Spatial heterogeneity of macrophytes in Lake Gallocanta (Aragón, NE Spain)

The spatial distribution of macrophytes (Ruppia drepanensis Tineo and Lamprothamnium papulosum (Wallr.) J. Gr. was studied along transects perpendicular to the shoreline in Lake Gallocanta (Aragon, NE Spain) in 1988 and 1990. In the shallow zone, a gradient from the shoreline to offshore waters was clear: Small R. drepanensis plants were the only colonizers of near shore waters affected by wave action and desiccation. R. drepanensis and L. papulosum coexisted at intermediate depths in the shallow zone. L. papulosum reached higher biomasses than R. drepanensis in the deepest parts of the shallow zone. In the deepest zone of the lake, stands of the two species did not overlap. Individual plants of R. drepanensis occured patchily within a sparse prairie of L. papulosum.