Impact of Climate Change on Potential Distribution of Chinese White Pine Beetle Dendroctonus armandi in China
Round 1
Reviewer 1 Report
General
The authors use Maxent modelling to estimate the distribution of the native bark beetle Dendroctonus armandi in China under climate change. Although I am no expert on Maxent the modelling work appears to be state-of-the-art. Furthermore, the manuscript is generally well written and well structured. My main objections are that the study is quite limited in scope, as it only describes the potential distribution of D. armandi under current climatic conditions and two future temperature scenarios. Also, the estimated changes in the distribution area of the beetle are quite small and undramatic. Although this is not necessarily a criticism, the authors could perhaps broaden the scope of their work by also modelling how the potential distribution of the beetles’ host tree will be affected by climate change. In line 109-110 they state that they modelled the distribution of the host tree using Maxent, but you don’t present any results of this modelling. The right place to discuss how climate change may affect the range of the host tree seems to be line 328-29.
I don’t think the description of how the centroid of the bark beetle distribution will shift is very useful. Firstly, the centroid is a somewhat theoretical entity with doubtful biological significance. Secondly, the predicted changes are quite modest and the changes do not go in any consistent direction. Thus, I suggest to remove this part from the manuscript (lines 250-259, the figure on page 10 (which completely lacks a figure legend, by the way), and elsewhere).
The discussion is quite general and could probably be shortened. See for example the discussion in line 296 to 318.
Specific comments
Title: if not required by the journal I would omit the taxonomic details from the title. The title already says that the study organism is a beetle.
Line 14: “distribution in China” is correct here, I think.
Line 15: “were the two major”
Line 16-18: this detailed description of the geographical distribution in China is perhaps not needed in the abstract. Very few readers outside China will know where these areas are located.
Line 21: you should explain briefly what this scenario entails, for the benefit of readers who are less familiar with the particulars of climate scenarios.
Line 36: I suggest to remove the text “are induced to” – it is not needed.
Line 39: “females that break”
Line 42: “number of beetle generations”
Line 44: “have occurred every year”
Line 46-47: I suggest that you rewrite this sentence. Firstly, the phrase “which has been acknowledged internationally in recent years” is superfluous. Secondly, it is obvious that global warming has global effects, so this is not very informative. Try to say something more profound or delete the whole sentence.
Line 47-48: “Because insects are poikilotherms and have short generation times, their life history is closely…”.
Line 54: I would delete “on an ongoing basis” – this is not needed.
Line 55: “may respond to”
Line 72: “provide a reference point”
Line 77: “of D. armandi’s distribution”
Line 80: “in the field”
Line 82: “distance between sampling points”. But why did you go to the effort of sampling two nearby occurrence points if you only used one of them?
Line 83-84: “The host tree P. armandii has distinctly…” “we judged beetle”
Line 87: “The trap used in this study [put the information about the trap here] consisted…”
Line 88-89: You should rephrase this sentence, since you haven’t described the attractant before. “As an attractant in the traps we used…”.”with a release rate of”
Line 92-93: “1.5 m above ground.”
Line 94: You must explain what T. klimeschi is.
Line 97-98: I don’t think this sentence is necessary – please remove.
Line 98-99: Perhaps you could distinguish between literature-based and field-based occurrence records in the map, using different shapes or colors?
Line 101: “We gathered presence data for the host P. armandii using three methods.”
Line 102: You probably didn’t ‘collect’ pine trees in the field (not ‘filed’). Perhaps ‘registered’ is a better word here?
Line 109-110: Here you write that you modelled the distribution of the host tree using Maxent, but where do you present the results of this modelling?
Line 114: It would be useful if you also expressed this in kilometers. Also, “were downloaded”.
Line 135: “To avoid overfitting…”
Line 153: this should be ‘is’ or ‘was’, not ‘are’.
Line 164: “Sampling intensity often varies…”
Line 168-69: You should explain the purpose of generating pseudo-absence points in a little more detail. And what exactly is ‘pseudo-absence points’ – is it just you assuming that coordinates with no confirmed presence of the species represent absence points? If so, which criteria did you use when you generated pseudo-absence points?
Line 181: remove the word ‘many’.
Line 186: “When running the training and test dataset independently…”
Line 188: “was excellent”
Line 191-94: I would list these variables at the end of this sentence, to improve readability.
Line 200-01: “and habitat suitability, and the response of five variables…”. You write five variables, but Figure 2 only shows four variables (Bio1 is missing).
Line 203: temperature range should be given from lowest to highest temperature (2 to 11).
Line 205: “variables were considered”
Line 206: give species name instead of “this bark beetle”.
Line 226: “, with a total suitable area of 16.75…, followed by the RCP…”
Line 227: “The additional suitable area still falls within the Tsinling and Daba Mountains”
Line 228: “the area of highly suitable habitat increases over time.”
Line 239: “the area of highly suitable habitat is…”
Line 240: “and the area of poorly suitable habitat is expected…”
Line 264: “Bark beetles comprise a large subfamily of true weevils but only a small fraction of the more than…”
Line 267: it is unclear what you mean by “effective concealment” and I think you should explain this in plain words.
Line 272: “Our findings confirmed that …”
Line 275-76: “Under all the climate scenarios we studied…to increase somewhat in the near future”.
Line 290: “and precipitation were found to be the variables that…”
Line 293: I think “winter” is the correct word here.
Line 319: “that the distribution of D. armandi is not limited…”
Line 335-36: This sounds very much like something you could have fixed by doing more sampling. Perhaps you want to rephrase and emphasize the relatively low number of geo-references occurrence points in available databases?
Line 336-37: “Although the Maxent model has been shown to perform well with small…”
Line 338: “only 23 environmental variables”
Line 339-42: I found this sentence confusing – should it say “not considering the effects of biotic factors”? This needs to be explained better.
Line 347-48: “All of the factors mentioned above may cause differences between predicted…”
Line 350-51: I don’t understand this sentence – you did not study bark beetle-induced tree mortality.
Line 352: remove “the”
Line 370: remove “the”
Line 372: “Under the future…”
Line 374-76: You must explain better why the modest changes in beetle distribution that you model will pose major challenges for forest management.
Figures & Tables
Figure 1: This can be simplified by omitting the longitude and latitude marks around the four sides (or at least two of them). The text “Legend” and the “boundary” symbol are also unnecessary. You don’t need the small insert map in the lower right corner either (as far as I know these islands are not officially considered a part of China by the UN). Finally, the species name should be spelled out in the figure legend.
Figure 2: You should provide a unit for all x-axes. The meaning of ‘precipitation seasonality’ should be explained in the figure legend, which by the way is very incomplete. You must certainly explained what is meant by ‘logistic output’ on the y-axes.
Figure 3: This map, and all the similar-looking maps in Fig. 4, should be revised to improve clarity. The actual distribution area of D. armandi is very small. Since we don’t need to see the whole of China you should ‘zoom in’ on the map and only show the center of the map. The word ‘Current’ inside the map is not needed. The black box you refer to in the figure legend is not visible. See also my comments to Fig. 1 for more comments that are relevant to Fig. 3 and 4.
Figure 4: In addition to my comments above I suggest to insert headings above the two columns of figure panels: ‘2030s’ to the left and ‘2050s’ to the right. I would remove all longitudes/latitudes, as they just clutter the figure. In the figure legend you can remove all the text in the parenthesis (line 234-36) since this is already explained in the figure itself. However, you should add an explanation of what the different RCP scenarios mean, plus explain the time intervals that are behind the 2030s and 2050s. Line 234: “Future distribution of suitable habitat for Dendroctonus armandi in China.”
Figure 5: The legend could start by “Predicted areas of different habitat suitability classes for Dendroctonus armandi…”. The y-axis needs an explanatory label and a unit (move the text that is hanging above the right hand bars). The descriptive text in the x-axis is too small to be readable. RCP2.6 and so on needs to be explained briefly. The legend inside the figure panel is not comprehensible – you must spell out ‘Highly suitable’ and so on. The font size also needs to be increased. Finally, you must use the same color coding for habitat suitability as you used in Fig. 4.
Table 1: The table legend is very incomplete. You should provide more information about the study, to give the reader more context. Remember that tables and figures should be understandable on their own. You need to explain some abbreviations (USGS, CVH, probably also GBIF). Also, some of the environmental variables are not self-explanatory and need some more explanation (isothermality, temperature seasonality, precipitation seasonality).
Table 2: I suggest that you also include the abbreviations for the environmental variables, for ease of comparison with Table 1. Line 196-97: “for predicting the distribution of Dendroctonous armandi.” You should briefly explain what you mean by ‘probability of selection’, perhaps in the table legend.
Author Response
Dear Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Impact of climate change on potential distribution of Chinese white pine beetle Dendroctonus armandi in China” (ID: forests-1163975). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red and added portion are marked in blue in the manuscript.
The main corrections in the manuscript and the responds to the reviewer’s comments are as flowing:
General
The authors use Maxent modelling to estimate the distribution of the native bark beetle Dendroctonus armandi in China under climate change. Although I am no expert on Maxent the modelling work appears to be state-of-the-art. Furthermore, the manuscript is generally well written and well structured. My main objections are that the study is quite limited in scope, as it only describes the potential distribution of D. armandi under current climatic conditions and two future temperature scenarios. Also, the estimated changes in the distribution area of the beetle are quite small and undramatic. Although this is not necessarily a criticism, the authors could perhaps broaden the scope of their work by also modelling how the potential distribution of the beetles’ host tree will be affected by climate change. In line 109-110 they state that they modelled the distribution of the host tree using Maxent, but you don’t present any results of this modelling. The right place to discuss how climate change may affect the range of the host tree seems to be line 328-29.
Re: Thanks for your valuable comments. At the beginning of modeling, host distribution was used as a variable to predict the distribution of the beetle. Therefore, host distribution was taken as a constancy. Based on results of variable selection, host distribution has little weight as a predictor variable, we hypothesize that at the macro-scale level the potential distribution of this beetle is limited more by temperature and precipitation variables than by the host distribution. In addition, the beetle has high host selectivity and it only attack P. armandii more than 30 years. In other words, there are enough hosts to provide for the beetles. Therefore, as a predictor variable, host distribution is filtered out during the modeling process. In this study, the modeling of species is mainly explained from the macro-level. Based on the current results, the next work might be to explain in detail how beetles track their hosts locally. However, the host distribution is dynamic in the future. Therefore, our only respond to the possible results of host trees facing the future climate: forest trees may persist via migration, adapt to the new conditions, or go locally extinct. Some research results showed the host distribution in Tsinling Mountains and Daba Mountains, namely located in occurrence area of this beetle, is conservative and the change is relatively small (1. The distribution shifts of Pinus armandii and its response to temperature and precipitation in China. PeerJ 2017, 5, e3807.; 2. Prediction of the Suitable Area of the Chinese White Pines (Pinus subsect. Strobus) under Climate Changes and Implications for Their Conservation. Forests 2020, 11(9), 996). In addition, it is worth noting that the gaps between the actual dispersal of P. armandii in the real world and the predicted by the models cannot be ignored. As a large-seeded pine species, in particular, has a short dispersal distance that is, limited to the area around the parent trees, and mainly rely on animal-dispersed, which are all adverse factors affecting its dispersal. Previous studies have indicated that most of the P. armandii seeds were dispersed less than 20 m. In other words, the long-distance seed dispersal events are almost impossible to achieve based on the current dispersal distance, which would mean zero dispersal on the scale of our models. Coupled with geographical barriers, such as mountains and rivers, communications between species are almost blocked, making the short-distance dispersal dominate in a local geographic range. There is likely to exist the mechanism that can broaden the dispersal of P. armandii seeds in a local geographic scale, but it is not clear yet. However, other studies have found no evidence of significant long-distance migrations. Therefore, the research about the range expansions associated with seed dispersal needs to be further explored. As you mentioned, we need to model how the potential distribution of the beetles’ host tree will be affected by climate change in future work. In particular, the local range changes of this beetle and its host.
The distribution of the host tree using Maxent is presented in specific comments – “Here you write that you modelled the distribution of the host tree using Maxent, but where do you present the results of this modelling?’
I don’t think the description of how the centroid of the bark beetle distribution will shift is very useful. Firstly, the centroid is a somewhat theoretical entity with doubtful biological significance. Secondly, the predicted changes are quite modest and the changes do not go in any consistent direction. Thus, I suggest to remove this part from the manuscript (lines 250-259, the figure on page 10 (which completely lacks a figure legend, by the way), and elsewhere).
The discussion is quite general and could probably be shortened. See for example the discussion in line 296 to 318.
Re: We have deleted this part according to your comments. In addition, we have also streamlined the paragraphs you mentioned.
Specific comments
Title: if not required by the journal I would omit the taxonomic details from the title. The title already says that the study organism is a beetle.
Re: We have revised it in the text according to your comment.
Line 14: “distribution in China” is correct here, I think.
Re: We have revised it in the text according to your comment.
Line 15: “were the two major”
Re: We have revised it in the text according to your comment.
Line 16-18: this detailed description of the geographical distribution in China is perhaps not needed in the abstract. Very few readers outside China will know where these areas are located.
Re: We have revised it in the text according to your comment. “Currently, the suitable area of D. armandi falls within the Qinling and Daba Mountains.”
Line 21: you should explain briefly what this scenario entails, for the benefit of readers who are less familiar with the particulars of climate scenarios.
Re: We have revised it in the text according to your comment. “the distribution expanded the most under the maximum greenhouse gas emission scenario (representative concentration pathway (RCP) 8.5).”
Line 36: I suggest to remove the text “are induced to” – it is not needed.
Re: We have revised it in the text according to your comment.
Line 39: “females that break”
Re: We have revised it in the text according to your comment.
Line 42: “number of beetle generations”
Re: We have revised it in the text according to your comment.
Line 44: “have occurred every year”
Re: We have revised it in the text according to your comment.
Line 46-47: I suggest that you rewrite this sentence. Firstly, the phrase “which has been acknowledged internationally in recent years” is superfluous. Secondly, it is obvious that global warming has global effects, so this is not very informative. Try to say something more profound or delete the whole sentence.
Re: We have deleted it in the text according to your comment.
Line 47-48: “Because insects are poikilotherms and have short generation times, their life history is closely…”.
Re: We have revised it in the text according to your comment.
Line 54: I would delete “on an ongoing basis” – this is not needed.
Re: We have deleted it in the text according to your comment.
Line 55: “may respond to”
Re: We have revised it in the text according to your comments.
Line 72: “provide a reference point”
Re: We have revised it in the text according to your comments.
Line 77: “of D. armandi’s distribution”
Re: We have revised it in the text according to your comments.
Line 80: “in the field”
Re: We have revised it in the text according to your comments.
Line 82: “distance between sampling points”. But why did you go to the effort of sampling two nearby occurrence points if you only used one of them?
Re: There are many forestry workers involved in sampling. These workers are divided into many groups, and then separate sampling, and finally all the data collected together. Therefore, it is possible that some points are relatively close in distance due to different source data. Therefore, we save one of them according to the requirements when the above situation appears.
Line 83-84: “The host tree P. armandii has distinctly…” “we judged beetle”
Re: We have revised them in the text according to your comments.
Line 87: “The trap used in this study [put the information about the trap here] consisted…”
Re: We have revised it in the text according to your comments.
Line 88-89: You should rephrase this sentence, since you haven’t described the attractant before. “As an attractant in the traps we used…”.”with a release rate of”
Re: We have made revised according to your comments.
“As an attractant in the traps were used to attract D. armandi. The attractant was purchased from the Sino-Czech Trading Company, Beijing, China, which was packed in a 15-mL slow-release polyethylene vial with a release speed of 200 mg/day.”
Line 92-93: “1.5 m above ground.”
Re: We have revised it in the text according to your comments.
Line 94: You must explain what T. klimeschi is.
Re: This is a mistake in writing and I have revised it in the text.
Line 97-98: I don’t think this sentence is necessary – please remove.
Re: We have deleted it in the text according to your comments.
Line 98-99: Perhaps you could distinguish between literature-based and field-based occurrence records in the map, using different shapes or colors?
Re: Yes. But the data collected in this study basically are from field investigation. After the field survey, we found that the occurrence points of literature were included in the data collected in the field. Therefore, the occurrence data from the literature only play a reference role, there is no distinction in this study.
Line 101: “We gathered presence data for the host P. armandii using three methods.”
Re: We have revised it the text according to your comments.
Line 102: You probably didn’t ‘collect’ pine trees in the field (not ‘filed’). Perhaps ‘registered’ is a better word here?
Re: We have revised it in the text according to your comments.
Line 109-110: Here you write that you modelled the distribution of the host tree using Maxent, but where do you present the results of this modelling?
Re: The distribution of the host tree using Maxent is as follows:
Line 114: It would be useful if you also expressed this in kilometers. Also, “were downloaded”.
Re: We have revised them in the text according to your comments. “approximately 4.7km × 4.7 km”
Line 135: “To avoid overfitting…”
Re: We have revised it in the text according to your comments.
Line 153: this should be ‘is’ or ‘was’, not ‘are’.
Re: We have revised it in the text according to your comments.
Line 164: “Sampling intensity often varies…”
Re: We have revised it in the text according to your comments.
Line 168-69: You should explain the purpose of generating pseudo-absence points in a little more detail. And what exactly is ‘pseudo-absence points’ – is it just you assuming that coordinates with no confirmed presence of the species represent absence points? If so, which criteria did you use when you generated pseudo-absence points?
Re: Sampling bias is a common problem in species distribution modeling. Sampling locations are usually biased toward areas which are conveniently accessed. This may result in the observed species distribution not reflecting the real distribution. To counter the sampling bias, “pseudo-absence” with the same spatial bias as the presence points are recommended to introduced into the model. To this end, Arc-GIS v. 10.2 was used to generate 1000 background points with the same bias.
Line 181: remove the word ‘many’.
Re: We have revised it in the text according to your comments.
Line 186: “When running the training and test dataset independently…”
Re: We have revised it in the text according to your comments.
Line 188: “was excellent”
Re: We have revised it in the text according to your comments.
Line 191-94: I would list these variables at the end of this sentence, to improve readability.
Re: We have made revised according to your comments.
Line 200-01: “and habitat suitability, and the response of five variables…”. You write five variables, but Figure 2 only shows four variables (Bio1 is missing).
Re: Yes, there are five figures in the text, but maybe due to the problem of picture format, one of the pictures moves and coincides with the other, so you see four pictures. We've readjusted them in the text.
Line 203: temperature range should be given from lowest to highest temperature (2 to 11).
Re: Yes, the minimum temperature of coldest month (Bio6) ranges from -11 to 2 °C.
Line 205: “variables were considered”
Re: We have revised it in the text according to your comments.
Line 206: give species name instead of “this bark beetle”.
Re: We have revised it in the text according to your comments.
Line 226: “, with a total suitable area of 16.75…, followed by the RCP…”
Re: We have revised it in the text according to your comments.
Line 227: “The additional suitable area still falls within the Tsinling and Daba Mountains”
Re: We have revised it in the text according to your comments.
Line 228: “the area of highly suitable habitat increases over time.”
Re: We have revised it in the text according to your comments.
Line 239: “the area of highly suitable habitat is…”
Re: We have revised it in the text according to your comments.
Line 240: “and the area of poorly suitable habitat is expected…”
Re: We have revised it in the text according to your comments.
Line 264: “Bark beetles comprise a large subfamily of true weevils but only a small fraction of the more than…”
Re: We have revised it in the text according to your comments.
Line 267: it is unclear what you mean by “effective concealment” and I think you should explain this in plain words.
Re: We have revised it in the text according to your comments. “However, due to it hides under the bark, measures to prevent and control outbreaks have not been fully effective.”
Line 272: “Our findings confirmed that …”
Re: We have revised it in the text according to your comments.
Line 275-76: “Under all the climate scenarios we studied…to increase somewhat in the near future”.
Re: We have revised it in the text according to your comments.
Line 290: “and precipitation were found to be the variables that…”
Re: We have revised it in the text according to your comments.
Line 293: I think “winter” is the correct word here.
Re: We have revised it in the text according to your comments. “During overwintering stage,…”
Line 319: “that the distribution of D. armandi is not limited…”
Re: We have revised it in the text according to your comments.
Line 335-36: This sounds very much like something you could have fixed by doing more sampling. Perhaps you want to rephrase and emphasize the relatively low number of geo-references occurrence points in available databases?
Re: We have revised it in the text according to your comments.
Line 336-37: “Although the Maxent model has been shown to perform well with small…”
Re: We have revised it in the text according to your comments.
Line 338: “only 23 environmental variables”
Re: We have revised it in the text according to your comments.
Line 339-42: I found this sentence confusing – should it say “not considering the effects of biotic factors”? This needs to be explained better.
Re: We have revised it in the text according to your comments.
Line 347-48: “All of the factors mentioned above may cause differences between predicted…”
Re: We have revised it in the text according to your comments.
Line 350-51: I don’t understand this sentence – you did not study bark beetle-induced tree mortality.
Re: We have revised it in the text according to your comments.
Line 352: remove “the”
Re: We have deleted it in the text according to your comments.
Line 370: remove “the”
Re: We have deleted it in the text according to your comments.
Line 372: “Under the future…”
Re: We have revised it in the text according to your comments.
Line 374-76: You must explain better why the modest changes in beetle distribution that you model will pose major challenges for forest management.
Re: We have revised it according to your comments. “The increase of high suitable area will form more population spread center, and more and more P. armandii stands need to be monitored and protected, which will pose a major challenge for forest managers.”
Figures & Tables
Figure 1: This can be simplified by omitting the longitude and latitude marks around the four sides (or at least two of them). The text “Legend” and the “boundary” symbol are also unnecessary. You don’t need the small insert map in the lower right corner either (as far as I know these islands are not officially considered a part of China by the UN). Finally, the species name should be spelled out in the figure legend.
Re: We have revised them in the text according to your comments. As for the small insert map in the lower right corner, we referred to the publishing standards of China.
Figure 2: You should provide a unit for all x-axes. The meaning of ‘precipitation seasonality’ should be explained in the figure legend, which by the way is very incomplete. You must certainly explained what is meant by ‘logistic output’ on the y-axes.
Re: We have revised them in the text according to your comments.
(Bio1: Annual mean temperature (°C); Bio6: Minimum temperature of coldest month (°C); Bio9: Mean temperature of driest quarter (°C); Bio15: Precipitation seasonality (Coefficient of variation) (%); Bio17: Precipitation of driest quarter (mm))
Figure 3: This map, and all the similar-looking maps in Fig. 4, should be revised to improve clarity. The actual distribution area of D. armandi is very small. Since we don’t need to see the whole of China you should ‘zoom in’ on the map and only show the center of the map. The word ‘Current’ inside the map is not needed. The black box you refer to in the figure legend is not visible. See also my comments to Fig. 1 for more comments that are relevant to Fig. 3 and 4.
Re: We have revised this figure in the text according to your comments. In addition, the resolution of all pictures has been improved. The original purpose of this study is to highlight the geographical distribution of Dendroctonus armandi in China, that is, the whole macro-level, so that readers can quickly and clearly understand the uniqueness of the beetle. Zooming in the occurrence area of D. armandi, we may need to elaborate most of the geographical features of this area, which is strange and boring for some readers who do not know China.
Figure 4: In addition to my comments above I suggest to insert headings above the two columns of figure panels: ‘2030s’ to the left and ‘2050s’ to the right. I would remove all longitudes/latitudes, as they just clutter the figure. In the figure legend you can remove all the text in the parenthesis (line 234-36) since this is already explained in the figure itself. However, you should add an explanation of what the different RCP scenarios mean, plus explain the time intervals that are behind the 2030s and 2050s. Line 234: “Future distribution of suitable habitat for Dendroctonus armandi in China.”
Re: We have made revised them in the text according to your comments.
“Figure 4. Future distribution of suitable habitat for D. armandi in China. The 2030s represents 2021-2040, and 2050s represents 2041-2060. (RCP2.6: the minimum greenhouse gas emission scenario; RCP4.5: the medium greenhouse gas emission scenario; RCP8.5: the maximum greenhouse gas emission scenario)”
Figure 5: The legend could start by “Predicted areas of different habitat suitability classes for Dendroctonus armandi…”. The y-axis needs an explanatory label and a unit (move the text that is hanging above the right hand bars). The descriptive text in the x-axis is too small to be readable. RCP2.6 and so on needs to be explained briefly. The legend inside the figure panel is not comprehensible – you must spell out ‘Highly suitable’ and so on. The font size also needs to be increased. Finally, you must use the same color coding for habitat suitability as you used in Fig. 4.
Re: We have revised them in the text according to your comments.
Table 1: The table legend is very incomplete. You should provide more information about the study, to give the reader more context. Remember that tables and figures should be understandable on their own. You need to explain some abbreviations (USGS, CVH, probably also GBIF). Also, some of the environmental variables are not self-explanatory and need some more explanation (isothermality, temperature seasonality, precipitation seasonality).
Re: We have revised it in the text according to your comments.
Table 1. Description of environmental variables used for modeling the habitat suitability distribution of D. aramndi in this study.
Mean diurnal range= Mean of monthly (max temp-min temp); Isothermality= Bio2/Bio7; temperature seasonality= Standard deviation* 100; precipitation seasonality=Coefficient of variation.
Note: USGS - United States Geological Survey; CVH - Chinese Virtual Herbarium; GBIF - Global Biodiversity Information Facility
Table 2: I suggest that you also include the abbreviations for the environmental variables, for ease of comparison with Table 1. Line 196-97: “for predicting the distribution of Dendroctonous armandi.” You should briefly explain what you mean by ‘probability of selection’, perhaps in the table legend.
Re: We have added the abbreviations for the environmental variables according to your comments. Note: An estimate of the probability of selection for each variable is based on the result of the cross-validation analysis.
Thanks for your valuable comments.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear authors
I read your article with interest. I am curious: does Dendroctonus armandi cause mortality only among Pinus armandii pines or does it have more hosts? What is the extent of the phenomenon?
Are there other species that form upland forests (which ones)? Are they natural, biodiverse forests or were they planted as monocultures, like spruce stands in Europe? see: Nowakowska, J. A., Hsiang, T., Patynek, P., Stereńczak, K., Olejarski, I., & Oszako, T. (2020). Health assessment and genetic structure of monumental Norway spruce trees during a bark beetle (Ips typographus L.) outbreak in the Białowieża Forest District, Poland. Forests, 11(6), 647.
Does mass development of insects threaten stands locally? Or is it more a matter of removing weakened trees (or groups of trees)? In the rich lowland forests of the Białowieża Forest, an outbreak of the bark beetle Ips typographus occurred in 2012 (which continues today) due to the abandonment of active forest protection in favour of a passive one (observation of natural processes). As a result, the proportion of spruce, which was around 33%, has dropped drastically to a few percent. Can similar changes be observed in China? In Europe, climate change, especially severe droughts (e.g. 2015) and the resulting weakening of trees are blamed for bark beetle outbreaks.
In the Białowieża Forest, high agreement was demonstrated between health assessment from the ground and assessment during aerial surveys. Was it similar in China when it came to insect population (actual occurrence) and prediction using models?
Can rapid detection, removal, and disposal of bark beetle-infested trees in forests prevent outbreaks from developing? What influence can environmental resistance, woodpecker populations, bacterial and viral insect diseases have on the model?
The above paper can be cited here L47 “Insects, which are poikilotherms, have short generation times; their life history is closely related to temperature.” or in the given examples in discussion (L304-3100 or to support L342 “Globally, there are at least 30 bark beetle species 342 that can cause landscape-scale plant mortality.”
I could not find the figures, they should be in the text near the place where they are discussed!
L161 – add “dot” after [31-32]
Author Response
Dear Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Impact of climate change on potential distribution of Chinese white pine beetle Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae) in China” (ID: forests-1163975). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red and added portion are marked in blue in the manuscript.
The main corrections in the manuscript and the responds to the reviewer’s comments are as flowing:
Comments
I read your article with interest. I am curious: does Dendroctonus armandi cause mortality only among Pinus armandii pines or does it have more hosts? What is the extent of the phenomenon?
Re: Dendroctonus armandi cause mortality only among healthy Pinus armandii pines and have the capacity to cause landscape-scale tree mortality. Among the hundreds of bark beetle species,
this bark beetle is special. Specially, this bark beetle only attacks healthy Pinus armandii more than 30 years and reproduce in live trees. During the outbreak period, a large number of host trees were killed by this beetle, and the Chinese government would invest a lot of money to manage them every year.
Are there other species that form upland forests (which ones)? Are they natural, biodiverse forests or were they planted as monocultures, like spruce stands in Europe? see: Nowakowska, J. A., Hsiang, T., Patynek, P., Stereńczak, K., Olejarski, I., & Oszako, T. (2020). Health assessment and genetic structure of monumental Norway spruce trees during a bark beetle (Ips typographus L.) outbreak in the Białowieża Forest District, Poland. Forests, 11(6), 647.
Re: I have referenced the article. As the only host trees of Dendroctonus armandi, all Pinus armandii populations originally belong to stable primary forests. Under normal conditions, pure forests of Pinus armandii are the most common and most of the populations formed a small patch pattern geographically. However, after P. armandii populations become seriously decimated, deciduous competitors in these forests increase significantly and form deciduous forests. The P. armandii and Quercus aliena var. acuteserrata mixed forest is one of the common forest types in the Tsinling Mountains. Specifically, P. armandii is considered to be a pioneer species, which can establish relatively stable populations during the stage of succession. Then, the Q. aliena var. acuteserrata was gradually dispersed by animal-mediated into P. armandii forests. Successionally, the mixed forest gradually formed after the Q. aliena var. acuteserrata consolidate its dominant status against P. armandii.
However, the specific impact, such as Health assessment and genetic structure, of Dendroctonus armandi outbreak on the host trees needs to be put on the agenda in the future.
Does mass development of insects threaten stands locally? Or is it more a matter of removing weakened trees (or groups of trees)? In the rich lowland forests of the Białowieża Forest, an outbreak of the bark beetle Ips typographus occurred in 2012 (which continues today) due to the abandonment of active forest protection in favour of a passive one (observation of natural processes). As a result, the proportion of spruce, which was around 33%, has dropped drastically to a few percent. Can similar changes be observed in China? In Europe, climate change, especially severe droughts (e.g. 2015) and the resulting weakening of trees are blamed for bark beetle outbreaks.
Re: Yes, the mass development this bark beetle posed a serious threat to the local stands. We used chemical control, biological control, attractant trapping and the removal of weakened trees to control of the pest. The results show that the removal of weakened trees is the most direct and effective, and can basically control the beetle. However, limited by the geographical conditions of the occurrence area, it is obviously not suitable for this measure to be implemented in large geographical range, but it is very effective in local geographical range. Different from other bark beetles, D. armandi has high host selectivity and it only attack P. armandii more than 30 years. Therefore, it seems that there is a close ecological relationship between the beetle and host in the long-term environment, including beneficial and harmful. Under natural conditions, field observation found that the host tree ratio decreased significant in areas with high altitude, but not significant at low altitude. At landscape level, the ratio of P. armandii has declined, but it only counts the number of adults, but the seedlings and young forest are not included. The beetle has been uninterruptedly population erupting for more than ten years, and it has been observed in filed that the beetle is serious in dry years. On the contrary, it is a little lower in rainy years. However, in the second year after the rainy year, the outbreak of this beetle is often very serious. At present, we have carried out research on this phenomenon.
In the Białowieża Forest, high agreement was demonstrated between health assessment from the ground and assessment during aerial surveys. Was it similar in China when it came to insect population (actual occurrence) and prediction using models?
Re: This research is carried out by the field survey, so it reflects the actual incidence to a certain extent. Due to the influence of basic conditions, aerial surveys were not carried out. However, compared with the predicted results of the model, these findings are highly similar to the actual results. Of course, some factors, such as human factors, may be ignored, which also makes the predicted results have some errors with the actual. In the discussion of the model performance, we also made a response.
Can rapid detection, removal, and disposal of bark beetle-infested trees in forests prevent outbreaks from developing? What influence can environmental resistance, woodpecker populations, bacterial and viral insect diseases have on the model?
Re: As you mentioned in the third question above, the rapid detection, removal, and disposal of bark beetle-infested trees in forests are the most direct and effective. For other measures, such as the introduction of predatory natural enemies, it not only has a very low survival rate, but also has no effect at all; attractant trapping not only did not reduce the local population density, but instead caused local damage. There are still many problems to be solved. As with the fourth question, the biological and abiotic factors you mentioned may affect the prediction of the model. Therefore, we need to consider more factors in future work. In the performance discussion part of the model in this study, we also add the discussion of this part.
The above paper can be cited here L47 “Insects, which are poikilotherms, have short generation times; their life history is closely related to temperature.” or in the given examples in discussion (L304-3100 or to support L342 “Globally, there are at least 30 bark beetle species 342 that can cause landscape-scale plant mortality.”
I could not find the figures, they should be in the text near the place where they are discussed!
L161 – add “dot” after [31-32]
Re: We have added the reference according to your comments. In addition, we also check and correct the same question throughout the manuscript.
Thanks for your valuable comments.
Author Response File: Author Response.docx
Reviewer 3 Report
The reviewed manuscript is a very good addition to the tools needed to local manage the Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae) populations. The work is not long and this is its advantage. The introduction is written clearly, and its content corresponds well with the proposed goals of the research. The study presents well-defined research goals, although there are no hypotheses here. Here, 60 papers are cited and there is no problem with self-citations. The cited literature is correct and new. Methodically, the work is based on the widely used research protocol in the field of SDM. The methodological procedure is described here very precisely which is an advantage. The number of repetitions used for modeling is not large, but the authors have explained this limitation of their research in an accessible way. The figures shown are of very good quality, although I believe Figure 2 is not necessary.In general, the results show that the scenarios used in the model on a larger scale do not indicate that the range of this species will change dramatically. The most significant factors among the factors examined were the minimum temperature of coldest month and precipitation seasonality.
The editorial side of the work is good. I cannot judge the language side, although it seems very good to me.
The authors did not avoid editorial mistakes and should refer to a few minor issues:
L34: What do you mean "pionier species" here?
L94: T. klimeschi??
L205-207 This sentence does not match the results and is a far-reaching simplification.
L223 Does the range of pine also change during modeling with different scenarios or was the ceach considered a constancy? It needs to be cleared.
L238 Italic
L263 There is no description of the figure 6.
Also: Why does the centroid move in such a strange way? First north and then south? This aspect is not discussed at all.
L268-271 It is a far-reaching simplification.
L335-348 Move it to the end of the disscussion.
Author Response
Dear Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Impact of climate change on potential distribution of Chinese white pine beetle Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae) in China” (ID: forests-1163975). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red and added portion are marked in blue in the manuscript.
The main corrections in the manuscript and the responds to the reviewer’s comments are as flowing:
Comments and Suggestions for Authors
The reviewed manuscript is a very good addition to the tools needed to local manage the Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae) populations. The work is not long and this is its advantage. The introduction is written clearly, and its content corresponds well with the proposed goals of the research. The study presents well-defined research goals, although there are no hypotheses here. Here, 60 papers are cited and there is no problem with self-citations. The cited literature is correct and new. Methodically, the work is based on the widely used research protocol in the field of SDM. The methodological procedure is described here very precisely which is an advantage. The number of repetitions used for modeling is not large, but the authors have explained this limitation of their research in an accessible way. The figures shown are of very good quality, although I believe Figure 2 is not necessary. In general, the results show that the scenarios used in the model on a larger scale do not indicate that the range of this species will change dramatically. The most significant factors among the factors examined were the minimum temperature of coldest month and precipitation seasonality.
The editorial side of the work is good. I cannot judge the language side, although it seems very good to me.
Re: Thanks for your valuable comments.
The authors did not avoid editorial mistakes and should refer to a few minor issues:
L34: What do you mean "pionier species" here?
Re: Here, "pionier species" referred to that Dendroctonus armandi is the first species to colonize host trees. Then, D. armandi attracts beetles of the same or different species to invade the host tree, so as to survive together on the host tree and establish an ecosystem of bark beetles and host trees.
L94: T. klimeschi??
Re: This is a mistake in writing and I have revised it in the text.
L205-207 This sentence does not match the results and is a far-reaching simplification.
Re: We have deleted it in the text according to your comments.
L223 Does the range of pine also change during modeling with different scenarios or was the each considered a constancy? It needs to be cleared.
Re: Yes. At the beginning of modeling, host distribution was used as a variable to predict the distribution of the beetle. Therefore, host distribution was taken as a constancy. Based on results of variable selection, host distribution has little weight as a predictor variable, we hypothesize that at the macro-scale level the potential distribution of this beetle is limited more by temperature and precipitation variables than by the host distribution. In addition, the beetle has high host selectivity and it only attack Pinus armandii more than 30 years. In other words, there are enough hosts to provide for the beetles. Perhaps it is important to explain in detail how beetles track their hosts locally. Therefore, the host distribution is set to constancy based on the macro-level in this study. However, the host distribution is dynamic in the future. Some research results showed the host distribution in Tsinling Mountains and Daba Mountains, namely located in occurrence area of this beetle, is conservative and the change is relatively small (1. The distribution shifts of Pinus armandii and its response to temperature and precipitation in China. PeerJ 2017, 5, e3807.; 2. Prediction of the Suitable Area of the Chinese White Pines (Pinus subsect. Strobus) under Climate Changes and Implications for Their Conservation. Forests 2020, 11(9), 996).
We have explained it in the methodological procedure and responded in the fourth paragraph of the discussion.
L238 Italic
Re: We have revised it in the text according to your comments.
L263 There is no description of the figure 6.
Also: Why does the centroid move in such a strange way? First north and then south? This aspect is not discussed at all.
Re: We have adjusted them in the text according to your comments. After careful consideration,
we think the centroid move may not reflect real changes. Firstly, the centroid is a somewhat theoretical entity with doubtful biological significance. Secondly, the predicted changes are quite modest and the changes do not go in any consistent direction. In addition, the centroid move in such a strange way may confuse many readers without actual support. Thus, we suggest to remove this part from the manuscript.
L268-271 It is a far-reaching simplification.
Re: We have revised this sentence in the text according to your comments. “Our findings confirmed that D. armandi was restricted to the Qinling Mountains and Daba Mountains, despite there being large numbers of hosts in northern and southwestern China.”
L335-348 Move it to the end of the discussion.
Re: We have moved it to the end of the discussion according to your comments.
Thanks for your valuable comments.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Impact of climate change on potential distribution of Chinese white pine beetle…
By Ning, Tang, Chen
Maxent modelling of host tree distribution: I appreciate the clarification of this topic in your response letter. It would be useful if you incorporated some of these clarifications into the manuscript, e.g. the explanation of how host distribution carried little weight as a predictor variable for the modelling of beetle distribution. You could also include a discussion/some speculation about how climate change is expected to affect the host tree distribution, based on the papers you cite in your response letter.
Line 45: missing word (“Because insects are poik…”)
Line 74: “distribution of D. armandi…”
Line 81-82: I suggest rephrasing this: “…from the bark, as P. armandii responds to attack by D. armandi by releasing large amounts of distinctly fluid resin.”
Line 82-3: “…we used pheromone-baited traps to detect…” or “we used traps baited with xxx to detect…”.
Line 83-5: “The traps consisted of six identical black plastic funnels aligned vertically over a cup (model YBQ-LD-004, Geruibiyuan Technology Co., Ltd., Beijing, China),”
Line 86-89: You need to explain clearly what kind of attractant you used. Was it e.g. a pheromone or host kairomones? “As an attractant we used <describe bait here> (Sino-Czech Trading Company, Beijing, China) packed in a 15-mL slow-release polyethylene vial with a release rate of 200 mg day-1”.”
Figure 1: I think you should spell out the genus names in the figure caption to make it more stand-alone. Regarding the use of national maps versus internationally accepted maps I think the journal should set its own rules and guidelines.
Line 109-111: I don’t quite understand this sentence and think it needs some revision.
Table 1: spell out ‘Dendroctonus’ in the table caption. ‘Mean diurnal range’ – there seems to be a surplus parenthesis in the explanation text.
Line 138-41: I suggest that you improve the readability of this sentence by changing it to an active voice, to avoid having the verb at the very end: “To avoid overfitting of the models due to multicollinearity within environment variables, we selected variables…”
Line 167-68: “Sampling intensity often varies between sites and sampling sites are usually biased toward areas which are more accessible.”
Line 173-76: “To reduce sampling bias, it is recommended to introduce “pseudo-absence points” with the same spatial bias as the presence points into the model… with the same bias [34].”. You should explain how you identified/quantified the sampling bias in your dataset – it is not obvious to me how you were able to mirror this bias in your pseudo-absence points.
Line 198-95: this is how I suggested to revise the text: “Based on the regression coefficients and percentage contributions of the environmental variables used in the model, we selected the following five variables as the most important ones determining the habitat suitability of D. armandi: minimum temperature of coldest month (Bio6, 1.4832; 29.9%), precipitation seasonality (Bio15, -0.8965; 19.3%), mean temperature of driest quarter (Bio9, 0.7865; 16.8%), annual mean temperature (Bio1, -0.4614; 11.4%), precipitation of driest quarter (Bio17, -0.2488; 9.8%) (Table 2).”
Line 197: I would spell out genera names in all figure and table captions.
Line 198: you should use e.g. an asterisk (*) in the heading to the probability column to refer to the table footnote. The footnote itself could say “* The probability of selection for each variable was based on the result of a cross-validation analysis.”. You need to explain the ‘cross-validation analysis very briefly in the footnote itself – not refer to it as if it is already known to the reader.
Figure 2: I think the figure caption still needs to provide a little more context. I suggest replacing the first sentence in the figure caption with the following sentence: “Quantitative relationship between environmental variables and habitat suitability to Dendroctonus armandi.”
Figure 3 and Figure 4: I maintain my strong recommendation to zoom in on these maps. Now they include a lot of unsuitable habitat for D. armandi, whereas the actual current and potential future available habitat are presented in very low resolution. This makes absolutely no sense to me as a reader. If you want to show the location of D. armandi’s distribution relative to the whole country, you could do that by adding a small inset map showing China with a small black box representing the zoomed-in distribution maps.
Line 257-58: “However, because the beetle spends most of its life cycle protected under the bark, measures to…”
Line 262: I think “D. armandi is restricted to…” is correct here.
Line 286: “During the autumn and winter, the larvae…”
Line 297-98: “Maintaining an appropriate seasonality is critical for bark beetle population growth and outbreak potential”.
Line 299: “…even leading to widespread mortality”.
Line 301-03: “D. armandi will persist…”, but I am not that I understand the argument you are making here.
Line 320-21: “Firstly, there was a relatively low number of geo-references occurrence points of D. armandi in available databases.”. But maybe you could highlight that you also collected many additional occurrence points.
Line 324: it is unclear if the sentence starting with “The model is based on…” is part of the second limitation or if it is a separate third limitation.
Line 327: “which is clearly a…”
Line 335-36: it is still not clear to me if you are referring to a general pattern observed in bark beetles here, or if this is supposed to be about your study system. If it is a general observation you need to substantiate this by adding some references. “Usually, tree mortality induced by bark beetles are correlated with climatic conditions during or before the mortality event (References needed).”
Line 353-66: this whole paragraph is a copy of the one two paragraphs up.
Line 374-76: “The increase in highly suitable habitat will increase the number of potential centers for build-up of D. armandi populations, meaning that more and more host trees need to be monitored and protected. This will pose a major challenge for forest managers.”
Author Response
Dear Reviewer:
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Impact of climate change on potential distribution of Chinese white pine beetle Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae) in China” (ID: forests-1163975). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red and added portion are marked in blue in the manuscript.
The main corrections in the manuscript and the responds to the reviewer’s comments are as flowing:
Comments and Suggestions for Authors
Impact of climate change on potential distribution of Chinese white pine beetle…
By Ning, Tang, Chen
Maxent modelling of host tree distribution: I appreciate the clarification of this topic in your response letter. It would be useful if you incorporated some of these clarifications into the manuscript, e.g. the explanation of how host distribution carried little weight as a predictor variable for the modelling of beetle distribution. You could also include a discussion/some speculation about how climate change is expected to affect the host tree distribution, based on the papers you cite in your response letter.
Re: We have added the explanation and discussion in the text according to your comments.
Line 45: missing word (“Because insects are poik…”)
Re: We have added it in the text according to your comments.
Line 74: “distribution of D. armandi…”
Re: We have revised it in the text according to your comments.
Line 81-82: I suggest rephrasing this: “…from the bark, as P. armandii responds to attack by D. armandi by releasing large amounts of distinctly fluid resin.”
Re: We have revised the sentence in the text according to your comments.
Line 82-3: “…we used pheromone-baited traps to detect…” or “we used traps baited with xxx to detect…”.
Re: We have revised the sentence in the text according to your comments.
Line 83-5: “The traps consisted of six identical black plastic funnels aligned vertically over a cup (model YBQ-LD-004, Geruibiyuan Technology Co., Ltd., Beijing, China),”
Re: We have revised the sentence in the text according to your comments.
Line 86-89: You need to explain clearly what kind of attractant you used. Was it e.g. a pheromone or host kairomones? “As an attractant we used <describe bait here> (Sino-Czech Trading Company, Beijing, China) packed in a 15-mL slow-release polyethylene vial with a release rate of 200 mg day-1”.”
Re: We have revised the sentence in the text according to your comments.
“As an attractant we used < bait: mixture of terpenes and pheromones> (Sino-Czech Trading Company, Beijing, China) packed in a 15-mL slow-release polyethylene vial with a release rate of 200 mg day-1.”
Figure 1: I think you should spell out the genus names in the figure caption to make it more stand-alone. Regarding the use of national maps versus internationally accepted maps I think the journal should set its own rules and guidelines.
Re: We have revised it in the figure caption according to your comments. Meanwhile, all other figures and tables with the same problem have also been revised.
Line 109-111: I don’t quite understand this sentence and think it needs some revision.
Re: We've r readjusted this sentence and added it to the discussion of host distribution.
Table 1: spell out ‘Dendroctonus’ in the table caption. ‘Mean diurnal range’ – there seems to be a surplus parenthesis in the explanation text.
Re: We have revised it in the text according to your comments.
Line 138-41: I suggest that you improve the readability of this sentence by changing it to an active voice, to avoid having the verb at the very end: “To avoid overfitting of the models due to multicollinearity within environment variables, we selected variables…”
Re: We have revised the sentence in the text according to your comments.
Line 167-68: “Sampling intensity often varies between sites and sampling sites are usually biased toward areas which are more accessible.”
Re: We have revised the sentence in the text according to your comments.
Line 173-76: “To reduce sampling bias, it is recommended to introduce “pseudo-absence points” with the same spatial bias as the presence points into the model… with the same bias [34].”. You should explain how you identified/quantified the sampling bias in your dataset – it is not obvious to me how you were able to mirror this bias in your pseudo-absence points.
Re: We have added this part content in the text according to your comments.
“As a result, there are a total of 1132 occurrence points with the same bias in this study. Next, we selected points for model calibration using a subsampling regime to reduce sampling bias and spatial autocorrelation. We generated models using all occurrence points and measured spatial autocorrelation among model pseudo-residuals (1 – probability of occurrence generated by model) by calculating Moran's / at multiple distance classes. Significance was determined using permutation tests. A minimum distance of 275 km was detected, so we selected the occurrence point that close to the centroid of each grid cell. This procedure reduced the number of occurrences to 138 points used for model calibration. The procedure greatly reduced sampling bias and spatial autocorrelation, resulting in evenly distributed occurrence points across space.”
Line 198-95: this is how I suggested to revise the text: “Based on the regression coefficients and percentage contributions of the environmental variables used in the model, we selected the following five variables as the most important ones determining the habitat suitability of D. armandi: minimum temperature of coldest month (Bio6, 1.4832; 29.9%), precipitation seasonality (Bio15, -0.8965; 19.3%), mean temperature of driest quarter (Bio9, 0.7865; 16.8%), annual mean temperature (Bio1, -0.4614; 11.4%), precipitation of driest quarter (Bio17, -0.2488; 9.8%) (Table 2).”
Re: We have revised the text according to your comments.
Line 197: I would spell out genera names in all figure and table captions.
Re: We have revised them in all figure and table captions.
Line 198: you should use e.g. an asterisk (*) in the heading to the probability column to refer to the table footnote. The footnote itself could say “* The probability of selection for each variable was based on the result of a cross-validation analysis.”. You need to explain the ‘cross-validation analysis very briefly in the footnote itself – not refer to it as if it is already known to the reader.
Re: We have revised it in the text according to your comments.
Figure 2: I think the figure caption still needs to provide a little more context. I suggest replacing the first sentence in the figure caption with the following sentence: “Quantitative relationship between environmental variables and habitat suitability to Dendroctonus armandi.”
Re: We have revised it in the text according to your comments.
Figure 3 and Figure 4: I maintain my strong recommendation to zoom in on these maps. Now they include a lot of unsuitable habitat for D. armandi, whereas the actual current and potential future available habitat are presented in very low resolution. This makes absolutely no sense to me as a reader. If you want to show the location of D. armandi’s distribution relative to the whole country, you could do that by adding a small inset map showing China with a small black box representing the zoomed-in distribution maps.
Re: We have revised them in the text according to your comments.
Line 257-58: “However, because the beetle spends most of its life cycle protected under the bark, measures to…”
Re: We have revised the sentence in the text according to your comments.
Line 262: I think “D. armandi is restricted to…” is correct here.
Re: We have revised the sentence in the text according to your comments.
Line 286: “During the autumn and winter, the larvae…”
Re: We have revised the sentence in the text according to your comments.
Line 297-98: “Maintaining an appropriate seasonality is critical for bark beetle population growth and outbreak potential”.
Re: We have revised the sentence in the text according to your comments.
Line 299: “…even leading to widespread mortality”.
Re: We have revised the sentence in the text according to your comments.
Line 301-03: “D. armandi will persist…”, but I am not that I understand the argument you are making here.
Re: We recommend deleting this sentence.
Line 320-21: “Firstly, there was a relatively low number of geo-references occurrence points of D. armandi in available databases.”. But maybe you could highlight that you also collected many additional occurrence points.
Re: We have revised the sentence in the text according to your comments.
“Moreover, the occurrence points collected through the field are relatively limited.”
Line 324: it is unclear if the sentence starting with “The model is based on…” is part of the second limitation or if it is a separate third limitation.
Re: We have revised the sentence in the text according to your comments.
“…, which were not considered the effects of biotic factors, …”.
Line 327: “which is clearly a…”
Re: We have revised the sentence in the text according to your comments.
Line 335-36: it is still not clear to me if you are referring to a general pattern observed in bark beetles here, or if this is supposed to be about your study system. If it is a general observation you need to substantiate this by adding some references. “Usually, tree mortality induced by bark beetles are correlated with climatic conditions during or before the mortality event (References needed).”
Re: This a general pattern observed in bark beetles here and we have added the reference to substantiate it.
Line 353-66: this whole paragraph is a copy of the one two paragraphs up.
Re: Sorry, we have deleted whole paragraph.
Line 374-76: “The increase in highly suitable habitat will increase the number of potential centers for build-up of D. armandi populations, meaning that more and more host trees need to be monitored and protected. This will pose a major challenge for forest managers.”
Re: We have revised the sentence in the text according to your comme
Author Response File: Author Response.docx
Reviewer 2 Report
Dear authors
Thank you for your detailed responses and for completing the manuscript. I have no further comments and congratulate you on your interesting research
Author Response
Dear Reviewer:
Thank you for your letter again and for the comments concerning our manuscript entitled ““Impact of climate change on potential distribution of Chinese white pine beetle Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae) in China” (ID: forests-1163975).
Author Response File: Author Response.docx
