Is It Possible to Preserve the Full Diversity of Birds in Managed Oak–Lime–Hornbeam Forests?
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsABSTRACT
too long, please shorten it
KEYWORDS
in alphabetical order please
INTRODUCTION
good, clear and quite exhaustive
MATERIALS AND METHODS
- how far in km were the four stands?
This could be interesting in case
of spatial overlap of species among the stands
- how were the 151 plots divided among the four stands?
like 38 per plots?
- how far distant were the plots within each stand? this
is important to determine if they were spatially independent
or not
- rows 163-173: very unclear how the sign test was realized. Please rephrase
- table 1: unclear the meaning of the numbers among parentheses
and letters "a b c"
- Figure 5: because rows from 163 to 173 were unclear at least to me,
I cannot get the meaning of this graph
Author Response
Thank you for the review and for the detailed comments on our manuscript. The revisions suggested have been incorporated into the text. Below, we provide our responses to the individual comments.
Sincerely,
The Authors
ABSTRACT
too long, please shorten it
The abstract has been shortened.
KEYWORDS
in alphabetical order please
Keywords have been sorted.
INTRODUCTION
good, clear and quite exhaustive
MATERIALS AND METHODS
- how far in km were the four stands? This could be interesting in case of spatial overlap of species among the stands
The selected stands were located within the same forest complex. The distances between individual stands ranged from several hundred meters to slightly over a kilometer. The studied forest stands were therefore not located next to each other. They were separated and surrounded by other stands with a similar tree species composition.
- how were the 151 plots divided among the four stands? like 38 per plots?
The number of sample plots ranged from 34 for the old-growth forest, through 36 for the two cut stands, to 45 for the mature stand before cutting. The differences result from slight differences in the size of the stands and the shape of their boundaries. The sample plot grid was always oriented north-south, which also gave a different number of sample plots that fit into the stand. We also eliminated edge sample plots. For the analyses, we only took areas that were entirely within the selected stand.
- how far distant were the plots within each stand? This is important to determine if they were spatially independent or not
Sample plots were located at the nodes of the 80 x 80 m grid so the distances between them were always equal. Therefore, the centers of the sample plots were not chosen subjectively. We included this information in the methodology chapter.
- rows 163-173: very unclear how the sign test was realized. Please rephrase
The description has been expanded.
- table 1: unclear the meaning of the numbers among parentheses and letters "a b c"
The following values are provided in order: Mean (coefficient of variation) and (min–max). The letters “a b c” represent the results of a post hoc test for multiple comparisons. All information is presented in Table 1. The information in parentheses is explained in the table header, while details of the statistical tests are included in the table footnote: “Values marked with different letters differ significantly at p < 0.05 as evaluated by the nonparametric Kruskal–Wallis test, corrected with a post hoc test for multiple comparisons; F – values evaluated by the one-way ANOVA test.”
- Figure 5: because rows from 163 to 173 were unclear at least to me, I cannot get the meaning of this graph
We applied the sign test, a nonparametric statistical method used to compare two groups (e. g. Baguley 2018). The sign test is based on the signs of the differences between paired observations, rather than on the magnitude of these differences. In our study, bird species were treated as statistical units, and the compared variable was their density in different forest stands. In simplified terms, the test indicates statistically significant differences when substantially more species show higher densities in one stand compared to the other.
Baguley, T. (2018). Serious Stat: A guide to advanced statistics for the behavioral sciences. Bloomsbury publishing.
In this case, the test showed that a significantly higher number of cavity-nesting species occurred in one of the forest stands (p < 0.05, Z = 2.294). No significant differences were found for canopy nesters or ground/near-ground nesters (p=1.00 Z=0.000 and p = 0.34 z=0.949.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsYou provide an interesting description of bird assemblies in four differently managed stands of oak-lime-hornbeam forest. You state in the description of the study are that you conducted this study in four forests. However, it may be more accurate to state that the study was conducted in four stands of an oak-lime-hornbeam forest. See my specific comments, but your study may lack statistical rigor because you had a single replicate of each forest condition. Replicates are crucial for establishing statistical significance in your findings.
Comments for author File: Comments.pdf
Author Response
You provide an interesting description of bird assemblies in four differently managed stands of oak-lime-hornbeam forest. You state in the description of the study are that you conducted this study in four forests. However, it may be more accurate to state that the study was conducted in four stands of an oak-lime-hornbeam forest. See my specific comments, but your study may lack statistical rigor because you had a single replicate of each forest condition. Replicates are crucial for establishing statistical significance in your findings.
Thank you for the review and for the detailed comments on our manuscript. The revisions suggested have been incorporated into the text. Below, we provide our responses to the individual comments.
Sincerely,
The Authors
Page 2 – line 88: The manuscript did not describe the characteristics of vegetation in the matrix surrounding the four stands that were investigated. Vegetation communities adjacent to each stand probably had an effect on bird assemblies within each stand, especially since the stands were relatively small. Also, how far apart were each of the study stands from each other?
The studied stands are part of a large forest complex covering over 100 km2. The distances between individual stands ranged from several hundred meters to slightly over a kilometer. They are surrounded by stands of similar species composition and age. Therefore, we believe that the neighborhood did not affect the species composition or bird density.
Page 3 – lines 97-107: I have two concerns regarding the stands selected for sampling in this study. The first concern is that stand size ranged from 24.95 ha to 35.56 ha all of which are relatively small and could be considered fragments of habitat in a fragmented landscape. Stand size (and perhaps shape) may have had an effect on species and numbers of birds detected that was not related to the habitat characteristics of each stand. The other concern is that one replica of each treatment that you evaluated essentially means that you had one sample from each treatment. A small sample size reduces the statistical power of a study, meaning it's less likely to detect a true effect if one exists.
According to the literature, an area of over 20-30 ha is sufficient for counting small birds. During the breeding season, birds are territorial and attached to their nesting site and the immediate surroundings where they feed. If the neighboring areas were of a completely different nature, e.g. meadows or forests with a different species composition of trees, this would indeed have an impact on our stands. It is true that we selected only one stand representing a given phase. The limited area allowed for precise bird counts to be continued for 4 years. Comparing the species composition of the bird community and the density of breeding pairs (Fig. 4) in subsequent years, we see recurring trends. We also observed logical relationships such as the appearance of non-forest species in cut stands or the dominance of hole-nesters in forests with a rich base of holes, etc.
Page 3 – lines 106-107: It is not clear to me what “In all four forests the main tree stand was over 100 years old…” means.
The type of forest described is usually multi-age and multi-layered stands. The information about age refers to the dominant tree species. This means that the stand may contain individual older trees and naturally or artificially appearing young generations of trees.
Page 3 – lines 109-110: The panels A-D need to be upgraded so that they are more decipherable. A scale indicator and North arrow would also be helpful.
Photos of selected stands have been brightened and their features are more visible. We also added a North arrow. We did not add a scale because the map is only schematic. The sizes of some elements, e.g. the circle marking the Niepołomice Forest, are larger than in reality for visibility. The scale could give misleading impressions.
Page 3 – line 119: Visual estimation of canopy cover may lead to less than robust results.
Page 3 – lines 117-123: It is not clear how canopy cover at 30, 20, and 10 m was measured. And, how was the cover at the seedling and sapling layers measured.
Both canopy cover at different levels and seedling and sapling layers were estimated. The estimates were made by people with great experience, which guaranteed results with sufficient accuracy for this type of research. Filling the space at three levels resembled a theoretical cut of the stand at a predetermined height and the projection of each of the three obtained images onto a flat surface of the sample plot.
Page 3 – lines 123-124: Key measurements of down and dead wood commonly include species, diameter, decay class, and volume (or biomass). Were these characteristics measured?
“Lying deadwood with a diameter of at least 7 cm and standing deadwood with a DBH ≥ 7 cm were measured. In the case of lying deadwood and snags (standing snapped trees), diameters were measured at both ends. In the case of entire standing dead trees, DBH was measured.”
These measurements made it possible to calculate the total volume of dead wood and the volume of standing and lying dead wood, i.e. the most important features from the point of view of the analysis of the breeding bird community.
Page 4 – lines 130-131: It would be helpful if the method to conduct bird counts were explained here. I was not able to access Tomiałojć (1980), so I could not familiarize myself with the method you used.
We have added information on the method of counting birds.
Page 4 – line 133: Use of tariff tables should be explained here. This is an English language journal with primarily an English speaking audience. The Czuraj (1990) publication is not very helpful in that regard.
The description has been expanded. The tariff tables developed by Czuraj (1990) are species-specific volume tables that estimate tree volume based on diameter at breast height (DBH) and total tree height.
Page 4 – line 137: “Thickness” is not a characteristic I am familiar with. Based on Yang and Radtke (2022), this is related to bark thickness. Is that correct?
We have revised the description to clarify that it refers to the tree diameter distribution based on diameter at breast height (DBH). This information is presented in Appendix A, Figure A1. The distribution is derived from field measurements of tree diameters (DBH) taken over bark, i.e., including bark thickness, as commonly applied in forest mensuration.
Page 4 – line 147: It would be helpful here to know how pairs of birds were counted.
We have added information on the method of counting birds.
Page 4 – lines 147-148: Why was density expressed in pairs per 10 ha?
We presented bird densities per 10 hectares of area because this is the commonly used unit for this systematic group. Most studies present their results this way by making them comparable among themselves.
Page 4 – line 171: Did you determine whether there were differences among years before you combined the data from all years?
Our aim was to compare whether the forest stands differed statistically in terms of the densities of bird species belonging to three ecological groups, distinguished by their nesting locations. In this statistical test, we analyzed the entire four-year study period, which in our opinion better reflects the availability of ecological niches in these forest stands. The arithmetic mean was used in the test. We did not assess differences between individual years. However, we can include a sign test for individual years as an appendix if required. Nonetheless, this would involve a large amount of data, making interpretation more difficult.
Page 5 – line 186: The meaning of 1–2 thick trees ha-1.is not clear.
This has been clarified, and the threshold of DBH > 85 cm has been added.
Page 7 – line 231: Were statistical differences in the characteristics of bird assemblages among years determined?
Differences in the density of particular bird groups across the study years are presented in Figure 4. However, the sign test was performed using arithmetic means calculated over the entire study period.
Page 7 – lines 236-237: The first mention of a species should be accompanied with their scientific nomenclature.
Latin names have been added.
Page 9 – line 271: It does not appear that the question posed in the title of the manuscript (Is it possible to preserve the full diversity of birds in managed oak-lime-hornbeam forests?) was actually addressed in the manuscript.
We have highlighted this topic more strongly in the discussion.
Page 9 – lines 276-277: While silvicultural management may be designed to imitate natural processes, this is not a given for all silvicultural practices. It depends on the objectives the silvicultural practices are designed to achieve. Elements of biological diversity may not be reduced depending on the management objectives.
In this sentence, we refer to the work of other authors. We have revised the wording to make it less categorical and to better reflect the broader context.
Page 10 – line 309: The rotation age of stands may also be governed by management objectives.
We have expanded the description to include management objectives
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsManuscript Report Summary
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Title: Is it possible to preserve the full diversity of birds in managed oak-lime-hornbeam forests? |
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Title and Abstract |
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The title is appropriate and indicates the main message of the paper No changes necessary. |
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The abstract is understandable by a non-specialist reader No changes necessary |
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Introduction |
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Does the introduction provide sufficient background information for readers not in the immediate field to understand the problem/hypotheses? |
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Yes
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Are the reasons for performing the study clearly defined? |
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yes |
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Are the study objectives clearly defined? |
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Yes
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Material and methods |
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Are the methods used appropriate to the aims of the study? |
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In line 127 Need to explain the methodology used in counting birds
as seen in Figure 1. The four selected forests that comprise the study area must be clearly visible (the photos are dark). |
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Results/Statistics |
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The results are clearly explained and presented in an appropriate |
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good |
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Discussion |
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The findings of the study are properly described in the context of the published literature.
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The conclusions address the aim of the study No changes necessary
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Literature Cited |
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The literature cited is appropriate, recent and balanced |
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Significance and Novelty |
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The claims are sufficiently novel to warrant publication No changes necessary |
Although a few additional details in the methodology render them more obvious for readers, thanks for such an excellent effort
Author Response
Thank you for the positive review and for the comments on our manuscript. The suggested revisions have been incorporated into the text. Below, we provide our responses to the individual comments.
Sincerely,
The Authors
|
Title: Is it possible to preserve the full diversity of birds in managed oak-lime-hornbeam forests? |
|
Title and Abstract |
|
The title is appropriate and indicates the main message of the paper No changes necessary. |
|
The abstract is understandable by a non-specialist reader No changes necessary |
|
Introduction |
|
Does the introduction provide sufficient background information for readers not in the immediate field to understand the problem/hypotheses? |
|
Yes |
|
Are the reasons for performing the study clearly defined? |
|
Yes |
|
Are the study objectives clearly defined? |
|
Yes
|
|
Material and methods |
|
Are the methods used appropriate to the aims of the study? |
|
In line 127 Need to explain the methodology used in counting birds We have added information on the method of counting birds.
as seen in Figure 1. The four selected forests that comprise the study area must be clearly visible (the photos are dark). Photos of selected stands have been brightened and their features are more visible. |
|
Results/Statistics |
|
|
The results are clearly explained and presented in an appropriate good |
|
|
Discussion |
|
|
The findings of the study are properly described in the context of the published literature. |
|
|
The conclusions address the aim of the study No changes necessary |
|
|
Literature Cited |
|
|
The literature cited is appropriate, recent and balanced |
|
|
Significance and Novelty |
|
|
The claims are sufficiently novel to warrant publication No changes necessary |
|
Although a few additional details in the methodology render them more obvious for readers, thanks for such an excellent effort
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsI still have concerns about lack of replication of sample sites and combination of data across years without verifying that there not differences among years. Other responses to your replies are included in the attached document.
Comments for author File: Comments.pdf
Author Response
Response to Revision of Manuscript forests-3640631: Is it possible to preserve the full diversity of birds in managed oak-lime-hornbeam forests?
Thank you for the revised review. Below we provide responses to the individual comments. The revisions have been incorporated into the main text of the manuscript, and the Appendix has also been expanded.
Page 2 – line 88: The manuscript did not describe the characteristics of vegetation in the matrix surrounding the four stands that were investigated. Vegetation communities adjacent to each stand probably had an effect on bird assemblies within each stand, especially since the stands were relatively small. Also, how far apart were each of the study stands from each other?
The studied stands are part of a large forest complex covering over 100 km2. The distances between individual stands ranged from several hundred meters to slightly over a kilometer. They are surrounded by stands of similar species composition and age. Therefore, we believe that the neighborhood did not affect the species composition or bird density.
Response: The distances between stand should be reported in the manuscript. It should also be documented in the manuscript what the composition and structure of the adjacent stands are to establish that the matrix did not affect the species composition or bird density.
This has been incorporated into the manuscript.:
„The studied forest stands were not adjacent to one another, with distances between their nearest corners ranging from 250 to 1000 meters. However, each stand bordered managed forests with a species composition very similar to that of the studied sites, dominated primarily by oak, and less frequently by lime, alder, or hornbeam. Nonetheless, all adja-cent stands contained these species in varying proportions. The age of the dominant tree species in the surrounding stands was as follows: in the old-growth forest (Lipówka Na-ture Reserve), 49–189 years; in the stands surrounding the mature stand, 49–179 years; those surrounding the initial gap-cut stand, 20–159 years; and those surrounding the ad-vanced gap-cut stand, 34–124 years. Within each stand, tree age structure was heterogeneous”
Page 3 – lines 97-107: I have two concerns regarding the stands selected for sampling in this study. The first concern is that stand size ranged from 24.95 ha to 35.56 ha all of which are relatively small and could be considered fragments of habitat in a fragmented landscape. Stand size (and perhaps shape) may have had an effect on species and numbers of birds detected that was not related to the habitat characteristics of each stand. The other concern is that one replica of each treatment that you evaluated essentially means that you had one sample from each treatment. A small sample size reduces the statistical power of a study, meaning it's less likely to detect a true effect if one exists.
According to the literature, an area of over 20-30 ha is sufficient for counting small birds. During the breeding season, birds are territorial and attached to their nesting site and the immediate surroundings where they feed. If the neighboring areas were of a completely different nature, e.g. meadows or forests with a different species composition of trees, this would indeed have an impact on our stands. It is true that we selected only one stand representing a given phase. The limited area allowed for precise bird counts to be continued for 4 years. Comparing the species composition of the bird community and the density of breeding pairs (Fig. 4) in subsequent years, we see recurring trends. We also observed logical relationships such as the appearance of non-forest species in cut stands or the dominance of hole-nesters in forests with a rich base of holes, etc.
Response: Recognize the potential affect the relatively small sizes of the study stands may have on your results and then justify your stand sizes using literature citations to support your findings. Considering the lack of replication in your samples; justify your finding by addressing the statistical ramifications of lack of replication. Also, justify your response above with citations and discussions from the literature that support your conclusions on lack of replication.
A paragraph addressing this issue has been added to the discussion. We highlighted the plot size, the immediate surroundings of the studied stands, as well as the lack of replication. Relevant literature has been added.
„"In this manuscript, we compare four different forest stand types, each represented by a single site. Due to the lack of replication, the results do not reflect the full variability that may occur in bird assemblages within these forest types. However, owing to the high accuracy of both forest structure and bird data, the study provides a well-grounded illustration of the complex set of factors underlying habitat–animal relationships. Therefore, despite certain limitations, this approach is commonly used (e.g. Baláž & Balážová 2012, Lin et al. 2011, Thompson et al. 1990), and the limited area of the sample plots is consistent with the principles of the mapping method for breeding bird territories (Sutherland 1996)."
We have already conducted our own research using this methodology and successfully published it, e.g.
Bujoczek, M., Rybicka, J., & Bujoczek, L. (2020). Effects of disturbances in a subalpine forest on its structural indicators and bird diversity. Ecological Indicators, 112, 106126.
Similar studies have also been conducted by other authors in various habitats, e.g.
Baláž, M., & Balážová, M. (2012). Diversity and abundance of bird communities in three mountain forest stands: effect of the habitat heterogeneity. Pol. J. Ecol, 60(3), 629-634.
Lin, C. W., Hsu, F. H., & Ding, T. S. (2011). Applying a territory mapping method to census the breeding bird community composition in a montane forest of Taiwan. Journal of Forest Science, 26(3), 267-285.
Ribon, R., Marini, M.Â. (2016). Small territory sizes and high densities of insectivorous birds in an Atlantic Forest secondary fragment, Brazil. Rev. Bras. Ornitol. 24, 303–313 https://doi.org/10.1007/BF03544359
Richard K. Broughton, Ross A. Hill, Stephen N. Freeman, Paul E. Bellamy, Shelley A. Hinsley. (2012). Describing Habitat Occupation by Woodland Birds with Territory Mapping and Remotely Sensed Data: An Example using the Marsh Tit (Poecile palustris), The Condor: Ornithological Applications, 114,812–822, https://doi.org/10.1525/cond.2012.110171
St-Louis, V., Fortin, MJ. & Desrochers, A. (2004). Spatial association between forest heterogeneity and breeding territory boundaries of two forest songbirds. Landscape Ecology 19, 591–601 https://doi.org/10.1023/B:LAND.0000042849.63040.a9
Thompson, Frank R. III; Fritzell, Erik K. (1990). Bird densities and diversity in clearcut and mature oak-hickory forest. Research Paper NC-293. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station
Sutherland, W. J. (Ed.). (2006). Ecological census techniques: a handbook. Cambridge university press.
Zammarelli, M. B., Ayres, M. P., Ter Hofstede, H. M., Lutz, D. A., & Holmes, R. T. (2024). Territory sizes and patterns of habitat use by forest birds over five decades: Ideal free or ideal despotic?. Ecology Letters, 27(12), e14525.
Page 3 – lines 106-107: It is not clear to me what “In all four forests the main tree stand was over 100 years old…” means.
The type of forest described is usually multi-age and multi-layered stands. The information about age refers to the dominant tree species. This means that the stand may contain individual older trees and naturally or artificially appearing young generations of trees.
Response: I still do not understand what that statement means.
We removed the sentence about stand age. In Poland, stand age is assigned to all forest stands based on the dominant tree species, even in uneven-aged stands. In this study, diameter at breast height (DBH) distributions are presented (Appendix), which provide a more accurate description of the studied stands than stand age
Page 3 – line 119: Visual estimation of canopy cover may lead to less than robust results.
Response: Provide more detail on how observations were made and establish validity of the technique using literature citations.
The following explanation and references have been added to the text:
„Visual estimation of canopy cover is a widely used method and, when applied with sufficient experience, provides reliable results (Paletto & Tosi 2009; Chmura et al. 2016)."
Visual estimation of canopy cover is a widely used method. The field assessments were conducted by a person with extensive experience—over 20 years—in field measurements, and we are confident that the values are reliable. It is worth noting that visual estimation of canopy cover is also applied in National Forest Inventories across Europe. In a representative study (Chmura et al., 2016), visual estimates of canopy closure were compared with results obtained using hemispherical photography. The authors concluded that although the visual method is less precise, it can be used effectively and yields reliable results when performed by an experienced observer. This was confirmed by high correlations between the results of the two methods.
Examples of studies include:
Paletto, A., & Tosi, V. (2009). Forest canopy cover and canopy closure: comparison of assessment techniques. European Journal of Forest Research, 128, 265-272.
Chmura, D., Salachna, A., & Sierka, E. (2016). Comparison of visual estimation of the canopy cover with the canopyscope assessment. Sylwan, 160(06).
Page 3 – lines 117-123: It is not clear how canopy cover at 30, 20, and 10 m was measured. And, how was the cover at the seedling and sapling layers measured.
Both canopy cover at different levels and seedling and sapling layers were estimated. The estimates were made by people with great experience, which guaranteed results with sufficient accuracy for this type of research. Filling the space at three levels resembled a theoretical cut of the stand at a predetermined height and the projection of each of the three obtained images onto a flat surface of the sample plot.
Response: Provide more detail on how observations were made and establish validity of the technique using literature citations.
We expanded the description and added relevant references to the text. Below, we present a schematic overview of how canopy cover was measured at 30, 20, and 10 m. In the case of the seedling and sapling layers, cover estimation followed commonly accepted principles, such as those applied in the National Forest Inventory (NFI 2015). This is one of the main methods used in forestry, alongside exact counts. However, when dealing with larger areas, counting all seedlings and saplings is not feasible; therefore, we applied visual estimation of surface cover. Very similar methods are widely used in phytosociology (Braun-Blanquet 1932; Wikum & Shanholtzer 1978).
Braun-Blanquet, J. (1932). Plant sociology. The study of plant communities.
Wikum, D. A., & Shanholtzer, G. F. (1978). Application of the Braun-Blanquet cover-abundance scale for vegetation analysis in land development studies. Environmental management, 2(4), 323-329.
NFI 2015. The National Forest Inventory. State Forests National Forest Holding. Stary Sękocin.
Page 4 – line 171: Did you determine whether there were differences among years before you combined the data from all years?
Our aim was to compare whether the forest stands differed statistically in terms of the densities of bird species belonging to three ecological groups, distinguished by their nesting locations. In this statistical test, we analyzed the entire four-year study period, which in our opinion better reflects the availability of ecological niches in these forest stands. The arithmetic mean was used in the test. We did not assess differences between individual years. However, we can include a sign test for individual years as an appendix if required. Nonetheless, this would involve a large amount of data, making interpretation more difficult.
Response: There may have been a difference among years. If there was, it would not be appropriate to combine these data.
We added the densities of the analyzed groups for each year to the appendices. The differences in density are minor and do not affect the conclusions of the study regarding the quality of the individual stands analyzed
Page 7 – line 231: Were statistical differences in the characteristics of bird assemblages among years determined?
Differences in the density of particular bird groups across the study years are presented in Figure 4. However, the sign test was performed using arithmetic means calculated over the entire study period.
Response: There may have been a difference among years. If there was, it would not be appropriate to combine these data.
We added the densities of the analyzed groups for each year to the appendices. The differences in density are minor and do not affect the conclusions of the study regarding the quality of the individual forest stands analyzed. We would also like to emphasize that the manuscript does not aim to investigate population dynamics of individual species—which can be substantial in the case of birds—but rather the quality of the studied forest stands as habitats for particular bird groups. From this perspective, multi-year averages provide more reliable data than observations conducted in a single year.
Figure A3. Density of canopy nesters (A), cavity nesters (B), and birds nesting on or near the ground (C) in the respective study years.
Author Response File: Author Response.pdf
