosystem. This seems ‘too local’ for an international audience. Consider removing.
Response 17: Good suggestion! We deleted this paragraph.
Point 18: Introduction: L135-136: But, what is the justification of studying the herbaceous layer? Is it only because in your region there are few studies on this topic or is it because there is a global research question that remains unanswered? What would be that question? Please clarify.
Response 18: As the Point 17’ suggestion, we deleted this paragraph.
Point 19: Introduction: L145-146: But in your work you do not compare adults versus seedlings or juveniles, neither you assessed competition ability for nutrients and water. Please consider rewriting your hypothesis.
Response 19: Good suggestion! We provided our hypothesis on the basis of previous studies, and examined our hypothesis in this study. We revised our hypothesis and provided the relative references. Please see L110-115.
Point 20: Introduction: L147: By ‘physically isolates’ you mean that seeds do not reach the soil and do no germinate?
Response 20: Good question! “Physically isotaltes” means: (1) Physical damage to understory plants can arise from massive deposits of coarse necromass and litter in the short term, and can also prevent seedling establishment by inhibiting seed germination and seedling growth [35,38-39]. Please see L398-400; (2)Although some plant seeds could germinate during wet season, their primary roots were unable to pass through thick litter layer to reach mineral soil before next dry season came, which likely resulted in seedling mortality. Please see L415-418.
Point 21: Introduction: L148-153: What is the difference between objectives 1 and 2? My surmise is they are similar. To ‘investigate’ the effects of roots, litter and drought on the herbaceous layer you need to ‘analyze’ the interaction among those factors.
Response 21: Good suggestion! We revised our research objective as “Our research objective was to investigate the impact of plant roots, forest litter and seasonal drought on the dependent variables of diversity and abundance of plants, mean and maximum height of plant seedlings, and yearly primary production of plant seedlings in the herbaceous layer near the ground of forest.” Please see L 115-119.
Point 22: Materials and Methods: L203-205: What was the abundance of these species in your plots before the experiment? It is important to characterize the previous conditions in order to isolate possible effects of the previous status of the soil and vegetation before the study begins.
Response 22: Good question! (1) the forest in this study is a mature forest, canopy and shrub species are dense, and there covers thick floormss on the ground surface. There is rare grasses, ferns and one-year seedlings of woody species on the forest ground surface, which could be showed clearly in the Figure 1B. Occasionally one or two small grasses or ferns in the subplot were removed before starting this study; (2) we added soil carbon and mineral nutrients in the end of “2.1 Study Sites” as “The soil is typically red sandy loam developed from argillaceous rocks and carbonate rocks with the apparent characteristics of weak acid (pH=5.3~5.8), low organic matter (53.46~73.25g/kg), few soil microbes (0.51-0.58g/kg for soil microbial biomass carbon and 0.08-0.12g/kg for soil microbial biomass nitrogen) and low soil mineral nutrient contents (0.197-0.245% for soil total nitrogen, 0.039~0.048% for soil total phosphorus, 174~2.25% for soil total potassium, 0.173~0.222% for soil calcium, 0.192~0.227% for soil magnesium, 0.004~0.006% for soil sulphur) in soil samples of 0-10cm depth.”. Please see L174-181.
Point 23: Materials and Methods: L215-216: This is clearly a split-plot design. Please be aware that split-plot designs have two errors. One associated to the main plot and one associated to the subplot. This usually changes the significance of effects compared to a randomized block design.
Response 23: Thank you very much for reminding us, we have already considered the two errors during we analyzed the data.
Point 24: Materials and Methods: L218: And what are the results of this population census? I am confused with the previous status of your plots.
Response 24: Good question! (1) Ground surface in the study plots was covered by thick dry floormass, and only a few of grasses or ferns occurred, similar with the situation in the control plot pic of Figure 1(a); (2) the two 1ha field research plots were a research platform for our research team. We have more than 20 researchers doing their research at the same time, like collecting litterfall, studying nitrogen deposition, measuring soil microbes and animal. In the beginning to establish this field research platform, we had to investigate plant composition, i.e. plant individual census. We did not refer to these data, but the other two manuscripts (one is about forest litterfall, and one is about forest structure and plant composition) need these census data of plant individual. So, we deleted this sentence “The census of plant individuals was performed in June and July 2019.” after our careful discussion. Thank you very much.
Point 25: Materials and Methods: L222-223: What was the water content in the unwatered plot? Did the soil profile receive water to supply water demands on summer? Depending on the type of soil, they can hold water during winter that can be used by plants on spring-summer. I do not think that your unwatered plots were ‘completely dry’ during your experiment. Please clarify.
Response 25: Good suggestion! We revised this paragraph as “During this study, the soil moisture in control and watered plots was not manipulated during the wet season, because soil moisture with > 40% could meet the requirement of plant growth; while the watered plot was artificially irrigated during the dry season, because all plant individuals in the herbaceous layer of the study plots withered away with < 4%. The watered plot was irrigated weekly in the dry season, maintaining gravimetric soil moisture of 0-10cm depth at > 40%.” Please see L193-198.
Point 26: Materials and Methods: L228: What happened with the aboveground biomass (the shoot)? Did you cut it and leave only roots? What was the roots density in your treatments? Was it similar or some treatments had more roots density than others? Do you have adult trees within your plots?
Response 26: Good question! (1) As we mentioned above, there was not any plants in the 1m×1m subplots before we conducted experimental treatment; we removed them when we occasionally met one or two small grasses or ferns with abovegroud stems and leaves as well as underground roots; (2) the 1m×1m subplots were small without including woody adult trees; (3) we simultaneously conducted another study in these subplots to collect 0-10cm soil and determine soil microbial biomass carbon and nitrogen. There had a few of plant roots in the control plot; of course, as mentioned in the methods section, we removed all roots with diameter > 1cm; (4) there is adult trees in the 20m×20m research blocks, but there is not any woody trees and seedlings > 1a.
Point 27: Materials and Methods: L234-241: Please provide a picture or drawing for a better understanding.
Response 27: Good suggestion! We provided a drawing for a better understanding. Please see Figure 3.
Point 28: Materials and Methods: L251: How did you measure water content? Do you have records for the unwatered plots?
Response 28: Good question! We inserted a soil hygrometer into 10cm soil layer and determined soil moisture. We examined the hygrometer one time every weekend during dry season, and watered the watered subplots when soil moisture < 40%. We kept the unwatered plots (i.e., control plots) in its natural status.
Point 29: Materials and Methods: L252-255: Please provide a better explanation.
Response 29: Good suggestion! We revised the words L252-255 to “We inserted a soil hygrometer (FC28 Hygrometer) into soil layer with 10cm depth in watered subplots, checked it every weekend, and applied around 10L water to each subplot keeping soil moisture was > 40%. Forest litter on the top of fiberglass screens was swept away in time for unblocking sunlight and throughfall; all seeds on each fiberglass screen were collected and evenly returned to the corresponding subplot.” Please see L230-235.
Point 30: Materials and Methods: L260: Then you have an ANOVA with Repeated Measures instead of a common ANOVA. Am I right? If so, please declare it in the corresponding section.
Response 30: Good question! We have performed a non-parametric Kruskal-Wallis ANOVA analyses. Please see L253-257.
Point 31: Materials and Methods: L260-263: I am lost here. Did you cut only the shoot and leave the roots depending on the treatment. Please clarify because here you say that ‘all seedlings were removed’.
Response 31: Good question! We removed all the seedlings including overground stems and leaves as well as underground roots. We added these information in our manuscript. Please see L241.
Point 32: Materials and Methods: L273: Why non-parametric analyses? Why not a generalized linear model for non- normal variables (i.e., counting) with a poisson distribution, and an ANOVA with Repeated Measures for continuous variables (height)? Please provide a rebuttal if you do not agree.
Response 32: Good question! (1) We designed and performed our study according to Cabins’ study (Cabin et al., 2002) which studied the impact of microsite (sub-canopy vs. Inter-canopy), water (supplemental vs. ambient), and weeding (all emerging alien species removed vs. Weeds not removed) on the regeneration of native and alien species within a Hawaiian dry forest preserve. We adopted the non-parametric Kruskal-Wallis ANOVA to analyze our data; (2) We initially analyzed before we performed the non-parametric Kruskal-Wallis ANOVA and found two groups of data (including plant individuals and maximum height) were not normally distributed, so that justifies the use of the non-parameteric K-W approach. And for consistency, we decided to use that for the statistical testing of all variables like Cabin’s study mentioned above.
Cabin, R.J.; Weller, S.G.; Lorence, D.H.; Cordell, S.; Hadway, L.J. Effects of microsite, water, weeding, and direct seeding on the regeneration of native and alien species within a Hawaiian dry forest preserve. Biological Conservation 2002, 104(2), 181-190. https://doi.org/10.1016/S0006-3207(01)00163-X.
Point 33: Materials and Methods: L271-274: What is the purpose of analyzing the main effects of irrigation separated from the effects of roots and litter? I see no much point on this and is one of the reasons of my rejection. Your hypothesis is about the interaction among factors and not on the independent effects of factors.
Response 33: Good question! Our original hypothesis was about the interaction among plant roots, forest litter and water like Cabin’s study that studied the impact of microsite (sub-canopy vs. Inter-canopy), water (supplemental vs. ambient), and weeding (all emerging alien species removed vs. Weeds not removed) on the regeneration of native and alien species within a Hawaiian dry forest preserve. We need to analyze and discuss what kind of impact these independent variables (including irrigation, plant roots and forest litter) individually have, and then analyze and summarize whether they have a synergistical effect on the these dependent variables like species richness, plant individuals, plant height and primary production. Like Cabin’s study, they analyzed and discussed all those variables including microsite, water and weeding individually and synthetically, although they did not refer to synergistical effect.
Point 34: Materials and Methods: L282-290: I do not understand this analysis. You are basically doing the same of the first analysis i.e., comparing the main effects of irrigation.
Response 34: Good question! “2.4. Data Analysis” section have three paragraphes: the first introduces the methods to analyze the statistical differences among the eight different experimental treatments of five group data (Figure 4-6); the second introduces the methods to analyze the individual and comprehensive impact of independent variables on five groups of dependent variables (Table 3); and the third focused on the synergistic effect of three independent variables on the five dependent variables (Figure 7).
Point 35: Results: Please ‘interpret’ your results. Do not be ‘redundant’. Most of the information provided in the text is easily seen in figures. You must interpret what one can not see in figures.
Response 35: Good suggestion! We revised our results as interpreting our figures and tables. We deleted all the word parts which could be seen obviously in the figures and tables and added some contents to explain it.
Point 36: Results: L295: Here and in the complete paragraph: what do you mean by 4.3/m2 species? Did you mean that you found 4.3 species in a square meter? If so, please write properly.
Response 36: Good question! We used the mean number among three replications. We have already revised it.
Point 37: Results: L303: What do you mean by ‘different composition’?
Response 37: Good question! “...; the R+L- and R-L+ subplots had the similar number of plant species but different composition;...” means that the R+L- subplot had 5 plant species, the R-L+ subplot had 5 plant species; “different composition” means these 5 plant species and 5 plant species were not totally same (Table 1).
Point 38: Results: L326: I wonder how you analyzed ‘maximum height’. For example, say that you have 10 plants with an average height of 40 cm and one of these 10 plants measures 100 cm. Is 100 cm your maximum height? If so, how did you average it and run ANOVAs with one data?
Response 38: Good question! We added the method to determine the data of maximum height of plant seedlings in each subplot in the “Materials and Methods” section as “Maximum height of plant seedlings was measured using the heighest plant individual in each subplot. ”; Please see L249-250. That means your example is right in the Point 38. We avarage it and run ANOVAs among three experimental replications.
Point 39: Results: L356: Is ‘primary production’ similar to ‘dry biomass’? You basically dried your samples and determined the resultant mass after been dried in the oven. Net primary production (NPP) is the amount of biomass or carbon produced by primary producers per unit area and time, obtained by subtracting plant respiratory costs (Rp) from gross primary productivity (GPP) or total photosynthesis. Please use an appropriate term.
Response 39: Good suggestion! We replaced all the term “primary production” by “dry biomass” in our manuscript.
Point 40: Results: L386-Table 3: I see that all main effects and interactions were significant at p < 0.05. Just curious because it is hard to find significant triple interactions when you have so many factors (3 factors in your case) with few replicates (3 in your case). It is important that you analyze your data with the proper model. In your case I think you should try to use a split-plot design to see if triple interactions (water + root + litter) still remain significant. It is possible that triple (even double) interactions disappear. If triple interactions are all highly significant then you accept your hypothesis which is great.
Response 40: Good suggestion! We reanalyzed our data according to a split-plot design. Please see following table.
|
Treatment |
Species richness |
The number of plant individuals |
Mean height of plant seedlings |
Maximum height of plant seedlings |
Dry biomass of plant seedlings |
|
Water |
0.044 |
0.050 |
0.011 |
0.033 |
0.047 |
|
Roots |
0.021 |
0.048 |
0.009 |
0.001 |
0.049 |
|
Litter |
0.002 |
0.009 |
0.047 |
0.039 |
0.050 |
|
Water + Roots |
0.001 |
0.003 |
0.005 |
0.008 |
0.035 |
|
Water + Litter |
0.001 |
0.002 |
0.001 |
0.001 |
0.013 |
|
Roots + Litter |
< 0.000 |
< 0.000 |
0.002 |
0.006 |
0.003 |
|
Water + Roots + Litter |
< 0.000 |
< 0.000 |
< 0.000 |
< 0.000 |
< 0.000 |
Point 41: Results: L392: Is this the same that the triple interactions of your Table 3? My surmise is yes. If so, then why conducting a different analysis to communicate the same results. Please clarify what is the purpose of your 3 different statistical analyses of subheading 2.4.
Response 41: Good question! The objective of Table 3 was to show how independent variables including water, roots, litter and their interactions impact the five dependent varibales including species richness, number of plant individuals, mean and maximum heigh of plant seedlings, and dry biomass of plant seedlings. The objective of L392 to Figure 7 was to show whether the three independent variables had a synergistic effect on the five dependent variables.
“2.4. Data Analysis” section have three paragraphes: the first introduces the methods to analyze the statistical differences among the eight different experimental treatments of five group data (Figure 4-6); the second introduces the methods to analyze the individual and comprehensive impact of independent variables on five groups of dependent variables (Table 3); and the third focused on the synergistic effect of three independent variables on the five dependent variables (Figure 7).
Point 42: Results: Figure 6: I see that in your panels you use ‘sum, average, and maximum’? Why was that? The caption of the figure is not clear. What is the rationale here? Clarify.
Response 42: Good question! “Synergistic would mean that the effects of the interacting variables is greater than the sum of the effects of the variables acting independently when the other factors are not varied.” The objective of Figure 7 was to show whether the three independent variables had a synergistic effect on the five dependent variables. That is the reason we marked “Sum vs. Watered”. “Sum” means the value of five dependent variables in the corresponding subplots, and “Watered” means the value in the watered subplot. Taking “Species richness” as an example: CR-L- (the impact of plant roots and forest litter on species richness), WR+L+ (the impact of water on species richness), and WR-L-(the impact of plant roots, forest litter and water, i.e., synergistic effect). Because the plant mean and maximum heights had different characteristics as the other three dependent variables, we respectively used mean and maximum values in the correspongding subplots, being respectively marking “Average” and “Maximum”.
We revised the caption of the figure for more clear.
Point 43: Discussion: L418-437: OK, but this seems more than a minireview on forest litter than discussing your results with the existing literature. Please consider shortening or merging with your results. In addition, why you discuss the effects of litter separated from roots and drought. Again, you should focus on the triple interaction (if still exists after re-running your analyses).
Response 43: Good suggestion! We shortened and merged this paragraph and next one for explaining the impacts of forest litter on plant diversity and seedling growth in the herbaceous layer and the results in our study.
Forest litter, plant roots and water are the three independent variables in our study. Only analyzed and discussed clearly their individual function on the dependent variables, and we could explain more clearly their triple interaction on the five dependent variables. And we discussed their triple interaction on the five dependent variables in the last section. Please see the section “4.4. Synergistic Effect of Plant Roots, Forest litter and Seasonal Drought on Plant Diversity and Seedling Growth in the Herbaceous Layer”.
Point 44: Discussion: L438-447: This paragraph seems quite unbalanced with the previous paragraph. I suggest merging them trying to explain the rationale of your results and not simply saying what you observed in the field.
Response 44: Good suggestion! We merged it with last paragraph and explained our study results.
Point 45: Discussion: L448: Similar to subheading 4.1. Why you separate the discussion of the factors under study? You should focus on discussing the interaction among factors.
Response 45: Good suggestion! We shortened and merged it with next paragraph, and focused more contents on the last section about the interaction among independent factors.
Point 46: Discussion: L448-466: This paragraph is too generalist. Please discuss and connect based on your ecosystem and your species trying to provide possible mechanisms.
Response 46: Good suggestion! We revised, shortened and merged it with next paragraph based on our forest ecosystem and plant species, and tried to provide possible mechanism. Please see L448-453.
Point 47: Discussion: L467-469: This are ‘Results’. Do not repeat it again.
Response 47: Good suggestion! We deleted it.
Point 48: Discussion: L469-477: Please provide appropriate references for this 4 reasons on your ecosystem and at least in your species or similar species. You do not measure any of these variables so you must provide an appropriate rationale. Which secondary metabolites?
Response 48: Good suggestion! We provided appropriate references for this 4 reasons.
Point 49: Discussion: L477: Which mechanisms are you referring here? The 4 reasons abovementioned or the presence of secondary metabolites?
Response 49: Good question! We discussed it and gave our results. Please see L448-453.
Point 50: Discussion: L479: Here you are referring to the interaction between roots and litter (R+L+) but your subheading is only about roots. Why?
Response 50: Good suggestion! We deleted it and added the discussion on plant roots. Please see L448-453.
Point 51: Discussion: L494-499: This is obvious and repetitive. Please provide an explanation or possible mechanisms operating here.
Response 51: Good suggestion! We deleted this part and provide an explanation here. Please see L469-474.
Point 52: Discussion: L499-507: This explanation is too basic. If you are talking about different species, you should at least provide some information about their ecological requirements and compare it with environmental conditions at your study site.
Response 52: Good suggestion! We revised this part as “Many seeds that were buried in thick forest litter could germinate and grow into small seedlings at the beginning of wet season, like S. wallichii, Q. franchetii, Q. acutissima and all grass species; and they withered away during next dry season in control plot. While, many herbaceous plants and some seedlings of woody plants mentioned above could survive next dry season in watered plot. These study results are consistent with previous studies [43,73-74]. In addition, in the R+L+ subplot of control plot, a small amount of Hypnum plumaeforme Wils. grew in wet season and withered in the dry season, while there were only two plant species (C. camphora and P. carnosa) in the R+L+ subplot of watered plot with one individual for each. This is probably because consistently wet litter can continuously decompose and release nutrients to support adult tree species and potentially certain seedlings in the herbaceous layer on the ground surface in the R+L+ subplot in watered plot, and adequate soil moisture and released nutrients from forest litter can afford adult tree species and some bryophyte flora only during wet season in the R+L+ subplot in control plot.” Please see L469-481.
Point 53: Discussion: L510-522: This paragraph seems not adequate for your study. It is too general. Please be specific in discussing your ecosystems and your species.
Response 53: Good suggestion! We revised this part tightly according to our study. Please see L494-502.
Point 54: Discussion: L522: ‘It is believed’ is not a happy sentence. Provide evidence.
Response 54: Good suggestion! We revised this sentence and cited three publications. Please see L502-505.
Point 55: Discussion: L525-528: There is no contribution of this paragraph to the discussion of your work. Please consider removing it.
Response 55: Good suggestion! We removed this part.
Point 56: Discussion: L538-540. Why ‘apparent’? You reported significant effects of roots, litter and drought in Table 3. This is a fact.
Response 56: Good suggestion! We revised “apparent” to “the fact”.
Point 57: Discussion: L542: An what is this supposed ‘dominant role’? I was expecting an explanation and not simply say that factors under study ‘plays a dominant role’?
Response 57: Good question! We deleted this part and provided some explanation to clarify the synergistic effect of the three independent variables here.
Point 58: Discussion: L544-553: Basically, this is a repetition of your results. You are not providing a proper discussion.
Response 58: Good suggestion! We revised this part and provided some discussion. Please see L516-524.
Point 59: Conclusions: L555: I think it is not appropriate to start this section with ‘In summary’.
Response 59: Good suggestion! We replaced “In summary” with “The results of this study showed that .......”. Please see L526.
Point 60: Conclusions: L558-560: This is a repetition of what you have already said in the first paragraph.
Response 60: Good suggestion! We deleted it and added “This supports our original hypothesis. More importantly, synergistic effects of the three independent variables on the five dependent variables of plant seedlings was the fact, indicating that environmental factors to regulate forest’s structure and plant composition were complex and unpredictable.” Please see L529-533.
Point 61: Conclusions: L562: Replace ‘in collaboration’ with’ in combination’.
Response 61: Good suggestion! We replaced “collaboration” with “combination”. Please see L535.
Point 62: Conclusions: L563-565: This is not a conclusion of your study. It is a simple declaration of next steps.
Response 62: Yes, you are right! We moved it to the “Discussion” section. Please see 524-528.
Point 63: Conclusions: L565-569: This paragraph seems more appropriated for the Discussion section.
Response 63: Good suggestion! We moved it to the “Discussion” section. Please see it L418-422.
Point 64: Conclusions: L569-570: As I was expecting that you clarify some possible mechanisms here, I think that your work must be probably considered as a short communication after major revisions.
Response 64: Good suggestion! We provided a possible mechanism for synergistic effect occurrence. Please see it L537-545.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors responded properly to all my comments/suggestion. I believe that the manuscript is acceptable now.
Reviewer 2 Report
Please be aware that you state a question in the Introduction (Lines 68-69). Be sure that you are providing an approprioate answer in the Conclusion section. It mus be a perfect match between them.
Author Response
Dear reviewer and editor,
We sincerely appreciate your time and effort in reviewing and commenting our manuscript entitled “Roots, litter and seasonal drought together inhibit plant growth in the herbaceous layer in a subtropical moist forest of southwestern China”. Thank you very much for your suggestion! Please see our response below.
Point: Please be aware that you state a question in the Introduction (Lines 68-69). Be sure that you are providing an approprioate answer in the Conclusion section. It mus be a perfect match between them.
Response: Good question! We provide an explanation for the question stated in the “Introduction” section (L68-69) in the “Conclusion” section. Please see L507-517.
Author Response File: Author Response.docx
