Now that I have been trained in recreation ecology, I am super sensitive to people hiking off-trail . Hiking with me can be no fun; if I see so much as a boot toe slip off the designated trail and hit vegetation, you will hear some sass from my direction. However, a recent article from The Canadian Field-Naturalist has raise an interesting question about recreation impacts: Are trail impacts always negative? Can there be an ecological benefit to recreational use of trails to certain species? A pair of researchers from Agriculture and Agri-food Canada (which I assume is their equivalent to the U.S. Department of Agricultue) had observed that certain native, orchid species can often be found on the edge of recreation trails. The presence of such sensitive species seems counter-intuitive. So Paul Catling and Brenda Kottiuk investigated the question of whether or not orchids could be benefiting from the presence of trails.
The study was conducted in six Canadian recreational areas that were known to have large orchid populations. The researchers looked for four species of native orchids. Some of the study sites included only a single species of orchid while others contained all species. At each site the researchers collected the frequency of orchids at multiple near-trail areas (less than 1.5m from the trail) and multiple “far from a trail” areas (greater than 1.5m from the trail). At the time of the study, all orchid species were flowering or fruiting which allowed for easy identification and for the researchers to measure plant fecundity (essentially, how much the plants are reproducing).
Turns out that hikers are not the only ones that like trails, orchids like them too! Higher densities of orchids were found in the sites at close proximity to trails as compared to far-from-trail sites. This finding was consistent across all study sites. The number of orchid plants decreased as the distance from trails increased. More flowering plants were found close to the trail as compared to farther from the trail. However, a greater proportion of orchids were flowering at the far-from-trail sites.
It appears as if trail disturbance has a significant positive impact on native orchid species in Canada. Despite the fact that a lower proportion of orchids were flowering near the trail, the sheer different in total frequency was enough to make up for any near-trail loss in fecundity. What’s happening here? Shouldn’t the orchids be getting trampled to death by hikers? Or crushed by bikers? Well, it turns out that orchids do well in areas of disturbance. Although trampling does damage plants and compact soil, it also reduces competition between species, exposes mineral soil, and causes changes to light and microclimate. Trampling may cause just enough disturbance to benefit species like orchids.
The results of this study are particularly interesting, as the authors point out, because the normal reaction of managers to finding rare species (such a orchids) along a trail is to close the trail to recreation. The thought is that recreation may disturb the species. However, in the case of Canadian orchids, limiting or cutting off recreation could actually have negative consequences for the species. This study also highlights the bias among many recreation ecologists to only examine the “bad” and never the “good” impacts of recreation use. There may need to be a paradigm shift where our research frames recreation infrastructure as a possible benefit to the ecosystem under some circumstances and not just a bane to the ecosystem.
Paul M. Catling, & Brenda Kostiuk (2012). Come Wild Canadian Orchids Benefit from Woodland Hiking Trails – and the Implications The Canadian Field-Naturalist, 125