Variabilidad especial y temporal en la comunidad de cladóceros de la Ciénaga de Paredes (Santander, Colombia) a lo largo de un clclo anual

Abstract

In the Ciénaga de Paredes (73° 45′-73° 49′ W and 7°26′-7°29′ N), located in the Department of Santander (Colombia), the composition, and the spatial and temporal variation of the cladoceran community structure was determined with samples taken with a 68 μm vertical-hauled net, at eight sampling stations in an annual cycle (February 1998 to January 1999). To evaluate the structure, Hill numbers (N0, N1 and N2) and evenness were used. The sampling support was calculated with the Chao 1 and 2 estimators. The existence of significant differences for Hill numbers, evenness, numeric density, water column, pH, OD, and temperature among field trips and among stations, was analysed through an ANOVA. The species and morphospecies found (31), had a tropical, subtropical, and cosmopolitan distribution; belonging to temporary water bodies, floodplains or "ciénagas". The highest abundances were registered for Moina minuta, Moina cf. micrura, Diaphanosoma brevireme and Ceriodaphnia cornuta, which represented 81.9 % of the total collected individuals. The results obtained with the richness estimates suggest that if the sampling effort were increased using the same techniques, the morphospecies' number would have not increased. With regard to the structure's spatial variation, the station V showed higher evenness, richness, and diversity, but lower numeric density; this condition shows the difference between this station and the other ones; its atypical trend is explained by this station being near to the main tributary of the "Ciénaga" ("Quebrada La Gómez"). Regarding the temporal variation, the cladocerans' community structure changed between field trips, since the evenness and the richness showed significant differences, reflected by the variation in the relative abundance of the morphospecies but not in the cladocerans' abundance. This was caused by the fluctuations in rainfall and water level. © Asociación Española de Limnología.