The Impact of Roadkill on Cervid Populations in Lithuania

Round 1

Reviewer 1 Report

I think this research issue is very good!  I have some suggestions to exchange with the authors:

 

Title:

 

I am very intrested in the title"what's the impact of roadkills of cervids on population abundance "?  But, after read this manuscript, I think the answers is not very excellent. Hope the authors will revise the manuscript and make the story easy and clear.  Maybe this title can be improved? 

 

Abstract:

 

1. I can not find any conclusion of this research, commonly, the conclusion should be list at the end of the abstract.

 

Keywords:

 

1. please add "road ecology"

 

Introduction:

 

1. Line 42, please delete "being", you write it twice.

 

2. Line 89, here is the aim of this research, similar to the title of this manuscript, and the next paragraph the aim was divided into three questions.  I think at least question 3rd is not related to the aim!  Question 1 and 2 together can not answer the aim of this research!

 

Materials and Methods:

 

1. Fig1: What's mean of the black dots?

 

2. Line 156, please add one reference for formula 2. How to calculate EN and BV?

 

 

 

Results:

 

1.Line 213, I can not understand what's the meaning of this paragraph. I think it's not enough to only compared roadkills within fenced roads section, if you compare roadkill in fenced road with that of unfenced road, I think it will be better.

 

2. Line 220, here the population number 3860 and 20676, I am curious this data, how to investigate? Or you infer it from some references?   I can't find the method.

 

 

 

Discussion

 

1. Concerning the second paragraph, since 40% of A. alces roadkills on roads in forests, and the average length of the fenced road sections is longer in forests (Line 113), I am confused about the efficiency of those fence? Can the fence prevent the moose entering the road? Why so many moose were killed on the roads in forests? Or not enough wildlife crossing structures were constructed for moose?

 

2. Line 262-264, here is numbers of not reported roadkills of Red deer are equal to those registered. I think this is a very serious problem!  Why the governmental agency neglect so many data? I hope to see some clarification.  

 

3. I think the cervids-vehicle collisions should cause some Life death and property loss, Lithuanian Police Traffic Supervision Service should have lots of these records. I think authors may discuss this.

 

Conclusions:

 

1. Totally I don't agree with this conclusions. I think it should answer the questions asked from the title and aim.  

Author Response

Answers attached:

Author Response File: Author Response.pdf

Reviewer 2 Report

Documenting, collating, and analysing the roadkill and hunting records for all of Lithuania is impressive. These finds do have the potential to be useful for understanding both the impact of ungulates on humans driving vehicles, but also the extent of the impact on ungulate populations. I hope that you will realise this goal

Further comments have been provided in the attached document.  

Comments for author File: Comments.pdf

Provided in the attached document.

Be aware, that there are many places where the English expression needs to be improved that have not been identified in the review.  

Author Response

Answers attached:

Author Response File: Author Response.pdf

Reviewer 3 Report

This study looks specifically at the impact of roadkill on cervids on population abundance by examining the efficiency of ungulate-vehicle collision registration data, which makes a useful contribution to the literature. There are some interesting results in this study which I really enjoyed. However, there are also a few issues that I believe the authors should consider that might improve or clarify the paper:

 

1. I enjoyed reading this paper, however, it took me a while to follow what the authors were planning to do at the beginning, since the title did not view Lithuania as a case study, and the Introduction section covered (1) forest as an important driver of roadkill, (2) UVC in European countries, and (3) registration efficiency in terms of UVC. I think the authors need a little bit of re-framing here to indicate the main research questions and the significance of this study.

 

2. Lines 124-132: A few concerns are as follows: (1) What is “professional roadkill registration” (Line 128)? I’m assuming this refers to the “professional survey carried out at Nature Research Centre”? Then I would suggest adding a brief introduction about the Lithuanian Police Traffic Supervision Service data, given that “the main source of UVC data is the Lithuanian Police Traffic Supervision Service”; (2) the descriptions of derived roadkill numbers (Lines 124-127) should be placed below the introduction of data collection (Lines 128-132), and it would great to see the detailed roadkill numbers derived from each source; (3) I wonder if by any chance there were duplicated records (either within one source or across two sources) identified and how they were handled.

 

3. Lines 137-151: The authors need to improve this section with greater clarity given the concerns I have about the RI: (1) there could be road-killed cervids that were also not recorded by the Nature Research Centre; (2) it was unclear how the potential duplicated records (if any) within one data sources were handled; (3) since the RI is expressed as the number of road-killed cervids per km, it would be a very small number with a long line after the decimal point; (4) “where 1750 is the length of main roads, and 4926 is the length of national roads in km” – the total lengths of the main/national roads might have changed significantly over the 20 years, the authors therefore need to justify why it is reasonable to use these lengths in equation 1; (5) Table 1 should be placed in the Result section (or supplementary material).

 

4. Lines 152-156: The name and characteristics of the data source for hunted animals are unclear.

 

5. Lines 159-160: “…, as well as proportion of roadkills in fenced and non-fenced areas were presented as mean and 95% CI, …” I think this is very useful information for understanding the effectiveness of these fences which in turn could provide insights to facilitate improvement and/or planning of mitigation measures, why not cover it as a side objective of this study?

 

6. Line 196: I think the authors need a clear definition for “forest-related roadkill” – is it roadkill of forest-related species (e.g. forest roe deer in contrast to field roe deer) or is it roadkill that occurred at a road section covered by forests? Also, what is the significance of determining the proportion of roadkill that occurred in forest habitats in contrast to any species' habitat?

 

7. Lines 326-334: This study is subject to several limitations that are not mentioned in this section. For example, the professional roadkill registration did not cover regional roads; the potential changes in the road network in the study area over the 20 years; potential mismatching between two data sources; etc.

 

 

8. Lines 335-341: This study aims to assess the impact of roadkill of forest ungulates on population abundance with three specific objectives (i.e. the proportion of unregistered UVC; the number of UVC in relation to the number of hunted animals; and the proportion of roadkill in forest habitat), however, the conclusions here seem irrelevant.

The English language is well written in general, however, there are a few minor editing required to clear the way for acceptance of the manuscript. Examples include (but are not limited to) the following points:

 

1. Consider replacing “Roadkills” with “road-kills” or “roadkill”.

 

2. Line 137: “Estimation how many…” should be “Estimation of” or “Estimating”.

 

3. Line 138: “RI = kc/L, expressed as the number of killed” – should use “road-killed” to avoid potential confusion.

 

 

4. Lines 159-160: “…, as well as proportion of roadkills in fenced and non-fenced areas…” should be “as well as the proportion of”

Author Response

Answers attached:

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The overall argument of your paper remains obscure to me.  You indicated in the introduction that the concern is about the impact of cervids on vegetation diversity, but then have not provided any background literature or data about the impacts of cervids on vegetation, and whether this varies with the different ungulate species you have monitored.

In the conclusion you seem to suggest that the paper was about the safety of drivers and how this is accounted for in the planning and management of these species.  If this is the point of your paper, then driver safety should feature in your introduction and be connected to your results.  You should also be discussing the planning and management in your introduction, and your discussion should be arguing about how it should change to reflect your findings.

I attach here your revised paper with extensive comments, including suggested rewordings.

I remain confused and concerned by the calculations you've done and whether the assumptions you've made are valid.  Without further information about the distance and location of your sampling, to demonstrate that you sampled across the whole of Lithuania, or that you sampled randomly, I think it is highly likely that your sampling is not representative, which would mean that your estimations are not valid.

I think figures 3, 4 and 5 remain misleading if there are dots occurring on top of each other.

I think there is great potential in this paper, but further work is required.

Comments for author File: Comments.pdf

Expression remains an issue and contributes to confusion about the design and outcomes of the study.  Extensive suggestions of alternative wording have been provided in comments, sometimes with two versions because the reviewer could not be certain of the authors' intentions.

Author Response

Thank you for your time and comments. Our answers are in the attached file (including those in PDF)

Author Response File: Author Response.pdf