Recreational trails in Boulder, Colorado, and consequences for vegetation composition and richness

Abstract

Recreational trails are essential because they provide a place to be active across the U.S. They can change the condition of native ecosystems by compacting soil, reducing vegetation cover, and facilitating the spread of non-native plant species. In this study, I analyzed the effects of trail proximity on vegetation composition and species richness at Chautauqua Park in Boulder, Colorado. I used transect sampling at varying distances from trailheads and trail edges in prairie/grassland and montane forest ecosystems. A total of 18 native and six non-native species were recorded. Native vegetation cover was up to 25% lower near trailheads in the prairie region, where this effect was statistically significant. In the montane forest, native cover appeared lower near trailheads, but the difference was not statistically significant and could be due to random variation or other uncontrolled factors. Similar patterns were present along trail edges, especially in the montane forest, but most differences were not statistically significant, likely due to small sample sizes or variability in site conditions, except for soil/litter cover and species richness. In the montane forest ecosystem, species richness appeared lower within 5 meters of trail edges, which may reflect disturbance effects, though results should be interpreted with caution because of the small sample size and observational design. These patterns indicate that human recreational activity contributes to shifts in plant community structure. In prairie trails, non-native species like smooth brome were dominant near trailheads, while native cover increased with distance from disturbance. Proper management methods are likely to decrease edge-related impacts by managing invasive species and preserving native biodiversity. This exploratory study is limited in replication and statistical power and should be considered a probe analysis that gives direction for future research.