Estructura de las comunidades de diatomeas epilíticas, en el Río Fonseca, Provincia de Chiriquí, Panamá

A study of the community of ephilitic diatoms in upstream (Soloy) and downstream (Paso Ganado) of Fonseca River was performed, in order to obtain information about the structure of these community in function of spatial and temporal variation (dry and rainy season). 3880 valves were counted in which the major number of species was presented by the genera Nitzschia (11), Navicula (9), Gomphonema (7) and Fragilaria (6). The values of the similarity index of Jaccard and Morisita revealed communities with dissimilar structures, both spatial and temporally. Soloy presents major richness and evenness of species during the dry season. According to the Biological Value index (IVB), the dominant specie that characterized this metacommunity was Cymbella turgidula and the genus Navicula. The number of species between communities was not affected by environment pressure (dry and rainy seasons). However, their presence, abundance and persistence are attributed to variations on physicochemical conditions of the water body, possibly caused by the hydroelectric construction and farming activities carried out along the river.