Abundance and movement of gastropods in response to vegetation and cover in a southeastern Australian saltmarsh

Abstract

Southeast Australian saltmarshes are endangered ecological communities under threat from various anthropogenic factors including climate change. As climate change drives sea-level rise mangrove encroachment and saltmarshes are squeezed at their landward edge, our lack of knowledge of the ecological interactions and any associations between saltmarsh vegetation and fauna becomes concerning, especially given the importance of saltmarsh for fisheries and as a blue carbon habitat. This study investigated the association of saltmarsh vegetation and the abundance and movement of gastropods in a typical coastal saltmarsh at Patonga, New South Wales, Australia. Densities of the gastropods including Phallomedusa solida, Ophicardelus spp. and Littoraria luteola were significant in vegetated Salicornia quinqueflora and least in unvegetated saltmarsh and areas where mangroves had encroached. Experiments that translocated Ophicardelus spp. and manipulated cover revealed that these patterns were actively maintained by Ophicardelus spp., which dispersed up to 40 cm and 1.4 m after 3 and 24 h, respectively, away from unvegetated saltmarsh and mangroves. The results of this study suggest that both habitat and cover influence the abundance and movement of gastropod dynamics in southeastern saltmarsh. Given future anticipated saltmarsh loss, further investigations are needed on the unknown functional role of gastropods in saltmarsh ecosystems.