| Title | Zoobenthic communities of inlets and outlets of high altitude Alpine lakes |
| Abstract | Due to their sensitivity, remote mountain lakes and streams are not only vulnerable to environmental change but also excellent sensors of such changes. Notwithstanding their importance as an ultimate resource of unpolluted waters, the alpine biome remains one of the less studied ecosystems in the world. This study involved the analysis of a database of zoobenthic communities collected in 36 inlets and 44 outlets of Swiss (Canton Bern) and Italian (Piedmont, Trentino-Alto Adige) Alpine lakes. All the streams are above the tree line and were sampled qualitatively in September/October (mostly in 2000) by disturbing the substrate and concentrating the dislodged animals with a standard pond net (250 µm mesh size).
Generally higher population densities and taxon richness were found in the outlets than in the inlets. 57% of taxa were common to the two stream types, with 17% found exclusively in the inlets and 26% in the outlets. Piedmont had the highest number of taxa found only in the region, Trentino-Alto Adige the lowest number. Insects represented 89% and 81% of the zoobenthic community of inlets and outlets respectively. Among the insects, Diptera prevailed, with Chironomidae accounting for 68% of the mean inlet communities and 45% of those found in the outlets. The subfamily of Diamesinae was far more abundant in the inlets (16%) than in the outlets (1%). In contrast, the outlets hosted more Ephemeroptera, Trichoptera, Plecoptera, Oligochaeta and Tricladida. Some significant differences regarding the distribution of some species were found along the west-east and south-north gradients. The lakes appeared to affect the structure of the stream zoobenthic community by ameliorating the harsh physico-chemical conditions of the tributaries but no evidence was found indicating an increase in organic matter. In fact, filter feeding invertebrates did not show any significant increase in the outlets, though the number of these taxa was higher downstream of the lakes. |
| Source | Hydrobiologia (The Hague. Print) 562, pp. 217–229 |
| Keywords | macro invertebratesAlpine streamsprotected areaslake effectAlps |
| Journal | Hydrobiologia (The Hague. Print) |
| Editor | Kluwer Academic Publishers, Boston, Paesi Bassi |
| Year | 2006 |
| Type | Articolo in rivista |
| Authors | Maiolini B.(1), Lencioni V.(1), Boggero A., Thaler B.(2), Lotter A.F.(3), Rossaro B.(4) |
| Text | 52906 2006 macro invertebrates Alpine streams protected areas lake effect Alps Zoobenthic communities of inlets and outlets of high altitude Alpine lakes Maiolini B. 1 , Lencioni V. 1 , Boggero A., Thaler B. 2 , Lotter A.F. 3 , Rossaro B. 4 1 Museo Tridentino di Scienze Naturali, Sezione di Zoologia degli Invertebrati e Idrobiologia, Trento; 2 Biologisches Landeslabor Umweltagentur, Laives BZ ; 3 Dept. Palaeoecology, Lab. of Palaeobotany and Palynology, University of Utrecht The Netherlands ; 4 Dipartimento di Biologia, Sez. di Ecologia, Universita di Milano Due to their sensitivity, remote mountain lakes and streams are not only vulnerable to environmental change but also excellent sensors of such changes. Notwithstanding their importance as an ultimate resource of unpolluted waters, the alpine biome remains one of the less studied ecosystems in the world. This study involved the analysis of a database of zoobenthic communities collected in 36 inlets and 44 outlets of Swiss Canton Bern and Italian Piedmont, Trentino Alto Adige Alpine lakes. All the streams are above the tree line and were sampled qualitatively in September/October mostly in 2000 by disturbing the substrate and concentrating the dislodged animals with a standard pond net 250 µm mesh size . Generally higher population densities and taxon richness were found in the outlets than in the inlets. 57% of taxa were common to the two stream types, with 17% found exclusively in the inlets and 26% in the outlets. Piedmont had the highest number of taxa found only in the region, Trentino Alto Adige the lowest number. Insects represented 89% and 81% of the zoobenthic community of inlets and outlets respectively. Among the insects, Diptera prevailed, with Chironomidae accounting for 68% of the mean inlet communities and 45% of those found in the outlets. The subfamily of Diamesinae was far more abundant in the inlets 16% than in the outlets 1% . In contrast, the outlets hosted more Ephemeroptera, Trichoptera, Plecoptera, Oligochaeta and Tricladida. Some significant differences regarding the distribution of some species were found along the west east and south north gradients. The lakes appeared to affect the structure of the stream zoobenthic community by ameliorating the harsh physico chemical conditions of the tributaries but no evidence was found indicating an increase in organic matter. In fact, filter feeding invertebrates did not show any significant increase in the outlets, though the number of these taxa was higher downstream of the lakes. 562 Published version Articolo in rivista Kluwer Academic Publishers 0018 8158 Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia. The Hague. Print Hydrobiologia Dordrecht The Hague. Print Hydrobiologia Boston The Hague. Print Hydrobiologia London The Hague. Print angela.boggero BOGGERO ANGELA TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici |
