Dr RAFAEL Magris1,2, Prof Natalie Ban2
1Chico Mendes Institute for Biodiversity Conservation, Brasília, Brazil, 2School of Environmental Studies, University of Victoria, Victoria, Canada
Sediment disturbances are one of the most important threats affecting many marine species and causing profound ecological shifts. With an increase in suspended sediment concentration and deposition, alterations of the physical and chemical environment can reduce suitability of habitats, resulting in physical displacement of organisms or forcing them to migrate to other areas. However, to date, the majority of studies have only addressed the physiological and behavioural responses at the organism level. Here, we collate all available information to compare the extent of impacts across a variety of biological responses, taxonomic groups, habitats and stressor types (i.e. light attenuation, suspended and settling sediments). We used meta-analyses to evaluate sediment disturbance effects on community composition and structure, abundance, behaviour, morphology, physiology and on early developmental stages across 1,115 observations found in 69 publications. The sediment effects were most pronounced for changes measured at the community level, indicating that these disturbances can disrupt whole ecosystems and affect species’ geographic range. Primary producers were also particularly sensitive to increased sediments. Our analyses revealed evidence for an interaction between light, suspended sediment, and sedimentation, which is likely to trigger a much broader negative effect on marine ecosystems. Cumulative and interacting effects across all these stressors should be emphasised by future research to evaluate the overall vulnerability of marine biodiversity to sediment disturbances and to specify under which circumstances sediments would lead to more extensive degradation.
Dr Magris graduated with a PhD in 2016 at James Cook University (Australia), working on marine protected area design. Currently, he works for the national agency on biodiversity conservation in Brazil with an interest in marine conservation and cumulative impact mapping.