The Biogeography of Forest Soil Microbial Functional Diversity Responds to Forest Types across Guangxi, Southwest China
, Feng Wang 1,2,3,†, Tongqing Song 1,2,3,*, Qiujin Tan 4, Hu Du 1,2,3, Fuping Zeng 1,2,3, Kelin Wang 1,2,3, Hao Zhang 1,2,3 and Zhaoxia Zeng 1,2,3Round 1
Reviewer 1 Report
Specific comments on the manuscript entitled " The biogeography of forest soil functional diversity responds to forest types across Guangxi, South West China”.
Abstract
Line 16 change…while soil microorganisms… to while the spatial distribution of soil microorganisms and factors driving their distribution are still unclear.
Line 21 change microbial distribution to The distribution of microorganisms in forest soils…..
Line 23 change smaller to lower
Line 25 change that the heterogeneous… suggested a heterogeneous distribution of microbial functional diversity in forest soils is related to forest types but also see later comments on natural forests vs plantations
Introduction
Line 50 change chemical soil to soil chemical properties
Line 51 to 54 check the sense of this sentence
Line 59 use metres rather than meters
Line 74 specify what variables – soil variables?
Methods
Line 85. Can the authors include an internationally recognised soil classification system?
Line 92 change Trees age to Tree age
From where were the increment cores taken i.e. DBH and did each core make the pith?
What was the minimum diameter and height for trees recorded? What was considered a stem to include in the estimate of stand density? Stand height is not reported in Table 1. It is not clear in Table 1 if stand density values are numbers of individuals per 10x10m quadrant or for each 20x50m plot. For clarity it would be better to report stand density as stems per hectare.
The stand descriptors are just a point in time and do not reflect a measure of productivity. Do the authors have a measure of productivity that they can include?
Line 95 It is not clear if the forest floor and litter layers were dealt with in the soil sampling protocol. Were they sampled as part of the 0-20cm soil depth? If they were included in the sample that would affect the bulk density, pH, carbon and nitrogen content and C:N. Based on the data reported these important soil layers were included in the 0-20cm soil sample – is this the case?
Change ration to ratio in table 1.
Line 96 Clarify if samples were collected from corners and centre of each 20x50 metre plot, i.e. the main plot.
Results
Line 174 change sub heading to Stand, environmental and soil characteristics across Guangxi
Include a description of the stand characteristics and environmental gradients. For example, the mean stand age is less than 30 years, so the question is that a result of large-scale afforestation and a lot of the stands sampled are in fact plantations and not natural forests? If so, this raises the question about previous land use, in the case of the 1-year old forests sampled. Do the authors have any data on previous land use?
Line 179 change higher to greater. Check elsewhere the use of higher, highest vs greater or larger, greatest, largest
Line 184 change the amount of soil microbial………. To Soil microbial diversity…
Line 187 change …. lognormal but…. To lognormal but transformation with a Cox-Box transformation resulted in a more normal distribution.
Line 189 specify which soils
Line 195 change was shown to is shown…….
Line 208 change high to large
Line 209 change other parts to the rest of the region……………
Line 213 change title to Regional distribution of microbial functional diversity in forest soils across the Guangxi territory.
Figures 6a&b are not that clear and can be improved so that the axes can be easily read.
Discussion
Line 270 change …and therefore to …and used this data to ……
Line 276-277 what about the influence of previous land use and plantation management practices?
Line 302 change which also be found to …. which has also been seen in …….
Line 309 delete …..which indicated…………….function of microorganisms.
Line 310 to 314. The authors need to provide data to support these statements
Line 331 what is meant by medium – quality or quantity of litter/exudates?
Line 352
The authors need to consider if plantations are more prominent than natural forests. This might explain some of the observed relationships between vegetation, climate, soils and microbial functional diversity. The pattern of vegetation/plantations is more likely to affected land use change and afforestation polices and not the natural patterns of vegetation in relation to soil and climate. Hence, some of the unexpected relationships between microbial functional diversity and pH.
How the forest floor and litter layers were treated in the soil sampling protocol may also affect some of the observed relationships between soil properties and the diversity of microbial function. The amount of organic matter included in the soil sample could also reflect stand age, productivity, etc
An overall comment is that the authors need to include a reflection on the suitability of their sampling scheme to address the questions they were asking. Are 185 bulked soil samples from 1 plot per site robust enough to look at spatial patterns covering an area of nearly 240,00 square kilometres? Is this sampling intensity justified?
Conclusion
Rewrite after considering some of the issues raised
Author Response
Reviewer #1
Abstract
Point 1: Line 16 change…while soil microorganisms… to while the spatial distribution of soil microorganisms and factors driving their distribution are still unclear.
Response 1: According to your comments, we changed the “while soil microorganisms as the link between the two, their spatial distribution patterns and driving factors are still unclear” to “while the spatial distribution of soil microorganisms and factors driving their distribution are still unclear” in Line 16.
Point 2: Line 21 change microbial distribution to The distribution of microorganisms in forest soils…..
Response 2: We have changed “Microbial distribution……” to “The distribution of microorganisms in forest soils…..” in Line 21.
Point 3: Line 23 change smaller to lower
Response 3: We have changed “smaller” to “lower” in Line 23.
Point 4: Line 25 change that the heterogeneous… suggested a heterogeneous distribution of microbial functional diversity in forest soils is related to forest types but also see later comments on natural forests vs plantations
Response 4: We have changed Line 25 “…… suggested that the heterogeneous and spatial distribution of functional diversity responded to forest types ……” to “…… suggested a heterogeneous distribution of microbial functional diversity in forest soils is related to forest types……”.
Introduction
Point 5: Line 50 change chemical soil to soil chemical properties
Response 5: Line 50 We changed “chemical soil properties……” to “soil chemical properties……”.
Point 6: Line 51 to 54 check the sense of this sentence
Response 6: We checked this sentence in Line 51-54 and we changed to “Therefore, the differences in the spatial patterns of vegetation, soil, and soil microorganisms are well understood, while how microbes feedback to the distribution of the vegetation-soil system remain unclear”.
Point 7: Line 59 use metres rather than meters
Response 7: we changed “meters” to “metres”.
Point 8: Line 74 specify what variables – soil variables?
Response 8: Yes. The variables were specified to soil variables.
Methods
Point 9: Line 85. Can the authors include an internationally recognised soil classification system?
Response 9: Sorry for this. Here, we just provide the reference of ‘China Soil’ about the soil type, and the detailed soil classification system is demonstrated in the reference. Therefore, we did not mention the soil classification system here.
Point 10: Line 92 change Trees age to Tree age
Response 10: We changed “trees ages” to “tree age” in Line 91 and 92.
Point 11: From where were the increment cores taken i.e. DBH and did each core make the pith?
Response 11: The increment cores were taken at about 10 cm above tree DBH when in natural forests. And each tree in natural forests was made the pith by core. The changes was made in Line 93.
Point 12: What was the minimum diameter and height for trees recorded? What was considered a stem to include in the estimate of stand density? Stand height is not reported in Table 1. It is not clear in Table 1 if stand density values are numbers of individuals per 10x10m quadrant or for each 20x50m plot. For clarity it would be better to report stand density as stems per hectare.
Response 12: The minimum diameter and height for trees recorded indicates that the minimum values of diameter and height for trees in the 185 plots according to the statistical analysis.
Thanks for your comment about stand height. In the Table, we did not report the stand height due to the values attained from roughly estimation by observation not precisely measurement. Meanwhile, we deleted the related description about the stand height in the Methods.
About the stand density, a stem with DBH ≥2 cm in the plot was considered to include in the estimate of stand density. In the manuscript, the stand density value was the number of individuals per each 20 × 50m plot. For the clarity, we accepted your suggestion and reported stand density as stems per hectare in the whole manuscript.
Point 13: The stand descriptors are just a point in time and do not reflect a measure of productivity. Do the authors have a measure of productivity that they can include?
Response 13: This is a very good question about the manuscript. In the study, we just indeed investigated the stand a point in time which cannot reflect productivity. Probably, productivity may be an indicator about the distribution of soil organisms. However, due to the limited time, people, and money, it is very difficult to finish the investigation about productivity. Therefore, we just adopted the stand investigation a point in time.
Point 14: Line 95 It is not clear if the forest floor and litter layers were dealt with in the soil sampling protocol. Were they sampled as part of the 0-20cm soil depth? If they were included in the sample that would affect the bulk density, pH, carbon and nitrogen content and C:N. Based on the data reported these important soil layers were included in the 0-20cm soil sample – is this the case?
Response 14: Sorry for this mistake about the soil sampling protocol. The litter layers were not included in the soil samples of 0-20 cm soil depth. Therefore, we added “after removing the litter” in Line 96.
Point 15: Change ration to ratio in table 1.
Response 15: We changed it in Table 1.
Point 16: Line 96 Clarify if samples were collected from corners and centre of each 20x50 metre plot, i.e. the main plot.
Response 16: We added “20 × 50 m” in Line 96 to clarify the plot.
Results
Point 17: Line 174 change sub heading to Stand, environmental and soil characteristics across Guangxi
Response 17: We changed the sub heading “Variation of environmental factors in Guangxi forest soils” to “Stand, environmental and soil characteristics across Guangxi”.
Point 18: Include a description of the stand characteristics and environmental gradients. For example, the mean stand age is less than 30 years, so the question is that a result of large-scale afforestation and a lot of the stands sampled are in fact plantations and not natural forests? If so, this raises the question about previous land use, in the case of the 1-year old forests sampled. Do the authors have any data on previous land use?
Response 18: This is a good question. On one hand, during the investigation, we have attained the information about the plantations before afforestation. On the other hand, forest types at some degree indicated the land use. In the discussion, we added some content about land use or forest types in red fond.
Point 19: Line 179 change higher to greater. Check elsewhere the use of higher, highest vs greater or larger, greatest, largest
Response 19: We have revised the higher to greater. After careful check, we found 4 places the use of higher in the manuscript and changed to larger in red font.
Point 20: Line 184 change the amount of soil microbial………. To Soil microbial diversity…
Response 20: We changed “The amount of soil microbial functional diversity……” to “Soil microbial diversity……”.
Point 21: Line 187 change …. lognormal but…. To lognormal but transformation with a Cox-Box transformation resulted in a more normal distribution.
Response 21: we changed “lognormal but better fit a normal distribution after Cox-Box transformation” to “lognormal but transformation with a Cox-Box transformation resulted in a more normal distribution”.
Point 22: Line 189 specify which soils
Response 22: We added “forest sampling” to specify the soils in Line 189.
Point 23: Line 195 change was shown to is shown…….
Response 23: We changed “was” to “is” in Line 195.
Point 24: Line 208 change high to large
Response 24: According to the advice, we did it in Line 208.
Point 25: Line 209 change other parts to the rest of the region……………
Response 25: We changed “other parts” to “the rest of the region” in Line 209.
Point 26: Line 213 change title to Regional distribution of microbial functional diversity in forest soils across the Guangxi territory.
Response 26: We change title “Map of forest soil microbial functional diversity on the scale of the Guangxi territory” to “Regional distribution of microbial functional diversity in forest soils across the Guangxi territory”.
Point 27: Figures 6a&b are not that clear and can be improved so that the axes can be easily read.
Response 27: According to your advice, we remade Figure 6.
Discussion
Point 28: Line 270 change …and therefore to …and used this data to ……
Response 28: we have revised it.
Point 29: Line 276-277 what about the influence of previous land use and plantation management practices?
Response 29: This is a good question. Our manuscript focused on the spatial distribution of soil microbial diversity and the affecting factors which mainly collected from a point at one time. Accordingly, we may underestimate the influence of previous land use and plantation management practices. However, in the manuscript, we added some discussion about the effect of the previous land use and plantation management practices on the distribution of forest soil microbial functional diversity across Guangxi.
Point 30: Line 302 change which also be found to …. which has also been seen in …….
Response 30: We revised it.
Point 31: Line 309 delete …..which indicated…………….function of microorganisms.
Response 31: We deleted the sentence “which indicated…………….function of microorganisms”.
Point 32: Line 310 to 314. The authors need to provide data to support these statements
Response 32: We accepted your comments. The results of Fig.7 a-e support the statements and we added it after the statement.
Point 33: Line 331 what is meant by medium – quality or quantity of litter/exudates?
Response 33: It should be medium quantity of litter or plant exudates. We added quantity after medium in Line 331.
Point 34: Line 352
The authors need to consider if plantations are more prominent than natural forests. This might explain some of the observed relationships between vegetation, climate, soils and microbial functional diversity. The pattern of vegetation/plantations is more likely to affected land use change and afforestation polices and not the natural patterns of vegetation in relation to soil and climate. Hence, some of the unexpected relationships between microbial functional diversity and pH.
Response 34: Thanks for your comments. In the discussion, we have added the point about plantation and natural forests in the discussion.
How the forest floor and litter layers were treated in the soil sampling protocol may also affect some of the observed relationships between soil properties and the diversity of microbial function. The amount of organic matter included in the soil sample could also reflect stand age, productivity, etc
In Materials and Methods, we demonstrated the soil sampling protocol about floor and litter layers.
An overall comment is that the authors need to include a reflection on the suitability of their sampling scheme to address the questions they were asking. Are 185 bulked soil samples from 1 plot per site robust enough to look at spatial patterns covering an area of nearly 240,00 square kilometres? Is this sampling intensity justified?
This is a good question. Definitely, the samples is more the truth is nearer to. However, it is impossible to collect thousands samples to address the question. Based on the GS+ and ArcGIS software and theory, we chose 185 samples enough to represent all the forest types and across Guangxi region.
Conclusion
Point 35: Rewrite after considering some of the issues raised
Response 35: According to the above raised issues, we rewrote the section of Conclusion.
Reviewer 2 Report
The study “The biogeography of forest soil microbial functional diversity responds to forest types across Guangxi, Southwest China” by Peng and colleagues relates environmental factors of five different forest types to functional diversity of carbon use. They found forest type and organic matter content being the main drivers impacting the Shannon index of functional diversity.
Regarding the number of samples it would be interesting to see how many samples were taken from each type of forest. This can hardly be see on the map in Fig. 1. Especially the number of samples given in Fig. 1 do not look like 185 (or 187). Are there so many overlaps or could there be a mistake in the figure? Furthermore, in lines 89 and 155-157 you mention 187 samples and two of them had to be discarded. If the information is not important, you should skip it and only mention the 185 throughout the manuscript.
Regarding stepwise regression (165-167) and PCA (Fig. 7), why have you excluded TP and TK (106-107)? They also do not appear in Table 1.
In Materials & Methods nothing is said about ANOVA/Kruskal-Wallis test and according post hoc tests, although Figs. 6 and S1 suggest such kinds of statistics have been applied. Also the used software needs to be mentioned.
Regarding Figs. 2 and 3, these graphics are more of technical purpose, e.g. in Fig. 2 Shannon index is not differentiated between forest types but indicates the need for transformation, I suggest giving both as Supplemental Material. Due to Fig. 4 there is also some redundancy in Fig. 2.
Regarding the parameters given in Table 1 including TP and TK it would be of much more interest whether these differ between the five forest types rather than summarising them as bulk.
Regarding Fig. 5(b), the text says (219-220) Stand density would be correlated with component 2, but it disappears under component 3 and comparing Average DBH and Stand age, Stand density seems to be quite low. Do you mean Bulk density instead, which, however, shows lower correlation than Stand age.
Regarding lines 295-298, are you not comparing apples to oranges? pH is strongly related to structural diversity, while you looked for functional diversity. Therefore this argumentation appears to be weak. Rather you should take the opportunity discussing differences in impacting factors between structural and functional diversity here. Though you should be careful as you did not measured structural diversity.
A similar point seems to be in lines 337-338, where the cited source (at least according to its title) deals with structural diversity and thus might be less suitable for your discussion.
In lines 300-302 and 370 you are discussing a finding for C:N which you have not mentioned in Results. Similarly, there is a discussion in lines 310-312 about bulk density. You should extend the according Results section accordingly.
In lines 302-306 you compare your results with findings based on N:P, but your study lacks further investigation of the TP you measured and according N:P (at least you do not mention it anymore after lines 106-107). Therefore this is not a valid comparison unless you include TP and N:P in your analysis.
In lines 318-321 you discuss stand age only under the aspect of more carbon sources, which I read as quantity. But does the age of a forest not also reflects a stage of succession and, thus, differences in vegetation and, accordingly, differences in organic matter input quality? Such a discussion would be a good transition to the following parts.
I do not understand the conclusions in lines 329-331. Low bulk density was not shown for the forest types mentioned in the sentences before and I do not understand from where the relation of medium litter/exudates input comes from.
For the discussion in lines 334-336 it would be good to know how diverse the different forest types are.
In lines 346-349 the statement appears to be too strong. On the one hand you would need a statistical test to underline the mentioned significance and on the other hand the low percentage (<10% in total for both axes) questions a strong evidence.
In lines 357-360 mentioning of texture comes somewhat out of nowhere, as you have not mentioned texture of the study sites.
The study would greatly benefit from some direct information about the outcomes of the EcoPlates. For instance, where there certain sources that were best or hardly used by specific forest types and, if yes, could these specifically be related to environmental parameters? The pooling by kind of source as shown in Fig. S1 might overlook more subtle differences.
Minor points:
Please check the English.
Occasions in the text where “nitrogen” means “total nitrogen” it should be written in full or the abbreviation TN should be used in order to better differentiate from “available nitrogen”.
Fig. 1 The caption must be placed below the figure. The upper part of the figure might be reduced in size in order to fit into the white space on page 3.
125–126 Is it not the other way round, i.e. substrate OD minus control OD?
137 Error in the formula: “I” -> “-“
141–145 What software did you use for determining Shannon, K-S test and the parameters given in Table S1? Do not forget mentioning the developers.
145 For future studies do not use Kolmogorov-Smirnov test anymore, as it is not very reliable. There are better alternatives like Q-Q-plots.
146 “GS+ 9.0” needs information on its developers (company, place).
152 “Table 2S” -> “Table S2”
154 Add developers’ details on ArcGIS (company, place).
158 Add developers’ details on SPSS (company, place).
162 R needs a citation (use command “citation()”). Have you used any packages, e.g. vegan, then these need to be cited too (e.g. command “citation(“vegan”)”).
166 “SOC, nitrogen” -> “SOC, total nitrogen” (you mention available nitrogen in the same sentence).
167-170 I do not understand what you mean by forest quantification by the given numbers.
Table 1 The table heading mentions “median”, but there is none in the table. Skip for MAP the last decimal place in the Standard error and CV, as Min., Max., and Mean also just have got one decimal place. What does the Standard error for Bulk density mean? Correct “C:N ration” to “C:N ratio”.
184 “amount” -> “value”
187 “Cox-Box” -> “Box-Cox”
Fig. 2 Clarification is needed of what is displayed. Does (a) show raw data or data without outliers? And for (b) you should indicate that Box-Cox transformed data are shown. Otherwise the hint on simulated lognormal curves might be misleading.
Fig. 4 What does the encircled R mean? Is it necessary or can it be removed?
Fig. 6 The caption mentions “Distribution of mean value”. I guess you refer to the average of the five pooled subsamples? However, that term is somewhat misleading as no means are indicated within the figure. Furthermore, the caption says that the whiskers indicate standard errors. That is quite uncommon for box-plots. Normally the whiskers indicate the maximum and minimum values which are not designated as outliers. Especially when you indicate the Standard Error of the Mean an indicator (often a diamond) is needed to show where the mean is. Furthermore, the caption mentions differentiation between mild and extreme outliers. On the hand a definition of what mild and extreme are is need and on the other hand no stars indicating the extreme ones can be seen in the graphic.
247-250 The mentioning of high SOC for bamboo forests needs more explanation as, according to Fig. 7, it is orthogonal to TN and AN.
Fig. 7 The percentages for each axis should be given in order to compare the single forest types with the overall values in Fig. 5. In (a) “Average_DBH” instead of “Stand_DBH” is written; please unify.
265-266 Check content within parenthesis: Why starts the range with lower values? What does “Types*” mean? RSE should be explained.
274 and more Try to avoid referencing back to main text figures and tables.
307 Change “absorb” to “take up”.
310-312 Rearrange the sequence of arguments in the sentence. Currently it sounds as if soil stabilisation governs the C and N availability, which is only via interdependencies partly true.
346 Change “woody” to “forest”.
348 Change “through” to “as indicated by”.
Table S1 In the header you should write Kolmogorov-Smirnov test rather than abbreviating it. How can the number of samples be the same, when you have removed outliers? “CV”, “Skew”, and “K-S test” in the table’s header need to be explained below the table. In the table I would change “Removing outliers” to “Outliers removed”. Change “Cox-Box” to “Box-Cox”. Below the table, “Raw, raw data” should be removed, as “Raw data” is already given in the table. Skip “Removing outliers, Data after removing outliers;” as this is self-explaining. But you should explain how you define an outlier. Correct “Cox-Box” to “Box-Cox” and mention, whether the transformed data were raw data or data without outliers. Change “abnormal” to “non-normal”. You mention “Shannon, Shannon index.”, but it does not appear in the table.
Fig. S1 Place the caption below the graphic.
Fig. S2 Place the caption below the graphic.
Author Response
Reviewer#2 comments
The study “The biogeography of forest soil microbial functional diversity responds to forest types across Guangxi, Southwest China” by Peng and colleagues relates environmental factors of five different forest types to functional diversity of carbon use. They found forest type and organic matter content being the main drivers impacting the Shannon index of functional diversity.
Point 1: Regarding the number of samples it would be interesting to see how many samples were taken from each type of forest. This can hardly be see on the map in Fig. 1. Especially the number of samples given in Fig. 1 do not look like 185 (or 187). Are there so many overlaps or could there be a mistake in the figure? Furthermore, in lines 89 and 155-157 you mention 187 samples and two of them had to be discarded. If the information is not important, you should skip it and only mention the 185 throughout the manuscript.
Response 1: Thanks for your constructive comment. There were 185 samples used in the manuscript. The number of samples given in Fig.1 looks less than 185, because the distances among some sapling plots were too near to been shown in Fig.1.
In Line 89 and 155-157, we think the information about the 187 samples and two of them was discarded. Therefore, we changed 187 to 185 in Line 89 and deleted the sentence “Soil microbial, physicochemical, vegetation, and topographical characteristics were available for 185 of the 187 soils we studied, because two samples were contaminated and thus discarded.” in the manuscript.
Point 2: Regarding stepwise regression (165-167) and PCA (Fig. 7), why have you excluded TP and TK (106-107)? They also do not appear in Table 1.
Response 2: Based on many documents, soil total phosphorus (TP) and total potassium (TK) were not the important factors influencing the soil microbial diversity. Therefore, in the manuscript, we excluded TP and TK in PCA, stepwise regression. While we added the information of TP and TK as the basic in Table 1.
Point 3: In Materials & Methods nothing is said about ANOVA/Kruskal-Wallis test and according post hoctests, although Figs. 6 and S1 suggest such kinds of statistics have been applied. Also the used software needs to be mentioned.
Response 3: According to your comment, we added related information about ANOVA, the Kolmogrorov-Smirnov test, and the Kruska-Wallis test in Materials & Methods in red fond.
Point 4: Regarding Figs. 2 and 3, these graphics are more of technical purpose, e.g. in Fig. 2 Shannon index is not differentiated between forest types but indicates the need for transformation, I suggest giving both as Supplemental Material. Due to Fig. 4 there is also some redundancy in Fig. 2.
Response 4: We accepted your comment and placed Figs. 2 and 3 as Fig. S1 and Fig. S2, respectively.
Point 5: Regarding the parameters given in Table 1 including TP and TK it would be of much more interest whether these differ between the five forest types rather than summarising them as bulk.
Response 5: We added TP and TK in Table 1.
Point 6: Regarding Fig. 5(b), the text says (219-220) Stand density would be correlated with component 2, but it disappears under component 3 and comparing Average DBH and Stand age, Stand density seems to be quite low. Do you mean Bulk density instead, which, however, shows lower correlation than Stand age.
Response 6: Yes. Based on the Fig.5b (Fig.3b in the revised manuscript), in the first three components, soil bulk density shower lower correlation than stand age.
Point 7: Regarding lines 295-298, are you not comparing apples to oranges? pH is strongly related to structural diversity, while you looked for functional diversity. Therefore this argumentation appears to be weak. Rather you should take the opportunity discussing differences in impacting factors between structural and functional diversity here. Though you should be careful as you did not measured structural diversity.
Response 7: We changed the sentence to “Soil total nitrogen and available nitrogen were the most important variation for the functional diversity of soil mircoorganisms (Fig.3b), which has also been documented for the structural diversity by Lan et al. [38].”
Point 8: A similar point seems to be in lines 337-338, where the cited source (at least according to its title) deals with structural diversity and thus might be less suitable for your discussion.
Response 8: We added “which resulted in soil microbial functional diversity” after the sentence.
Point 9: In lines 300-302 and 370 you are discussing a finding for C:N which you have not mentioned in Results. Similarly, there is a discussion in lines 310-312 about bulk density. You should extend the according Results section accordingly.
Response 9: We added the finding about C:N ratio in Results and deleted the content about bulk density in the discussion.
Point 10: In lines 302-306 you compare your results with findings based on N:P, but your study lacks further investigation of the TP you measured and according N:P (at least you do not mention it anymore after lines 106-107). Therefore this is not a valid comparison unless you include TP and N:P in your analysis.
Response 10: Thanks for your advice. We deleted the sentence “In other ecosystems, such as temperate steppes, the soil N:P ratio was the main driver of soil microbial functional diversity [40]. The inconsistency of these findings may be related to the different ecosystems types (forest vs steppe) as well as climate zones (P-limited in tropical and subtropical forests [41] vs N-limited in temperate ecosystems [40, 42]).”. Meanwhile, we deleted the corresponding references.
Point 11: In lines 318-321 you discuss stand age only under the aspect of more carbon sources, which I read as quantity. But does the age of a forest not also reflects a stage of succession and, thus, differences in vegetation and, accordingly, differences in organic matter input quality? Such a discussion would be a good transition to the following parts.
Response 11: Thanks for your comments. We added “and better quality of carbon input” in the sentence.
Point 12: I do not understand the conclusions in lines 329-331. Low bulk density was not shown for the forest types mentioned in the sentences before and I do not understand from where the relation of medium litter/exudates input comes from.
Response 12: We deleted “with low soil bulk density and large carbon and N concentration”. Litter/exudates input are very connective to forest types. For example, bamboo forest and evergreen broadleaf forest have less litter/exudates input than coniferous forest and deciduous forest.
Point 13: For the discussion in lines 334-336 it would be good to know how diverse the different forest types are.
Response 13: Given the coherence in the manuscript, the sentence was deleted.
Point 14: In lines 346-349 the statement appears to be too strong. On the one hand you would need a statistical test to underline the mentioned significance and on the other hand the low percentage (<10% in total for both axes) questions a strong evidence.
Response 14: We changed the sentence “These results indicated that the spatial distribution of soil microbial functional diversity would reflect the forest types at the regional scale, and may result from different responses of soil microorganisms to changing soil carbon/nitrogen concentrations during forest development [50]” to “These results indicated that the spatial distribution of soil microbial functional diversity would reflect the forest types at the regional scale to some degree, with different responses of soil microorganisms to changing soil carbon/nitrogen concentrations during forest development [50]”.
Point 15: In lines 357-360 mentioning of texture comes somewhat out of nowhere, as you have not mentioned texture of the study sites.
Response 15: We deleted the texture in Line 357-360.
Point 16: The study would greatly benefit from some direct information about the outcomes of the EcoPlates. For instance, where there certain sources that were best or hardly used by specific forest types and, if yes, could these specifically be related to environmental parameters? The pooling by kind of source as shown in Fig. S1 might overlook more subtle differences.
Response 16: The comment is a good advice about the analysis of the outcomes of the EcoPlates. It is indeed certain carbon sources that were best or hardly used by specific forest types and the pooling by kind of source as shown in Fig.S3 (Fig.S1 in the manuscript) might overlook some subtle differences. However, in the study, we just try our best to find the basic rules about the carbon sources for forest types due to too many data. In the future, we will consider to analyze certain carbon sources in specific forest types.
Minor points:
Please check the English.
Point 17: Occasions in the text where “nitrogen” means “total nitrogen” it should be written in full or the abbreviation TN should be used in order to better differentiate from “available nitrogen”.
Response 17: We changed “nitrogen” to “total nitrogen” when in the text “nitrogen” means “total nitrogen”.
Point 18: Fig. 1 The caption must be placed below the figure. The upper part of the figure might be reduced in size in order to fit into the white space on page 3.
Response 18: We placed the caption “Different symbols represent different types of forests.” below the Fig.1.
Point 19: 125–126 Is it not the other way round, i.e. substrate OD minus control OD?
Response 19: Yes, sorry for the mistake. We changed it.
Point 20: 137 Error in the formula: “I” -> “-“
Response 20: Sorry for the error. We deleted “I” in the formula.
Point 21: 141–145 What software did you use for determining Shannon, K-S test and the parameters given in Table S1? Do not forget mentioning the developers.
Response 21: Sorry for forgetting mentioning the software. We added the related analysis method in Materials and Methods in red fond.
Point 22: 145 For future studies do not use Kolmogorov-Smirnov test anymore, as it is not very reliable. There are better alternatives like Q-Q-plots.
Response 22: Okay. Thanks for your comments. In future studies, we will choose Q-Q-plots instead of Kolmogorov-Smirnov.
Point 23: 146 “GS+ 9.0” needs information on its developers (company, place).
Response 23: we added the developers after “GS+ 9.0”.
Point 24: 152 “Table 2S” -> “Table S2”
Response 24: we changed Table 2S and Table 1S to Table S2 and Table S1, respectively.
Point 25: 154 Add developers’ details on ArcGIS (company, place).
Response 25: we added the developers’ details after “GS+ 9.0”.
Point 26: 158 Add developers’ details on SPSS (company, place).
Response 26: we added the developers’ details on SPSS 18.0.
Point 27: 162 R needs a citation (use command “citation()”). Have you used any packages, e.g. vegan, then these need to be cited too (e.g. command “citation(“vegan”)”).
Response 27: We provided a detailed information about R language after R and provided the “MASS” package was used during the process of stepwise regression.
Point 28: 166 “SOC, nitrogen” -> “SOC, total nitrogen” (you mention available nitrogen in the same sentence).
Response 28: We changed “nitrogen” to “total nitrogen”.
Point 29: 167-170 I do not understand what you mean by forest quantification by the given numbers.
Response 29: Forest type is not a detailed value to demonstrated, in order to analysis the forest types on the distribution of soil microbial functional diversity. We have to quantification them by numbers.
Point 30: Table 1 The table heading mentions “median”, but there is none in the table. Skip for MAP the last decimal place in the Standard error and CV, as Min., Max., and Mean also just have got one decimal place. What does the Standard error for Bulk density mean? Correct “C:N ration” to “C:N ratio”.
Response 30: We deleted median in the table heading. We deleted the second number after the decimal. The standard error for Bulk density should be 0.02 not -.02. Sorry for this mistake. It should be C:N ratio not C:N ration and we changed it.
Point 31: 184 “amount” -> “value”
Response 31: we have changed “the amount of soil microbial functional diversity” to “soil microbial diversity”.
Point 32: 187 “Cox-Box” -> “Box-Cox”
Response 32: we changed “Cox-Box” to “Box-Cox”, and other places
Point 33: Fig. 2 Clarification is needed of what is displayed. Does (a) show raw data or data without outliers? And for (b) you should indicate that Box-Cox transformed data are shown. Otherwise the hint on simulated lognormal curves might be misleading.
Response 33: Thanks for your reminder. We added “with raw data” after (a) and “with the data after Box-Cox transformation” after (b) to clarify the simulated lognormal curves.
Point 34: Fig. 4 What does the encircled R mean? Is it necessary or can it be removed?
Response 34: The encircled R means the direction of North and cannot been shown due to lower word version. And we remade the figure.
Point 35: Fig. 6 The caption mentions “Distribution of mean value”. I guess you refer to the average of the five pooled subsamples? However, that term is somewhat misleading as no means are indicated within the figure. Furthermore, the caption says that the whiskers indicate standard errors. That is quite uncommon for box-plots. Normally the whiskers indicate the maximum and minimum values which are not designated as outliers. Especially when you indicate the Standard Error of the Mean an indicator (often a diamond) is needed to show where the mean is. Furthermore, the caption mentions differentiation between mild and extreme outliers. On the hand a definition of what mild and extreme are is need and on the other hand no stars indicating the extreme ones can be seen in the graphic.
Response 35: we remade Fig.6 (Fig.4 in the revised manuscript) and changed the caption of “the mean value” to “the average value”.
Point 36: 247-250 The mentioning of high SOC for bamboo forests needs more explanation as, according to Fig. 7, it is orthogonal to TN and AN.
Response 36: we added Fig.5 (Fig.7 in the manuscript) after the sentence to support the view.
Point 37:Fig. 7 The percentages for each axis should be given in order to compare the single forest types with the overall values in Fig. 5. In (a) “Average_DBH” instead of “Stand_DBH” is written; please unify.
Response 37: According to your comment, we remade Fig.5 (Fig.7 in the manuscript).
Point 38:265-266 Check content within parenthesis: Why starts the range with lower values? What does “Types*” mean? RSE should be explained.
Response 38: In the “Types*”, * indicates the forest types reached significant relationship with soil microbial functional diversity (p<0.05). While in the parenthesis, we have shown the p value and we deleted the * signal.
Based on the p value, we think it is not necessary to keep RSE and deleted it.
Point 39: 274 and more Try to avoid referencing back to main text figures and tables.
Response 39: we changed “more” to “large”.
Point 40: 307 Change “absorb” to “take up”.
Response 40: we revised it.
Point 41: -312 Rearrange the sequence of arguments in the sentence. Currently it sounds as if soil stabilisation governs the C and N availability, which is only via interdependencies partly true.
Response 41: We rearranged the sentence to “This is also partly demonstrated why the soil C:N ratio and available nitrogen explained much of the positive correlation with soil microbial metabolic function in the study”.
Point 42: 346 Change “woody” to “forest”.
Response 42: we changed it.
Point 43: 348 Change “through” to “as indicated by”.
Response 43: we revised it.
Point 44: Table S1 In the header you should write Kolmogorov-Smirnov test rather than abbreviating it. How can the number of samples be the same, when you have removed outliers? “CV”, “Skew”, and “K-S test” in the table’s header need to be explained below the table. In the table I would change “Removing outliers” to “Outliers removed”. Change “Cox-Box” to “Box-Cox”. Below the table, “Raw, raw data” should be removed, as “Raw data” is already given in the table. Skip “Removing outliers, Data after removing outliers;” as this is self-explaining. But you should explain how you define an outlier. Correct “Cox-Box” to “Box-Cox” and mention, whether the transformed data were raw data or data without outliers. Change “abnormal” to “non-normal”. You mention “Shannon, Shannon index.”, but it does not appear in the table.
Response 44: According to your comments, we revised it carefully.
Point 45: Fig. S1 Place the caption below the graphic.
Response 45: We placed the caption below the graphic Fig.S1.
Point 46: Fig. S2 Place the caption below the graphic.
Response 46: We placed the caption below the graphic Fig.S2.
Reviewer 3 Report
Dear Authors! I with great pleasure read your article entitled „The biogeography of forest soil microbial functional diversity 2 responds to forest types across Guangxi, Southwest China”. The manuscript presents interesting studies on the assessment of changes infunctional biodiversity inforest ecosystems. All relevant scientific preliminaries were provided, the methods were adequately described. The subject of forest soil biodiversity is a relatively new topic. There is no such information in the literature. It is good that the authors have started such research. The Biolog method is most appropriate and very sensitive when it comes to changes in functional diversity in a given environment.
The results are clearly presented, with good conclusions. All tables and graphs are clear, understandable and necessary. The overall quality of the presentation is good. The references are sufficient and necessary. Below I present a few comments regarding figures, statistical analysis and references. In my opinion, these comments can improve the quality of your paper.
I don't feel qualified to review the English used by the authors but I understood well all the text. I haven't found any mistakes.
The article is well written, but I have some suggestions:
- Do you have a photos of sampling places? If yes, please add them in text of paper. For readers it will be interesting to see this sampling places.
- The quality of the charts is very poor. It's hard to read what's wrong with them. Please correct the charts as recommended by the journal.
- Do the authors have more chemical results of the samples (reaction or other) that could be correlated with the results of Biolog?
- Please see some of the publications below to help you discuss your results. Similar studies have been performed in these publications.
Microplot long-term experiment reveals strong soil type influence on bacteria composition and its functional diversity. Applied Soil Ecology, DOI10.1016/j.apsoil.2017.10.033.
Community-level physiological profiles of microorganisms from different types of soil characteristic to Poland – a long-term microplot experiment. Sustainability. 2019, 11, 56., https://doi.org/10.3390/su11010056.
Wish good luck in your current and future studies.
Author Response
Dear Authors! I with great pleasure read your article entitled, The biogeography of forest soil microbial functional diversity 2 responds to forest types across Guangxi, Southwest China”. The manuscript presents interesting studies on the assessment of changes in functional biodiversity in forest ecosystems. All relevant scientific preliminaries were provided, the methods were adequately described. The subject of forest soil biodiversity is a relatively new topic. There is no such information in the literature. It is good that the authors have started such research. The Biolog method is most appropriate and very sensitive when it comes to changes in functional diversity in a given environment.
The results are clearly presented, with good conclusions. All tables and graphs are clear, understandable and necessary. The overall quality of the presentation is good. The references are sufficient and necessary. Below I present a few comments regarding figures, statistical analysis and references. In my opinion, these comments can improve the quality of your paper.
I don't feel qualified to review the English used by the authors but I understood well all the text. I haven't found any mistakes.
Thanks for your positive comments on our manuscript. We have revised the manuscript carefully according to your comments.
The article is well written, but I have some suggestions:
- Point 1: Do you have a photos of sampling places? If yes, please add them in text of paper. For readers it will be interesting to see this sampling places.
Response 1: we have photos of sampling places and added them in text as supplementary materials (Fig.S1).
- Point 2: The quality of the charts is very poor. It's hard to read what's wrong with them. Please correct the charts as recommended by the journal.
Response 2: according to your and the journal comments, we remade most of the figures in the revised manuscript.
- Point 3: Do the authors have more chemical results of the samples (reaction or other) that could be correlated with the results of Biolog?
Response 3: Sorry for the uncomprehensive consideration for the experiment, we just have the data of TP, TK, but not reaction nor other. In the Table 1, we added the results of TP and TK.
- Point 4: Please see some of the publications below to help you discuss your results. Similar studies have been performed in these publications.
Microplot long-term experiment reveals strong soil type influence on bacteria composition and its functional diversity. Applied Soil Ecology, DOI10.1016/j.apsoil.2017.10.033.
Community-level physiological profiles of microorganisms from different types of soil characteristic to Poland – a long-term microplot experiment. Sustainability. 2019, 11, 56., https://doi.org/10.3390/su11010056.
Response 4: we added the two references to broaden the discussion.
Round 2
Reviewer 1 Report
Specific comments on the manuscript entitled " The biogeography of forest soil functional diversity responds to forest types across Guangxi, South West China”.
On one hand the authors have addressed most of the recommended changes but have not provided adequate responses in a couple of circumstances. For example, the authors chose not to reflect on the selection of the 185 sample plots refered to in line 89 so it is still not clear how these were selected. They need to provide details of the methods and approach for selecting these plots so as to provide a through account of their methods so others can apply this method
The authors have not really explored the issue of prior land use history and the establishment of plantations in the region of this study. For example, 25 soil samples were collected from Eucalyptus forests and 63 soil samples collected from warm coniferous forests. Of this last forest type, it is likely that many of the sample locations are plantations, with a prior land use. Are these legacy effects of prior land use impacting more on observed patterns of microbial diversity than might be expected? We might expect large differences in soil properties due to agricultural practices such as fertilizer inputs or as a consequence of historical topsoil erosion and exposure of subsoils. These landuse impacts could have long lasting impacts on microbial diversity and this needs to be addressed in more detail throughout the manuscript and the conclusions modified to highlight the importance of plantations in determining the observed patterns in figure 2.
An overall comment is that the quality of this manuscript can still be improved by closer attention to detail of the written language. For example,
Line 27 change larger soil nitrogen to greater total soil nitrogen
Figure 4bOil-tea camellia is missing the number of soil samples
For example line 66 change their feedbacks to their feedback on plant and soil properties remain………
Line 92- 93 clarify where the increment cores were collected
Check the number of decimal points required for each unit in table 1
Caption figure 5 labels in diagrams for Pre-yr and Tem-Yr are not define in the caption or do they correspond to the MAP or MAT?
Line 292 change …..were the most important variation …. To ….. accounted for the most variation in functional variation…….
Line 312-313 revise the sentence as older forests do not necessarily produce better quality carbon, carbon quality will depend on the species which may reflect species choice in the case of plantations. Avoid the use of forestation in the context of stand age
Line 315 change affect landuse to reflect land use…….
In what sense are microbes favoured – diversity of function? Be more specific here.
Line 342 change ..of.. to ……determining…….
Line 354 during forest development. add and plantation establishment to the end of the sentence
Author Response
Specific comments on the manuscript entitled " The biogeography of forest soil functional diversity responds to forest types across Guangxi, South West China”.
On one hand the authors have addressed most of the recommended changes but have not provided adequate responses in a couple of circumstances. For example, the authors chose not to reflect on the selection of the 185 sample plots refered to in line 89 so it is still not clear how these were selected. They need to provide details of the methods and approach for selecting these plots so as to provide a through account of their methods so others can apply this method
Response: Sorry for the unclear description. We rewrote the sentences about the method of selecting sample plots. “Five forest types were selected based on the distribution area and volumn of each forest type, and the sample plots of each forest type were established according to young, middle, near-mature, mature and over-mature sequence”.
The authors have not really explored the issue of prior land use history and the establishment of plantations in the region of this study. For example, 25 soil samples were collected from Eucalyptus forests and 63 soil samples collected from warm coniferous forests. Of this last forest type, it is likely that many of the sample locations are plantations, with a prior land use. Are these legacy effects of prior land use impacting more on observed patterns of microbial diversity than might be expected? We might expect large differences in soil properties due to agricultural practices such as fertilizer inputs or as a consequence of historical topsoil erosion and exposure of subsoils. These landuse impacts could have long lasting impacts on microbial diversity and this needs to be addressed in more detail throughout the manuscript and the conclusions modified to highlight the importance of plantations in determining the observed patterns in figure 2.
Response: This is a good question. We added the sentence “However, our study neglected the effects of prior land use history and agricultural practices in plantations such as fertilizer inputs on the patterns of microbial diversity.” in the conclusion.
An overall comment is that the quality of this manuscript can still be improved by closer attention to detail of the written language. For example,
Line 27 change larger soil nitrogen to greater total soil nitrogen
We changed it.
Figure 4bOil-tea camellia is missing the number of soil samples
We added the number of soil samples in Oil-tea camellia.
For example line 66 change their feedbacks to their feedback on plant and soil properties remain………
We changed it.
Line 92- 93 clarify where the increment cores were collected
Sorry for the error of missing “DBH” and we added it after “tree”.
Check the number of decimal points required for each unit in table 1
We unified the number of decimal points in Table 1.
Caption figure 5 labels in diagrams for Pre-yr and Tem-Yr are not define in the caption or do they correspond to the MAP or MAT?
We have unified the labels of MAP and MAT for mean annual precipitation and temperature, respectively.
Line 292 change …..were the most important variation …. To ….. accounted for the most variation in functional variation…….
We changed it.
Line 312-313 revise the sentence as older forests do not necessarily produce better quality carbon, carbon quality will depend on the species which may reflect species choice in the case of plantations. Avoid the use of forestation in the context of stand age
We deleted “due to long forestation”.
Line 315 change affect landuse to reflect land use…….
We changed it.
In what sense are microbes favoured – diversity of function? Be more specific here.
We changed “soil microbes” to “soil microbial diversity of function”.
Line 342 change ..of.. to ……determining…….
We changed it.
Line 354 during forest development. add and plantation establishment to the end of the sentence
We added “during forest development and plantation establishment” to the end of the sentence.
Reviewer 2 Report
The study “The biogeography of forest soil microbial functional diversity responds to forest types across Guangxi, Southwest China” was revised and, thus, improved by Peng and colleagues. However, some of the points raised by Reviewer#2 were overlooked (at least there was no according reply) or are still not fully clear:
Point 1: “Regarding the number of samples it would be interesting to see how many samples were taken from each type of forest. […]”
Point 3: Still nothing is said about the post hoc tests used for current Figs. 4 and S4.
Point 5: “Regarding the parameters given in Table 1 […] it would be of much more interest whether these differ between the five forest types rather than summarising them as bulk.”
Point 6: As you confirm that stand density better correlates with component 2 than bulk density, but bulk density can be seen in current Fig. 3b, while stand density disappears under component 3, you should emphasize that stand density is graphically hidden despite it has the better correlation in order to avoid confusion of the readers regarding stand density and bulk density.
Point 9: You mentioned you have removed the reference to bulk density in the discussion, but the occasion I meant (current line 301-302, “looser soils”) still mentions it.
Point 12: You need a reference for the medium quantity litter/exudates part or is it already covered by the references in the following sentence?
Point 13: You replied the sentence was deleted, but it is still there in current lines 328-330. But a deletion would also affect the lines until 333. Thus, can my point “For the discussion in lines [328-330] it would be good to know how diverse the different forest types are.” solved in another way?”
Point 14: Your reply referred to current lines 351-354, but my point was ”In lines [339-342 of the current version] the statement appears to be too strong. On the one hand you would need a statistical test to underline the mentioned significance and on the other hand the low percentage (<10% in total for both axes) questions a strong evidence.”
Point 29: I am sorry, but I still do not get your point. Do you mean, you assigned an arbitrary value (quantitative) to each forest (qualitative) just for enabling calculation? If my guess is correct, does it has an impact on the outcome, when evergreen broadleaf gets 1 and warm coniferous gets 5 or could it also be vice versa?
Point 35a: Regarding current Fig. 4: “[…] the caption says that the whiskers indicate standard errors. That is quite uncommon for box-plots. Normally the whiskers indicate the maximum and minimum values which are not designated as outliers. Especially when you indicate the Standard Error of the Mean an indicator (often a diamond) is needed to show where the mean is. […]”
Point 35b: Regarding current Fig. 4: “[…] the caption mentions differentiation between mild and extreme outliers. […] a definition of what mild and extreme are is need[ed].” Especially as Fig. 4a has no asterisks the definition seems to differ between 4a and 4b.
Point 38: (current line 260) “Check content within parenthesis: Why starts the range with lower values?”
Point 39: There seems to be a misunderstanding. With “more” I meant there are more occasions than just in line 274 (currently 268) for the following point: “Try to avoid referencing back to main text figures and tables.”
Point 41: For the following point “Rearrange the sequence of arguments in the sentence. Currently it sounds as if soil stabilisation governs the C and N availability, which is only via interdependencies partly true.” it appears you got the wrong lines. I referred to current 300-303, while you changed current 303-305.
Point 44: “[…] you should explain how you define an outlier. […]” for Table S1
New point: In line 184 it is said, Shannon index ranged up to 3.38, while 189-190 say 0.5% were larger than 3.38 suggesting there are larger values than mentioned in 184.
New and incomplete minor points:
91 “DBH” is mentioned, but the abbreviation is explained much later in that sentence
100 Remove the space between “cores” and “.”
126 Change “control substrate well” to “control well”
134, 141 Change “Shannon-Weaver” to “Shannon-Wiener”. That is an often occurring mistake.
136 The minus is still missing in the formula (see point 20)
145, 153, 156, 172 Software developers’/companies’ names are still not mentioned (cf. points 23, 25, 26).
162 In citing R the place is missing (cf. point 27)
162 Citation for MASS is missing (cf. point 27)
191-192 Change “Fig. S2” to “Fig. S3”; remove “Fig. S3” from the parenthesis at the end due to redundancy.
Fig. 5 Instead of “MAT” and “MAP” you use “Tem_year” and “Pre_year”, respectively. Throughout the manuscript and also still in the caption of Fig. 5 you use “MAT” and “MAP”. Please unify.
338 Change “Fig.4S” to “Fig.S4”
377 Change “abnormal” to “non-normal” (see former point 44)
Fig. S1 Indicate the according forest types.
388-389 Place ”(b)” after “or”.
Author Response
The study “The biogeography of forest soil microbial functional diversity responds to forest types across Guangxi, Southwest China” was revised and, thus, improved by Peng and colleagues. However, some of the points raised by Reviewer#2 were overlooked (at least there was no according reply) or are still not fully clear:
Thanks for your constructive comments, we revised the manuscript carefully.
Point 1: “Regarding the number of samples it would be interesting to see how many samples were taken from each type of forest. […]”
Response 1: The number of the samples taken from each type of forest were shown in the Fig.4.
Point 3: Still nothing is said about the post hoc tests used for current Figs. 4 and S4.
Response 3: we added the sentence “with Tukey’s post-hoc test” after “The one-way analysis of variation (ANOVA)”.
Point 5: “Regarding the parameters given in Table 1 […] it would be of much more interest whether these differ between the five forest types rather than summarising them as bulk.”
Response 5: Here, we just try to demonstrate the basic information of the whole forest across Guangxi region rather than the differences between the five forest types.
Point 6: As you confirm that stand density better correlates with component 2 than bulk density, but bulk density can be seen in current Fig. 3b, while stand density disappears under component 3, you should emphasize that stand density is graphically hidden despite it has the better correlation in order to avoid confusion of the readers regarding stand density and bulk density.
Response 6: In order to avoid confusion, we delete the “stand density” for the second component due to relative small value.
Point 9: You mentioned you have removed the reference to bulk density in the discussion, but the occasion I meant (current line 301-302, “looser soils”) still mentions it.
Response 9: Sorry for this error. We deleted the sentence “The availability of carbon and nitrogen nutrient resources for microbes was generally larger in looser soils due to primary productivity and better stabilization of soil organic matter [15, 41].” in Line 301-303.
Point 12: You need a reference for the medium quantity litter/exudates part or is it already covered by the references in the following sentence?
Response 12: We added the references after the sentence.
Point 13: You replied the sentence was deleted, but it is still there in current lines 328-330. But a deletion would also affect the lines until 333. Thus, can my point “For the discussion in lines [328-330] it would be good to know how diverse the different forest types are.” solved in another way?”
Response 13: Sorry for mistakes of the lines. We added the sentence “for example, deciduous broadleaf forests vs warm coniferous forest,” after “more plant species diversify the resource pool” in Line 330.
Point 14: Your reply referred to current lines 351-354, but my point was ”In lines [339-342 of the current version] the statement appears to be too strong. On the one hand you would need a statistical test to underline the mentioned significance and on the other hand the low percentage (<10% in total for both axes) questions a strong evidence.”
Response: We changed “were” to “might be”. In the process of RDA, forward selection was chosen to pick out the factors with significant effects (p<0.05). Meanwhile, we added the sentence “Low variation (<10% in total for both axes) for carbon source use (Fig.S5) indicated that some important factors may be neglected in the study.”
Point 29: I am sorry, but I still do not get your point. Do you mean, you assigned an arbitrary value (quantitative) to each forest (qualitative) just for enabling calculation? If my guess is correct, does it has an impact on the outcome, when evergreen broadleaf gets 1 and warm coniferous gets 5 or could it also be vice versa?
Response: Sorry for the unclear description. The quantification of the forest types were based on the decreasing order of the composition of deciduous species.
Point 35a: Regarding current Fig. 4: “[…] the caption says that the whiskers indicate standard errors. That is quite uncommon for box-plots. Normally the whiskers indicate the maximum and minimum values which are not designated as outliers. Especially when you indicate the Standard Error of the Mean an indicator (often a diamond) is needed to show where the mean is. […]”
Response: In Fig.4, the caption is “Numbers in parentheses indicate the number of soil samples. Different letters indicate significant differences between forest types (P<0.05). The bars which are above and below the boxes represent the positive and negative standard error, respectively. The line segment at the median inside the rectangular box is treated as the median line. The circles represent mild outliers and the whiskers represent the extreme outliers”.
Point 35b: Regarding current Fig. 4: “[…] the caption mentions differentiation between mild and extreme outliers. […] a definition of what mild and extreme are is need[ed].” Especially as Fig. 4a has no asterisks the definition seems to differ between 4a and 4b.
Response: Mild outliers is >Q3+1.5*IQR or <Q1-1.5*IQR, and extreme outliers is >Q3+3* IQR or <Q1-3* IQR. Interquartile Range (IQR) represent a quadrant spacing, and also is 50% intermediate value in these values, Q1-25%, Median-50%, Q3-75%. IQR=Q3-Q1. We think that it is common in the Box Plot and do not show in the caption.
Point 38: (current line 260) “Check content within parenthesis: Why starts the range with lower values?”
Response: We deleted the R2=0.07 in the parenthesis because it has been demonstrated the variation in the text in order to avoid repeat.
Point 39: There seems to be a misunderstanding. With “more” I meant there are more occasions than just in line 274 (currently 268) for the following point: “Try to avoid referencing back to main text figures and tables.”
Response: Sorry for the misunderstanding. We changed “and in most” to “and more”
Point 41: For the following point “Rearrange the sequence of arguments in the sentence. Currently it sounds as if soil stabilisation governs the C and N availability, which is only via interdependencies partly true.” it appears you got the wrong lines. I referred to current 300-303, while you changed current 303-305.
Response: We deleted the sentence in Line 300-303 according to Point 9.
Point 44: “[…] you should explain how you define an outlier. […]” for Table S1
Response: The outlier is defined as > 3*mean + standard error or < 3*mean – standard error. We added the explanation for the definition of outliers in Table S1.
New point: In line 184 it is said, Shannon index ranged up to 3.38, while 189-190 say 0.5% were larger than 3.38 suggesting there are larger values than mentioned in 184.
Response: In Line 184, it is said “Most of the forest sampling soils (86.5%) yielded soil microbial functional diversity between 2.88 and 3.38, with 0.5% of the soils having soil microbial functional diversity larger than 3.38 and 13.0% having less than 2.88”.
New and incomplete minor points:
91 “DBH” is mentioned, but the abbreviation is explained much later in that sentence
We moved the abbreviation after the first occurrence of “DBH”.
100 Remove the space between “cores” and “.”
We removed the space between “cores” and “.”.
126 Change “control substrate well” to “control well”
We changed it.
134, 141 Change “Shannon-Weaver” to “Shannon-Wiener”. That is an often occurring mistake.
We changed it.
136 The minus is still missing in the formula (see point 20)
We added the minus in the formula.
145, 153, 156, 172 Software developers’/companies’ names are still not mentioned (cf. points 23, 25, 26).
We added the soft developers’/companies’ names.
162 In citing R the place is missing (cf. point 27)
We added the citation [33] for R language.
162 Citation for MASS is missing (cf. point 27)
We added the citation [34] for MASS package.
191-192 Change “Fig. S2” to “Fig. S3”; remove “Fig. S3” from the parenthesis at the end due to redundancy.
We changed it.
Fig. 5 Instead of “MAT” and “MAP” you use “Tem_year” and “Pre_year”, respectively. Throughout the manuscript and also still in the caption of Fig. 5 you use “MAT” and “MAP”. Please unify.
We changed “Tem_year” and “Pre_year” to “MAT” and “MAP” in Fig.5, respectively. And we remade Fig.5.
338 Change “Fig.4S” to “Fig.S4”
We changed it.
377 Change “abnormal” to “non-normal” (see former point 44)
We changed it.
Fig. S1 Indicate the according forest types.
We added the forest types about the photos.
388-389 Place ”(b)” after “or”.
We placed “(b)” after “or”.
