Urban coral reefs: Degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia

Towards an urban marine ecology: characterizing the drivers, patterns and processes of marine ecosystems in coastal cities

“…Urban sediment pollution, commonly the result of runoff from construction work and disturbance via dredging (Rogers 1990, Eggleton and Thomas 2004, Erftemeijer et al 2012, as well as other sources such as beach nourishment and landuse changes that alter catchment runoff (Colosio et al 2007, Zhang et al 2010, affects marine life in multiple ways. The resulting increase in turbidity reduces light penetration, photosynthesis (Falkowski et al 1990), and the maximum depth at which photosynthetic organisms can grow (Heery et al 2018a). Suspended sediments also reduce fish hatching success and larval survival (Auld and Schubel 1978), impede zooplankton feeding (Sew et al 2018), affect mobile fauna that rely on visual cues (Weiffen et al 2006), and alter a wide range of benthic ecosystem processes and patterns (Airoldi 2003), including the settlement and successful recruitment of organisms, the diversity of species, and competitive interactions -such as those between foundation macrophyte species and low-lying algal turfs (Gorgula and Connell 2004, Russell and Connell 2005, Gorman and Connell 2009, Knott et al 2009, Bauman et al 2015.…”

“…Urban stressors can be particularly detrimental for sensitive foundation species such as oysters, reef-building corals, seagrasses, mangroves and canopy-forming kelps, which structure marine ecosystems via the provisioning of biogenic habitat (Dayton 1972, Bertness andCallaway 1994). Even though the dynamics of decline vary among taxa and across locations (Terrados et al 1998, Waycott et al 2009, Polidoro et al 2010, Heery et al 2018a), loss in foundation species is generally tied to one or more of the three major drivers of marine urbanization (Rogers 1990, Hastings et al 1995, Airoldi 2003, Balestri et al 2004, Kirby 2004, Connell et al 2008, Strain et al 2014, Yaakub et al 2014a, Alleway and Connell 2015. In temperate areas, nutrient-rich, high sedimentation conditions can limit the recruitment and survival of canopyforming kelps while supporting opportunistic, turf-forming algal species that can act as kelp competitors (Airoldi 1998, Benedetti-Cecchi et al 2001, Gorgula and Connell 2004, Russell and Connell 2005, Coleman et al 2008, Gorman and Connell 2009.…”

“…Similarly, in the tropics, sediment pollution has multiple negative effects on corals. These decrease coral cover and disproportionately impact competitive, branching coral genera such as Acropora, which ultimately lowers reef complexity in urban areas (Heery et al 2018a). Ocean sprawl can also be an important driver of foundation species loss.…”

“…Several recent reviews have separately highlighted urbanrelated pollution and physical modifications of urban shorelines as critical components of urban marine ecosystem dynamics (Dafforn et al 2015, Firth et al 2016, Heery et al 2018a), but exploitation of marine resources is rarely discussed in an urban context (though see Li 2003, Baum et al 2016. The overarching characteristics of urban marine ecosystems that result from each of these factors and their potential combined effects have yet to be thoroughly considered.…”

The Status of Coral Reefs and Its Importance for Coastal Protection: A Case Study of Northeastern Hainan Island, South China Sea

“…Abutting the western border of the "Coral Triangle", the SCS hosts significant levels of biodiversity and provides important economic value and ecological services for neighboring countries and people [24][25][26]. However, these reefs and coastal zones have been subjected to a multitude of anthropogenic stressors due to rapid urbanization and population growth [27,28]. Some coral reefs in the northern SCS have suffered a dramatic decline over the past decades, especially in Hainan Island [29,30].The aims of this study are to: (1) characterize the coral communities and their status in the northeastern Hainan Island; (2) reveal hydrodynamic conditions and shoreline changes around coral reef over the past 20 years; (3) relate the coral reef degradation to coastal erosion; and (4) evaluate the role of coral reefs in coastal protection and explore various ways to protect coral reefs and adjacent coastlines.…”