Impacts of Off-Road Vehicles (ORVs) on Macrobenthic Assemblages on Sandy Beaches

Abstract

Sandy beaches are the prime sites for human recreation and underpin many coastal economies and developments. In many coastal areas worldwide, beach recreation relies on the use of off-road vehicles (ORVs) driven on the shore. Yet, the use of ORVs is not universally embraced due to social conflicts with other beach user groups and putative environmental consequences of vehicle traffic on sandy shores. Such ecological impacts of ORVs are, however, poorly understood for endobenthic invertebrates of the intertidal zone seawards of the dunes. Consequently, this study quantified the degree to which assemblages of intertidal beach invertebrates are affected by traffic. The study design comprised a series of temporally replicated spatial contrasts between two reference sites (no ORVs) and two beaches with heavy ORV traffic (in excess of 250,000 vehicles per year) located in SouthEast Queensland, Australia. Macrobenthic assemblages on ORV-impacted beaches had significantly fewer species at substantially reduced densities, resulting in marked shifts in community composition and structure. These shifts were particularly strong on the middle and upper shore where vehicle traffic was concentrated. Strong effects of ORVs were detectable in all seasons, but increased towards the summer months as a result of heavier traffic volumes. This study provides clear evidence that ORVs can have substantial impacts on sandy beach invertebrates that are manifested throughout the whole community.Demonstrating such an ecological impact caused by a single type of human use poses a formidable challenge to management, which needs to develop multi-faceted approaches to balance environmental, social, cultural, and economic arguments in the use of sandy shores, including management of ''beach traffic.''

Impacts of the ‘Pacific Adventurer’ Oil Spill on the Macrobenthos of Subtropical Sandy Beaches

“…Zones were defined through similarities in environmental characteristics, using group-average clustering, based on normalised Euclidean distance (Schlacher and Thompson 2007b). The cluster analyses included five environmental variables: (1) mean sediment grain size, (2) percent sediment moisture content, (3) elevation above low water, (4) slope and (5) the position of each sample relative to the effluent line (binary) (Schlacher et al 2008a). Broadly, our physically defined zones correspond, in general terms, to the biological zones defined by Dahl (1952), where the lower zone in this study is roughly congruent to the sublittoral fringe, the middle shore matches the midlittoral zone and the upper shore corresponds to Dahl's (1952) subterrestrial fringe.…”

“…1). We aimed to disperse sites equally along the length of the beaches, but their exact location in the spill area was dictated by logistical and operational constraints; reference sites were chosen based on previous sampling Thompson 2007a, 2008;Schlacher et al 2008a). All sites except Peregian beach (Per; Fig.…”

Oil spill response-related injuries on sand beaches: when shoreline treatment extends the impacts beyond the oil

“…Those authors also found that ghost crab densities were higher in areas of low to moderate traffic, while individuals were smaller in heavily impacted areas, suggesting alterations of the population structure. Heavily trafficked beaches also had lower abundance, species richness, and diversity of intertidal macrobenthos, and strong changes in the community structure were driven by the low abundances of cirolanid isopods (Schlacher et al 2008). Direct crushing appeared to be the main cause of community change.…”

“…Globally, many studies (e.g. McLachlan & Jaramillo 1995, Defeo & McLachlan 2005, Dugan et al 2011, Schlacher et al 2008) have demonstrated that the structure and nature of the habitat, fauna, and services offered by the supratidal and intertidal (= supralittoral and littoral) differ substantially (Fig. 3).…”

Temporal changes in macrofauna as response indicator to potential human pressures on sandy beaches

“…Still, human recreational activities have been recognised to negatively affect beach fauna due to the intensive use of beaches (Schlacher and Thompson, 2012;Schlacher et al, 2011;Ugolini et al, 2008;Veloso et al, 2008) and to the impact of off-road vehicles (e.g. Schlacher et al, 2008a;Sheppard et al, 2009;Schlacher and Lucrezi, 2010;Walker and Schlacher, 2011).…”