Long-term Shifts in Coral Communities On Shallow to Deep Reef Slopes of Curaçao and Bonaire: Are There Any Winners?

Abstract

Tropical coral reefs are among the most biologically diverse and economically important ecosystems on earth. Nevertheless, we found dramatic changes in coral communities on the reef slopes of Curaçao and Bonaire since 1973. Cover and abundance declined for virtually all coral species. The data show a shift from communities dominated by framework building species (e.g., Orbicella spp.) to communities consisting of small opportunistic, phenotypically plastic, species, including few remaining structural colonies. Madracis mirabilis, Porites astreoides, Diploria strigosa, and Agaricia lamarcki are at present modest winners in the coral assemblage, although overall cover declined also for these species. Increased frequency and intensity of events inducing coral mortality and ongoing reduction in suitable hard substratum, provided by the remnants of large colony building species, could reduce the chance of these species to remain winners in the longer run. The observed loss in coral cover and the shift from larger structural to smaller opportunistic species reduced reef carbonate production by 67% and therewith, in combination with a trend toward smaller coral colonies, reef complexity. Alarmingly, reefs at upper-mesophotic depths (30-40 m) did not escape the general degradation of the coral community. The negative effects are larger around densely populated areas where local stressors are adding to degradation caused, for instance, by region wide mass bleaching. Without proper conservation and management this already dramatic degradation will continue and turn more and more coral species into losers.

40 Years of benthic community change on the Caribbean reefs of Curaçao and Bonaire: the rise of slimy cyanobacterial mats

“…& Didier M. de Bakker didier.debakker@wur.nl; didierdebakker@gmail.com triggered shifts in benthic species composition, competition, productivity and biodiversity (Hughes 1994;Jackson et al 2014;De Bakker et al 2016a). The Caribbean region and Gulf of Mexico have been particularly affected with an estimated decrease in scleractinian coral cover up to 80% on many reefs.…”

Staat van de natuur van Caribisch Nederland 2017 : een eerste beoordeling van de staat (van instandhouding), bedreigingen en managementimplicaties van habitats en soorten in Caribisch Nederland

“…De bodembedekking door levend koraal is de afgelopen 40 jaar gemiddeld met meer dan 50% afgenomen (Bak et al 2005a, de Bakker et al 2016, de Bakker et al 2017. Bij een verdere achteruitgang dreigen belangrijke ecosysteemdiensten zoals toerisme, visserij en kustbescherming de komende jaren sterk achteruit te gaan.…”

“…Lange-termijn data zijn alleen bekend van Bonaire en Curaçao, (Bak et al, 2005b;de Bakker et al, 2016;de Bakker et al, 2017 Bakker et al, 2016;de Bakker et al, 2017). Andere data worden besproken in Jackson et al (2014), maar de conclusies, namelijk een afname van bijna 50% van de oorspronkelijke bedekking gedurende de laatste 25-40 jaar, zijn dezelfde als hier (Fig.…”

“…(Gladfelter, 1982;Peters et al, 1983), waarmee een belangrijke kinderkamerfunctie voor jonge vis grotendeels weg is. Ook dieper is de plek van koraal veelal ingenomen door algen (Bakker et al, 2016(Bakker et al, , 2017.…”

Mesophotic Coral Ecosystems: A Geoacoustically Derived Proxy for Habitat and Relative Diversity for the Leeward Shelf of Bonaire, Dutch Caribbean

“…For example, van Duyl (1985) mapped out bottom types and benthic community structure around the leeward perimeter of the island from the shoreline to a depth of ∼10 m. There have been limited observations of reefs in Bonaire at greater depths and almost no work has been done to date at depths where Mesophotic Coral Ecosystems (referred to in the research literature as MCEs) exist. A recent study by De Bakker et al (2016) reported pressures and declines in coral assemblages even in depths of 30-40 m off Bonaire and Curaçao thus emphasizing the need to locate and characterize coral reef assemblages in mesophotic depths. MCEs in Bonaire have been shown to extend from 30 to 150 m water (De Meyer and MacRae, 2006;Keller, 2011).…”