„According to the European Biodiversity action plan for 2030, investing in and deploying green infrastructure should to be considered in planning and designing transport networks.”
François DAVENNE – Director General UIC
Source: Sustainable land use | UIC – International union of railways Mr Davenne’s speech – https://uic.org/events/IMG/pdf/mou_fdavenne_speech_uic.pdf
What do railroads have to do with it?
First of all, they are linear, they also cross other railway tracks. They are relatively well protected from further anthropogenic impacts, such as land development. It is also important that the railway lines cross a variety of natural habitats, such as forests, meadows and wetlands. In themselves, they offer a very interesting artificial habitat. The southern slope of the railway embankment is a good substitute for xerothermic habitats, and ditches and lower sites offer a variety of wetland habitats. These railroads that are in the soil cutting offer sheltered and sunny conditions that can also be very attractive to some species.
So what’s the catch?
This is a certain risk for butterflies. In 2017, a team of scientists led by Luis Borda de Agua from the University of Lisbon published the book „Railway Ecology” in which they argue that railways have a different impact on wildlife than roads due to different traffic volumes and average speeds, but the problem remains same: possible collisions. There are no studies on butterfly-train collisions, not many studies on mammals or birds, in fact, but the conclusions seem to be the same in both cases. The benefits outweigh the losses for local rail lines, lower speed and traffic volumes and, of course, unused tracks.
Only collisions?
Unfortunately not. Glyphosate and other herbicides can also affect butterflies, as well as poorly planned mechanical mowing. Although PKP Polskie Linie Kolejowe declares spraying only once a year, Deutsche Bahn and Swiss Federal Railways have announced that glyphosate and other weed control herbicides along railroad tracks will be phased out by 2025. How to protect caterpillars and their host plants from extinction? If we analyze the list of local species that we would like to protect, there is a certain regularity. Many species have a larval phase from May to August. They then begin to pupate and often hide underground or attach to stems. In the case of manual mowing, the risk is lower, but it is hard to imagine manually mowing 200 km of a railway line. Therefore, mosaic or selective mowing seems to be the solution. The track itself or the top of the embankment occupies a relatively small percentage of the total area. Then slopes and ditches can be well-designed ecosystems that do not require frequent intervention.
