A Multispecies Assessment to Identify the Functional Connectivity of Amphibians in a Human-Dominated Landscape

Round 1

Reviewer 1 Report

The study proposes functional and structural connectivity models for five species of amphibia in a highly transformed landscape in northern Switzerland. Using population data and expert opinion the study basically applies the software Circuitscape for modeling connectivity patterns of multiple species.

The study is well structured and clearly developed. However, a question arises about the significance of the connectivity models for proposing conservation strategies. The discussion seems to be more theoretical. Perhaps it is necessary to relate the study results to the need for conserving other groups of species and to actual or future conservation strategies.  

Author Response

Reviewer 1, submitted 25.03.2020:

The reviewer suggests a need to better relate the significance of our results to conservation strategies for amphibians and potentially other groups of species. We would like to highlight that we discuss specific implications of our models for various conservation strategies on lines 364-379. These include how the models can support basic protective or restorative measures, like identifying important and sensitive existing movement corridors that need protecting, or suggesting where a new stepping-stone pond could successfully be added to the network to bolster connectivity. We have now added a new sentence on line 289 to broadly acknowledge the implications of our results for conservation strategies. We also added the sentence on line 309 which introduces how our models could be opened up to meet the conservation needs of other species groups. Lastly, we link the value of the model results in designing green infrastructure to an actual conservation strategy on line 377 by directly mentioning the incorporation of the GI concept in the EU2020 Biodiversity Strategy

Author Response File: Author Response.docx

Reviewer 2 Report

This paper was published as a master thesis:

Evaluating the landscape connectivity of five amphibian species
using circuit theory
Master Thesis
Supervisor / Referee: Janine Bolliger
Co-Referee: Felix Kienast
Location: WSL Landscape Dynamics - Landscape Ecology Research Group
Greg Churko
Master of Biology ETH
13-923-067
March 7th, 2016

https://kbnl.ch/wp-content/uploads/2016/05/3.3_MasterThesis_Greg-Churko.pdf

 

Many papers have been published in this area, after the presentation of the master. However, the authors have not updated their reference list.

My main concern, therefore, is the need to update the paper, taking into account all the new developments in this area.

I consider that the mnuscript cannot be published without a complete uptdate of its conceptual framework.

Regarding landscape connectivity, I would consider to model the distribution of the target species, according to relevant ecogeographical variables, and then calculate the habitat suitability of the different areas, in order to find possible favorable corridors.

I hope that the authors will manage to prepare a new version.

 

 

 

Author Response

Reviewer 2, submitted 19.03.2020:

            We agree that the foundational literature behind the paper is in need of updating. As such, we added the following citations from contemporary papers to the paper to supplement the original citations:

• Line 31: Allen et al. 2020
• Lines 37 and 326: Reed et al. 2017
• Line 37: Marrotte et al. 2017
• Line 37: Fleischmann et al. 2017
• Line 38 and 382: with Koen et al. 2019
• Line 37: Fatterbert et al. 2015
• Line 335: Abrahms et al. 2016
• Line 34: Naidoo et al. 2018
• Line 34 and 326: Milanesi et al 2017
• Line 34 and 328: Zeller et al. 2018

 

            However, we disagree that it is necessary to rework the entire conceptual framework of the paper. The reviewer’s suggestion to redo the analysis based instead on habitat suitability is problematic. This option was well known and available to us when we initiated the study. Though estimating landscape connectivity using habitat suitability estimates can be a viable approach for some species, e.g. wide-ranging carnivores (Fatterbert et al. 2015), it is poorly suited to amphibians. Not only do amphibians have two distinct life stages in water and on land, they also have seasonal migrations between land and water habitat in addition to the migrations between breeding sites that we are focusing on. Deriving dispersal tendencies from a habitat suitability analysis for these species risks confounding these life history traits. If the basis of the reviewer’s comment is a desire for more empirically derived movement estimates, we agree, but genetic analysis or telemetry methods would be more suitable approaches. We address these options in the discussion paragraph starting on line 324. These are, however, resource-intensive approaches for one species, let alone five, and were beyond the purview of the original master thesis. Connectivity analysis based on expert opinion has a long history in the literature and, though susceptible to bias and incomplete knowledge (Zeller et al. 2012, Bolliger and Silbernagel, 2020), is still relevant today (Reed et al. 2017). We added the sentence on line 326 to address parts of this argumentation and add useful citations to interested readers.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors managed to update the reference list, but this was not translated into substancial changes and updates in the main text. 

This could still be improved.