Influence of Fires on Desert Plant Communities at the Chernye Zemli (SW Russia)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The present manuscript identifies the features of pyrogenic succession of vegetation in the east of Kalmykia for areas affected by the fires between 1987 and 2020, based on Landsat images. Considerations were taken into account the vegetation on 55 sites in and near the Chernye Zemli state natural biosphere reserve that burned at different times or were not affected by fires over the past 35 years and characterized changes in vegetation cover associated with fire impacts. The descriptions were grouped into chronological stages according to the time elapsed since the last fire, or into groups according to the frequency of fires. Comparisons of projective cover of species among the groups were then conducted by taking the Mann-Whitney and Spearman tests. The paper is well written and well structured, containing useful information for fire ecological workers.

 

Lots of data are obtained and presented in the manuscript; however, there are lack of comparisons of them with the parallel studies in the open literature. At the movement, throughout the entire section of Results, no any dialogues were attempted to made with the previous fire regimes studies available worldwide, including the well-known contribution by the scholars from Forest Service, USDA (for instance, the recent publications from Dr. Alan A. Ager et al.).

 

There are some other eminent issues in the paper; for example, the abstract is too lengthy, which should be refined and shortened. The statements made in the conclusion section are too broad in technical sense. It is evident that, the concluding remarks placed in the last section should be more specific to certain ecological scopes with the revelation of their significance in the involved research field.

 

This paper should be suitable to be published after making major changes at these aspects.

Comments on the Quality of English Language

n/a

Author Response

Comments	Author’s response
Reviewer 1
Lots of data are obtained and presented in the manuscript; however, there are lack of comparisons of them with the parallel studies in the open literature. At the movement, throughout the entire section of Results, no any dialogues were attempted to made with the previous fire regimes studies available worldwide, including the well-known contribution by the scholars from Forest Service, USDA (for instance, the recent publications from Dr. Alan A. Ager et al.).	Lots of studies of Forest Service and USDA mainly are not very suitable as reference for our study region because its scope is mainly forest wildfires and forest communities. But our study focuses on fires in completely treeless communities, that are much similar to North American prairies than to forests. But we are thankful for you recommendation in general. We added some information about studies of pyrogenic successions in sagebrush biome of Great Basin (including USDA).
There are some other eminent issues in the paper; for example, the abstract is too lengthy, which should be refined and shortened.	We corrected the abstract.
The statements made in the conclusion section are too broad in technical sense. It is evident that, the concluding remarks placed in the last section should be more specific to certain ecological scopes with the revelation of their significance in the involved research field.	In Conclusions section, we now concentrated on the influence of fires on plant communities in the studied area.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is clear, relevant for the field of influence of fires on biota.

 

The manuscript is well structured: hypotheses are formulated, methods, results obtained on their basis and conclusions are presented. 

 

The cited references are mostly recent publications and relevant. It doesn’t include an excessive number of self-citations. 

 

The manuscript is scientifically sound. The experimental design is appropriate to test the hypothesis. 

 

The manuscript’s results are reproducible based on the details given in the methods section. 

 

Figures are appropriate.  All of them properly show the data.

 

Tables are appropriate. All of them properly show the data. All of tables are easy to interpret and understand. 

 

The data is interpreted appropriately and consistently throughout the manuscript.

 

There are minor comments on the figures:

Figure 1. Part of the area "Chernye Zemli" is cut by a rectangle with a general view. Perhaps it makes sense to move the map so that the area is fully visible.

 

Figure 3. The diagonal line is poorly readable. It is recommended to make it contrast and/or thicker.

Author Response

Figure 1. Part of the area "Chernye Zemli" is cut by a rectangle with a general view. Perhaps it makes sense to move the map so that the area is fully visible.	We have corrected the map.
Figure 3. The diagonal line is poorly readable. It is recommended to make it contrast and/or thicker.	We now made this line more bright.

Reviewer 3 Report

Comments and Suggestions for Authors

General Comments:

Interesting and informative manuscript regarding the fire and grazing dynamics and the effect on local plant biodiversity in Chernye Zemli reserve. The manuscript is generally well-written.

More information is required regarding the spread of the fire, how is it propagated and what is the intensity like? Which is the primary fuel and cause?

Ordination analyses, e.g., NMDS or similar, would have been appropriate for the analyses and informative for the reader, why were this type of method not utilized? Consider including.

More information is required for the shrub recovery within the structure of the system, primarily regarding the re-establishment, germination and dispersion. Does some of them utilize extensive seedbanks, disperse from outside the burnt area or use under-ground regeneration structures? Add to intro and/or discussion.

The same applies in general for the flora, how frequent do the flora utilize seedbanks, disperse from outside and utilize under-ground structures for the regeneration? Perhaps the easiest way of showing this is to include a column in Table S1 for annual/perennial, storage organs and seedbank prevalence and then reflecting it within the discussion.

Specific Comments:

1.     Lines 137-140. Specify if only vascular plants were assessed, in contrasts to bryophytes or others.

Figures and Tables:

1.     Figures 3. The right-hand side observation is likely an outlier, remove the observation and re-run the analysis. This would also allow for greater interpretability of the rest of the graph for the reader.

2.     Table 5. The non-corrected p-values should not be discussed in the test, as the correction was clearly justified. Therefore, it is not enough to simply state at the bottom of the table that all comparisons were non-significant while still using the uncorrected numbers in the text. The mentioned section of the results should reflect the proper results of the analysis.

Comments on the Quality of English Language

Generally good, some minor spelling errors.

Author Response

More information is required regarding the spread of the fire, how is it propagated and what is the intensity like?	Fire propagated with natural conditions of steppe: high summer temperatures, strong winds and low quantity of potential barriers help fire to propagate on large territories. With term “intensity” we mean temperature reached in flame, so we changed this term in the beginning of Introduction to avoid misunderstanding,
Which is the primary fuel and cause?	Primary fuel for fires is mortmass (dead dried parts of plants), especially leafs and stems of cespitose grasses. Due to specific climatic conditions of southern steppes, most of plants have short vegetation period here and produce lots of flammable mortmass already in early summer. As a result, fire-dangerous season lasts from early summer to late autumn. Cause of most fire events in region is careless handling of fire by locals, much rarely there are non-human causes of fire (dry thunderstorms, etc.).
Ordination analyses, e.g., NMDS or similar, would have been appropriate for the analyses and informative for the reader, why were this type of method not utilized? Consider including.	We added NMDS in subsection 3.4 of Results section
More information is required for the shrub recovery within the structure of the system, primarily regarding the re-establishment, germination and dispersion. Does some of them utilize extensive seedbanks, disperse from outside the burnt area or use under-ground regeneration structures? Add to intro and/or discussion.	Subshrubs and shrubs are very vulnerable for fire. In most cases, only rare individuals of subshrubs and shrubs survive the fire. For species in our study, there is no resprouting from underground part of plant or root neck. So, there is no re-establishment of individuals. And the only way of shrub recovery is seed bank that includes seeds in soil and intake of seeds from neighbor territories. We added information about primary way of (sub)shrubs recovery in Introduction
The same applies in general for the flora, how frequent do the flora utilize seedbanks, disperse from outside and utilize under-ground structures for the regeneration? Perhaps the easiest way of showing this is to include a column in Table S1 for annual/perennial, storage organs and seedbank prevalence and then reflecting it within the discussion.	We added the column “Life cycle” (annual, biennial, perennial) in Table 1.
Lines 137-140. Specify if only vascular plants were assessed, in contrasts to bryophytes or others.	Specified.
1.     Figures 3. The right-hand side observation is likely an outlier, remove the observation and re-run the analysis. This would also allow for greater interpretability of the rest of the graph for the reader.	This is not an outlier in a sense of our analysis. It is a dominant species (Poa bulbosa) with projective cover that is much higher than the cover of other species in both groups of areas. We repeated the analysis without it and received similar results (p=0.00007, r=0.61). To make a plot more clear, we now provide it in log coordinates.
Table 5. The non-corrected p-values should not be discussed in the test, as the correction was clearly justified. Therefore, it is not enough to simply state at the bottom of the table that all comparisons were non-significant while still using the uncorrected numbers in the text. The mentioned section of the results should reflect the proper results of the analysis.	Method of multiple testing correction, in our opinion putting both unadjusted and adjusted p-values into a table allows for better understanding of the data. No numbers from these table were used in the text. We now changed the phrase “projective covers differed most significantly” to “projective covers differed most noticeably” in the text. As Bonferroni correction is a very stringent.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The present manuscript identifies the features of pyrogenic succession of vegetation in the east of Kalmykia for areas affected by the fires between 1987 and 2020, based on Landsat images. Considerations were taken into account the vegetation on 55 sites in and near the Chernye Zemli state natural biosphere reserve that burned at different times or were not affected by fires over the past 35 years and characterized changes in vegetation cover associated with fire impacts. The descriptions were grouped into chronological stages according to the time elapsed since the last fire, or into groups according to the frequency of fires. Comparisons of projective cover of species among the groups were then conducted by taking the Mann-Whitney and Spearman tests. The paper is well written and well structured, containing useful information for fire ecological workers.

 

It is clear that some eminent issues have been mitigated in the revised paper manuscript. However, one important reference is still missing in the discussion section, that is “Restoration of fire in managed forests: a model to prioritize landscapes and analyze tradeoffs” authored by Ager and co-workers. The understanding established in this paper should be helpful to expanding the ideas addressed in the discussion section. At the movement, the conclusion section looks incomplete with some key missing information such as the claim of the innovation in the adopted methodologies etc. A blank line should be inserted after this section for separation purposes.

 

More editorial work needs to be handled with care; for instance, the font sizes for the tick labels and coordinate parameters in Figure 4 should be enlarged in consistence with those shown in Figure 3. All the mathematical symbols must be set in italic style. Also, remove the brackets from Table 2.

 

This paper should be suitable to be published after making such necessary but minor changes.

Comments on the Quality of English Language

n/a

Author Response

It is clear that some eminent issues have been mitigated in the revised paper manuscript. However, one important reference is still missing in the discussion section, that is “Restoration of fire in managed forests: a model to prioritize landscapes and analyze tradeoffs” authored by Ager and co-workers. The understanding established in this paper should be helpful to expanding the ideas addressed in the discussion section.	We added references on A. Ager and co-workers in text of Discussion
At the movement, the conclusion section looks incomplete with some key missing information such as the claim of the innovation in the adopted methodologies etc.	We added one paragraph.
A blank line should be inserted after this section for separation purposes.	Inserted
More editorial work needs to be handled with care; for instance, the font sizes for the tick labels and coordinate parameters in Figure 4 should be enlarged in consistence with those shown in Figure 3.	Fonts at Figure 4 corrected
All the mathematical symbols must be set in italic style.	Corrected.
Also, remove the brackets from Table 2.	Removed

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have improved the manuscript according to reviewer comments.

Author Response

We did not find any comments by Reviewer 3.