Herbaceous Layer Response to Overstory Vegetation Changes in Quercus mongolica Fisch. ex Ledeb. Forests in Korea

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Article entitled ‘Herbaceous Layer Response to Overstory Vegetation Changes in Quercus mongolica Forests in Korea’ in which ecological processes driving succession were assesed using zeta diversity and species turn- over. Importantly, ‘International Long Term Ecological Research Network guidelines’ were followed by selecting 1ha plot which were further sub-divided into 100 subplots during data collection from 2014 to 2020. Their results revealed that zeta diversity shifting (from power to exponential) indicated a shift from deterministic to stochastic processes, thereby unveiling the need of  Long Term Ecological Research in forests with changing overstory canopy. The researchers concluded that These results suggest that sharp changes in shrub layer population densities exert dynamic ecological pressure on short-term species composition in the understory vegetation.

 

Abstract: It is well written in concise form

 

Introduction:

-Quercus mongolica Author citation should be added on its first use

-Introduction is OK but can be strengthened by adding few comparative lines on global forested  landcapes-Few recent references in terms of tropical forests such as cited below may be added by authors where different layers impact on ecological functioning is elucidate

“Effects of Invasive Alien Plants on Floristic Diversity and Soil Physico-­ Chemical Characteristics in Hailakandi District, Assam, an Indo Burma Hotspot Region.” Tropical

Ecology 66, 2: 303–320. https:// doi. org/ 10. 1007/ s4296 5- 025-00387- 8.

 

Materials and Methods:

-Line 90-Please add Author citation of Lindera obtusiloba

- Line 140-NIFOS  may be expanded if not done earlier in text

Results:

-Line 255-256: Please add Author citation of plants which are used first time in text

 

Author Response

Thank you for your insightful comments.
Please find the attached file containing our point-by-point responses to the reviewers' suggestions.
The revised manuscript includes all changes marked in red text for your convenience.
Thank you again for your time and consideration.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper reports about the establishment of a new forest monitoring site in central South Korea together with monitoring results based on the first few surveys. Site selection and the applied methodology followed the ILTER standards. Sampling design were appropriate and followed international standards. Monitoring results were properly described and interpreted. I liked that authors used complex methods and the related results were excellently linked producing interesting conclusions about the main processes, trends and mechanisms. The text is generally well written and clearly documented. However, the whole paper is confusing because the authors mixed two types of publications (1, introduction to a new LTER site 2, analyzing specific scientific question about the response of herbaceous layer to the structure and dynamics of overstorey vegetation (cf title).

The Abstract has been focused on the case study similarly to the texts of the Results and Discussion sections. However, Introduction was devoted to the ILTER, reviewing the related motivations, principles and methodology. I suggest revising the manuscript and focusing on the case study (according to the present title) with a completely new Introduction. The new Introduction should ends with specific questions, hypotheses and should provide the specific research background.

Publishing a separate baseline paper with details about the establishment of the new monitoring site is also important. However, it could be a separate (and more detailed) publication where all the ILTER information could be reviewed as well. Authors emphasized that representative forest area was chosen for the new monitoring site and areas with heavy human disturbances were avoided. However, the detailed information about the history and dynamical state of the new site is missing. (But results gave some insights about the ongoing dynamics from a short-term perspective.) Are these forests pristine forests, never logged and affected only by natural disturbances? How big is the total forested area around the monitoring site? Adding description of the landscape context and details about the history of vegetation and about the history of potential human impacts are also necessary.

 

Further comments

Abstract L 18: Please, mention also that four surveys were performed during the seven years.

Abstract L 24-26. I agree that more long-term monitoring is necessary. However, I suggest writing more careful conclusion about the found forest transition. There are recurrent disturbances and stress events in forests inducing several local dynamical phases where temporal disassembly is followed by reassembly. Longer period of monitoring and more surveys are necessary for assessing the dynamical state of a forest.

Material and Methods:

L 119-120: Can the higher rainfall responsible for the stochastic state recorded in the 2020 survey? (where stochasticity could be explained by the high amount of newly established species with random spatial distributions after the increased precipitation)

L 142: “we divided the area into four …” can be misleading. I suggest writing: “we positioned four separate 50x50m plots that represented better the vegetation patterns than a single 1ha plot”.

L 148-1497: Survey dates show irregular pattern. What was the reason for this irregular pattern?

L 156: If I understood well, the Braun-Blanquet method only in small plots and only for the understorey vegetation was applied. I strongly recommend extending the coenological sampling to the shrub and tree layers as well. Plant species’ coverages in the upper layers should be sampled in the 10x10m plot (cf Fig 3).

L 156: give formula for diversity and evenness indices or cite related textbook or original methodology papers.

L 156: add references about the NMDS method.

L 193: Add “(Table 2)” to the end of the sentence.

L 203-204: the term “environmental variable” for tree basal area and density can be misleading. I suggest the term: “explanatory variables”

L 214: this formula is about the community level species turnover. However, you analyzed also the species level turnover (cf. Table 8). I suggest to mention here also the measures for the species level rates.

L 239-242: You have a single site with four monitoring plots and temporal series of data. This implies various spatial and temporal autocorrelations in data. Please explain what was the data table (variables x replicates) and what was the sample size you used. I personally do not expect that accounting for the autocorrelations would change considerable your results. Still this issue should be clarified.

Results:

Table 6. Write that all species listed or add criteria for selection.

L 365-366: This sentence is not clear. The magnitude of change could appear between 2017 and 2020. The term “Starting in 2020” is confusing.

Results of the zeta diversity analyses are very interesting. I do not criticize your interpretation. I suggest only to consider that the next survey of zeta could support power function model again.

Table 8. Meaning of variable “mean” is not clear here. How can you interpret? Rather you could use the difference between rate of immigration and emigration representing a balance or the overall direction and magnitude of changes.

Discussion: Relevant and interesting. Author focused on the actual forest. I miss some more comparison with other forests in Korea or globally. (The standard LTER methodology is useful for such comparative evaluations.)

L 574:  “Consequently, evenness decreased.” However, as I can read evenness increased from 2017 to 2020 (Table 5). Please, clarify.

Author Response

Thank you for your insightful comments.
Please find the attached file containing our point-by-point responses to the reviewers' suggestions.
The revised manuscript includes all changes marked in red text for your convenience.
Thank you again for your time and consideration.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors considered and improved all points that I suggested. The responses to my comments were clear and satisfying. They enlarged the Introduction with research background specifically related to understory vegetation organization and dynamics and added satisfying information about the study site history and context to the Material and Methods section. New references were added reviewing similar studies. This is now a clear and well documented paper providing valuable evidences.