Dredging fundamentally reshapes the ecological significance of 3D terrain features for fish in estuarine seascapes

Abstract Context Landscape modification alters the condition of ecosystems and structure terrain, with widespread impacts on biodiversity ecosystem functioning. Seafloor dredging a diversity flora fauna in many coastal landscapes, these processes also transform three-dimensional terrain features. The potential ecological significance changes urban seascapes has, however, not been investigated. Objectives We examined effects variation fish assemblages 29 estuaries eastern Australia, tested whether how associate Methods surveyed baited remote underwater video stations quantified nine complementary metrics (e.g. depth, aspect, curvature, slope, roughness), extracted from bathymetry maps created multi-beam sonar. Results Fish abundance were strongly linked to seafloor both natural dredged estuaries, highest shallow waters near features high curvature. Dredging, significantly altered transformed for assemblages. Abundance switched being correlated lower roughness steeper slopes higher gentler estuaries. Conclusions Contrasting fish-terrain relationships highlight previously unrecognised dredging, but indicate that plasticity use might be characteristic landscapes. Incorporating into spatial conservation planning help improve management outcomes, we suggest different approaches would needed modified