Veronika Mitterwallner is a sports ecologist at the University of Bayreuth. In an interview with MIT Technology Review, she talks about her study in which she and colleagues examined the environmental impact of mountain bikes – including those with an electric drive.
Ms. Mitterwallner, in one of the very first review articles, you presented the consequences of cycling for nature – and mountain biking in particular. How did you come up with the topic?
Veronika Mitterwallner.
(Image: University of Bayreuth)
That was for two reasons. Personally, I really enjoy spending time in the mountains, both on foot and by bike. The tranquility and the experience of nature have a very positive, grounding and relaxing effect. But in doing so, I also began to wonder what effect I was having on my natural environment in return. At the same time, the topic was increasingly being discussed in the media – in my view, often on an emotional, less factual level.
For both reasons, my colleagues and I decided it was imperative to establish a factual, evidence-based foundation – and started to systematically collate scientific knowledge on the effects of mountain biking on natural systems. What is really new about our study is that we also researched studies on the ecological effects of electrically assisted mountain bikes.
Biking is generally considered to be environmentally friendly. Why isn’t that necessarily the case with mountain biking?
Cycling mostly takes place in urban terrain or at least on paved paths, which is why one might not speak of a direct interaction with natural systems. However, a road or settlements are also built where natural ecosystems previously were – and in the process soil is compacted, sealed and barriers for animal and plant species are created. However, cycling is environmentally friendly in terms of CO2 emissions, which are negligible compared to cars.
Mountain biking takes place directly in natural ecosystems such as forests, meadows or mountains and thus also interacts more directly with soil, vegetation and wildlife. Even if the system is disturbed in the process, this is not necessarily harmful to the environment. Disturbances can certainly have a positive effect on biodiversity.
After city bikes in particular were initially electrified, e-drives and batteries are now increasingly being found in mountain bikes as well. Do these worsen the negative effects on nature? Why?
Unfortunately, this cannot yet be conclusively assessed. We had to realize that the length of studies on the effects of electrified mountain biking is still very thin. In our review, we therefore used the results of conventional mountain biking to discuss the extent to which the changes in riding behavior when using electrical support lead to an intensification of the effects. Since the electric motor allows you to go faster, longer and farther – as well as helping you to overcome a greater difference in altitude and negotiate technically difficult passages – we see potential for electrified mountain biking to take place in more sensitive, previously untouched systems.
This would have negative effects above all when driving off-road, which is easier with an electric motor than without. At the same time, electrification opens up mountain biking for other groups of people than before and you can see that the sales figures are increasing enormously and in some cases more e-MTBs are being sold than conventional MTBs. This could also be an indication that more people are mountain biking in natural systems. Unfortunately, it is difficult to say whether there is a kind of load limit for ecosystems or individual species. This can hardly be separated from other influences and depends on how stable the population is and how tolerant the individual species is to disturbances.
You write that creating a route for the first time is a particular problem. Why is that?
The vegetation is destroyed when it is first planted, the soil is compacted and partially removed. After that, there are hardly any other changes, except that there is more erosion on the path itself, as long as it is not paved – since plants and their roots do not have a fixing effect and the soil is less able to absorb water due to compaction. However, it must also be said that the small-scale increase in habitat heterogeneity can promote the diversity of the adjacent plant community.
What advice do you have for communities that want to build a mountain bike trail, for example for tourism reasons?
I would consider repurposing existing paths to prevent the landscape from fragmenting again. Areas used for other purposes, such as former ski slopes or back roads, could also be suitable. If the mountain bike trail is also to be built in sensitive habitats or protected landscape areas, nature conservation reports can assess whether the construction is likely to endanger protected animal and plant species.
What you write also applies to the creation of a network of paths for hikers or runners. Are mountain bike trails really worse?
That’s difficult to rate. It’s true that the same path networks are used for the most part, which is why it’s difficult to separate effects. Although there are studies that have separated the activities and then analyze their effects on soil or plants, these are difficult to transfer to reality, where the individual behavior of the respective athlete is also very important. For example, at what times they are on the road and whether they leave the path. In addition, one would have to include the actual proportion of mountain bikers and hikers in the country, which would certainly vary from area to area.
Many cyclists see themselves as the most ecological road users. Do we have to reconsider this in view of the consumption of raw materials for the vehicles and the possible damage to nature caused by road construction?
In my personal opinion: No, you don’t have to. However, you should think about where and when you move and be considerate of the natural and social environment. It is always a question of relation. The current human-caused climate crisis – and the biodiversity crisis we find ourselves in – has worse consequences for natural ecosystems than mountain biking. There are also studies that show that outdoor sports such as mountain biking increase ecological awareness, which in turn can have a positive impact on our everyday and sporting behavior in relation to the environment.
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