Recreational Trail Impacts on the Plant Communities of Castle and Castle Wildland Provincial Parks in Southern Alberta

I measured the effect of recreational trails on plant species richness, community
composition, and the presence of exotic and rare species in the Castle Provincial Parks of
Alberta, Canada, by surveying 142 transects adjacent to or far from trails. I also
characterized the habitat of species from the rare genus Botrychium Swartz and tested a
species distribution model (SDM) to identify suitable Botrychium habitat. Plant
communities near trails had higher species richness, shifts in composition, and greater
occurrence of exotic plant species. These effects extended farther from off-highway
vehicle (OHV) trails than from footpaths, but only in mixed/broadleaf and shrubland
vegetation. The SDM was not a strong predictor of Botrychium presence, but I found
Botrychium in 29% of surveyed sites. To minimize trail effects such as colonization by
exotic species, managers should prioritize closing trails to OHVs or limiting OHV traffic,
particularly in mixed/broadleaf and shrubland vegetation.