Comparing the impacts of different types of recreational trails on grey box grassy-woodland vegetation: lessons for conservation and management

Abstract

Tourism and recreation are popular in natural areas but can damage plant communities, including those of high conservation value in protected areas. This includes impacts from recreational trails, but what type of trail has the most impact and why? We compared the impacts of five different trails (narrow, intermediate and wide bare earth trails, intermediate gravel trails and wide tarmac trails) on the endangered grey box grassy-woodland (Eucalyptus microcarpa (Maiden) Maiden) in Belair National Park near Adelaide in South Australia. First, the extent, width and area of recreational trails in the remnant woodland were mapped. Then, vegetation parameters were recorded in quadrats at three distances from the edge of trails in the woodland, with 10 replicate sites per trail type and single quadrats at 10 control sites (i.e. total 60 sites, 160 quadrats). All trails resulted in vegetation loss on the trail surface and along the edges of the trails, as well as changes in vegetation composition, including reductions in shrubs and bulbs close to the trail. The most common types of trail were bare earth trails with an average width of 2.5 m (50% of trails) which resulted in the greatest soil loss (>88 000 m3) and vegetation loss (33 899 m2 or 3.4 ha) in the 167 ha woodland remnant overall. Wider (5.4 m) hardened tarmac trails, however, were associated with low species richness, high cover of exotic grasses and few herbs, shrubs and bulbs compared with vegetation away from trails and closer to other trails. Therefore a mixed approach to the provision of trails may be most appropriate, with hardened trails used in areas of highest use, but in some circumstances leaving trails unhardened may be more appropriate where they are likely to remain narrow and where there is less likely to be erosion and/or safety issues.