RESUMEN
There has been an increase in recognition of the benefits of employing nature-based coastal protection strategies to adapt to the impacts of climate change (e.g., increased storminess, sea-level rise). To enable broader use of nature-based methods, coastal managers and policymakers need to consider the placement and social acceptance of any methods considered. Most published spatial planning models for nature-based coastal protection currently do not utilise social data during site selection. We conducted a public survey of 452 respondents from Singapore, a highly urbanised coastal city-state, to assess Singaporean's perceptions of climate change impacts on coastal areas and their support of nature-based coastal protection. We also assessed the respondents willingness to accept trade-offs for the prioritisation of nature-based coastal protection and subsequently spatially mapped them. The results showed a high awareness of the potential impacts of climate change on coastal areas. Nature-based coastal protection was highly supported as the associated benefits, such as protection of wildlife and their habitats and climate change reduction, were aligned with public values of coastal areas. However, nature-based coastal protection may not be prioritised over human-made structures due to the perception that they are less effective, and respondents may not be willing to undergo 1) replacement of their favourite coastal area, 2) increased taxes, and 3) relocation, for their prioritisation. Through spatially mapping the relevant trade-offs, we found that only 11.1% of coastal areas had moderate or high likelihood of social barriers to nature-based coastal protection, highlighting their potential in Singapore. These findings underscore the importance of incorporating social factors in government land use planning decisions.
RESUMEN
Urban shorelines undergo substantial hydrodynamic changes as a result of coastal engineering and shoreline armouring that can alter sedimentation, turbidity, and other factors. These changes often coincide with major shifts in the composition and distribution of marine biota, however, rarely are hydrodynamic-mediated factors confirmed experimentally as the mechanism underpinning these shifts. This study first characterized hydrodynamic-related distribution patterns among epilithic and epiphytic microinvertebrates on urban seawalls in Singapore. We found reduced microinvertebrate abundances and distinct microinvertebrate community structure within benthic turf algae in areas where coastal defences had reduced wave energy and increased sediment deposition, among other hydrodynamic-related abiotic changes. Low-exposure areas also had reduced densities of macroinvertebrate grazers and less dense turf algae (lower mass per cm2) than adjacent high-exposure areas. Using harpacticoid copepods as a model taxon, we performed a reciprocal transplant experiment to discern between the effects of exposure-related conditions and grazing. Results from the experiment indicate that conditions associated with restricted wave energy from shoreline engineering limit harpacticoid population densities, as transplantation to low-exposure areas led to rapid reductions in abundance. At the same time, we found no effect from grazer exclusion cages, suggesting harpacticoids are minimally impacted by exposure-related gradients in gastropod macrograzer densities over short time scales. Given the key role of intertidal microinvertebrates, particularly harpacticoids, in nearshore food webs, we postulate that human-engineered hydrodynamic regimes are an important factor shaping marine ecosystem functioning in urban areas.