With mountain biking on the rise in New Zealand there is a continuing debate over the environmental impact of trails and their riders, and whether this is a reason to not build more trails.
The conclusion I’ve come to is that in the grand scheme of things, the impact of mountain bikers and their trails is minor, but not completely insignificant. However, at the very least no more of an impact than walkers and hikers and their trails.
In essence, New Zealand and the world have much bigger problems than a few, well managed, mountain bike tracks. Therefore we should reject environmental impacts as a reason not to build trails. However, we should be thinking about how we minimise their impact. For example, not building trails through bird nesting environments, making sustainable trails that need minimal changes to the environment .
Below is my reasoning for this conclusion. Now to stress: being a researcher and for those out there with a research background, clearly this isn’t a full, every stone turned over master piece. This is meant to be a quick scan of the evidence to demonstrate the main trends. I am more than happy for the provision of contravening or agreeing evidence.
There’s two things to consider when investigating the impact of bikes and trails on the environment:
- what is the relative impact of mountain biking on the environment compared with other human activities, and
- what is the impact of mountain biking on the environment compared with other similar activities, such as walking or hiking and horse riding.
Mountain biking vs other human activities
Compared with other human activities (e.g. road building, car manufacturing) the effect of mountain biking on the environment is minor, (albeit not completely insignificant).
Human activities that affect the environment could be broadly categorised into the following:
- Introductions and invasive species
- Energy industry
- Light pollution (that is the opposite of dark!)
- Manufactured products
So where does biking fit in and how does it compare with these other activities? Biking could fit into technology, introductions and invasive species, manufactured products and transport (war if you count our arguments with local residents).
Technology: clearly a lot of research goes into making our modern bikes so one could argue this has an impact on he environment, through energy use etc., whether that is anywhere near other research on automobiles, pharmaceuticals, technology we have no idea, but I would doubt if it is.
Introductions and invasive species: those (now generally bigger) wheels take tiny seeds and spread them around the place, but these could be good seeds (native plants) as much as bad. And in New Zealand alone the invasive species introduced and spreading like wildfire long before mountain bikes came along.
However, whilst in the grand scheme of things it is unlikely that mountain bike tread has a huge impact on distributing invasive species, it does seem to have some impact (but I stress here: no more than walkers or hikers). For example one study showed more invasive plants growing next to trails. Another study showed that mountain bikers (along with hikers too) do cause the spread of invasive species when the go off course (rather than use a formed track). which is one thing to bear in mind. So we should have caveats around this when we’re building trails.
Manufacturing: Interestingly there are 100 million bikes produced every year, compared with 42 million cars. That’s over three bikes produced every second, every year. Clearly there is a carbon footprint associated with the manufacturing of bikes, and that affects the environment, but probably not more than other manufactured goods. For example 20 billion shoes are made every year, or 634 per second!
In essence, we really should consider whether we really need that new seat post or whether the old one can be fixed, or if we can squeeze another year out of your bike (even if the wheels are the ‘wrong’ size.
Transport: the main use of bicycles and mountain bikes is for transport (whether that is for fun or necessity). Not withstanding the other factors mentioned above cycling itself as an activity has little impact on the environment i.e. there are no emissions from bikes. So at the very least once you have your bike, riding it around is carbon neutral.
Now this is the interesting part. Opponents to mountain biking trails will often tell you that mountain bikers damage the environment, causes disruption to birds and insinuate that this is more so than walking or other activities. According to research this is not the case.
One of the best studies that looks at this is from Canada (a fine biking nation) and is a literature review of other studies. It’s called, Mountain Biking: A Review of the Ecological Effects, 2010.
Soil: Status: de-bunked
In all studies looked at in the Canadian literature review walking and horses had a greater impact on soil than riding. However the effects on soil of mountain biking were impacted on by how well the trails were made, their planning etc and when they were used (in wet whether the effects were worse as with all activities). So in this way, we can minimise the impact of trails on have environment by building well made, sustainable tracks.
Vegetation: Status: partially de-bunked.
Studies (in the Canadian review) found that with any activity where trails are built there is obviously going to be a loss of vegetation. With these trails there invasive and non-native plants were found in close proximity to these trails (no difference between types of activities). As for seeds being spread: see above!
Wildlife: partially de-bunked.
The main studies conclude that cycling is actually more silent than many other sports that use trails and put stress on wildlife. Specifically in New Zealand there is a debate about whether trails destroy habitats and scare/kill bird populations. Interestingly the chart below shows the main ways birds are killed by humans (or their pets). World wide 550 million birds are killed flying into windows! All the factors below will effect bird populations in NZ. Biking does not feature on the graph. It is likely that whilst clearing trees will effect birds somewhat it would not cause too much effect.
Interestingly though studies do show displacement of birds disturbances for wildlife where trails are built. but long terms effects have not been well studied. Incidences of direct mountain-bike caused wildlife mortality are rare. the conclusion, more study needs to be conducted.
So that concludes my brief look into the effects of biking on the environment. My conclusion? Biking definitely has some impact on the environment but probably no more than other activities such as hiking. Some impact can be mitigated against. In the grand scheme of things, the enjoyment and enhancement on life and health of riding outweighs the effects on the environment. When compared with other activities e.g. road building, urban developments, the impact is minor, if not insignificant.