Author/Editor		Brancelj, Anton; Kernan, Martin; Jeppesen, Erik; Rautio, Milla
Title		Cladocera remains from the sediments of remote cold lakes: a study of 294 lakes across Europe
Type		članek
Source		In: Catalan J, Curtis CJ, Kernan M, editors. Patterns and factors of biota distribution in remote European lakes. Stuttgart: Schweizerbart science publishers,
Publication year		2010
Volume		str. 269-94
Language		eng
Abstract		Sediment cores were taken from 294 lakes in 12 different remote mountain areas in Europe (from Greenland to Finland in the north and from Spain to Bulgaria in the south) for the analyses of Cladocera remains. Surface samples (O - 0.5 cm) were analysed to exarnine the contemporary distribution of Cladocera. These were compared with sub-samples from the pre-industrial period (depth> 15 cm) to assess changes in species composition over time. In total, the remains of 42 different Cladoceta taxa were identified in the surface sediments. The number of taxa per lake decreased from north to south, which also corresponded to a gradient of increasing altitude. On average, 12 taxa per lake were found in northern regions (Scotland, North Finland = high-Iatitude lakes) and ca. 4 taxa in the southern regions (Romania, Bulgaria, Slovenia, Austria = high-altitude lakes). The most common taxa, occurring in the majority of lakes, were Alona affinis, Chydorus sphaericus, Daphnia longispina gr., Alona quadrangularis and Acroperus harpae. Most other species were also widely distributed across several of the lake districts, suggesting that all cold water lakes in Europe are equally favourable habitats for c1adocerans. Eurycercus glacialis and Eubosmina longispina were the most abundant species restricted to specific regions, the former to Greenland and the latter to Northern Finland. Multivariate statistical analyses showed that the taxa assemblages were primariIy determined by biogeographical factors. Dispersallimitations at high altitudes may be the most important factor for the differences in species diversity among districts. Physical, chemical and trophic conditions appeared to explain httle of the vari.ation independent of geographicaJ location, though the potential role of fish predation is discussed. Comparisons between the top and the bottom section of the sediment cores revealed similar taxa numbers, but most cores, although only marginaJly, differed in taxa assemblage.
Descriptors		FRESH WATER ECOSYSTEM GEOLOGIC SEDIMENTS CRUSTACEA POPULATION DENSITY EUROPE