Future Scenarios for Olive Tree and Grapevine Potential Yields in the World Heritage Côa Region, Portugal
Round 1
Reviewer 1 Report
The article is valuable and comprehensive. I would like to appreciate the amount of work that the authors invested in this research and the practical applicability of the outcomes of this paper.
Here are a few comments to help improve current study:
- Fig. 1- need clearly visible names of rivers (panel c)
- Fig 2 - schematic representation is an excellent overview of study design. Maybe, the key input parameters for the models listed in lines 134 – 136 could be included below the arrows in the scheme, put thinner arrows and slightly increase the text below the arrows. (for visual attention, optional)
- It seems that this study represents good outcome when combining different models as in the case of olives compared to observed slight modelling limitation for well established grapevine model. One can see the need not only for the application of existing models but for a thoughtful combination of several models, crop and site-specific. (reffering to lines 233-234)
- According to Fig. 1 b and c, it seems more water sources (rivers) in northern parts of studied region? E.g. wild grapevine (Vitis vinifera sylvestris) in natural habitats in Europe is found mostly near rivers, lakes (waters), that is what possibly model for grapevine did not take into consideration?
- Fig 5 - use purple color for grapevine distribution as in Fig. 1 b (optional!)
- In the line 282 – it would be infomative briefly discuss on irrigation in studied region and possible restrictions regarding PDO, if exist?
- It would be interesting to briefly include in Discussion section: direction of model-development regarding daily/hourly extremes in temperatures (optional!)
Further considerations: One of the short-to-long term measures for perrenial crop to think of to alleviate climate change impact and stressful crop conditions would be measures to periodically 'rest the crop', such as seen for annual crops (crop rotation or fallows).
Author Response
Reviewer #1
The article is valuable and comprehensive. I would like to appreciate the amount of work that the authors invested in this research and the practical applicability of the outcomes of this paper.
Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study. In particular, we have restructured some parts of the manuscript to comply with the suggestions from the reviewers. The point-by-point replies are provided below and highlighted in blue font, as well as the corresponding changes in the manuscript.
Here are a few comments to help improve current study:
Fig. 1- need clearly visible names of rivers (panel c)
Reply: Done.
Fig 2 - schematic representation is an excellent overview of study design. Maybe, the key input parameters for the models listed in lines 134 – 136 could be included below the arrows in the scheme, put thinner arrows and slightly increase the text below the arrows. (for visual attention, optional)
Reply: Although we agree with the reviewer, including such large amount of text in the figure will make the figure very cluttered, decreasing the overall presentation of the figure. We would like to keep this figure as it is, if possible.
It seems that this study represents good outcome when combining different models as in the case of olives compared to observed slight modelling limitation for well established grapevine model. One can see the need not only for the application of existing models but for a thoughtful combination of several models, crop and site-specific. (reffering to lines 233-234)
Reply: we have included a new sentence to address this issue.
Line 252-253: “In effect, this study suggests that the combination of crop models could indeed be beneficial for site-specific modelling of different crops.”
According to Fig. 1 b and c, it seems more water sources (rivers) in northern parts of studied region? E.g. wild grapevine (Vitis vinifera sylvestris) in natural habitats in Europe is found mostly near rivers, lakes (waters), that is what possibly model for grapevine did not take into consideration?
Reply: Although we know that there are indeed Vitis vinifera sylvestris in the regions, more specifically, close to the water sources, the STICS model is only calibrated for commercial vineyards.
Fig 5 - use purple color for grapevine distribution as in Fig. 1 b (optional!)
Reply: We thank the reviewer for his/her suggestion, however for a higher contrast between the two colors, we opt to keep the figure as is.
In the line 282 – it would be infomative briefly discuss on irrigation in studied region and possible restrictions regarding PDO, if exist?
Reply: We have included the following text in the manuscript to address this issue:
Lines 286-289: “Nonetheless, over the last years, the increase in water and heat stress has been leading to a shift in these policies, and irrigation is becoming more accepted and adopted.”
It would be interesting to briefly include in Discussion section: direction of model-development regarding daily/hourly extremes in temperatures (optional!)
Reply: We also think this is very interesting, however, we do not develop the crop models within our group, being merely users and model “evaluators”.
Further considerations: One of the short-to-long term measures for perrenial crop to think of to alleviate climate change impact and stressful crop conditions would be measures to periodically 'rest the crop', such as seen for annual crops (crop rotation or fallows).
Reply: Regarding a rest period and crop rotation, we do not think this would be practical for the growers, especially in commercial vineyards and olive groves, since a period of rest would require at least 3+ years to resume production. We must take into account that these crops are already very resilient to water and heat stress, and other measures should be considered.
Reviewer 2 Report
The manuscript consists in the running of two already estabilished agrometeorological models in the Coa region, in Portugal, an area where olive growing and viticulture represent two relevant industries.
The models produce only a yield potetial (% of current yield), under two climate change scenarios. Results highlight that viticulture could be significantly affected by warming trends, whereas olive trees could exibit higher resilience. The paper is well-written, except for a fe typos, and the topic is extremely actual.
The main shortcoming of the ms is that the entire paper is not grounded on any kind of data, yet on simple conceptualization of visual assessments of maps produced by the model. As a result, the work is not scientifically sound, most of the discussion is speculative or vague and based on cliches.
Extrapolating data seems quite simple and, for instance, number of ha (or %) changing class of yield potential when passing from the current situation to one of the two scenarios would make the paper interesting and not speculative.
I suggest the authors to rework results and discussion, the ms would gain a lot
Specific comments are provided in the attchment
Comments for author File: 
Comments.pdf
Author Response
Reviewer #2
The manuscript consists in the running of two already estabilished agrometeorological models in the Coa region, in Portugal, an area where olive growing and viticulture represent two relevant industries.
The models produce only a yield potetial (% of current yield), under two climate change scenarios. Results highlight that viticulture could be significantly affected by warming trends, whereas olive trees could exibit higher resilience. The paper is well-written, except for a fe typos, and the topic is extremely actual.
The main shortcoming of the ms is that the entire paper is not grounded on any kind of data, yet on simple conceptualization of visual assessments of maps produced by the model. As a result, the work is not scientifically sound, most of the discussion is speculative or vague and based on cliches.
Extrapolating data seems quite simple and, for instance, number of ha (or %) changing class of yield potential when passing from the current situation to one of the two scenarios would make the paper interesting and not speculative.
I suggest the authors to rework results and discussion, the ms would gain a lot
Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study. In particular, we have restructured some parts of the manuscript to comply with the suggestions from the reviewers. The point-by-point replies are provided below and highlighted in blue font, as well as the corresponding changes in the manuscript.
Regarding the nature of the study, we agree with the reviewer that these type of studies are projections for the future. The study of climate change impact assessment on crops is of great value to growers in this region, since it provides guidelines to mitigate the negative impacts of a warmer and dryer future. Furthermore, we should highlight that these two models were already calibrated under field conditions for these two crops in several previous studies, providing high agreements with observational datasets.
Specific comments are provided in the attachment
Reply: All the comments in the pdf are addressed below.
Line 19: if validation is the aim of the paper, data must be presented
Reply: The part “validating the crop model outputs” was removed
Line 22: some details are needed. what does it mean 'most of the region'?
Reply: Changed to :” decrease in potential yields throughout the region”
Line 25: What kind of measures? unrelated to the work outputs
Reply: We have added the following: “based on changing certain management practices”
Line 111: check grammar (is encompasses)
Reply: Corrected
Line 125: what does it mean present conditions? is it an average of x years?
Reply: Added the years “1981-2005”.
Line 152: Does the model take into account winter chilling requirements? In some regions, viticulture is limited due to the scarce amout of hours passed at <7°C.
Reply: Both models take into account limiting temperatures for growth and development. We do not wish to discuss the model structure in detail, as this was already done by the original developers and in other several studies.
Line 205: This statement should be based on data. Did the model produce any output in terms of numbers (i.e. number of Ha within a single class of yield potential, or % of the total)?
Reply: The text was re-written to avoid wrong interpretations:
Lines 208-211: “This is a clear indication that the model is suitable for modelling the olive potential yields, also in agreement with previous studies [4, 48]. In the recent-past, the model projects that the high potential yield areas are very limited spatially. In effect, our results indicate that almost all the region is divided into two yield classes”
Line 207: Can you sort out how many of the olive tree fields fall into the >75% class?
Reply: The area of maximum potential productivity is very low, accounting for approximately 3% of the entire Côa area.
Line 213: If I am right, the two scenarios decribe the 2041-2070 situation. This should be reported in the fig 4 and 5 captions and better highlighted in results.
Reply: Done.
Line 221: There is no data? How many Ha passed from <25% to 25-50% or higher classes under the two scenarios, respectively?
Reply: We understand the reviewer point, providing the area in hectares would indeed provide a measure of climate change. Nonetheless, given that the area of olive/grapevine is not fixed and can change (increase/decrease) in the future, would provide a false statement for the growers. Therefore, our study is based only on the zoning of potential areas for cultivation, based on the 4 classes.
Line 234: Like above, some details are needed
Line 240: Very vague if data is not reported
Line 256: Very vague, and not grounded on data, just on figures visual interpretation
Line 257: Actually the disappearing of area guaranteeing at least 75% of current yield seems quite dramatic to me. Also the advancements of <25% could produce huge effects on local economy. Do authors have data about the number of ha passing from a class to another?
Line 260: Like above, statemets are speculative if not grounded on some data extrapolation
Reply: Please see reply to the previous question. Also, regarding the nature of the study, we agree with the reviewer that these types of studies are projections for the future. The study of climate change impact assessment on crops is of great value to growers in this region, since it provides guidelines to mitigate the negative impacts of a warmer and dryer future. Furthermore, we should highlight that these two models were already calibrated under field conditions for these two crops in several previous studies, providing high agreements with observational datasets.
Line 280: gramar
Reply: Corrected
Reviewer 3 Report
Comments on “Future scenarios for olive tree and grapevine potential yields in the World Heritage Côa region, Portugal” manuscript
- The title of the manuscript is concise and very relevant for the readers who are informed about the subject and location of the research.
- The manuscript is very well organized and contains all expected paragraphs: Abstract, Introduction, Results, Discussions, Material and Methods, Conclusions and References, Funding and Acknowledgments.
- In the abstract can be found concisely information about the content of the manuscript, the motivation for the research, expected results, discussions correlated with the other similar findings and main conclusions.
- Keywords are well chosen for a faster search of the article and citations.
- The introduction paragraph described the Côa region, and the main crops which are source of income for most of the inhabitants of this area. It is well noted that different varieties of vines are influenced by climatic conditions, especially temperature, especially in recent decades when the growing area has expanded to the north. The main factors involved in the growth and development of vines and olive groves are mentioned and used in the different dynamic crop models. The Figure 1 provides an overview of the Côa region, which is welcome for those who are not connoisseurs of this region.
- Both models for olive tree and grapevine were confirmed before in other research and crops. Maps for temperature and precipitations in the Côa region are useful in understanding the crop models application and results. The experiment and methods used are appropriate for this study. The information provided is sufficient for other researchers to reproduce the experiment described.
- The results are clearly explained and presented in an appropriate format and the figures and tables show essential data without duplication in text. No additional graphics or tables could add clarity to the text.
- Discussion paragraph provide the context in which results are important. Connections are made to the broader literature, including what was cited in the Introduction section. The discussions confirm that the grapevine growing area will be strongly influenced by climatic conditions, especially by the high temperature associated with drought, while the olive tree crop will be reach higher elevations to escape unfavorable climate conditions.
- The conclusions clearly show that crop models are useful for olive tree and grapevine crops in the Côa region with potential application for the future climate variability and continuous changes.
- References are appropriate, relevant to the study and covered completely in the list.
- Author’s contribution and specification for the funding and acknowledgement are a plus for the manuscript.
Author Response
Reviewer #3
Comments on “Future scenarios for olive tree and grapevine potential yields in the World Heritage Côa region, Portugal” manuscript
The title of the manuscript is concise and very relevant for the readers who are informed about the subject and location of the research.
The manuscript is very well organized and contains all expected paragraphs: Abstract, Introduction, Results, Discussions, Material and Methods, Conclusions and References, Funding and Acknowledgments.
In the abstract can be found concisely information about the content of the manuscript, the motivation for the research, expected results, discussions correlated with the other similar findings and main conclusions.
Keywords are well chosen for a faster search of the article and citations.
The introduction paragraph described the Côa region, and the main crops which are source of income for most of the inhabitants of this area. It is well noted that different varieties of vines are influenced by climatic conditions, especially temperature, especially in recent decades when the growing area has expanded to the north. The main factors involved in the growth and development of vines and olive groves are mentioned and used in the different dynamic crop models. The Figure 1 provides an overview of the Côa region, which is welcome for those who are not connoisseurs of this region.
Both models for olive tree and grapevine were confirmed before in other research and crops. Maps for temperature and precipitations in the Côa region are useful in understanding the crop models application and results. The experiment and methods used are appropriate for this study. The information provided is sufficient for other researchers to reproduce the experiment described.
The results are clearly explained and presented in an appropriate format and the figures and tables show essential data without duplication in text. No additional graphics or tables could add clarity to the text.
Discussion paragraph provide the context in which results are important. Connections are made to the broader literature, including what was cited in the Introduction section. The discussions confirm that the grapevine growing area will be strongly influenced by climatic conditions, especially by the high temperature associated with drought, while the olive tree crop will be reach higher elevations to escape unfavorable climate conditions.
The conclusions clearly show that crop models are useful for olive tree and grapevine crops in the Côa region with potential application for the future climate variability and continuous changes.
References are appropriate, relevant to the study and covered completely in the list.
Author’s contribution and specification for the funding and acknowledgement are a plus for the manuscript.
Reply: We would like to thank the Reviewer for his/her careful reading of the manuscript and comments. The positive feedback is appreciated amongst the authors.
Reviewer 4 Report
The manuscript titled “Future scenarios for olive tree and grapevine potential yields in the World Heritage Côa region, Portugal” tries to establish projections about the future of olive and vineyard cultivation in the Portuguese region of Côa. The main goal is to establish two crop models for the aforementioned vineyard and olive grove forecast cultivation. Starting with spatial datasets on current location of crops, current yields, climatic data, soil data, altitude and orientation data, and data for each plant, the manuscript establishes the yields in the near past and the future yields in two different climate change scenarios depending on the CO2 emissions until the middle or the end of the 21st century. As the main results presented, it augurs a good future for the olive grove and a less promising future for the vineyard. It also proposes, in the discussion part, some agri-environmental measures that can alleviate the negative effects of climate change, such as improving the efficiency of the use of water and cover cropping technique.
My general evaluation of the proposed publication is uneven depending on the aspects considered. In general, the manuscript is well written and clearly developed and meets all the formal requirements for a scientific publication. The results obtained may be interesting, above all, for the orientation of local agrarian policies. It also shows a good knowledge of international databases and apparently these data are used with precision and skill to obtain interesting results.
However, the proposed manuscript presents some “transversal” problems:
I am not a specialist in the use of large databases or mathematic models. Therefore, I may not be the ideal person to judge the manuscript. In any case, and to meet my commitment, I will give my opinion. The mathematics models are referenced but reading the text it is impossible to get an idea of how they work. Therefore, the goodness of the conclusions obtained cannot be verified since the starting data and the method used to obtain them are not known.
The graphs that appear in the results must be improved: they present excessive categories that are not later reflected in the graphs. In addition, the colors displayed in the legend for interpretation do not match those that later appear on the graph.
The discussion of such a large study is very complex. The viability of the studied crops is fundamentally based on the yield, but to make political decisions of draft, aspects as important as the quality of the products and the prices should be considered. It is also true that the influence of soil and climatic factors on quality is difficult to establish. Moreover, the evolution of prices is very difficult to foresee in the medium and long term.
From the study it can be deduced that in general the cultivation of vineyards will deteriorate in terms of yields. It recommends a change and careful choice of plant material, mainly varieties and rootstocks, however, it does not make any reference to the varieties and rootstocks currently used or to possible recommendations for the future, so the recommendation remains a bit vague and general.
In the case of the olive grove, it is possible to dedicate to the cultivation of this plant areas of higher altitude and with lower temperatures today. However, this change of cultivation area can be complicated as the new lands used can result with inadequate soils or, above all, with low water availability.
Regarding the recommended practices to mitigate the effects of climate change, the following should be taken into account: improving the efficiency of water use seems an inalienable objective in any case, but also the availability of water must be taken into account: in the new areas is there that availability of water no matter how well it can be used??. Regarding the use of plant covers, it should be noted that there are not many experiences of this technique in arid or semi-arid climates. Cover crops consume part of the available water and therefore if they are not managed well, they can suppose an additional and limiting competition with the crop.
Specific issues to improve:
Line 125: figure 3 about the temperature and precipitation data is very interesting but there are many categories in the legend that are not reflected on the map, therefore it would be convenient to reduce that number of categories in the legend.
Line 160: future climate change scenarios should be better defined.
Line 177: the use of edafo-transfer functions should be taken with great caution, at least it should be stated which functions are used, not just reference them.
Line 187: in table 2 appear that the available soil depth is 2 m, it is practically impossible in the soils that we know in our area.
Line 196: a point is missing before the word “secondly”. In any case, it would be useful to explain better how the different classes are stated with respect to the yields of the recent past.
Line 213: the colors of the legend must match the colors of the figure, especially the range of blue is not well distinguished. It is essential for a good interpretation of the figure. It is shocking that in the current situation there are only two categories or colors of potential yields, without intermediate steps (especially the yellow category).
Line 237: the same thing happens with the colors, those of the legend do not correspond to those of the graphs and it makes the interpretation difficult. It is shocking that in the two climate change scenarios the results are very similar except for the disappearance in the worst case of the yellow category.
Line 261: be very careful with the displacement of the olive grove to the areas of low temperatures and high current elevations. In these areas, the future climatic changes scenario may be favorable, but the soil conditions and especially the water availability may be compromised, since the higher the elevation the less the water availability, as there are no major rivers or reservoirs.
Line 279: the cover crop technique proposal in woody crops is very interesting for improving the soil quality, but in semi-arid areas with low water availability it is necessary to be very careful in controlling the covers as they can compete in a limiting way with the crop.
line 287: when talking about the selection of plant material (varieties and rootstocks) one could be more specific when indicating current and future options to mitigate the effects of climate change.
Line 292: for the transfer of olive cultivation, especially to higher areas, the availability of property must also be taken into account. It is noted throughout the manuscript that the farms tend to be small and therefore probably the olive grove farmers, or the viticulturist does not have available plots at all altitudes in the region.
Author Response
Reviewer #4
The manuscript titled “Future scenarios for olive tree and grapevine potential yields in the World Heritage Côa region, Portugal” tries to establish projections about the future of olive and vineyard cultivation in the Portuguese region of Côa. The main goal is to establish two crop models for the aforementioned vineyard and olive grove forecast cultivation. Starting with spatial datasets on current location of crops, current yields, climatic data, soil data, altitude and orientation data, and data for each plant, the manuscript establishes the yields in the near past and the future yields in two different climate change scenarios depending on the CO2 emissions until the middle or the end of the 21st century. As the main results presented, it augurs a good future for the olive grove and a less promising future for the vineyard. It also proposes, in the discussion part, some agri-environmental measures that can alleviate the negative effects of climate change, such as improving the efficiency of the use of water and cover cropping technique.
My general evaluation of the proposed publication is uneven depending on the aspects considered. In general, the manuscript is well written and clearly developed and meets all the formal requirements for a scientific publication. The results obtained may be interesting, above all, for the orientation of local agrarian policies. It also shows a good knowledge of international databases and apparently these data are used with precision and skill to obtain interesting results.
Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study. In particular, we have restructured some parts of the manuscript to comply with the suggestions from the reviewers. The point-by-point replies are provided below and highlighted in blue font, as well as the corresponding changes in the manuscript
However, the proposed manuscript presents some “transversal” problems:
I am not a specialist in the use of large databases or mathematic models. Therefore, I may not be the ideal person to judge the manuscript. In any case, and to meet my commitment, I will give my opinion. The mathematics models are referenced but reading the text it is impossible to get an idea of how they work. Therefore, the goodness of the conclusions obtained cannot be verified since the starting data and the method used to obtain them are not known.
Reply: We acknowledge the reviewer’s comment. However, we should point out that the present research does not intend to validate these crop models, as these were already extensively validated in previous research by many previous studies, by several scientists and in several regions, not only by the current co-authors. Nonetheless, it is clear that the models are well suited for these crops as they completely match the land cover of the selected crops. Hence, the present study provides a yield delta/difference between present and future scenarios. These differences correspond to the influence of future climatic conditions on these crops and are of great value for the farmers in this region.
The graphs that appear in the results must be improved: they present excessive categories that are not later reflected in the graphs. In addition, the colors displayed in the legend for interpretation do not match those that later appear on the graph.
Reply: We have corrected the color pallet issues in the legends and have reduced the classes in Figure 2.
The discussion of such a large study is very complex. The viability of the studied crops is fundamentally based on the yield, but to make political decisions of draft, aspects as important as the quality of the products and the prices should be considered. It is also true that the influence of soil and climatic factors on quality is difficult to establish. Moreover, the evolution of prices is very difficult to foresee in the medium and long term.
From the study it can be deduced that in general the cultivation of vineyards will deteriorate in terms of yields. It recommends a change and careful choice of plant material, mainly varieties and rootstocks, however, it does not make any reference to the varieties and rootstocks currently used or to possible recommendations for the future, so the recommendation remains a bit vague and general.
Reply: We have included in the manuscript a discussion on the varieties and rootstocks:
Lines 292-297: “Presently, in the Côa region, Touriga-Franca, Touriga-Nacional and Aragonez are the most the grapevine varieties, while the olive varieties of Galega, Cornicabra, Carrasquenha, Negrinha, Madural e Cobrançosa are the most planted ones. These grapevine and olive varieties have already proven to have a high resilience to adverse climatic conditions in the present, but may be challenged under future scenarios.”
In the case of the olive grove, it is possible to dedicate to the cultivation of this plant areas of higher altitude and with lower temperatures today. However, this change of cultivation area can be complicated as the new lands used can result with inadequate soils or, above all, with low water availability.
Reply: We have added a sentence to highlight the issue raised by the reviewer.
Lines 212-214: “Furthermore, some of these areas also present other challenging conditions for cultivation, such as poor soils and low water availability.”
Regarding the recommended practices to mitigate the effects of climate change, the following should be taken into account: improving the efficiency of water use seems an inalienable objective in any case, but also the availability of water must be taken into account: in the new areas is there that availability of water no matter how well it can be used??. Regarding the use of plant covers, it should be noted that there are not many experiences of this technique in arid or semi-arid climates. Cover crops consume part of the available water and therefore if they are not managed well, they can suppose an additional and limiting competition with the crop.
Reply: We have now included new sentences in the manuscript to highlight these issues.
Lines 306-308: “Regarding the new areas for cultivation, some issues should be taken into consideration, such as water availability, proper soil characteristics, and suitable terrain conditions for planting and management.”
Lines 25-287: “Regarding cover crops, special attention should be given to the selection of a proper seed mix, not competing with the main crop for soil water during the driest season.”
Specific issues to improve:
Line 125: figure 3 about the temperature and precipitation data is very interesting but there are many categories in the legend that are not reflected on the map, therefore it would be convenient to reduce that number of categories in the legend.
Reply: This issue was corrected.
Line 160: future climate change scenarios should be better defined.
Reply: A new scenario description was added.
Lines 161-165: “In RCP4.5, CO2 emissions are assumed to increase until the mid-21st century, decreasing afterward, whereas the CO2 emissions continue to rise until the end of the 21st century in RCP8.5 [6]. These CO2 emission differences between scenarios are particularly relevant in terms of the increase in global temperature, resulting in a higher increase in temperature in RCP8.5, compared to RCP4.5. ”
Line 177: the use of edafo-transfer functions should be taken with great caution, at least it should be stated which functions are used, not just reference them.
Reply: We feel that describing the functions used would require a large extention of the manuscript , increasing it’s length and decreasing it’s overall readability. Therefore we would like to keep the reference to the original edafo-transfer function, if possible.
Line 187: in table 2 appear that the available soil depth is 2 m, it is practically impossible in the soils that we know in our area.
Reply: We agree with the reviewer, however, the dataset used provides a “Maximum unimpeded root depth”, this represents the maximum in a given region, not the specific conditions.
Line 196: a point is missing before the word “secondly”. In any case, it would be useful to explain better how the different classes are stated with respect to the yields of the recent past.
Reply: The dot was corrected. Regarding the potential yields it now reads:
“Firstly, the obtained potential yields, for the recent-past and future periods, were normalized regarding the maximum potential yields in the recent-past. This normalization process allows comparing the potential yields in percentages between 0-100%. Secondly, the potential yield was divided into four classes: 0-25% - low yield, 25-50% - low-moderate yield; 50-75% moderate-high yields; 75-100% high yields.”
Line 213: the colors of the legend must match the colors of the figure, especially the range of blue is not well distinguished. It is essential for a good interpretation of the figure. It is shocking that in the current situation there are only two categories or colors of potential yields, without intermediate steps (especially the yellow category).
Reply: The color issue was corrected.
Line 237: the same thing happens with the colors, those of the legend do not correspond to those of the graphs and it makes the interpretation difficult. It is shocking that in the two climate change scenarios the results are very similar except for the disappearance in the worst case of the yellow category.
Reply: The color issue was corrected.
Line 261: be very careful with the displacement of the olive grove to the areas of low temperatures and high current elevations. In these areas, the future climatic changes scenario may be favorable, but the soil conditions and especially the water availability may be compromised, since the higher the elevation the less the water availability, as there are no major rivers or reservoirs.
Reply: We have now included new sentences in the manuscript to highlight these issues.
Lines 306-308: “Regarding the new areas for cultivation, some issues should be taken into consideration, such as water availability, proper soil characteristics, and suitable terrain conditions for planting and management.”
Line 279: the cover crop technique proposal in woody crops is very interesting for improving the soil quality, but in semi-arid areas with low water availability it is necessary to be very careful in controlling the covers as they can compete in a limiting way with the crop.
Reply: We have now included new sentences in the manuscript to highlight these issues.
Lines 25-287: “Regarding cover crops, special attention should be given to the selection of a proper seed mix, not competing with the main crop for soil water during the driest season.”
line 287: when talking about the selection of plant material (varieties and rootstocks) one could be more specific when indicating current and future options to mitigate the effects of climate change.
Reply: We have included in the manuscript a discussion on the varieties and rootstocks:
Lines 292-297: “Presently, in the Côa region, Touriga-Franca, Touriga-Nacional and Aragonez are the most the grapevine varieties, while the olive varieties of Galega, Cornicabra, Carrasquenha, Negrinha, Madural e Cobrançosa are the most planted ones. These grapevine and olive varieties have already proven to have a high resilience to adverse climatic conditions in the present, but may be challenged under future scenarios.”
Line 292: for the transfer of olive cultivation, especially to higher areas, the availability of property must also be taken into account. It is noted throughout the manuscript that the farms tend to be small and therefore probably the olive grove farmers, or the viticulturist does not have available plots at all altitudes in the region.
Reply: We understand the reviewer’s concern, this issue is now stated in the manuscript.
Line 311: “Nonetheless, given that the structure of the Côa region is composed by small farms, this would be very difficult to implement.”
Round 2
Reviewer 2 Report
Authors corrected minor stylistic issues, but ignored the main shortcoming reported in the first revision.
As a mater of fact, the manuscript is still totally not grounded in any kind of data and all the discussion and conclusions are speculative. Results reports a vague visual interpretation of colour changes in the map, they mainly consists in stating that an unexplained quantity of land is going to change colours under climate change scenarios. Just as an exaple
.. In some westerly regions, the decrease is indeed severe, passing from moderately-high yields to low yields....
...Although a catastrophic scenario is not predicted to occur, some areas may still experience large decreases in yield. Nonetheless, for most of the region, including part of the Douro Superior winemaking sub-region, the projected potential yields will still be within the moderately-high class, in both future scenarios...
A large portion of the central area of the Côa region, which until the present showed very low suitability for olive production, most likely due to low temperatures at higher elevations, will tend to improve its climatic conditions for olive tree growth.
Some regions, most of the region, a large portion of,... I guess that this needs to be translated into numbers (in ha, or in % of land changing class) in order that the manuscript could achieve a minimal scientific soundness.
Author Response
Reply: We would like to thank the Reviewer for his/her comments, and we would also like to thank the reviewer for clarifying this point. We didn’t understand that the reviewer was asking for the numbers in terms of area. We have now added a new table (Table 3), summarizing the changes in yield classes in terms of area (ha).
