The Filtering Effect of Oil Palm Plantations on Potential Insect Pollinator Assemblages from Remnant Forest Patches
Round 1
Reviewer 1 Report
The paper brings original reuslts of authors´research and suits the scope of the journal. The structure of the paper follows a structure of a scientific paper.
Some comments for improvement of the paper are as follows:
1. Methods used by data analysis should be described in more detail.
2. In conclusions better underline the novelty of the paper, add information regarding limitation of the study and e direction of the further research.
The english writing is at the scientific level, only minor editing is needed.
Author Response
The paper brings original reuslts of authors´research and suits the scope of the journal. The structure of the paper follows a structure of a scientific paper.
Some comments for improvement of the paper are as follows:
- Methods used by data analysis should be described in more detail.
Morphospecies individuals were analysed at the level of trap (6 traps × 6 transects) and repeated samples (18 samples) from each trap station were pooled. All statistical analyses of morphospecies abundance and diversity were completed in R statistical software.
Second order or higher linear functions were fitted to the models to illustrate the relationship between insect diversity and distance from the ecotone.
- In conclusions better underline the novelty of the paper, add information regarding limitation of the study and e direction of the further research.
Please see the Conclusions section 5. Here we draw out the unique findings and interpret them in the context of the limitations of the study.
Reviewer 2 Report
The reviewed manuscript is an interesting and well-conducted study on insect biodiversity across transects straddling native forest habitat and oil palm plantations in Malaysia. While the survey and analysis methods are mostly sound, I am uncertain that the study truly investigates pollinator species of oil palm in the landscape, and so I suggest reframing the premise of the study to focus more on general insect biodiversity. Investigating insect composition and diversity in the area is a valid and needed area of research in its own right. However, to determine alternate pollinator species of oil palm, some sort of visitation study or pollination observation would need to be done. The authors can mention in the discussion that some of these insects may be “potential” pollinators, and more study is needed to determine which (if any) pollinate oil palm, but any more than that is outside the scope of this research as I see it.
Line comments:
L2: Suggest replacing “potential insect pollinator assemblages” with “insect community composition” or similar
L17: unsure what authors mean by “moot point”. Clarify or rephrase
L32: suggest removing “oil palm” as a keyword as it is already in the title
L80: Unclear what soft and hard boundaries are- define these terms
L109, 118: make sure that HCV areas is defined in L109
L130: I am unclear why the authors put a focus on Apidae and Diptera as “potential pollinators” when it seems already established that thrips are the main pollinators of oil palm. Is there any research to show that these groups pollinate oil palm in other areas? Apologies if I’ve missed explanation of this.
L131: “are also examined” – rewrite sentence to avoid passive voice. I.e. “We examined…”
L155: Figure 1: use black font for all transect labels on map, the white is hard to read. Define the meaning of light and dark green in the figure legend
L177: Please provide further explanation of methods of morphospecies identification including any published methods, keys and books used.
L190: Define how categories of trees, poles, and saplings were determined
L211: Provide R version used
L216: Chao1 misspelled
L333: Figure 6: make figure legend larger and outside of the panels, preferably at the bottom of the figure.
L378-381: Include Thysanoptera (known pollinators of oil palm) in the main figures in addition to the other orders. Discussion of this result should be expanded.
L385: Why are bee species plotted differently than the other species in this and other figures? It’s unclear why only 2 transects are plotted and they are plotted separately. Were these the only two transects where bees were found?
L446-469: Remove or reword discussion of filtering of “habitat specialists”. The authors did not measure specialism or generalism of any order or species, other than known oil palm specialists of Thysoptera. It is true that habitat homogenization can lead to a reduction in specialist species, but this should not be framed as a result of this study.
L506: pollination supplementation would have to be proved by a pollinator observation study as well as a pollinator exclusion experiment with measurement of fruit set.
Conclusions section overly long and needs focus and clarification of conflicting statements. Suggest condensing to only main conclusions that can actually be drawn from measured data.
L560: This sentence is not a true statement. Diversity can be measured in many other ways (evenness, genetic diversity, functional diversity, etc). Remove
L586: provide reference for this policy
L591: You state on L476 that forest can serve as a reservoir for predators of pollinators that affect yield. So the statement that “including forest fragments…has only positive benefits for oil palm productivity” cannot be true
L614: reivise “X.X”
L620: define IBEC
Supplementary Information
Figure S1: place order labels on each figure panel as in main text
Figures S2 and S3: I am not familiar with this type of analysis, and much more information is needed to understand these figures. Define axes, colors, what functional range means at habitat and global scale.
English is fine and the manuscript is well written. Some typos and editing errors throughout, can be easily revised before next submission with a more thorough proofread.
Author Response
The reviewed manuscript is an interesting and well-conducted study on insect biodiversity across transects straddling native forest habitat and oil palm plantations in Malaysia. While the survey and analysis methods are mostly sound, I am uncertain that the study truly investigates pollinator species of oil palm in the landscape, and so I suggest reframing the premise of the study to focus more on general insect biodiversity. Investigating insect composition and diversity in the area is a valid and needed area of research in its own right. However, to determine alternate pollinator species of oil palm, some sort of visitation study or pollination observation would need to be done. The authors can mention in the discussion that some of these insects may be “potential” pollinators, and more study is needed to determine which (if any) pollinate oil palm, but any more than that is outside the scope of this research as I see it.
We agree entirely with this sentiment and is the reason we refer repeatedly throughout the manuscript to “potential insect pollinator assemblages” and chose the specific orders we did as all of these have been implicated as possible pollinators of oil palm. Our intention is to follow-up this study with observations of the pollinator visitations.
Line comments:
L2: Suggest replacing “potential insect pollinator assemblages” with “insect community composition” or similar
See response above
L17: unsure what authors mean by “moot point”. Clarify or rephrase
The word “moot” in this context means “debateable” or “questionable” or “highly uncertain”– we clarify in the clause that follows the statement that so much forest has been cleared that the effect of native pollinators from forest is “highly uncertain”. We have replaced “moot” with “uncertain”.
L32: suggest removing “oil palm” as a keyword as it is already in the title
Done
L80: Unclear what soft and hard boundaries are- define these terms
Have added in explanation in parentheses “It is clear that oil palm plantations present a boundary barrier, varying in effect from soft (a moderately permeable barrier to cross-boundary movement) to hard (impermeable boundary with little penetration into oil palm) depending on the functional traits of the native species…”
L109, 118: make sure that HCV areas is defined in L109
Done
L130: I am unclear why the authors put a focus on Apidae and Diptera as “potential pollinators” when it seems already established that thrips are the main pollinators of oil palm. Is there any research to show that these groups pollinate oil palm in other areas? Apologies if I’ve missed explanation of this.
Flies and bees make up the largest groups of insect pollinators worldwide. We examined their functional diversity here just in there is a missing functional class that thrips fill. We make this clearer in the text. “The functional diversity of two important pollinator groups, flies (Diptera) and bees (Apoidae) were examined, seeking a functional gap filled by thrips that are known to pollinate oil palm.”
L131: “are also examined” – rewrite sentence to avoid passive voice. I.e. “We examined…”
Done throughout
L155: Figure 1: use black font for all transect labels on map, the white is hard to read. Define the meaning of light and dark green in the figure legend
Done.
L177: Please provide further explanation of methods of morphospecies identification including any published methods, keys and books used.
Inserted reference to method used to identify morphospecies
L190: Define how categories of trees, poles, and saplings were determined
Done
L211: Provide R version used
Done
L216: Chao1 misspelled
Corrected
L333: Figure 6: make figure legend larger and outside of the panels, preferably at the bottom of the figure.
Have not made this change as it is a matter of personal preference – we prefer the format submitted.
L378-381: Include Thysanoptera (known pollinators of oil palm) in the main figures in addition to the other orders. Discussion of this result should be expanded.
It was not possible to model the Thrips in the same way as the other orders as too few specimens were captured for comparison.
L385: Why are bee species plotted differently than the other species in this and other figures? It’s unclear why only 2 transects are plotted and they are plotted separately. Were these the only two transects where bees were found?
There were only two sets of transects – one in Bukit Durang and the other in HCV 4 – see methods. Comparatively few bees were recorded and were analysed separately as potential pollinators of oil palm. Here we illustrate that bees were similarly abundant in both forest patches of very different size, although few in number in both.
L446-469: Remove or reword discussion of filtering of “habitat specialists”. The authors did not measure specialism or generalism of any order or species, other than known oil palm specialists of Thysoptera. It is true that habitat homogenization can lead to a reduction in specialist species, but this should not be framed as a result of this study.
We have edited the text so that our references to specialism and generalism are made with reference to what has been found by other studies and how our work supports these findings or not.
L506: pollination supplementation would have to be proved by a pollinator observation study as well as a pollinator exclusion experiment with measurement of fruit set.
Yes, agreed – this is our next step. We have altered the text to read “…have the potential to supplement pollination…”
Conclusions section overly long and needs focus and clarification of conflicting statements. Suggest condensing to only main conclusions that can actually be drawn from measured data.
L560: This sentence is not a true statement. Diversity can be measured in many other ways (evenness, genetic diversity, functional diversity, etc). Remove
Removed
L586: provide reference for this policy
This is a policy adopted by management on the estate – no specific reference available.
L591: You state on L476 that forest can serve as a reservoir for predators of pollinators that affect yield. So the statement that “including forest fragments…has only positive benefits for oil palm productivity” cannot be true
Revised to say “…has mainly positive benefits…”
L614: reivise “X.X”
L620: define IBEC
Supplementary Information
Figure S1: place order labels on each figure panel as in main text
Done
Figures S2 and S3: I am not familiar with this type of analysis, and much more information is needed to understand these figures. Define axes, colors, what functional range means at habitat and global scale.
We have defined the axes, colours and refer the reader to the methods for further information. As this is supplementary information, if the reader requires further detail they can source it through the references.
Comments on the Quality of English Language
English is fine and the manuscript is well written. Some typos and editing errors throughout, can be easily revised before next submission with a more thorough proofread.
A thorough proofread has been conducted.
Reviewer 3 Report
The topic of the article is interesting.
However, I would like to make some observations as follows.
The paper aims must be clearly expressed in the Abstract.
The paper should objectively indicate the contribution of the work to the field and the progress of the research.
Would it be possible to the author to add the process flow diagram to get the idea of the overall process?
Line 143 - the unit of mean annual rainfall is m?
Line 239 – replace (Schleuter et al., 2011) by [70]
Line 440 –Edwards, Edward is not [76]; Edwards, Edward is [60]
Author Response
The topic of the article is interesting.
However, I would like to make some observations as follows.
The paper aims must be clearly expressed in the Abstract.
This we do “In this study, we investigate the value of small high conservation value (HCV) forests as sources of potential native insect pollinators of oil palm in northern Sarawak. We further examine the filtering effect of oil palm dominated landscapes on the species assemblages of six insect orders…”
The paper should objectively indicate the contribution of the work to the field and the progress of the research.
Again – please see concluding sentences of abstract and Conclusions section of the Discussion.
Would it be possible to the author to add the process flow diagram to get the idea of the overall process?
After assessment, and not being clear what is meant by the “overall process” we have not implemented this suggestion.
Line 143 - the unit of mean annual rainfall is m?
Corrected
Line 239 – replace (Schleuter et al., 2011) by [70]
Corrected
Line 440 –Edwards, Edward is not [76]; Edwards, Edward is [60]
In the submitted copy of the manuscript the citation numbers have been corrected as they were not copied in Endnote format after 75 in the original submission. I leave this to your production team to check.
Round 2
Reviewer 2 Report
Thank you for your revision and response. While the manuscript is improved, I still feel that the premise of the paper is misleading. It is true that bees are the most efficient and widespread pollinators of plants worldwide. However, there is still no clear presentation of literature or observations to reasonably hypothesize bees or flies as potential pollinators of oil palm specifically. I do not think the paper has been revised enough to be acceptable for publication in Land.
