Many species of birds breeding on ocean beaches and in coastal dunes are of global conservation concern. Most of these species rely on invertebrates (e.g. insects, small crustaceans) as an irreplaceable food source, foraging primarily around the strandline on the upper beach near the dunes. Sandy beaches are also prime sites for human recreation, which impacts these food resources via negative trampling effects. We quantified acute trampling impacts on assemblages of upper shore invertebrates in a controlled experiment over a range of foot traffic intensities (up to 56 steps per square metre) on a temperate beach in Victoria, Australia. Trampling significantly altered assemblage structure (species composition and density) and was correlated with significant declines in invertebrate abundance and species richness. Trampling effects were strongest for rare species. In heavily trafficked plots the abundance of sand hoppers (Amphipoda), a principal prey item of threatened Hooded Plovers breeding on this beach, was halved. In contrast to the consistently strong effects of trampling, natural habitat attributes (e.g. sediment grain size, compactness) were much less influential predictors. If acute suppression of invertebrates caused by trampling, as demonstrated here, is more widespread on beaches it may constitute a significant threat to endangered vertebrates reliant on these invertebrates. This calls for a re-thinking of conservation actions by considering active management of food resources, possibly through enhancement of wrack or direct augmentation of prey items to breeding territories.
School of Science and Engineering, The University of the Sunshine Coast, Q-4558, Maroochydore, Australia;Centre for Integrative Ecology, School of Life and Environmental, Deakin University, Geelong, Australia;Centre for Integrative Ecology, School of Life and Environmental, Deakin University, Geelong, Australia;Australian Rivers Institute - Coast & Estuaries, and School of Environment, Gold Coast Campus, Griffith University, Southport, Australia;School of Science and Engineering, The University of the Sunshine Coast, Q-4558, Maroochydore, Australia;School of Science and Engineering, The University of the Sunshine Coast, Q-4558, Maroochydore, Australia;School of Science and Engineering, The University of the Sunshine Coast, Q-4558, Maroochydore, Australia;Centre for Integrative Ecology, School of Life and Environmental, Deakin University, Geelong, Australia;Department of Ecology, Evolution and Natural Resources, Rutgers, The State University of New Jersey, 55 Commercial Ave, New Brunswick, NJ, 08901, United States of America;Centre for Integrative Ecology, School of Life and Environmental, Deakin University, Geelong, Australia
Recommended Citation:
Thomas A. Schlacher,Lucy K. Carracher,Nicholas Porch,et al. The Early Shorebird Will Catch Fewer Invertebrates on Trampled Sandy Beaches[J]. PLOS ONE,2016-01-01,11(8)