Dust as a contributor to the road-effect zone: A case study from a minor forest road in Australia

The road-effect zone is a concept developed to describe the impact of influences such as noise, vibration, light and dust associated with roads and traffic on the surrounding area. Although many aspects associated with the road-effect zone have been investigated, the influence of dust remains poorly understood. Gap Creek Road, a minor road traversing forest near Brisbane, Australia, was upgraded in 2010 by sealing and realignment. The present study compares pre- and post-construction dust levels within the forest, and the diversity and abundance of ground-dwelling mammals near (2-5 m) and far (80-100 m) from the road. Prior to the upgrade, dust levels were very high with deposition rates equivalent to a major daily dust storm. The key influence of the upgrade was the almost complete elimination of this dust production; hence, we predicted that species richness and abundance of small mammals near the road would increase significantly after the upgrade. Pre-upgrade surveys confirmed that the forest supported a diverse and abundant community of ground-dwelling mammal species with eight species detected, including in highly dust-affected sites near the road. Following the upgrade, there was little change in the abundance of species, though some were significantly more abundant away from the road. These results suggest that, in certain environments, dust may have far less impact on ground-dwelling mammals than expected.