Estructura de las comunidades de corales y octocorales de Isla de Aves, Venezuela, Caribe Nororiental

Abstract

Structure of the coral and octocoral communities of Isla de Aves, Venezuela, Northeast Caribbean. The Isla de Aves Wildlife Refuge is the northernmost portion of the Venezuelan territory generating 135 000km 2 of Exclusive Economic Zone. Studies on coral communities are scarce and old (1970s), due to its location 650km northeast of La Guaira Port and because it has military facilities. To upgrade baseline information we estimated size structure, percent live cover, species composition and abundance of corals and octocorals. We evaluated 16 sites around the island using the AGRRA Protocol (band-transects 10 m 2 ) between 1.5 and 21m depth (n=67 transects), and visual surveys conducted in other five sites. We recorded 2 327 colonies belonging to four hydroid species and 36 species of stony corals in 11 families. The values for diversity, dominance and evenness of the coral community ranged between 0.78 and 2.12 (SW), 0.15 and 0.61 and 0.57 y 0.92 respectively. Most coral species had relative abundance values under 3%, except Porites astreoides (25.57%), Pseudodiploria strigosa (18.22%) and Siderastrea siderea (14.44%). They were represented mostly by smaller colonies, between 3 and 30cm in maximum diameter and between 0 and 5cm high. A total of 13 octocoral species belonging to three families were identified. Pseudopterogorgia americana was the most abundant species. The mean percent of live coral (including hydrocorals) was 22.30% (SE=1.73) (15.45% for dead coral, SE=3.28). Dead coral had the highest percentage of dissimilarity between sites (9.21%) (ANOSIM) and 16.57% contribution (SIMPER analysis). Octocoral live cover ranged from 0 to 21.35% with a mean of 6.38% (SE=0.99). Research on benthic communities of Isla de Aves should continue, especially in the deeper areas, to assess ecological conditions. Rev. Biol. Trop. 62 (Suppl. 3): 115-136. Epub 2014 September 01.Key words: corals, octocorals, abundance, diversity, Isla de Aves, Venezuela.El estudio de comunidades coralinas en Venezuela se ha desarrollado especialmente en localidades como el Parque Nacional Archipié-lago de Los

The History of a Remote Caribbean Cay, Isla Aves, and Its Terrestrial Biota: A Review and New Data

“…The vertical arrows indicate the dates of three hurricanes known to pass directly over Isla Aves (see text). Data from Anonymous (1835); Bisbal (2008); Brownell and Guzman (1964); Butterlin (1956);De Vaynes van Brakell (1857, 1879; Dirección de Hydrografía (1820); Dudley (1647); Furlong (1796Furlong ( , 1798Furlong ( , 1800Furlong ( , 1804; Gala et al (1857);Garcia Cruz et al (2015); Gibbs (1860); Hadgialy (1945);Hammelberg (1901); Harding (1896); Hummelinck (1952a); Labat (1722); Laurance (1849); Lazo (2015); Maloney and Schubert (1968); Mitchell (1957); Oldendorp (1777); Pereira et al (2018); Phelps (1953); Pinchon (1952); Urbani Patat (2019); Vera and Buitrago (2012); Yranzo et al (2014);and Zuloaga (1955); the field study by two of the present authors, HH, FT (1966), and the spatial analysis by another present author, SKK (2021).…”

“…Acropora palmata also has one of the highest rates of growth of all species of coral in the Caribbean (Perry et al 2013). However, due to the regionwide mass mortalities of Acropora that began in the mid-1980s (Aronson and Precht 2001), three decades later Yranzo et al (2014) documented the virtual disappearance of this large framework-building species from around Isla Aves. Reduced coastal protection by its fringing reef and the consequent decrease in accretion of carbonate due to the loss of Acropora palmata and other corals, as well as other marine organisms such as molluscs, foraminifera, echinoids, and coralline algae that also importantly produce essential carbonate sediment, certainly makes the future of Isla Aves much less certain.…”

“…Isla Aves lies within the Caribbean hotspot of biodiversity, one of 25 such areas designated for the world (Myers et al 2000). Various aspects of the marine biota of the reef at Isla Aves have been studied, including the fish fauna (Brownell et al 1973;Brownell and Guzmán 1974; 87 species in 65 genera and 41 families), corals (Yranzo et al 2014; 4 hydroid species, 36 species of stony corals, and 13 of octocorals), sponges (Villamizar et al 2019; 77 species), and plankton (Pereira et al 2018;191 species).…”

Fitoplancton del Refugio de Fauna Silvestre Isla de Aves: el territorio venezolano más septentrional

“…Posee 600 m de longitud en sentido norte-sur y 130 m en sentido este-oeste con una superficie de 42.000 m 2 (ver figura 1). Es un área afectada por el paso de tormentas y huracanes, y ha sido considerada de bajo impacto antropogénico, debido a que no tiene presión de pesca y turismo, con un desarrollo de actividades humanas muy bajo, ya que la población residente en la isla es de 15 personas aproximadamente (Yranzo et al, 2014).…”

“…Las comunidades fitoplanctónicas incluyen a las microalgas suspendidas en la columna de agua que están a la merced de la dinámica costera. Este grupo de organismos fotosintetizadores constituye la base de la trama alimentaria en la mayor parte de las comunidades marinas, ya que además de utilizar los nutrientes elementales del agua y transformarlos en materia orgánica (Yilmaz, Yardimci, Elhag & Dumitrache, 2018), es responsable en gran proporción de la productividad primaria oceánica (Arrigo et al, 1999;Luz y Barkan, 2000). Asimismo, el fitoplancton es capaz de responder rápidamente ante las fluctuaciones hidrográficas, explicando la mayoría de los procesos oceánicos y es considerado, el principal regulador de oxígeno y dióxido de carbono de la atmósfera (Troccoli, 2001).…”