Measuring change in the sandy beach environment

Globally, coastal environments are at risk from the multiple effects of climate change and urbanisation. Both the recession of sandy beaches and the strategies of management put in place to mitigate it have the potential to disrupt the ecology of sandy beaches, and their important ecosystem services. Nevertheless, the threat this poses to meiofauna, the small invertebrates which underpin sandy beach food webs, is presently difficult to assess because: (1) the extent of beach management practices are not documented and (2) the scales at which meiofauna naturally vary, spatially and temporally, remain poorly understood. This thesis sought to redress these deficiencies. Through a survey of beach managers and a literature search, the extent of nourishment practices in Australia was assessed. On a global scale, most Australian projects were small but frequent. Most projects occurred in urbanised areas as a response to extreme weather, with little monitoring of efficacy or biological impact. A series of small scale surveys assessed the spatial and temporal scales of variation in sandy beach meiofauna. Variation was strongly correlated with elevation, sediment water content and granulometry. Significant natural variation was found between adjacent days, years and between geomorphically similar sections of adjacent beaches. Finally a case study was conducted to assess whether coastal lagoon dredging - part of beach dredge and fill project, impacted meiobenthic communities. An impact was detected, sites within the dredged lagoon recorded changes which were not observed in undisturbed lagoons. Sites within the dredged lagoon also showed greater spatio-temporal variability than those in undisturbed lagoons. Overall, this thesis adds to growing evidence that the coastal environment is facing increasing pressures. In order to assess their impact on important sandy beach ecosystems, rigorous experimental designs are needed to detect environmental impacts over significant background spatial and temporal variation.