Low level off-road vehicle (ORV) traffic negatively impacts macroinvertebrate assemblages at sandy beaches in south-western Australia.

Rebecca Davies,Peter C Speldewinde,Barbara A Stewart

doi:10.1038/srep24899

Abstract

Off-road vehicle use is arguably one of the most environmentally damaging human activities undertaken on sandy beaches worldwide. Existing studies focused on areas of high traffic volumes have demonstrated significantly lower abundance, diversity and species richness of fauna in zones where traffic is concentrated. The impact of lower traffic volumes is unknown. This study aimed to investigate the impacts of relatively low-level vehicle traffic on sandy beach fauna by sampling invertebrate communities at eight beaches located in south-western Australia. We found that even low-level vehicle traffic negatively impacts the physical beach environment, and consequently, the ability of many species to survive in this habitat in the face of this disturbance. Compaction, rutting and displacement of the sand matrix were observed over a large area, resulting in significant decreases in species diversity and density, and measurable shifts in community structure on beaches that experienced off-road vehicle traffic. Communities at impact sites did not display seasonal recovery as traffic was not significantly different between seasons. Given a choice between either reducing traffic volumes, or excluding ORV traffic from beaches, our results suggest that the latter would be more appropriate when the retention of ecological integrity is the objective.

Highlights

Sandy beaches represent an important transition zone between marine and terrestrial environments[1], where physical interactions between sediment and water movement determine beach morphology[2]
Both zones displayed significant differences in species richness and species diversity among control and impact sites; the differences were more noticeable for the upper than for the lower zone. This is in contrast to the study of Schlacher et al.[23] who reported similar abundances, species richness and species diversity among impact and control beaches for lower zones in Queensland
Schlacher et al.[23] reported traffic numbers that were significantly higher than observed in our study, they found that 91% of this traffic traversed the upper and middle shore

Summary

Introduction

Sandy beaches represent an important transition zone between marine and terrestrial environments[1], where physical interactions between sediment and water movement determine beach morphology[2]. Off-road vehicle (ORV) use is arguably one of the most environmentally damaging human activities undertaken on sandy beaches[6,7] and can dramatically alter the physical properties of coastlines through the compaction, rutting and displacement of the sand matrix[8] This vehicle traffic can substantially decrease organic matter in soils[9] and can change the microclimate of the sand[5]. We sampled both ORV-impacted and non-impacted beaches to (i) describe the habitat and sediment characteristics of these beaches, (ii) document ORV traffic distribution and impact on the physical environment of beach faces of ORV-impacted beaches, and (iii) investigate the invertebrate fauna response to this ORV traffic This is the first study of the impacts of ORV traffic on macroinvertebrate fauna in south-western Australia, and is the first to document impacts of relatively low-level traffic in Australia

Objectives

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Results

Conclusion