Mountain biking is generally considered a recreational activity that causes more impact to the environment than non-mechanized activities like hiking. Mountain biking has become a very popular outdoor recreation activity in the United States and it’s popularity is increasing across the globe as well. On a flight from Philadelphia to Salt Lake City a couple of summers ago, I sat next to an woman from Australia who was training to be on Australia’s Olympic Mountain Biking Team; she was coming to Utah to train in Park City. Australia is one of the countries that has seen a major increase in the popularity of mountain biking and thus an increase in the construction of mountain bike trails in parks and protected areas. Recreation ecologists in Australia have just recently begun to examine the ecological impacts of mountain biking in their country and it’s unique ecosystems.
Catherine Pickering et al. (2011) recently examined the impacts of mountain biking as compared to hiking on subalpine grasslands in Australia. In the United States, subalpine systems are often very sensitive to recreation impacts. Pickering and her team approached the study using traditional recreation ecology methodology and essentially set up a “trampling study” style experimental design to examine recreation loads and the resulting impacts. Additionally, they looked at the impact of mountain biking occurring off of designated trails, a subject which has not been examined very much in the recreation ecology literature.
The study was conducted in Kosciuszko National Park in south eastern Australia. In this park, mountain bikers are expected to stay on the designated trail during summer months. However, as with any recreational activity, there is rarely 100% compliance with such recommendations. Pickering and her colleagues set up off-trail “trampling” lanes with a set number of passes by the mountain bike or hiker as the treatments. Mountain bike passes ranged from 25 passes to 500 passes and hiking passes were 200 or 500 passes. Additional treatment lanes were set up at a slope to see if the nature of the topography had any effect on the recreation impact of the activity.
Results showed, not surprisingly, that mountain biking has negative impacts on vegetation and soil. Mountain biking significantly decreased vegetation height, even at very low levels (25 passes) of recreation use. Additionally mountain biking caused vegetation to be crushed, soil to be compacted, and led to changes in species composition and the loss of some subalpine species in the community. Slope did have an effect on the level of impact; riding up or down slope caused more impact than riding on a gentle slope.
However, these results seems pretty obvious as all recreational activity causes some level of impact and even just hiking off-trail leads to similar types of impacts (like crushed vegetation and compacted soil). Pickering et al. found that the severity of mountain biking impacts and hiking impacts were the same except at the highest level (500 passes) of impact. It appears that in off-trail areas of a subalpine grassland, low and moderate levels of hiking and biking use cause the same amount of impact. However, it is important to note, and the authors do make this point, that the off-trail mountain biking use was conducted under “ideal conditions”. Meaning that the bikers did not brake hard while riding, did not cut sharply with their tires, and the study was conducted under very dry soil conditions. Therefore, the findings that mountain biking and hiking cause similar levels of impact in subalpine grasslands may not hold true under normal riding conditions or when soil conditions are wet. Finally, Pickering and her colleagues point out that besides damage to soil and vegetation, mountain biking impacts can also include visual impacts and ecological damage caused by the building of features such as jumps and ramps.
Mountain biking is an issue of increasing concern for managers of parks and protected areas. Not very much research has been conducted examining the impacts of off-trail mountain bike use and the sensitivity of different ecosystems to mountain biking. Like hiking, mountain biking will always cause some level of impact. However, trail design and an understanding of how different ecosystems respond to mountain biking pressures can minimize the impacts caused by mechanized recreation.
Pickering CM, Rossi S, & Barros A (2011). Assessing the impacts of mountain biking and hiking on subalpine grassland in Australia using an experimental protocol. Journal of environmental management, 92 (12), 3049-57 PMID: 21856066