The effects of the invasive mussel, Limnoperna fortunei, on associated fauna in South American freshwaters: importance of physical structure and food supply

PAULA SARDIÑA, DANIEL H. CATALDO AND DEMETRIO BOLTOVSKOY

FUNDAMENTAL AND APPLIED LIMNOLOGY

Int. Association of Theorical Applied Limnology

Lugar: Alemania; Año: 2008 vol. 173 p. 135 - 144

1863-9135

We examined the importance of the introduced Asian golden mussel (Limnoperna fortunei) in structuring invertebrate communities in South American freshwaters. An experiment using artifi cial substrata (i.e., concrete tiles with either a layer of living mussels, a layer of intact empty shells that mimicked living mussels, or blank tiles) showed that, when considered in bulk, invertebrates (density and biomass) are enhanced signifi cantly in the presence of live mussels (as compared with shells only and blank tiles). On a taxon-by-taxon basis, however, signifi - cantly higher densities and biomass on live mussel tiles than on blank and/or shells-only tiles were found only for Oligochaeta, which would especially benefi t from the feces and pseudofeces produced by the living mussel beds. At the end of the experiment, the amount of accumulated sediment on the tiles differed greatly among treatments, with values up to three times higher on shells-only tiles than on live-mussel and blank tiles. Dead mussels act as a sediment trap, whereas the activity of live mussels helps keep the tiles less clogged with sediments. On the other hand, proportions of organic matter were two times higher in the presence of live mussels than in the other two treatments. Although the physical structure created by mussel shells plays a signifi cant role, we conclude that the activity of living mussels is of major importance for controlling invertebrate numbers, biomass and diversity. invertebrate communities in South American freshwaters. An experiment using artifi cial substrata (i.e., concrete tiles with either a layer of living mussels, a layer of intact empty shells that mimicked living mussels, or blank tiles) showed that, when considered in bulk, invertebrates (density and biomass) are enhanced signifi cantly in the presence of live mussels (as compared with shells only and blank tiles). On a taxon-by-taxon basis, however, signifi - cantly higher densities and biomass on live mussel tiles than on blank and/or shells-only tiles were found only for Oligochaeta, which would especially benefi t from the feces and pseudofeces produced by the living mussel beds. At the end of the experiment, the amount of accumulated sediment on the tiles differed greatly among treatments, with values up to three times higher on shells-only tiles than on live-mussel and blank tiles. Dead mussels act as a sediment trap, whereas the activity of live mussels helps keep the tiles less clogged with sediments. On the other hand, proportions of organic matter were two times higher in the presence of live mussels than in the other two treatments. Although the physical structure created by mussel shells plays a signifi cant role, we conclude that the activity of living mussels is of major importance for controlling invertebrate numbers, biomass and diversity. invertebrate communities in South American freshwaters. An experiment using artifi cial substrata (i.e., concrete tiles with either a layer of living mussels, a layer of intact empty shells that mimicked living mussels, or blank tiles) showed that, when considered in bulk, invertebrates (density and biomass) are enhanced signifi cantly in the presence of live mussels (as compared with shells only and blank tiles). On a taxon-by-taxon basis, however, signifi - cantly higher densities and biomass on live mussel tiles than on blank and/or shells-only tiles were found only for Oligochaeta, which would especially benefi t from the feces and pseudofeces produced by the living mussel beds. At the end of the experiment, the amount of accumulated sediment on the tiles differed greatly among treatments, with values up to three times higher on shells-only tiles than on live-mussel and blank tiles. Dead mussels act as a sediment trap, whereas the activity of live mussels helps keep the tiles less clogged with sediments. On the other hand, proportions of organic matter were two times higher in the presence of live mussels than in the other two treatments. Although the physical structure created by mussel shells plays a signifi cant role, we conclude that the activity of living mussels is of major importance for controlling invertebrate numbers, biomass and diversity. invertebrate communities in South American freshwaters. An experiment using artifi cial substrata (i.e., concrete tiles with either a layer of living mussels, a layer of intact empty shells that mimicked living mussels, or blank tiles) showed that, when considered in bulk, invertebrates (density and biomass) are enhanced signifi cantly in the presence of live mussels (as compared with shells only and blank tiles). On a taxon-by-taxon basis, however, signifi - cantly higher densities and biomass on live mussel tiles than on blank and/or shells-only tiles were found only for Oligochaeta, which would especially benefi t from the feces and pseudofeces produced by the living mussel beds. At the end of the experiment, the amount of accumulated sediment on the tiles differed greatly among treatments, with values up to three times higher on shells-only tiles than on live-mussel and blank tiles. Dead mussels act as a sediment trap, whereas the activity of live mussels helps keep the tiles less clogged with sediments. On the other hand, proportions of organic matter were two times higher in the presence of live mussels than in the other two treatments. Although the physical structure created by mussel shells plays a signifi cant role, we conclude that the activity of living mussels is of major importance for controlling invertebrate numbers, biomass and diversity. Limnoperna fortunei) in structuring invertebrate communities in South American freshwaters. An experiment using artifi cial substrata (i.e., concrete tiles with either a layer of living mussels, a layer of intact empty shells that mimicked living mussels, or blank tiles) showed that, when considered in bulk, invertebrates (density and biomass) are enhanced signifi cantly in the presence of live mussels (as compared with shells only and blank tiles). On a taxon-by-taxon basis, however, signifi - cantly higher densities and biomass on live mussel tiles than on blank and/or shells-only tiles were found only for Oligochaeta, which would especially benefi t from the feces and pseudofeces produced by the living mussel beds. At the end of the experiment, the amount of accumulated sediment on the tiles differed greatly among treatments, with values up to three times higher on shells-only tiles than on live-mussel and blank tiles. Dead mussels act as a sediment trap, whereas the activity of live mussels helps keep the tiles less clogged with sediments. On the other hand, proportions of organic matter were two times higher in the presence of live mussels than in the other two treatments. Although the physical structure created by mussel shells plays a signifi cant role, we conclude that the activity of living mussels is of major importance for controlling invertebrate numbers, biomass and diversity.