Presence and Absence of Beehives as a Management Tool for Reducing Elephant-Induced Tree Mortality

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I have the great interest in this topic on beehive, elephant and trees. After my finish reading of this MS, I get to say this study has its merit. However, the results are not really interesting and convincing for me. 

The study was not well designed. The study was divided into three phases. Phase 1 and 2 seemed rational, while phase 3 seemed not rational. Intuitively, phase 3 should be set before phase 1 as a baseline. More rational, the phase 1, phase 2 and phase 3 should be replaced by 3 scenarios being implemented at the same period with cautious control of contextual setting mainly determined by emergence of wild elephant.  The current setting of three phases and corresponding findings implies the same emergence of wild elephant, which could not a robust assumption and might be wrong to a large extent. 

Regarding the literature published and cited by the author, I did find the results stated in this MS have been reported. Then, what is the unique findings of this MS? What is the knowledge gap being filled? 

The statement of beehive is not consistent in the whole article. In the section of introduction, the beehive is described a combination of preventing elephant damage, and making economic return. If so,  the beehive should not be removed from the trees. To this sense, again, Phase 3 was redundantly designed.

Three pictures, indicating three different setting of beehives, were not informative and failed to indicate the real situation caused by the elephants. 

Since I am not a native English speaker, I have no suggestion for language of this MS. 

 

Author Response

Comment 1: The study was not well designed. The study was divided into three phases. Phase 1 and 2 seemed rational, while phase 3 seemed not rational. Intuitively, phase 3 should be set before phase 1 as a baseline. More rational, the phase 1, phase 2 and phase 3 should be replaced by 3 scenarios being implemented at the same period with cautious control of contextual setting mainly determined by emergence of wild elephant.  The current setting of three phases and corresponding findings implies the same emergence of wild elephant, which could not a robust assumption and might be wrong to a large extent. 

Reply: Thank you for this comment and we understand where the reviewer is coming from with this statement. As we are writing a Brief Report, we failed to mention that we had published a paper before the commencement of the beehive project (Cook et al. 2017 - Forest Ecology and Management journal), where we showed alarming declines of marula trees. We thus implemented the bee project in this protected area and then due to logistic constraints, had to close it down eventually. So whilst we did not plan the Phases 1-3 from the start, the closure of the project actually allowed us the opportunity to assess these trees after the removal of the beehives to see if the mortality rates increased once more, which they indeed did do so. We have made edits to the following phrase in the Introduction: 

"Initial results over nine months (year 2015) suggested that marula trees containing beehives had a significantly reduced probability of receiving elephant impact in comparison to marula trees without beehives (7), reducing marula tree mortality from 8.1% per annum before the addition of beehives (2013-2015) (16), to 2% per annum after the addition of beehives (2015-2020) (8). Owing to logistic constraints with study site accessibility and the need for the active beehives to be hung at a new location, Elephants Alive, the South African not-for-profit company responsible for this research, slowly reduced the number of beehives within the study site after 2020, until all beehives were removed after seven years in 2022."

We have also added the following to the Discussion: "Whilst the annual mortality rate in phase 3 (8.7%) surpassed the reported annual mortality rate of 8.1% prior to the addition of beehives (16), it is still a large increase from 3.1% when beehives were present."

 

Comment 2: Regarding the literature published and cited by the author, I did find the results stated in this MS have been reported. Then, what is the unique findings of this MS? What is the knowledge gap being filled? 

Reply: We believe that we have justified the results of this paper by now pointing out that not only did the presence of beehives drastically decreased the decline of marula trees, but their subsequent removal due to logistic constraints resulted in a major decline once again. We also show how the beehives may have acted as a barrier for elephants impacting the control trees in the site, emphasized in the Discussion: "The presence of the beehives on trees may have had a small spatial effect on protecting the surrounding trees from elephant impact by potentially decreasing the time that elephants spent in the study site (suggested by the increased decline of the original unprotected trees between Phases 2-3." None of this is presented in our previous papers, as and the purpose of this Brief Report (not full manuscript) is to showcase these new results, we believe that we have justified the purpose of showcasing the impact that the presence and absence of beehives have had on marula tree persistence.  

 

Comment 3: The statement of beehive is not consistent in the whole article. In the section of introduction, the beehive is described a combination of preventing elephant damage, and making economic return. If so,  the beehive should not be removed from the trees. To this sense, again, Phase 3 was redundantly designed.

Reply: We have now pointed out that the project was closed due to logistic constraints with site accessibility. We thus emphasize that it was not due to the failure of the project. Whilst it is unfortunate that the beehives had to be moved elsewhere, it did indeed present us with the opportunity to re-asses all of the trees, now with no beehives (Phase 3), so as to assess what happened to these trees now that no bees were present. We therefore show how the mortality rate drastically increases to a level only seen before bees were present. We hope that this is now clear in our manuscript. 

 

Comment 4: Three pictures, indicating three different setting of beehives, were not informative and failed to indicate the real situation caused by the elephants. 

Reply: We have added a new graphic design to better illustrate the three Phases so that is it more clear to the readers. 

Reviewer 2 Report

Comments and Suggestions for Authors

The authors assessed the use of beehives as a management strategy to reduce elephant damage on marula trees in South Africa.

The main question addressed by the research was whether trees with beehives were better protected from elephant browsing than trees without beehives.

The research is considered novel because, although beehives have been used to protect trees from elephant browsing, there was no experimental assessment of the efficiency of this strategy. Therefore, this research adds experimental evidence and insights into elephant management strategies. The subject of the research is suitable for Diversity because protecting trees maintains and increases the diversity of plants and their associated animals and other organisms.

The manuscript text conveys the authors’ thoughts clearly and unambiguously. The theory underlying the research has been succinctly given. Research design, data collection, handling, and analysis have been carried out using proper methods. The data has been appropriately interpreted.

The research questions were elaborately addressed by a specific experiment. The efficacy of beehives for protecting trees from elephant browsing was determined and assessed with a 3-phase experiment: beehives, reduced beehives, no beehives on trees.

The manuscript has included all the relevant to the research references. Tables and Figures are useful and nicely laid out. The quality of the data supports the analysis and conclusions. All arguments and conclusions have been supported by relevant references.

Overall, the research design, analysis, and discussion have been very well carried out, in line with the produced evdence. The manuscript presented novel research that can be considered a significant contribution to the field of elephant damage management.

Author Response

Thank you to Reviewer 2 for their comments on the manuscript. We appreciate the feedback and will not comment further as we did not detect any changes in the review.

Reviewer 3 Report

Comments and Suggestions for Authors

REV

Good manuscript reporting an interesting conservation/management problem (the protection of trees by elephant’s damages using beehives). Manuscript is well written, experimental protocol is good, statistic is strong, data are reliable. Figures are very explicative. I like this type of paper and I think that it deserves to be published, as soon as possible, after MINOR REVISIONS. Perhaps some more references could be added (see, e.g., about citizen management and on the BACI approach, below). I added below some minor comments that, I hope, could improve a bit this good manuscript.

MINOR POINTS

Authors should specificate that they used a treatment/control design (trees with beehives vs. trees without beehives). They should cite also the BACI approach (before-after-control-impact) in conservation (Smith, E. P. (2002). BACI design. Encyclopedia of environmetrics, 1, 141-148; and applications: e.g., PLoS One, 7(3), e32569, https://doi.org/10.1371/journal.pone.0032569

and Insect Conservation and Diversity, 15(1), 149-156).

The authors should clarify what the weaknesses of using beehives may be. For example, is it possible that in the presence of people (e.g., shepherds) or other stakeholders this method may not guarantee safety? See, for example, GeoJournal, 2020, 85: 565-577.

In the final considerations it can be added whether this approach (use of beehives) can also be adopted autonomously by stakeholders, thus adopting a citizen management approach (much more pervasive and effective than an approach started in an institutional way only by managers). See Israel Journal of Ecology and Evolution, 68(1-4), 8-12,  https://doi.org/10.1163/22244662-bja10029. I would like to read something about a citizen managements carried out by people in this regard. For example: Is it possible to train operators among local people?

About beehives (fences) and elephants see also: Conservation Science and Practice, 2(10), e260; Oryx, 53(1), 92-99, PLoS One, 11(5), e0155690 and others. Please add them.

Add the role of the anonymous reviewers and editors in the Acknowledgements.

Have a nice work.

Comments for author File: Comments.pdf

Author Response

Comment 1: Authors should specificate that they used a treatment/control design (trees with beehives vs. trees without beehives). They should cite also the BACI approach (before-after-control-impact) in conservation (Smith, E. P. (2002). BACI design. Encyclopedia of environmetrics, 1, 141-148; and applications: e.g., PLoS One, 7(3), e32569, https://doi.org/10.1371/journal.pone.0032569 and Insect Conservation and Diversity, 15(1), 149-156).

Reply: Thank you. both of these points have now been included in the manuscript.

 

Comment 2: The authors should clarify what the weaknesses of using beehives may be. For example, is it possible that in the presence of people (e.g., shepherds) or other stakeholders this method may not guarantee safety? See, for example, GeoJournal, 2020, 85: 565-577.

Reply: Thank you, this  was a very good point. We have added the safety concerns in the Discussion section. 

 

Comment 3: In the final considerations it can be added whether this approach (use of beehives) can also be adopted autonomously by stakeholders, thus adopting a citizen management approach (much more pervasive and effective than an approach started in an institutional way only by managers). See Israel Journal of Ecology and Evolution, 68(1-4), 8-12,  https://doi.org/10.1163/22244662-bja10029. I would like to read something about a citizen managements carried out by people in this regard. For example: Is it possible to train operators among local people?

Reply: Thank you for this comment. We have added this statement in the final paragraph of the Discussion and referenced accordingly.

 

Comment 4: About beehives (fences) and elephants see also: Conservation Science and Practice, 2(10), e260; Oryx, 53(1), 92-99, PLoS One, 11(5), e0155690 and others. Please add them.

Reply: Thank you for these suggestions. We have added the oryx reference. The other 2 refer to Asian elephants and honey bees and as we are just writing a brief report on the African situation, we have chosen to only select the African references. 

 

Comment 5: Add the role of the anonymous reviewers and editors in the Acknowledgements.

Reply: This has now been included in the Acknowledgements section.