the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
European pollen-based REVEALS land-cover reconstructions for the Holocene: methodology, mapping and potentials
Ralph Fyfe
Marie-Jose Gaillard
Anna-Kari Trondman
Florence Mazier
Anne-Birgitte Nielsen
Anneli Poska
Shinya Sugita
Jessie Woodbridge
Julien Azuara
Angelica Feurdean
Roxana Grindean
Vincent Lebreton
Laurent Marquer
Nathalie Nebout-Combourieu
Miglė Stančikaitė
Ioan Tanţău
Spassimir Tonkov
Lyudmila Shumilovskikh
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- Final revised paper (published on 08 Apr 2022)
- Preprint (discussion started on 26 Oct 2021)
- Supplement to the preprint
Interactive discussion
Status: closed
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RC1: 'Comment on essd-2021-269', Qinghai Xu, 15 Nov 2021
Pollen-based quantitative reconstruction of past vegetation and land-use is necessary for the evaluation of climate models, land-use scenarios and the study of past climate-land cover interactions. In recent years, with the help of the ERV models and the Landscape Reconstruction Algorithm (LRA, including the REVEALS and LOVE models), makes it possible to quantify plant cover from pollen records at a regional spatial scale. This study collected the original RPP values from sixteen study regions and verified the quality of RPP values; Finally, they provided a synthesized RPPs dataset of 54 taxa in Europe, and then reconstructed the history of 12 plant functional types (PFTs) and three land-cover types (LCTs) during the Holocene based on 31 selected RPP values and REVEALS model, the results provided valuable basis for climate modelling studies.
Some comments and suggestion listed below:
Q1: Why the British had sparse distribution of Evergreen Trees (such as Pinus and Picea) during the Holocene?
line 114: What does the "reliable number of sites" mean in Figure 1B? Please provide detailed description for Figure 1.
line 127: Does the "j" represent for the total number of species included for pollen proportion calculation?
line 296: There has only 3 PFTs which are composed 12 taxa in Summer green trees (ST); and 3 PFTs which are composed 10 taxa Open land
(OL), see Table 1.
line 322: Evergreen Trees
line 410: The mean count size across all samples is 3550. Is that right?Citation: https://doi.org/10.5194/essd-2021-269-RC1 -
CC1: 'Reply on RC1', Esther Githumbi, 23 Nov 2021
Thank you for your comments, we are grateful that you have taken the time to go through the manuscript. I will respond to the questions and comments in the same order.
Q1: Why the British had sparse distribution of Evergreen Trees (such as Pinus and Picea) during the Holocene?
The REVEALS uses the pollen counts of the taxa in the reconstruction and so the simple answer is that the sparse distribution observed is because of the low evergreen tree taxa pollen counts in the records. However if you are asking from an ecological point of view then I have passed the question to collaborators who are experts about the British Isles Holocene land-cover.
line 114: What does the "reliable number of sites" mean in Figure 1B? Please provide detailed description for Figure 1.
Reliable number of sites means grid cells that have multiple large lakes\bogs, we explain this further in section 4.1 from line 422 but we will provide a detailed description of the figure as requested.
line 127: Does the "j" represent for the total number of species included for pollen proportion calculation?
yes
line 296: There has only 3 PFTs which are composed 12 taxa in Summer green trees (ST); and 3 PFTs which are composed 10 taxa Open land\(OL), see Table 1.\line 322: Evergreen Trees
The mistakes have been noted and will be corrected.
line 410: The mean count size across all samples is 3550. Is that right?
Yes, most (77%) of the counts are above 1000 (line 409). Each sample is an aggregation of counts for a time window inorder to obtain a large enough count for a reliable REVEALS reconstruction (lines 205, 405). We will also discuss that sentence to see if there is a way to clarify it further in the text.
Citation: https://doi.org/10.5194/essd-2021-269-CC1 -
AC1: 'Reply on RC1', Esther Githumbi, 07 Jan 2022
Thank you for your comments, we are grateful that you have taken the time to go through the manuscript. I will respond to the questions and comments in the same order.
Q1: Why the British had sparse distribution of Evergreen Trees (such as Pinus and Picea) during the Holocene?
The REVEALS uses the pollen counts of the taxa in the reconstruction and so the simple answer is that the sparse distribution observed is because of the low evergreen tree taxa pollen counts in the records.
line 114: What does the "reliable number of sites" mean in Figure 1B? Please provide detailed description for Figure 1.
Reliable number of sites means grid cells that have multiple large lakes\bogs, we explain this further in section 4.1 from line 422 but we will provide a detailed description of the figure as requested.
line 127: Does the "j" represent for the total number of species included for pollen proportion calculation?
yes
line 296: There has only 3 PFTs which are composed 12 taxa in Summer green trees (ST); and 3 PFTs which are composed 10 taxa Open land\(OL), see Table 1.\line 322: Evergreen Trees
The mistakes have been noted and will be corrected.
line 410: The mean count size across all samples is 3550. Is that right?
Yes, most (77%) of the counts are above 1000 (line 409). Each sample is an aggregation of counts for a time window inorder to obtain a large enough count for a reliable REVEALS reconstruction (lines 205, 405). We will also discuss that sentence to see if there is a way to clarify it further in the text.
Citation: https://doi.org/10.5194/essd-2021-269-AC1
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CC1: 'Reply on RC1', Esther Githumbi, 23 Nov 2021
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RC2: 'Comment on essd-2021-269', Mary Edwards, 29 Nov 2021
General comments
This paper concerns the use of Holocene pollen records to estimate taxon distributions and land-cover changes (LCC) through time for Europe, including the Mediterranean. It describes in detail the current state of the art use of the Landscape Reconstruction Algorithm (LRA) for the most intensely studied continental area--Europe. Of particular interest is the reduction of bias in pollen representation that allows a more accurate reconstruction of the interplay of open and forested land through time, a major proportion of which is likely related to anthropogenic land-use change.The paper provides information on the general approach, data sources and sites, and choice of methods. It includes a detailed comparison of the numerous studies that have generated relative pollen productivity (RPP) values and a justification of the choices made in the production of the set of values used in this new iteration. The main sources of uncertainty are discussed and future improvements to methods and data are anticipated. Several useful tables provide a comprehensive list of regional studies, RPPs (including inconsistencies among studies) and data sources. Maps provide examples of the reconstructions through time.
Overall, this is an important contribution that brings together a large body of work and makes much information accessible in one place. It is carefully contructed, comprehensive and well explained.
Specific comments
p 27-28. Given the likelihood that the maps created by this approach will be used in various other applications (which are indeed mentioned in the discussion), some idea of progress towards a more "believable" depiction of LCC it might be useful: i) some comments on how far the process has come, compared with simple pollen-based maps or landcover maps generated by other means, and ii) perhaps a "health warning" that the data (RPPs and maps) are still approximations, for which there are suitable but also unsuitable applications. Some mention of this is made in the discussion of the use of the LOVE package for local sites, such as might be of interest in archaeology. It is quite difficult to use this package (that is, to bring together the right site and the right data); given that, and the easy information the maps provide, it might be useful to emphasise that single grid cells on don't reflect "local" information.P 29. It would be good if the first sentence acknowledges that while the LRA goes far beyond anything attempted before in the way of bias correction for pollen-based reconstructions, it is built on previous ideas, notably, the R-value approach of Davis, which was taken up by many other authors, including Prentice (who is mentioned) and actually, biomization, which because it uses a square-root function, does, in a non-specific way, reduce the impact of high pollen producers on large-scale reconstructions of vegetation cover.
Technical
The map figures have great value, and it might be worth reviewing how easily they can be read and interpreted.
- Fig 1: difficult to distinguish lake and bog colours
- Figs 2-6: ensure error circles are visible on dark cell colours. It takes high magnification to see them and even then they are indistinct. Many are large and therefore important to show.
Table B2 should read Romania (is correct in Tab C1)
The manuscript is well written and largely devoid of typos. I did spot a few (this list is unlikely to be comprehensive though).
L 147 should read The Prentice model OR Prentice's model
L163, no colon require after the verb "are"L409 Start sentence with "Seventy-seven percent"
L410 no comma needed
L414 reword to "pollen from ruderals, for example, is often related..."
L513 naturally open (no hyphen)
Citation: https://doi.org/10.5194/essd-2021-269-RC2 -
CC2: 'Reply on RC2', Esther Githumbi, 01 Dec 2021
Thank you for taking the time to read our manuscript and providing a lst of constructive comments. I would like to acknowledge that we have seen the comments and I\we will provide a detailed response to each of them in the next few days.
Citation: https://doi.org/10.5194/essd-2021-269-CC2 -
CC3: 'Reply on RC2', Esther Githumbi, 21 Dec 2021
Please find below detailed responses to the comments.
Specific comments
- p 27-28. Given the likelihood that the maps created by this approach will be used in various other applications (which are indeed mentioned in the discussion), some idea of progress towards a more "believable" depiction of LCC it might be useful: i) some comments on how far the process has come, compared with simple pollen-based maps or land cover maps generated by other means, and ii) perhaps a "health warning" that the data (RPPs and maps) are still approximations, for which there are suitable but also unsuitable applications. Some mention of this is made in the discussion of the use of the LOVE package for local sites, such as might be of interest in archaeology. It is quite difficult to use this package (that is, to bring together the right site and the right data); given that, and the easy information the maps provide, it might be useful to emphasise that single grid cells on don't reflect "local" information.
Response:
We appreciate the suggestions of a) making clear that the REVEALS maps are approximations of regional plant cover (not local cover!), b) developing a bit what is/are the advantage(s) of such reconstructions compared to pollen maps or maps based on other methods (e.g. biomization), and c) adding some words on the use of REVEALS vegetation cover for the application of the LOVE model. We take this comment into account by adding some text at the beginning of section 4.3 and restructuring the existing text.
- P 29. It would be good if the first sentence acknowledges that while the LRA goes far beyond anything attempted before in the way of bias correction for pollen-based reconstructions, it is built on previous ideas, notably, the R-value approach of Davis, which was taken up by many other authors, including Prentice (who is mentioned) and actually, biomization, which because it uses a square-root function, does, in a non-specific way, reduce the impact of high pollen producers on large-scale reconstructions of vegetation cover.
Response:
We agree that it is of importance to mention the R-Value Model of Davis and biomization in the context of this paper. We have taken into account this comment as follows:
- We develop the question of biomization in comparison to REVEALS reconstructions in the discussion under “Use of the REVEALS reconstructions” (see above).
- We deleted the first sentence of the section 7 Conclusions, i.e. “The LRA REVEALS and LOVE models (Sugita, 2007a, 2007b) are the only current land-cover reconstruction approaches based on pollen data that incorporate assumptions that reduce the biases caused by the non-linear pollen-vegetation relationship, differences in sedimentary archives and spatial scales.” Because this statement is not entirely correct, as highlighted.
- We mention Davis R-Value in section 2.1 and refer to other papers for the development of pollen-vegetation modelling from the R-Value to the REVEALS model.
Technical comments
- The map figures have great value, and it might be worth reviewing how easily they can be read and interpreted.
- Fig 1: difficult to distinguish lake and bog colours
- Figs 2-6: ensure error circles are visible on dark cell colours. It takes high magnification to see them and even then they are indistinct. Many are large and therefore important to show.
- Table B2 should read Romania (is correct in Tab C1)
- The manuscript is well written and largely devoid of typos. I did spot a few (this list is unlikely to be comprehensive though).
Response:
- We have done so far what we could to maximize the readability of Figures 1-6. We are also of the opinion that such Figures can be studied at the computer with zooming, which is a big advantage. Making these Figures very easily readable on paper would imply that we decrease significantly the number of Figures per Figure, which would decrease the number of maps we could include in the paper. However, we will rely on and follow the decision of the Editor in this issue and will follow it.
- We have implemented all corrections of points 4 and 5.
Citation: https://doi.org/10.5194/essd-2021-269-CC3 -
AC2: 'Reply on RC2', Esther Githumbi, 07 Jan 2022
We appreciate the time and effort taken in reviewing our manuscript and providing insightful comments. The authors considered the comments and tried our best to address every one of them.
Please find below detailed responses to the comments.
Specific comments
- p 27-28. Given the likelihood that the maps created by this approach will be used in various other applications (which are indeed mentioned in the discussion), some idea of progress towards a more "believable" depiction of LCC it might be useful: i) some comments on how far the process has come, compared with simple pollen-based maps or land cover maps generated by other means, and ii) perhaps a "health warning" that the data (RPPs and maps) are still approximations, for which there are suitable but also unsuitable applications. Some mention of this is made in the discussion of the use of the LOVE package for local sites, such as might be of interest in archaeology. It is quite difficult to use this package (that is, to bring together the right site and the right data); given that, and the easy information the maps provide, it might be useful to emphasise that single grid cells on don't reflect "local" information.
Response:
We appreciate the suggestions of a) making clear that the REVEALS maps are approximations of regional plant cover (not local cover!), b) developing a bit what is/are the advantage(s) of such reconstructions compared to pollen maps or maps based on other methods (e.g. biomization), and c) adding some words on the use of REVEALS vegetation cover for the application of the LOVE model. We take this comment into account by adding some text at the beginning of section 4.3 and restructuring the existing text.
- P 29. It would be good if the first sentence acknowledges that while the LRA goes far beyond anything attempted before in the way of bias correction for pollen-based reconstructions, it is built on previous ideas, notably, the R-value approach of Davis, which was taken up by many other authors, including Prentice (who is mentioned) and actually, biomization, which because it uses a square-root function, does, in a non-specific way, reduce the impact of high pollen producers on large-scale reconstructions of vegetation cover.
Response:
We agree that it is of importance to mention the R-Value Model of Davis and biomization in the context of this paper. We have taken into account this comment as follows:
- We develop the question of biomization in comparison to REVEALS reconstructions in the discussion under “Use of the REVEALS reconstructions” (see above).
- We deleted the first sentence of the section 7 Conclusions, i.e. “The LRA REVEALS and LOVE models (Sugita, 2007a, 2007b) are the only current land-cover reconstruction approaches based on pollen data that incorporate assumptions that reduce the biases caused by the non-linear pollen-vegetation relationship, differences in sedimentary archives and spatial scales.” Because this statement is not entirely correct, as highlighted.
- We mention Davis R-Value in section 2.1 and refer to other papers for the development of pollen-vegetation modelling from the R-Value to the REVEALS model.
Technical comments
- The map figures have great value, and it might be worth reviewing how easily they can be read and interpreted.
- Fig 1: difficult to distinguish lake and bog colours
- Figs 2-6: ensure error circles are visible on dark cell colours. It takes high magnification to see them and even then they are indistinct. Many are large and therefore important to show.
- Table B2 should read Romania (is correct in Tab C1)
- The manuscript is well written and largely devoid of typos. I did spot a few (this list is unlikely to be comprehensive though).
Response:
- We have done so far what we could to maximize the readability of Figures 1-6. We are also of the opinion that such Figures can be studied at the computer with zooming, which is a big advantage. Making these Figures very easily readable on paper would imply that we decrease significantly the number of Figures per Figure, which would decrease the number of maps we could include in the paper. However, we will rely on and follow the decision of the Editor in this issue and will follow it.
- We have implemented all corrections of points 4 and 5.
Citation: https://doi.org/10.5194/essd-2021-269-AC2
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CC2: 'Reply on RC2', Esther Githumbi, 01 Dec 2021