Species Richness Promotes Productivity through Tree Crown Spatial Complementarity in a Species-Rich Natural Forest
, Han Y. H. Chen 3, Zhiqiang Xiao 1,4, Dan Wan 1,5, Feng Liu 1, Yili Guo 6, Xiujuan Qiao 1,2 and Mingxi Jiang 1,2,*
Round 1
Reviewer 1 Report
The authors supported their study with a sufficient amount of recent literature, and complemented the excellent and extensive design of the experiment with sophisticated data analysis and very good argumentation. I have only a few minor comments.
L219: „Six is the number of years between the two censuses“ This information clearly follows from the range of years you provided earlier, or may have been used prior you provided the range. Here, on the end of paragraph, it is already redundant.
L221: „To examine how species richness affects crown spatial complementarity, we use simple linear regression…“ Figure 1. with R2 and regression line, so it is not appropriate on L243: to state that "Species richness is positively correlated with crown complementarity". Change the correlation to a much more unambiguous relationship.
For all graphs composed of several subgraphs, it would be appropriate to mark the subgraphs by a), b), etc.
L319: Tree crown spatial complementarity, which is determined by species’ intrinsic characteristics and growth plasticity to local environmental conditions [18, 32].“ It seems to me, that part of the sentence is missing.
L347-L349: „Variation in tree height, crown shape, and crown size increase with community-weighted mean of shade tolerance, which suggests that communities with a higher proportion of light-demanding species should have more variation in crown architecture.“ Doesn't the first part of the sentence contradict the second? I keep reading that sentence over and over and I feel like it does.
L407-L408 as well as L411-L412: Parts of the template remained in the manuscript. Please delete (or in the case of Data Availability, state the actual status).
Author Response
Reviewer 1:
Comments and Suggestions for Authors
The authors supported their study with a sufficient amount of recent literature, and complemented the excellent and extensive design of the experiment with sophisticated data analysis and very good argumentation. I have only a few minor comments.
Response: Thanks for the positive comments. We will revist the manuscript according to your suggestions point to point.
L219: „Six is the number of years between the two censuses“ This information clearly follows from the range of years you provided earlier, or may have been used prior you provided the range. Here, on the end of paragraph, it is already redundant.
Response: Thanks for your suggestions. I have deleted the sentence.
L221: „To examine how species richness affects crown spatial complementarity, we use simple linear regression…“ Figure 1. with R2 and regression line, so it is not appropriate on L243: to state that "Species richness is positively correlated with crown complementarity". Change the correlation to a much more unambiguous relationship.
Response: Thanks for your suggestions. We have revised the sentence and the new one is as follows: Species richness increases with crown complementarity in our subtropical forest (R2= 0.18, p< 0.01).
For all graphs composed of several subgraphs, it would be appropriate to mark the subgraphs by a), b), etc.
Response: Thanks for your suggestions. We have checked the five graphs. All subgraphs in each graph have their specfic order number, such as (a); (b)……
L319: Tree crown spatial complementarity, which is determined by species’ intrinsic characteristics and growth plasticity to local environmental conditions [18, 32].“ It seems to me, that part of the sentence is missing.
Response: thanks for your suggestions. I have revised the sentence and the new one is as follows: Tree crown spatial complementarity, which is determined by species-specific tree architecture and growth plasticity to local environmental conditions.
L347-L349: „Variation in tree height, crown shape, and crown size increase with community-weighted mean of shade tolerance, which suggests that communities with a higher proportion of light-demanding species should have more variation in crown architecture.“ Doesn't the first part of the sentence contradict the second? I keep reading that sentence over and over and I feel like it does.
Response: Sorry for that. It is a error. The new sentence is as follows: Variation in tree height, crown shape, and crown size increase with community-weighted mean of shade tolerance, which suggests that communities with a higher diversity of shade-tolerance among coexisting species should have more variation in crown architecture.
L407-L408 as well as L411-L412: Parts of the template remained in the manuscript. Please delete (or in the case of Data Availability, state the actual status).
Response: thanks for your suggestions. I have edited the reference [20] and [22]. The new references are as follows:
- Bohn, F. J., & Huth, A. (2017). The importance of forest structure to biodiversity–productivity relationships. Royal Society Open Science, 4(1), 160521.
- Zheng, L., Chen, H.Y., & Yan, E. (2019). Tree species diversity promotes litterfall productivity through crown complementarity in subtropical forests. Journal of Ecology, 107(4), 1852-1861.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The work is of great interest for studying the mechanism of species richness-productivity relationship. The authors presented the results base on a large data.
I hope that the comments below will help improve your manuscript.
1. Line 135-136：east-west and north-south are not match with reality. 2. Line 137-139: Please add the elevation ranges of two subplot.
3. Suggest adding soil types in Material and Method.
4. Line 145: The soil sampling depth in line 145 is 0-10,but in Table S3 is 0-30.
5. Line 191：two sequential “and”。
6. Figures: the resolution of the figures are not high.
7. Suggest adding 95% confidence intervals in bivariate relationships figures.
Author Response
Reviewer2:
The work is of great interest for studying the mechanism of species richness-productivity relationship. The authors presented the results base on a large data.
I hope that the comments below will help improve your manuscript.
1. Line 135-136：east-west and north-south are not match with reality.
Response: Sorry for the confusion. We measured the crown width at four cardinal directions: east, west,north, and south in the field, and calculated crown width at the east-west and north-south directions. The new sentences are as follows: Between June–July 2017, we measured tree diameter (D), total tree height (H), the height of the lowest foliage (F), and crown widths in four cardinal directions (east, west, north, and south) for a total of 11,337 individuals in two subplots within the BDGS 25 ha plot (Fig.S1). We calculated crown width in the east-west and north-south directions (represented by W1 and W2, where W1 > W2).
- Line 137-139: Please add the elevation ranges of two subplot.
Response:Thanks for your suggestions. We have already added elevation information of the subplots. The sentence is as follows: The elevation ranges from 1411.42 to 1455.03 m a.s.l and 1399.75- 1436.39 m a.s.l, respectively.
- Suggest adding soil types in Material and Method.
Response: Thanks for your suggestion. We have added soil information in L134-135 in the study area. The sentence is as follows: The main soil types are yellow soil and yellow-brown soil.
- Line 145: The soil sampling depth in line 145 is 0-10,but in Table S3 is 0-30.
Response: Thanks for pointing the error. It is “0-10 cm”. We have revised it in the Table S3.
- Line 191：two sequential “and”。
Response: Thanks for pointing the error. We have deleted one.
- Figures: the resolution of the figures are not high.
Response: Thanks for your suggestions. Figure 1-4 are redrawed in the R software. The resolution and size are greatly improved. Please see these figures in the manuscript.
- Suggest adding 95% confidence intervals in bivariate relationships figures.
Response: Thanks for your suggestions. All bivariate relationships figures have added 95% confidence intervals. Please see these figures in the manuscript.
Author Response File: Author Response.docx
Reviewer 3 Report
I found the manuscript rather well-structured and straightforward. The objectives, methods, and results are pretty much aligned so that there is cohesion among them. The reading was easy and capturing. The topic (tree crown spatial complementarity) is not fully original since many other papers cover similar correlations. Methods of analyses are also standard, yet most of them well-conducted for finding responses to the hypotheses stated.
The innovation stands in the subtropical region of study, likely one of the most septentrional conditions of these types of forests. This particularity was not mentioned in the introduction or in the rest of the manuscript.
Figures in general were rather fuzzy. PCA outcome was presented without a traditional ordination diagram that would have helped a lot in visualizing the main components to explain the 80% of the variation mentioned.
Finally, a discussion of these findings with similar results in other ecosystems would be great to enhance the uniqueness of the present research.
Author Response
Reviewer3:
Comments and Suggestions for Authors
I found the manuscript rather well-structured and straightforward. The objectives, methods, and results are pretty much aligned so that there is cohesion among them. The reading was easy and capturing. The topic (tree crown spatial complementarity) is not fully original since many other papers cover similar correlations. Methods of analyses are also standard, yet most of them well-conducted for finding responses to the hypotheses stated.
Response: Thnaks for the positive comments.
The innovation stands in the subtropical region of study, likely one of the most septentrional conditions of these types of forests. This particularity was not mentioned in the introduction or in the rest of the manuscript.
Response: Thanks for your suggestions. We added a few sentences into the last paragraph. These sentences are mainly to show the innovation stands in the subtropical region of study. Thy are as follows: The studied forest is located at the eastern Sichuan-western Hubei endemic plant genus distribution center (relic center), and has a high species diversity. It is also one of the most septentrional zone of the evergreen broad-leaved forest. Therefore, there is an urgent need explore the mechanisms underlying the SRPR in this species richness forest.
Figures in general were rather fuzzy. PCA outcome was presented without a traditional ordination diagram that would have helped a lot in visualizing the main components to explain the 80% of the variation mentioned.
Response: Thanks for your question. The visualization of PCA results is provided in the supplementary documents (Table S3 and Fig S2 and S3). As these results are not directly related to the main results, we put them into the supplementary documents.
Finally, a discussion of these findings with similar results in other ecosystems would be great to enhance the uniqueness of the present research.
Response: Thanks for your suggestion. We added a sentence in the discussion section. The sentence is mainly to compare the results of this study and results in the other region or forest types. The sentence is as follows: This result is consistent with studies from subtropical successional forests [22], temperate old-growth forest [17], and forest plantations [13].
Author Response File: Author Response.docx
