Phenology of Oenocarpus mapora H. Karst in Low-Terrace and High-Terrace Forests of the Madre de Dios Region, Peru

Round 1

Reviewer 1 Report

Review of the manuscript entitled: Phenology of Oenocarpus mapora H. Karst in low-terrace and high-terrace forests of the Madre de Dios Region, Peru.

Knowledge about the seasonal course of phenology is currently of particular importance as it can provide the basis for predicting changes in ecosystems and agricultural and forest production. Tropical regions are still very poorly known in terms of phenology, so I consider the research undertaken on Oenocarpus mapora in various altitudes to be fully justified.
Generally, the manuscript is well written. The introduction well illustrates the topic and the need for phenological research in the Amazon. The aim of the study is clearly specified. However, there is no research hypothesis. Hence the manuscript has descriptive character. I have no objections to Materials and methods. The results would be worth presenting the course of phenophases against the background of meteorological conditions. It will be helpful to follow the meteorological and phenological differences between the study sites. Figure 1 is very unreadable and needs to be improved. It is unknown what the standard number of plants in line 108 means.
In line 225, Brassica is mentioned as palm species. Would you mind checking that this is correct? To my knowledge, the genus Brassica belongs to the Brassicaceae (dicots) family. One species of Brassica oleracea is a popular vegetable grown in the temperate zone. Other Brassica species are also herbaceous plants that grow in this climate.
Each plant scientific name mentioned in the text for the first time should be given together with the author abbreviation, i.e. Oenocarpus mapora H. Karst. In each next time is sufficient to enter the shorter form of the Latin name, i.e. O. mapora in the main text.

Author Response

Point 1: Knowledge about the seasonal course of phenology is currently of particular importance as it can provide the basis for predicting changes in ecosystems and agricultural and forest production. Tropical regions are still very poorly known in terms of phenology, so I consider the research undertaken on Oenocarpus mapora in various altitudes to be fully justified. Generally, the manuscript is well written. The introduction well illustrates the topic and the need for phenological research in the Amazon. The aim of the study is clearly specified. However, there is no research hypothesis. Hence the manuscript has descriptive character. I have no objections to Materials and methods. The results would be worth presenting the course of phenophases against the background of meteorological conditions. It will be helpful to follow the meteorological and phenological differences between the study sites. Figure 1 is very unreadable and needs to be improved. It is unknown what the standard number of plants in line 108 means.

Response 1: In line 69, the hypothesis was added. The results and figure 1 were modified as suggested. In line 126, a paragraph was added to indicate the number of palms evaluated for each transect.

Point 2: In line 225, Brassica is mentioned as palm species. Would you mind checking that this is correct? To my knowledge, the genus Brassica belongs to the Brassicaceae (dicots) family. One species of Brassica oleracea is a popular vegetable grown in the temperate zone. Other Brassica species are also herbaceous plants that grow in this climate.

Response 2: In line 339, the changes were made as suggested.

Point 3: Each plant scientific name mentioned in the text for the first time should be given together with the author abbreviation, i.e. Oenocarpus mapora H. Karst. In each next time is sufficient to enter the shorter form of the Latin name, i.e. O. mapora in the main text.

Response 3: Throughout the article, changes were made to the scientific names of plants as suggested.

Reviewer 2 Report

Overall suggestions:

The authors investigated the seasonality of phenology of O. mapoa, which shows high economic and nutraceutical potential in Amazon. I suggest resubmission after major revision for several reasons. First, It is unclear if the presented results in the paper can support the study's main conclusion because of missing data in phenology. February to May phenology data is missing in the study, which is about one-third of the annual data necessary for circular statistics.  I recommend that the authors use an analysis method that does not depend on full-year data (the center of mass). In addition, the discussion part must be improved because some of the findings in the results are not sufficiently discussed in this section. For example, why are flower buds negatively correlated with the maximum temperature in the low-terrace forest (r=-0.946)? Why is the maximum temperature more important for flower buds than the minimum temperature (r=-0.946 vs.-0.443)? Why are ripe fruits positively correlated with the number of days of precipitation (r=0.861*)? Why the number of days of rainfall correlates better than the amount of rainfall with ripe fruits? Finally, not sufficient information is presented in the paper. For example, there are no figure and table captions in general; therefore, the authors failed to provide adequate information to readers.

Specific suggestions:

L42: Observation is carried out between June to January, which does not include several months. Please justify the reason for the gap in the observation; otherwise, February to May 2021 information should be presented. Furthermore, the correlation study cannot be taken as a face value because of the missing data. The authors should either justify their reason to perform a correlation study only using a subset of the months or present the complete yearly data.

Figure 3: Which site (low terrace or high terrace) is the metrological variables represented for? Since this study accounts for both areas, data for both sites should be presented in the figure.  

Table 4: It is hard to see how height correlates with monthly temperature or precipitation. Does the height of O. Mapora vary depend on the season? Also, the caption needs much detailed explanation about the variables and how they are defined.

L140 – L144: Why were the biometric characteristics collected in this study? I cannot find the information used elsewhere in the paper.

L146-L147: Seasonality and synchrony cannot be evaluated appropriately using circular statistics when data is missing for parts of the year. In this paper, a large portion (33%) of the seasonal information is missing; therefore, using circular statistics is inappropriate. I recommend the authors use other methods to account for seasonality and justify why a large portion of the seasonal data is missing.  

Discussion: Must be improved. Discussion points do not match well with the abstract where the main findings are elaborated. For example, in L223, the authors allocate a large portion about the association between height and phenology, which is not mentioned in the abstract. The paper has a lot of room to be improved as a fine piece summary that effectively explains the findings and implications of the study.  

Author Response

Point 1: The authors investigated the seasonality of phenology of O. mapora, which shows high economic and nutraceutical potential in Amazon. I suggest resubmission after major revision for several reasons. First, It is unclear if the presented results in the paper can support the study's main conclusion because of missing data in phenology. February to May phenology data is missing in the study, which is about one-third of the annual data necessary for circular statistics.  I recommend that the authors use an analysis method that does not depend on full-year data (the center of mass). In addition, the discussion part must be improved because some of the findings in the results are not sufficiently discussed in this section. For example, why are flower buds negatively correlated with the maximum temperature in the low-terrace forest (r=-0.946)? Why is the maximum temperature more important for flower buds than the minimum temperature (r=-0.946 vs.-0.443)? Why are ripe fruits positively correlated with the number of days of precipitation (r=0.861*)? Why the number of days of rainfall correlates better than the amount of rainfall with ripe fruits? Finally, not sufficient information is presented in the paper. For example, there are no figure and table captions in general; therefore, the authors failed to provide adequate information to readers.

Response 1: A circular statistical analysis was carried out since the variables have a cyclical nature and do not follow a normal distribution. According to the angle assigned to each of the evaluated months, the results do represent the phenological observations made. Discussion was modified as suggested. Likewise, the captions were increased in Figures 1, 3 and 4, as well as in Table 3.

Reviewer 3 Report

Introduction

• here I miss information about why You did this study or in better words, why do You think the study about phenology of given plant is important (for reader or for scientific community). Is there e.g. any connection between phenology and industrial exploitation? Etc.
• I would also recommend to develop more constitutive goals.

Material and methods

• Figure 1 – very difficult to read the legend. It is almost impossible to see where is the study area or study plots. Map is somehow full up with many information. I recommend to prepare the map as simple as possible. For example – I cannot see why is important to know the location of Ebla Trail, moreover You did not mentioned this trail in Your manuscript.
• Figure 2 – here I recommend to exclude the picture F and G – I´m not sure if these pictures are necessary.
• Chapter 2.4 – here You mentioned You used climate data from one meteorological station. I´m wondering if only one meteo station is enough for this type of study. Maybe the conditions in low-terrace forest and high-terrace forest are different and influence the timing of phenophases of O. mapora in different way. Could You please somehow comment this situation why You choose to have only one meteo station? Maybe there is no other stations, ok, but this must be mentioned in manuscript at least.

Results

• Line 171: please, explain what the “F” means
• Lines 164-189: explanation is somehow confusing. I don’t understand the Figure 4 – what is the meaning of the grey columns? Why the grey columns have different height? What does this means.
• In general – I do not understand what do You want to say. What is the main result/results of Your Here You describe what is displayed in figure 4 or table 3 but I miss the most important result and then other part results. From the figure 4 I can clearly see some differences among low-terrace forest and high-terrace forest but I do not understand clearly. For example – black arrow is almost everywhere equal but grey columns differ a lot. What does this mean?
• In this part of manuscript I also miss more information about climate data and I mean actual evaluation of observed period or year – is evaluated period normal (or warmer/colder) according to long-term data? Are there any specific changes in temperature or precipitation within the given period? Do You observe any long term changes of temp. and prec.? Etc.

Discussion

• Lines 223-237: it seems You also aiming on relationship among the height of palm and productivity. I think this could be mentioned within Your goals.
• Lines 232-237: Here You only repeat what is already written in “Results”. I think here You can describe and explain what does Your results mean.
• In general – here I miss some conclusions and opinions or judgment from You as an author. You describe here your results and then the reader can say “ok, and now what?” if You know what I mean. I think it would be much better if You describe what Your results mean, where is the point, why this is important and why we should know all You results.

Conclusions

Lines 293-295: this information could be part of the Results but more specific and based on real data.

Finally – very good, but try to do better line of the whole story which You want to tell. Overall You did conclusions after only one period of observations – this is in phenology word somehow little time. Please try to describe also why You did these observations only for one period (year) although all Your observers did very good job and I do believe it was challenging job.

Author Response

Introduction

Point 1: here I miss information about why You did this study or in better words, why do You think the study about phenology of given plant is important (for reader or for scientific community). Is there e.g. any connection between phenology and industrial exploitation? Etc.

I would also recommend to develop more constitutive goals.

Response 1: In line 63, a paragraph was added on the importance of palm trees and potential industrial exploitation of O. mapora.

Material and methods

Point 1: Figure 1 – very difficult to read the legend. It is almost impossible to see where is the study area or study plots. Map is somehow full up with many information. I recommend to prepare the map as simple as possible. For example – I cannot see why is important to know the location of Ebla Trail, moreover You did not mentioned this trail in Your manuscript.

Response 1: Figure 1 was modified as suggested.

Point 2: Figure 2 – here I recommend to exclude the picture F and G – I´m not sure if these pictures are necessary.

Response 2: Figure 2 was modified as suggested.

Point 3: Chapter 2.4 – here You mentioned You used climate data from one meteorological station. I´m wondering if only one meteo station is enough for this type of study. Maybe the conditions in low-terrace forest and high-terrace forest are different and influence the timing of phenophases of O. mapora in different way. Could You please somehow comment this situation why You choose to have only one meteo station? Maybe there is no other stations, ok, but this must be mentioned in manuscript at least.

Response 3: For this study, the meteorological conditions of the station "Monitoring Center 1" located in the "Los Amigos" Conservation Concession (Madre de Dios Region, Peru), were recorded. In the study area, there is another meteorological station located at a distance of 3.5 km from "Monitoring Center 1", however, it did not record complete data for the study period.

Results

Point 4: Line 171: please, explain what the “F” means

Response 4: In Material and Methods (line 197), it is indicated that the Watson-Williams F test was used to evaluate the differences in the mean angles of the phenological parameters. In lines 215 and 246, the meaning of this test was added.

Point 5: Lines 164-189: explanation is somehow confusing. I don’t understand the Figure 4 – what is the meaning of the grey columns? Why the grey columns have different height? What does this means.

In general – I do not understand what do You want to say. What is the main result/results of Your Here You describe what is displayed in figure 4 or table 3 but I miss the most important result and then other part results. From the figure 4 I can clearly see some differences among low-terrace forest and high-terrace forest but I do not understand clearly. For example – black arrow is almost everywhere equal but grey columns differ a lot. What does this mean?

Response 5: In the legend of Figure 4 (line 312), the meaning of the bars and the bold arrow were added. Likewise, in Material and Methods (line 193), a paragraph has been added to explain the null hypothesis made in the circular statistical analysis.

Point 6: In this part of manuscript I also miss more information about climate data and I mean actual evaluation of observed period or year – is evaluated period normal (or warmer/colder) according to long-term data? Are there any specific changes in temperature or precipitation within the given period? Do You observe any long term changes of temp. and prec.? Etc.

Response 6: During the evaluated period, the climatological data did not show greater variation with respect to previous years. Likewise, as shown in Figure 3, an increase of approximately 4 °C in the average temperature was observed from September to December, while an increase in rainfall was observed from November to January.

Discussion

Point 7: Lines 223-237: it seems You also aiming on relationship among the height of palm and productivity. I think this could be mentioned within Your goals.

Response 7: Productivity has been included within the objectives of the study.

Point 8: Lines 232-237: Here You only repeat what is already written in “Results”. I think here You can describe and explain what does Your results mean.

Response 8: This paragraph (line 347) was modified as suggested.

Point 9: In general – here I miss some conclusions and opinions or judgment from You as an author. You describe here your results and then the reader can say “ok, and now what?” if You know what I mean. I think it would be much better if You describe what Your results mean, where is the point, why this is important and why we should know all You results.

Response 9: The discussion was modified to explain the results obtained.

Conclusions

Point 10: Lines 293-295: this information could be part of the Results but more specific and based on real data.

Response 10: This paragraph was modified and was placed in Results (line 225).

Point 11: Finally – very good, but try to do better line of the whole story which You want to tell. Overall You did conclusions after only one period of observations – this is in phenology word somehow little time. Please try to describe also why You did these observations only for one period (year) although all Your observers did very good job and I do believe it was challenging job.

Response 11: In conclusions (line 450), a paragraph was added on the need to carry out long-term studies to evaluate the effects of the habitat and the interannual climatic variation on the flowering and fruiting pattern of this palm that presents a high potential in the Peruvian Amazon.

Round 2

Reviewer 1 Report

The authors have responded sufficiently to my comments. I have no objection to the current version of the manuscript.

Author Response

Point 1: The authors have responded sufficiently to my comments. I have no objection to the current version of the manuscript.

Response 1: We appreciate the reviewer's comments.

Reviewer 2 Report

I think the authors did a good job revising the discussion and captions. Many of the previous comments were addressed. However, there is one main concern with the paper. I am concerned to see issues with the gap in the phenology observation from February 2020 to May 2020 in this paper thus would like to recommend some edits:

First, I recommend representing the data in figure 4 with regular cartesian coordinates such that the x-axis represents the dates from June 2019 to January 2020, as in figure 3, instead of the current angular plot. It is quite confusing to readers that the author’s presentation of data in a cyclical fashion does not clarify that the data include many months of missing data. For example, in figure 4, there is no indication of missing months in the angular plot, thus is concerning because readers could easily think that the data exists but the phenological signal was insignificant from February to May in 2020. In fact, there is no inference about the phenological signals from February to May from this paper. 

Second, I would recommend the authors avoid using circular statistics since the presented data is not completely cyclic due to missing data, even though plant phenology is indeed cyclic. There is a serious flaw in using circular statistics without full cyclical coverage due to missing data from February 2020 to May 2020. Using circular statistics in this fashion violates critical underlying mathematical and statistical assumptions about the distribution of the data thus introduces inevitable bias to the statistics. Instead, I would recommend using a ‘center of phenological intensity’ metric, which is a mean date weighted by the intensity of phenology signals. In the R code, one could use weighted.mean() function, putting the date vector first and the intensity vector next. Such metric results in a more accurate estimation of mean dates than circular statistics with currently available data because it does not introduce any bias. 

Third, I am concerned that the paper does not discuss the missing phenology data from February 2020 to May 2020. I strongly feel that it needs some justification before concluding about the significant seasonal tendency of the phenological signals, for example by answering the following questions: How do we know that there is no phenological signal from February 2020 to May 2020 in terms of the leaves, flowers, bunches, and fruits? Has there been any study of Oenocarpus maporas phenology from February to May? What are the inferences from previous studies? 

Figure 3: Which site (low terrace or high terrace) do the metrological variables represent? It would be nice to have data for both sites if they are available. 

Table 4: Does the height of O. Mapora vary depending on the season?

Author Response

Point 1: I think the authors did a good job revising the discussion and captions. Many of the previous comments were addressed. However, there is one main concern with the paper. I am concerned to see issues with the gap in the phenology observation from February 2020 to May 2020 in this paper thus would like to recommend some edits:

First, I recommend representing the data in figure 4 with regular cartesian coordinates such that the x-axis represents the dates from June 2019 to January 2020, as in figure 3, instead of the current angular plot. It is quite confusing to readers that the author’s presentation of data in a cyclical fashion does not clarify that the data include many months of missing data. For example, in figure 4, there is no indication of missing months in the angular plot, thus is concerning because readers could easily think that the data exists but the phenological signal was insignificant from February to May in 2020. In fact, there is no inference about the phenological signals from February to May from this paper.

Response 1: Figure 4 was modified as suggested. In the Discussion (line 416), a study carried out for four consecutive years on the phenology of arborescent palms in an area close to our study area has been added.

Point 2: Second, I would recommend the authors avoid using circular statistics since the presented data is not completely cyclic due to missing data, even though plant phenology is indeed cyclic. There is a serious flaw in using circular statistics without full cyclical coverage due to missing data from February 2020 to May 2020. Using circular statistics in this fashion violates critical underlying mathematical and statistical assumptions about the distribution of the data thus introduces inevitable bias to the statistics. Instead, I would recommend using a ‘center of phenological intensity’ metric, which is a mean date weighted by the intensity of phenology signals. In the R code, one could use weighted.mean() function, putting the date vector first and the intensity vector next. Such metric results in a more accurate estimation of mean dates than circular statistics with currently available data because it does not introduce any bias.

Response 2: In Material and Methods (line 192), the description of the weighted mean analysis has been added. Table 3, Results and Discussion were modified according to the new analysis carried out.

Point 3: Third, I am concerned that the paper does not discuss the missing phenology data from February 2020 to May 2020. I strongly feel that it needs some justification before concluding about the significant seasonal tendency of the phenological signals, for example by answering the following questions: How do we know that there is no phenological signal from February 2020 to May 2020 in terms of the leaves, flowers, bunches, and fruits? Has there been any study of Oenocarpus mapora phenology from February to May? What are the inferences from previous studies?

Response 3: During February to May 2020, complete data on the phenology of O. mapora could not be recorded due to restrictions caused by the start of the COVID-19 pandemic in Peru. In the Discussion (line 416), a study carried out for four consecutive years on the phenology of arborescent palms in an area close to our study area has been added.

Point 4: Figure 3: Which site (low terrace or high terrace) do the metrological variables represent? It would be nice to have data for both sites if they are available. 

Response 4: In line 170, it is indicated that the meteorological station "Monitoring Center 1" is located in the low-terrace forest. It was not possible to obtain complete data on the climatic conditions of another meteorological station located 3.5 km from "Monitoring Center 1".

Point 5: Table 4: Does the height of O. Mapora vary depending on the season?

Response 5: No significant differences were found in the height of O. mapora depending on the season in low-terrace and high-terrace forests (p = 0.801 and p = 0.753, respectively).

Reviewer 3 Report

Dear colleagues,

I went through the revised manuscript, I checked the author´s responses on my revisions. I can say the manuscript was modified sufficiently for me.

Author Response

Point 1: I went through the revised manuscript, I checked the author´s responses on my revisions. I can say the manuscript was modified sufficiently for me.

Response 1: We appreciate the reviewer's comments.

Round 3

Reviewer 2 Report

The authors addressed all the comments.