Oligochaete assemblages of Swiss Alpine lakes

Abstract

The present paper describes the oligochaete assemblages of 12 Swiss Alpine lakes (1700-2500 m above sea level) in Canton Ticino. The lake catchment geology is dominated by gneiss. The scarcity of carbonate rocks leads to a low buffering capacity, increasing the lakes' sensitivity to acidification. Because of their very low phosphorus concentrations, they are defined as ultraoligotrophic. Oligochaetes were identified from kick-samples taken from the outflow and littoral zone of the lakes one to three times per year in 1991-1994, 2003 and 2007, when the lake water chemistry was also characterized. Oligochaete assemblages consisted of 19 species in total, 18 of which were found in the littoral zone, and 10 in the outlets. Amongst them, Cernosvitoviella goodhui Healy, 1975 was recorded in Switzerland for the first time. Principal component analysis (PCA), performed excluding the highly alkaline Lake Bianco (pH = 7.8 and alkalinity = 566 µeq L −1 ) due to its atypical chemical composition, divided the remaining lakes into two groups with different sensitivity to acidity: the first group of four lakes was characterized by a higher average pH (6.4) and alkalinity (32 µeq L −1 ), whilst the second group of seven lakes was characterized by a lower average pH (5.7) and alkalinity (5 µeq L −1). Multivariate analysis performed on data collated from the littoral zone highlighted geo-lithology as a key driver in determining the species distribution among lakes. When applied to the lake outlet data, a similar distinction between acidic and calcareous waters was implied. Precipitation influenced the oligochaete assemblage in the littoral zone. During years with higher annual rainfall, the relative abundance of Enchytraeidae increased, probably because their semi-aquatic nature allows them to colonize the littoral zones that dry out periodically.

Changes in midge assemblages (Diptera Chironomidae) in an alpine lake from the Italian Western Alps: the role and importance of fish introduction

“…The modern macrobenthic invertebrate community of Balma Lake is dominated by Diptera Chironomidae, which represent almost all of the whole observed community, as expected for high-altitude lakes (Bretschko, 1974;Kownacki et al, 2000;Fu ¨reder et al, 2006;Kownacki et al, 2006;Oertli et al, 2008;Fjellheim et al, 2009;Ciamporova-Zat'ovicova ´et al, 2010;Dumnicka et al, 2015;Novikmec et al, 2015). The chironomid littoral community was well diversified, with 12 taxa observed during the seasonal sampling campaigns.…”

Groundwater environmental DNA metabarcoding reveals hidden diversity and reflects land‐use and geology

“…Cernosvitoviella aggtelekiensis, an annelid species known to occasionally occur in groundwater, was recorded only one time in Switzerland under the synonym C. goodhui (Dumnicka et al, 2015). Our ASV, however, is only 94.6% similar to the reference sequence, and could belong to a closely related species, not listed in GenBank.…”

“…One of them is the copepod species complex Acanthocyclops vernalis/robustus , which is a very widespread taxon in the northern hemisphere and which has been observed both in surface and ground‐waters (Galassi, 2001). Cernosvitoviella aggtelekiensis , an annelid species known to occasionally occur in groundwater, was recorded only one time in Switzerland under the synonym C. goodhui (Dumnicka et al, 2015). Our ASV, however, is only 94.6% similar to the reference sequence, and could belong to a closely related species, not listed in GenBank.…”