Relationships with other abiotic and biotic ecosystem elements and functional roles of macrophytes

Abstract

Macrophytes are studied regarding other compartments of the hydrosystems, so much abiotic (water mass, physical environment), that biotic (epiphytic algae, invertebrates, fish). Macrophytes modify the physical habitat, reducing locally and diversifying the flow, trapping the sediments. They store the nutritive elements temporarily. For the biotic elements, the macrophytes are a support for the micro- and macro-algae of the periphyton, but the detailed relationships between macrophytes and microphytes remain to be elucidated. For invertebrates, the macrophytes are a diversified place of life. But the macrophytes are also a source of food for certain invertebrates, contrary to what was pled until recently. The relations macrophyte-fish are practically not of trophic nature, but are expressed directly in terms of medium of life and source of shelter or indirectly by the modifi cations involved on the physical or physicochemical elements of the habitat. The comparisons between biotypologies by macrophytes and invertebrates, on the one hand, macrophytes and fish, on the other hand, highlight a clear agreement of the determinisms, but also the specific characteristics to each group of organizations, which informs about their respective capacity of bioindication. A reflexion on the trophic networks concludes the matter.