The Importance of the Scots Pine for the Diversity of Forest Avifauna: The Augustów Forest as a Case Study
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsStudying the patterns of functioning of various elements of forest ecosystems is an urgent task, since climate warming, affecting some components, directly or indirectly affects others. Europe's pine forests are under threat from climate change, as has been shown in many studies. Changes in habitats that affect the nesting substrate of birds (or breeding biotope), destroying their established topical connections, can significantly change the avifauna, affect the ranges of species and even cause the extinction of some of them.
The manuscript is devoted to the search for such potentially vulnerable bird species associated with pine forests using the example of the Augustów Forest in Poland. This study is based on a 22-year time period.
In general, the study is interesting, the authors well substantiated its implementation, the research methodology is described in sufficient detail and does not raise doubts, statistical analysis of long-term data confirms the conclusions.
The authors identified a list of species that could potentially lose nesting substrate when old-growth pine trees disappear from habitats and suggested practical silvicultural measures that could reduce the effects of global warming on pine forests. This is valuable because such conclusions are based on many years of research into the nesting bird community of pine forests.
I have no fundamental comments on the manuscript; it can be published after minor corrections. No re-review is required.
Remarks
1. Keywords. I suggest this option “the Augustów Forest; Pinus sylvestris; global warming; pine-specialized birds; primary and secondary nesters”
2. Correct the format of references in the text to citation sources: replace the round brackets with square brackets.
3. Line 65: (11, 12, 13) replace with [11-13]
4. Lines 152-153. Need references for R software and packages.
5. Lines 248-250. Caption for Figure 5. You need to add the letters A-D in brackets to the diagram options in the caption. Diagrams do not need to show probabilities in standard form. Sufficient: P<0.001. It makes no sense to indicate twelve or sixteen decimal places. It is also necessary to clarify in the caption to this figure by what criterion the significance levels for pairwise comparisons are indicated here.
Author Response
Dear Reviewer,
Thank you for you valuable comments, that helped improve the manuscript.
Keywords are listed in alphabetical order .
References have been completed.
Changes in the text are indicated in dark blue font.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
General remarks:
1) In the “Material end Methods” section to include the reference of the used source of used avian taxonomy, Ex.: del Hoyo (Ed.) 2020. All the Birds of the World. Lynx Edicions, Barcelona., 1-967.
2) To introduce an abbreviation: “Scots Pine” - SP
Other remarks:
line 14 – “grouse” – not specified
line 60 – “animals assemblages” - animals assemblages
line 113 – “birds of prey, ………., owl species” – diurnal and nocturnal birds of prey
line 114 – “raven Corvus corax” - Common Raven Corvus corax
line 114 – “forest grouse” - not specified
line 125 – “capercaillie Tetrao urogallus” - Western Capercaillie Tetrao urogallus
line 126 – “hazel grouse Tetrastes bonasia” - Hazel Grouse Bonasa bonasia
line 131 – “smaller weights” – smaller body weights
lines 142-143 – “goshawk Accipiter gentilis” - Northern Goshawk Accipiter gentilis
line 143 – “buzzard Buteo Buteo” - Eurasian Buzzard Buteo Buteo
line 143 – “cormorant Phalacrocorax carbo” - Great Cormorant Phalacrocorax carbo
line 144 – “grey” – Grey
line 144 – “honey buzzard Pernis apivorus” - European Honney-Buzzard Pernis apivorus
lines 145 – “black kite Milvus migans” – Black kite Milvus migrans
lines 145 – “red kite Milvus milvus” – Red kite Milvus milvus
line 146 – “hobby Falco subbuteo” - Еurasian Hobby Falco Subbuteo
line 163 – “golden eye Bucephala clangula, the stock dove Columba oenas” – Common Goldeneye Bucephala clangula, the Stock dove Columba oenas
line 165 – “tengmalm's owl Aegolius funereus” - Boreal Owl Aegolius funereus
line 165 – “black” – Black
line 174 – “golden eye, stock dove and tengmalm's owl” – Please correct and unify the bird name throughout all manuscript.
line 200 – “lesser” – Lesser
line 200 – “tawny” – Tawny
line 201 – “great spotted woodpecker Dendrocopos major” - Great-spotted Woodpecker Dendrocopos major
line 212 – Fig. 2 could be of smaller size.
line 259 – “woodlark” – Woodlark
lines 259-260 – “nightjar Caprimulgus europaeus” - European Nightjar Caprimulgus europaeus
line 322 – “Ericaceae” – Ericaceae (not italic)
line 350 – in the “Conclusions” (and “Discussion” section) may be included a short paragraph on the ecological structure of the studied ornithocoenosis in various aspects, ex. g. resident, migratory, seedeaters, insectivorous, raptors, tree-hole-nesters, etc.
Comments on the Quality of English Language
Minor editing of English language required
Author Response
Dear Reviewer,
Thank you for your valuable comments, that helped improve our manuscrypt.
Changes in the text are indicated in dark blue font
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear Authors!
Manuscript “The Importance of the Scots Pine for the Diversity of Forest Avifauna: The Augustów Forest as a Case Study” is a case study of the importance of pine forests for maintaining avifauna diversity, using the Augustów Forest in northeastern Poland as a case study. The results of 20 years of research into the bird fauna are presented.
The purpose of the work described in the manuscript is to indicate those bird species that can indeed be considered as closely associated with pine trees as breeding grounds within the Augustów Forest in Poland, one of the largest forest areas in the country; and to determine the nature of any dependent relationships between bird populations and pine forests. From a biodiversity conservation perspective, it was taken into account that bird species that are actually adapted to pine forests may soon face potential threats, given ongoing changes in climatic conditions, and therefore those that determine site type and habitat. The authors suggested that the most strongly dependent bird species are those associated with the mature phase of forest development.
The work detailed here was conducted between 2001 and 2023. The level of dependence of various bird species in the Augustow Forest on the presence of Scots pine was assessed based on the percentage of nests and/or broods on, within or among Scots pine trees.
The study included birds of prey, woodpeckers, owls, grouse, ravens and other selected non-passerine birds.
Only species for which representative data were available on at least 40% of the populations for the entire territory were taken into account.
Bird species with at least 50% of nests or broods located in Scots pine or pine-dominated forests were considered breeding associated. Those bird species in which at least 50% of broods or nests were located on pine trees or directly in pine forests were considered to be associated with nesting with Scots pine.
The relationship was assumed to be very strong (specialized species) with a share of nesting on pine of at least 90%, strong (partially specialized species) with a share of nests of at least 70%, and moderate with a share of 51–70% (species opportunistically associated with Scots pine).
In the case of ground-nesting forest grouse birds, association with pine forests was assessed by the composition of the stands of the forest (Tetrao urogallus) or nesting territory (Tetrastes bonasia), suggesting very strong specialization in stands with at least 80% Scots pine trees, strong specialization in stands with 60–80% Scots pine and less than 60% opportunistically associated with Scots pine trees.
For bird species with a body weight of at least 300 g (or more) nesting in trees, the assessment was carried out based on the results of surveys carried out over the entire forest area, and for species with a smaller mass - at fifty representative sample sites with an area of 20 hectares, covering 10 –20% of the area of the entire forest complex.
In the statistical analysis of the results, the authors used the Wilcoxon test to compare the proportion of Scots pine among nesting trees and the proportion of Scots pine in nesting stands. The Kruskal-Wallis test was used to compare differences in the proportion of Scots pine in stands between forest development phases, by nest height groups, and by nest size groups. Forest development phases were divided into: 1–20 years – young, 21–60 years – middle-aged, 61–100 years – mature stands, >100 years – old stands. The height of the nest located above the ground was divided into four classes. The nests were also divided into four groups based on their size.
For visualization and correctness of logical conclusions, the authors used Logistic regression models (with a dichotomous variable of nest on Scots pine (1) and not on Scots pine (0) were used to determine the importance/influence of tree age on the choice of Scots pine and tree as a nesting site for of all studied species - both birds that build large tree nests and birds that use hollows in Scots pine trees.
A separate logistic model was created to determine how the proportion of Scots pine in a stand affected the likelihood of pine being selected as a nest tree.
Analyzes and plots were performed by the authors using the R software environment and R-Studio software using the packages: dunn.test, sjplot, Pastecs, ggplot2, ggpubr.
The results obtained by the authors are logically divided into two main components: 1. Bird species associated with the Scots pine and 2. Preferences for the age and proportion in the stand of Scots pine trees.
In summary, the results of the studies cited in the manuscript showed that the total abundance of more than 20 bird species is highly dependent on pines forest and on the pine trees themselves for nesting. Pine forests are of particular importance for supporting the nesting of forest grouse birds (grouse and hazel grouse). Among this group, 11 bird species were confirmed to be strongly associated with pine trees, with at least 90% of their broods in pine stands and nests in pine trees. The most important bird species strongly associated with pine trees include the capercaillie, the white-tailed eagle, the black kite, the raven, the hobby, as well as the black woodpecker, as well as cavity dependent secondary cavity-nesters. For example, the indicator species is the Black Woodpecker Dryocopus martius, which selects Scots pine for hollowing out nesting cavities. Its cavities were regularly used by some secondary cavity-nesting species. Also of high importance were the nests of the raven Corvus corax, which were secondarily occupied by some species of birds of prey. The importance of pine for birds increased with the age of the trees. Old Scots pines were chosen by the birds, who built large nests, placed them in the treetops and hollowed out large hollows. Interestingly, a fairly large proportion of the studied bird species had weak selectivity in using Scots pine trees as nesting trees.
Populations of pine-specialized bird species may be threatened in the future by the possibility of Scots pine shifting its range northward as a result of global warming. The conservation of Scots pine with changes in reforestation methods should be included in Polish forestry strategies and plans as a critical factor in maintaining populations of rare breeding bird species in Poland.
In general, evaluating this manuscript, we can say that the work has been done a lot and deserves all kinds of praise. Currently, it is quite difficult to find studies in the field of animal field ecology over such a long periodicity. The authors coped with the tasks successfully, both in the field of field research and in desk work. The statistical methods used by the authors have already been well established in the analysis of works on field ecology of animals, so their use is logical and consistent. The results obtained are beyond doubt and reliable. At the same time, regarding the generally positive nature of the manuscript, I have a number of questions for the authors.
1. I would like the authors to provide a complete list of bird species observed in this study. This list is very important for a complete understanding of the bird diversity of a given forest area. This can be presented in an appendix to the manuscript.
2. Why did the authors limit the list of species studied? Passerines are an extremely important part of the bird diversity!
3. The almost complete lack of comparison of the bird population from this forest area with the bird population of pine forests from other neighboring regions of Poland and other countries of Lithuania and Belarus also raises a question. As far as I know, quite large-scale studies of the bird population were carried out in these countries, combined with different types of forests, including pine. For example, at least it was possible to compare with Białowieża Forest, Poland
4. It seems to me that the thesis about the movement of the Scots pine range to the north as a result of global warming is not entirely correct. Since this type of tree, on the contrary, is very resistant to droughts and extreme temperatures, for example, it forms forests in the far southeast of the European part of Russia (south of 48º N). In this regard, on the contrary, pine forests can be outposts, refugia, for the existence of many boreal and subboreal species much south of their main habitats!
5. The authors should also have pointed out that the nesting period is only a short period of existence and interaction of pine forests and the birds inhabiting them. Thus, the post-nesting period and especially the winter periods can show other interactions between birds and pine trees. For example, the great spotted woodpecker is more strictly associated with pines forest during these periods due to its almost exclusive feeding on pine cone seeds, and the capercaillie almost completely switches to feeding on pine needles! In addition, pine forests become the main habitats of many migratory or nomadic boreal species from the north (nutcrackers, tits, siskins, crossbills) in those regions where there are few or no other coniferous forests.
6. Please check the English text again. There are spelling and stylistic errors, please check the correct English names of terms and objects.
Comments on the Quality of English Language
Please check the English text again. There are spelling and stylistic errors, please check the correct English names of terms and objects.
Author Response
Dear Reviewer,
Thank you for you valuable changes that helped improve the manuscrypt.
The complete list of avifauna was added as appendix.
With a survey methodology based on direct breeding finds, we do not have sufficient data on passerines.
We published the results of counts of ensembles of birds, mainly passerines in 2018: Zawadzka, D., Drozdowski, S., Zawadzki, G., Zawadzki, J., Mikitiuk, A. Importance of the old forest tree stands for bird diversity in managed pine forests - a case study from Augustów Forest (NE Poland) J. Ecol. 2018, 66, 2, 162-181.
In general, we have not been able to find publications showing associations with pine birds from other areas.
We have added a few sentences in the discussion on the similarities of bird assemblages. The data on the avifauna of the Bia這wie瘸 Forest are completely incomparable, since it is a natural deciduous forest, the species indicated as specialized to pine in our study do not occur there.
We have taken into account the other suggestions.
Changes in the text are indicated in dark blue font.
Author Response File: Author Response.pdf
