Ecological impacts of fire trails on plant assemblages in edge habitat adjacent to trails

Abstract

Fire trails provide access into vegetation for controlled burns in fire-prone regions of the world. We examined the ecological impacts of fire trails on plant assemblages in edge habitat adjacent to trails in eucalypt woodlands of World Heritage Blue Mountains National Park, southeastern Australia. We found that understory plant species richness, total plant density, and leaf mass per area (LMA) were significantly higher in fire-trail edge habitat than in the understory of interior woodland habitat without fire trails. Understory plant species composition also differed significantly between fire-trail edge and interior habitats. Higher total plant density, higher LMA, and compositional differences in understory assemblages of fire-trail edge habitat were significantly related to increases in the availability of photosynthetically active radiation. In addition, higher soil clay content in fire-trail edges, which is linked to increased soil water availability for plant growth, was significantly related to higher species richness and compositional differences in the understory, as well as to compositional differences in overstory assemblages. From a conservation and management perspective, we suggest that, although significant ecological effects of fire trails on plant assemblages in edge habitats were detected, our work provides evidence that fire trails are unlikely to lead to serious conservation issues such as local extirpations of native species or the facilitation of exotic plant invasion. Nevertheless, our study has identified those plant species that are unique to, or particularly sparse or common in, fire-trail habitat, which should be prioritized for demographic and distributional monitoring should the need arise to increase the extent of fire trails in the future.