Some Wild Canadian Orchids Benefit from Woodland Hiking Trails - and the Implications

Abstract

To clarify the impact that trails have on orchids we compared the occurrence of orchids on the lightly trampled edges of bare trails, with the occurrence of orchids in the surrounding woodland and noted the degree of disturbance. A two-way mixed analysis of variance, using six trails from across Canada, indicated that location by distance strata interaction was lacking. Orchid densities were consistently higher within a few meters of the bare portion of a trail than further away. The width of the disturbance gradient for two well-used trails in parks in Bruce County, Ontario, was determined with regression to be within 1 m from the edge of the bare portion of the trail. Calypso bulbosa var. americana on trails in in Alberta, Epipactis helleborine and Goodyera oblongifolia on trails in Ontario, Goodyera repens on trails in Northwest Territories and all native orchids (cumulatively) on trails on Flowerpot Island, Ontario demonstrated consistent and significant increased abundance within the trail disturbance gradients in comparison to their occurrence in the surrounding forest. More flowering plants of Goodyera oblongifolia and mature capsules of Epipactis helleborine occurred in the trail disturbance gradient than beyond suggesting a beneficial impact on fecundity. The disturbance gradient effect likely includes light trampling which reduces competition, compacts soil, and exposes mineral soil. The effect also includes increased light and microclimate differences near to the path. Landscape managers should recognize that in some situations orchids may benefit greatly from trails and that trails may be better considered as a benefit than as a problem.

Indirect effects of hiking trails on the community structure and diversity of trunk-epiphytic bryophytes in an old-growth fir forest

“…The openings in the canopy resulting from the construction of the hiking trail significantly increased light radiation and air temperature, but reduced the air humidity along the trail (Table 1), agreeing with the conclusions of Bright (1986) and Catling & Kostiuk (2011). It is suggested that these differences are related to reduced growth, vitality, and survival of mosses at forest edges (Hylander, 2005;Stewart & Mallik, 2006).…”

“…In addition, trail construction reduces tree and shrub canopies, and creates a disturbed mosaic of vegetation, or structural gaps where the abiotic environment (e.g. temperature, light and humidity) and the biotic conditions change to some degree (Bayfield, 1971;Boucher et al, 1991); thus, the trail also indirectly influences the forest structure and ground vegetation (Bright, 1986;Boucher et al, 1991;Roovers et al, 2004;Nepal & Way, 2007;Catling & Kostiuk, 2011). However, there have been few studies on the indirect effects of hiking trails, and thus, these are as yet poorly understood.…”

“…Hiking trails only create narrow internal gaps in a forest, and thus the community structure is similar on both sides of the trail, rather than being two distinct habitats or different vegetation communities, as occurs after fragmentation. Thus, trail establishment has usually been regarded as a lesser source of disturbance compared with fragmentation (Nepal & Way, 2007;Catling & Kostiuk, 2011), and the effect of hiking trails is not strictly similar to edge effects. Consequently, there has been less research into the effects of trails on epiphytic bryophyte communities and biodiversity.…”