A Review on Eurasian Otters in Urban Areas: Principles for the Enhancement of Biodiversity
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsReview
General notes
I have read the submitted manuscript. It contains a good literature review of the lifestyle, ecological preferences and place in natural ecosystems for this animal species. It should be especially noted that the principles proposed by the authors for supporting otter populations in urbanized habitats are supported by direct references to original studies in different countries. However, the work completely lacks any new data obtained as a result of the authors' original research… Therefore, this manuscript should be classified as a review rather than a research article. I leave it to the editor-in-chief to decide whether such materials can be published as a scientific article; many journals exclude this possibility. I have no significant comments on the content and scientific reliability of the information provided in the manuscript.
Some minor comments and questions are listed below:
Line 32 flagship species
The term is unclear, please express yourself more clearly.
Line 43 size and colour
Excuse me, what does size and especially color have to do with it? What significance do these external parameters have for nature conservation?...
Line 139 In terms of river morphology, otters prefer natural physical dynamics and little to no incisions or simplifications
Do not understand this expression, please, make it clearer, what simplifications?
Line 198 Smooth coated otters
Provide scientific Latin name here
Line 222 The utilization of daylighting by removing concrete was an effective method…
Do not understand this expression about daylighting and concrete, please, make it clear.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper gives a basic summary of the principles that could be used to allow for Eurasian otter restoration.
Line 38 – could improve the ecological status of what, the rivers, other species?
Line 43 – perhaps mention other species that can cause identification issues, such as mink.
Line 50 – it would also be good to include information somewhere here about the geographical distribution of this species. Their name to me always suggests that their distribution would be confined to Europe but in reality, they have a large distribution. Later on, it would also be good to see something about current population numbers. Are they stable across their whole geographic range or does this vary and why? Are they persecuted in the same way across their geographic range?
Lines 74-75 – is this RTA (road traffic accident) issue worse in urban environments?
Line 93 – what about breeding spaces (holts)?
Line 110 – please give a figure here for the projected increase in urbanisation worldwide (perhaps by area expected to become urbanized).
Overall comments about introduction – a very good summary of otters generally, but it is lacking a paragraph about their role as a key stone species. What makes otters important in an ecosystem? How do they promote habitat stability (line 31)?
Line 132 – and places to breed.
Lines 154-155 – unclear what this means ‘but would become more expansive as human disturbance increased’.
Overall comments – this is a very brief discussion of principles that could allow for increased otter numbers across the species range in urban areas. It is a nice summary, but it does lack depth and detail throughout and could have been a more extensive review of the literature around otter conservation and the conservation of other riparian mammals. For example there is no discussion about whether there are 'urban' otters or if some individuals use urban habitats as part of their range. It could be useful though to land managers who are keen to find ways to improve conditions for otters in urban and other environments.
Author Response
Please see attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsManuscript ID: diversity-3648373
A Review on Eurasian Otters in Urban Areas: Principles for the Enhancement of Biodiversity
Review
The aim of this review was to summarize the existing knowledge about Eurasian otters (Lutra lutra) in urban areas and to propose a set of principles aimed at enhancing urban habitats for Eurasian otters and thereby improving overall urban biodiversity.
So, authors aimed to:
- Outline key ecological behaviors and habitat requirements of Eurasian otters, especially within the context of urban environments.
- Identify current gaps and limited understanding regarding Eurasian otter presence and behavior in urban ecosystems.
- Develop six core principles to guide the enhancement of urban habitats, including: enhancing habitat structural complexity restoring natural riparian vegetation and habitats, safeguarding water quality, providing native prey species, reducing otter mortality risks, and promoting positive public perception and engagement in otter conservation.
To our best knowledge, no review article was published since 1990 that is specifically dedicated to the conservation of the European otter (Lutra lutra) in urban environments. Several recent empirical studies provide focused, city-scale insights on urban otter challenges, behavior, and management needs, especially from Hong Kong and southern Europe.
There is a strong need for a systematic review or meta-analysis on urban Lutra lutra conservation. Therefore, reviewed manuscript is valuable and is good to be published in Diversity after careful revision.
Critical comments
- Formulate Aim of the review, currently it is missing.
- Section Material and Methods is missing. At least, principles of reference selection must be given, no matter if these conform to PRISMA.
- While little is known about Lutra lutra in China (Line 100), there are many publications from Hong Kong.
- Wider perspective on urban biodiversity conservation must be give, not necessarily based on the otter.
Other comments
- To better readability, consider to add timeline, infographic or summarizing table.
- Add necessary spaces and use long dash for ranges, e.g., Line 46, not “40-60cm”, but “40–60 cm”
- Check for mistypes, e.g., Line 50, square brackets must be used, [14]
- Format text and references according journal requirements
- Back matter: funder roles are not disclosed in Conflict of interest part.
- Check for more references, the presented ones are too scarce.
Minimum recommended references to be included:
Tan, E. (2021). Wildlife tourism in urban destinations: Singapore’s urban otters and “biodivercity” story. In The hospitality and tourism industry in ASEAN and east Asian destinations (pp. 209-227). Apple Academic Press.
Dettori, E. E., Balestrieri, A., Zapata-Perez, V. M., Bruno, D., Rubio-Saura, N., & Robledano-Aymerich, F. (2021). Distribution and diet of recovering Eurasian otter (Lutra lutra) along the natural-to-urban habitat gradient (river Segura, SE Spain). Urban Ecosystems, 1-10.
Soanes, K., Sievers, M., Chee, Y. E., Williams, N. S., Bhardwaj, M., Marshall, A. J., & Parris, K. M. (2019). Correcting common misconceptions to inspire conservation action in urban environments. Conservation Biology, 33(2), 300-306.
Kowarik, I., Fischer, L. K., Haase, D., Kabisch, N., Kleinschroth, F., Konijnendijk, C., ... & von Haaren, C. (2025). Promoting urban biodiversity for the benefit of people and nature. Nature Reviews Biodiversity, 1-19.
McMillan, S. E., Wong, T. C., Hau, B. C., & Bonebrake, T. C. (2019). Fish farmers highlight opportunities and warnings for urban carnivore conservation. Conservation Science and Practice, 1(8), e79.
Duarte, J., Rodríguez, D., Farfán, M. Á., & Fa, J. E. (2021). Fishing in your backyard: otters that prey on urban resources.
Author Response
Please see attachments.
Author Response File: Author Response.pdf
