Investigating the magnitude and extent of recreational trail effects on plant communities in Waterton Lakes National Park

Abstract

Protected area managers are faced with the challenge of balancing environmental protection and recreation in a context of increasing wildfire frequency and severity. However, few studies have assessed how trail use levels, vegetation type, wildfire, and the interactions between them impact nearby plant communities. I assessed 70 trailside transects adjacent to low, medium, and high use trails and 14 off-trail transects in Waterton Lakes National Park, Alberta, Canada. I measured plant species richness and community composition at 0m, 2m, 5m, 10m and 15m from the trail edge, and tested for differences in these metrics based on distance from the trail, trail use level, vegetation type, burn status, and interactions between these factors. To calculate the total area of influence, I multiplied the extent of significant trail effects by the total trail length with the associated characteristics. As expected, species richness was elevated near trail edges compared to the 15m quadrat. However, species richness was highest along low and medium use trails relative to high use trails and off-trail. The occurrence of exotic species near trails was elevated post-fire, but only in coniferous forests. Additionally, the abundance of exotic species was higher 15m from trail edges in burned sites than unburned sites. Trails affect up to 3.1km2 (0.61%) of vegetation in Waterton, and up to 4.5km2 (0.89%) if informal routes have similar effects. The magnitude and extent of trail effects on plant communities depend on the complex interactions between trail use levels, vegetation type, and recent wildfire. While the total area affected is relatively small, it may increase as visitation increases and recreationalists continue to explore informal routes; therefore, this study serves as a baseline for ongoing changes caused by trails.