Taxocenosis Mollusca-Crustacea en raíces de Rhizophora mangle, delta del río Ranchería - La Guajira, Colombia

The submerged roots of Rhizophora mangle are an important support to some organisms community that form a subsystem, since they have their own organization and dynamic structure. Such roots serve as site for fish, shrimps, crabs and mussels breeding, among others. This research aim was to determine the distribution of Mollusca-Crustacea taxocenosis associated with the submerged roots of R. mangle and their relationship with some physicochemical variables of water in the Ranchería River estuary. The samplings were carried out between September 2014 and March 2015 in five sites three sites associate to the distributary El Riíto and two sites in the distributary Calancalá. Physicochemical variables (salinity, temperature, dissolved oxygen, pH, alkalinity, hardness and turbidity) were measured at each site in every month. At each site, two roots were randomly cut and were introduced in plastic bags with formalin 10 %. The samples were quantified and identified at the laboratory. For the entire study area, 38 taxa were collected, corresponding to 57.89 % to mollusks and 42.11 % of crustacea. Although the stations studied show certain differences regarding physiochemical factors, mainly salinity and pH, the taxocenosis is considered very uniform with a minimum similarity of 68 % among the sites. It is concluded that the bivalve Mytiliopsis leucophaeata and the amphipod Americorophium brevis were the most abundant species, since they are estuarine species typical of hard substrate, dominating the taxocenosis in the Ranchería River delta, which shows a low species richness of mollusks and crustaceans, mainly due to the broad change of salinity throughout the studied period.