Análisis poblacional de la malacofauna en la Isla del Amor, provincia de El Oro
Fecha
2018
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
El presente estudio analizó por primera vez la población de moluscos bentónicos en la isla del Amor, ubicada en Puerto Bolívar, provincia de El Oro. Los muestreos se realizaron de manera mensual de mayo a octubre de 2016. Se escogió al azar nueve puntos de muestreo en la zona intermareal, subdividiendo cada punto en estratos inframareal, mesomareal y supramareal. Se cuantificó un total de 5,167 individuos y se identificaron 28 especies de moluscos, distribuidos en tres clases, Gastropoda con 15 especies y una densidad total de 52 ind.m-2, Bivalvia con 12 especies y una densidad de 12 ind.m-2 y finalmente, Polyplacophora con un individuo significando una densidad de 0.01 ind.m-2. El gasterópodo de mayor abundancia fue Cerithium stercusmuscarum con 59,2% y una densidad poblacional de 38 ind.m-2, seguido del bivalvo Protothaca (Leukoma) aspérrima con 9,9%, que significó una densidad de 6 ind.m-2. En general, la diversidad de la isla del Amor se puede considerar como baja, con un valor de 1.57. En cuanto a las diferentes zonas, la mayor diversidad fue encontrada en la zona inframareal (1,625). La densidad poblacional de moluscos bentónicos no mostró un patrón de zonación (p=0.7934), lo que sugiere una distribución homogénea de las especies entre las zonas intermareales. En cuanto a la variación temporal, se registraron dos grupos bien definidos, siendo agosto, el mes que mostró la mayor riqueza específica durante el período de estudio.
The population of benthic mollusks was analyzed for the first time on the Amor Island, located in Puerto Bolivar, El Oro province. Sampling was conducted monthly from May to October 2016. Nine sampling points in the intertidal zone were chosen randomly, subdividing each point into inframareal, mesomareal and supramareal zones. A total of 5,167 individuals were quantified and 28 species of mollusks were identified, distributed in three classes, Gastropoda with 15 species and a total density of 52 ind.m-2, 12 species for Bivalvia with a density of 12 ind.m-2 and finally, Polyplacophora with only one individual which represented a density of 0.01 ind.m-2. The most abundant gastropod was Cerithium stercusmuscarum with 59.2% and a population density of 38 ind.m-2, followed by the bivalve Protothaca (Leukoma) asperrima with 9.9%, which represented a density of 6 ind.m-2. In general, the diversity of the Amor Island can be considered as low, with a value of 1.57. As for the different zones, the highest diversity was found in the inframareal zone (1,625). The population density of benthic mollusks did no show a zoning pattern (p = 0.7934), suggesting a homogeneous distribution of species between the intertidal zones. A 65% similarity was obtained between May to August, with August being the largest of species. The temporal variation showed two defined grupos, being August the month with the highest species richness during the study period.
The population of benthic mollusks was analyzed for the first time on the Amor Island, located in Puerto Bolivar, El Oro province. Sampling was conducted monthly from May to October 2016. Nine sampling points in the intertidal zone were chosen randomly, subdividing each point into inframareal, mesomareal and supramareal zones. A total of 5,167 individuals were quantified and 28 species of mollusks were identified, distributed in three classes, Gastropoda with 15 species and a total density of 52 ind.m-2, 12 species for Bivalvia with a density of 12 ind.m-2 and finally, Polyplacophora with only one individual which represented a density of 0.01 ind.m-2. The most abundant gastropod was Cerithium stercusmuscarum with 59.2% and a population density of 38 ind.m-2, followed by the bivalve Protothaca (Leukoma) asperrima with 9.9%, which represented a density of 6 ind.m-2. In general, the diversity of the Amor Island can be considered as low, with a value of 1.57. As for the different zones, the highest diversity was found in the inframareal zone (1,625). The population density of benthic mollusks did no show a zoning pattern (p = 0.7934), suggesting a homogeneous distribution of species between the intertidal zones. A 65% similarity was obtained between May to August, with August being the largest of species. The temporal variation showed two defined grupos, being August the month with the highest species richness during the study period.
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CERITHIUM STERCUSMUSCARUM, DENSIDAD POBLACIONAL, ISLA DEL AMOR, MALACOFAUNA, ZONACIÓN MAREAL