SOBRE LOS FILTROS QUE DETERMINAN LA DISTRIBUCIóN Y LA AbUNDANCIA DE LOS MACROINVERTEBRADOS DIáDROMOS Y NO-DíADROMOS EN CADA NIVEL JERARáRQUICO DEL PAISAJE FLUVIAL EN ISLAS

the fluvial ecosystems in islands are important because they shelter species with particular life histories. diadromous organisms such as fishes, shrimps, crabs and snails migrate regularly between low-order streams and estuaries or the ocean to complete their life cycles, and therefore are broadly distributed across marine basins. conversely, non-diadromous fauna, such as the insects, are restricted to particular insular regions due to their limited dispersal capability, relatively high speciation rates, and the island's isolation. as a consequence of the distinctive life histories coexisting in insular streams, it is necessary to provide information on the patterns of abundance and the driving processes throughout all levels within the spatial hierarchy (regions, segments, reach, habitats and microhabitats) in order to establish better management plans and conservation of these ecosystems. therefore, this paper presents a review about the main processes structuring diadromous and non-diadromous assemblages operating at each hierarchical level in island streams.