SEE PEER REVIEW

INTRO:

The topic of the abstract - the possibilities of road verges to function as compensatory habitats for species of meadows and eskers - is very interesting and of current interest. The original habitats have been declining fast and there are great possibilities in the road network for providing similar habitats. The authors have used an extensive dataset of the whole Finnish highway network to find valuable sites.

MERITS:

The analysis of the whole highway network of a country has a huge coverage. The approach of using GIS-analysis and Google Street View is very interesting. It seems convincing that the method has been first tested in pilot areas.

CRITIQUE:

The abstract has some language and grammar issues that make it a bit difficult to understand at some points. In addition, there are some points that make it difficult to follow: Railways are mentioned in the beginning and in the end, but apparently they were not analyzed here. They also state that they looked for "valuable habitats resembling the endangered esker habitats", but apparently habitats resembling meadows were also looked for.

If I inderstood correctly, almost all habitats similar to eskers or meadows were considered valuable (as there was no species data collected, the criterion were exposure, soil quality, slope, vegetation cover, coverage of different vegetation types, and proximity to conservation areas).  Since the data included all highway road verges in the whole country, I find it hard to believe that only 386 sites or the total length of  66 km is valuable. I have been driving on these roads a lot and I have also studied the plant species growing on road verges, and I am quite sure that a much larger proportion of the road verges is similar to eskers and meadows in terms of the above-mentioned criteria. A much larger number of sites and kilometers is potentially valuable, and to state that only these very few sites are valuable is risky because some land-owner might be mistaken to think that their land does not host biodiversity values and should not be managed accordingly. Therefore, I argue that the authors should either descibe their selection criteria more precisely, or reconsider their conclusions.

DISCUSSION:

The study is very important and has a potential to be very influential. The results could be used by land-owners and companies when planning the management of the road verges. However, the criteria for selecting the valuable sites should be checked to make sure that a large proportion of valuable habitats is recognized in the analysis. The conclucions should also consider the possiblity that the method used did not recognize all valuable habitats.

- - -
INTRO:

This abstracts describes a study analysing the spatial distribution and extent of the road and railway verges across whole Finland that may act as compensatory habitats for the endngered esker habitat types. 

MERITS:

There has been discussion that road verges may be of importance for the endagered habitat types as compensatory sites and therefore this study is welcome. Utilization of google street view to screen the sites is innovative.

CRITIQUE:

Given that the length of suitable road verges found is 66 km, the 13 hectares that was mentioned as the total area covered by the verges seems too small. That would mean that the suitable verges are only 2 meters wide on average and this seems too little.

There is some minor confusion about the habitat types studied as in the beginning it is stated that esker habitats are the focus but later they are compared to the total area of sunny meadows and esker habitats.

The language would benefit from some proofreading. 

DISCUSSION:

Worthwhile study on this importance of road and railway verges as compensatory habitats. Somewhat surprising that there are so little suitable area raising questions about the potential role of the verges. However, more details about the extent of the studied road and railway network need to be heard before such a conclusions can be drawn. Eager to hear the whole talk and the details.