Different Environmental and Phylogenetic Controls over the Altitudinal Variation in Leaf N and P Resorption Traits between Woody and Herbaceous Plants

Round 1

Reviewer 1 Report

The authors examined resoprtion of major nutrients (nitrogen and phosphorus) in 57 species of different growth forms, across a wide altitudinal gradient (> 2000 m elevation) in mountainous region in central China.

The sampling design and the elaboration of the data are both sound and their interpretation overall convincing. Of particular interest appears the critical evalutation of the role played by phylogeny in interpreting nutrient resorption of different plant gorwth forms in relation to altitude.

 

However, there are two critical points that the authors should consider for further improving the paper. 

1.       I could not find any data about lithology in the six sampling sites. Indeed, bedrock is a major factor that can influence soil nutrient status with different effects in relation to thermal variations associated with elevation. The authors could easily add information with this respect and cite, for example, this paper: Gerdol, R., Marchesini, R., & Iacumin, P. (2017). Bedrock geology interacts with altitude in affecting leaf growth and foliar nutrient status of mountain vascular plants. Journal of Plant Ecology, 10, 839–850.

2.       Sampling many species of different growth forms across a so wide altitudinal gradient is a clear strength of this study. However, it may happen that part of the variation in nutrient resorption is due to compostion changes across the gradient. The authors should provide some information about how species composition varies in relation to altitude in the six sampling sites.

 

I also noticed some minor points deserving corrections/adjustments. 

1.       The presentation of the data on nutrient proficiency, expressed as nutrient concentrations in senescing leaves (see Fig. 1 c,d) could convey the wrong idea that nutrient resorption proficiency is higher when nutrient concentrations in senescing leaves are higher. Conversely, the opposite is true because high nutrient concentrations in senescing leaves means incomplete resorption (Killingbeck 1996, reference #6). I am convinced that the authors are aware of this, nonetheless a short comment is useful for clarity.

2.       Although the paper is overall well written there are some typos/linguistic inaccuracies. Just for example I copy a sentence in the following (l. 183-186). Significance was testing (I would say TESTED) via comparison of the variance of standardized contrasts to random values obtained by shuffling trait data across the tips of the tree times. Some species were existed (I would say OCCURRED or WAS PRESENT) at more than one site among different altitudes, we used average values of these species uniformly. I guess that a linguistic check will certainly improve the quality of the paper.

3.       L. 193: What does CRE mean? I did not find explanation of this abbreviation throughout the paper.

4.       TABLE 2. The figures in this are rather difficult to read, at least in my pdf copy. I suggest to arrange this table horizontally in order to enlarge the columns and to highlight significant values, for example by using bold characters. What does GF mean? There are many lines with GF while the abbreviation in the caption is PGF (plant growth form).

Author Response

Thank you for your work on improving our manuscripts. The point-by-point response is attached as a Word file.

Author Response File: Author Response.docx

Reviewer 2 Report

I thank the authors for the quality of this article. This paper is well written and well organized. The objectives, methodology and results are clearly set out.

 

I just have a few comments:

 

- Title: I propose to change the title to: "altitudinal and phylogenetic controls of leaf N and P resorption traits in woody and herbaceous plants"

 

- Summary: line 18 "..significantly increased with altitude.." revise the word "increased" to be adequate with the results.

 

- line 140: delete the dot "." at the start of the line.

 

- Numbers: the resolution is not good especially for figs 1 and 3

 

- Table 2: the title must be in the same direction as the table.

Author Response

Thank you for your work on improving our manuscripts. The point-by-point response is attached as a Word file.

Author Response File: Author Response.docx