Structure and dynamics of food webs in Andean lakes

BEATRIZ E. MODENUTTI, ESTEBAN G. BALSEIRO, CLAUDIA P. QUEIMALIÑOS, DIEGO A. AÑÓN SUÁREZ, MARÍA C. DIÉGUEZ AND RICARDO J. ALBARIÑO

LAKES & RESERVOIRS RESEARCH AND MANAGEMENT

Blackwell

Año: 1998 vol. 3 p. 179 - 186

1320-5331

AbstractFood webs from oligotrophic Andean lakes of Bariloche region (41°S) are described. Their peculiarities in comparison withNorthern Hemisphere studies are noted. The endemic species composition, the extended euphotic zone, and the oxygenatedbottom allow a particular structure of the pelagic and benthic food webs. Experimental work with pelagic communities indicatesthat models based only on zooplankton body size are questionable and that nutrient enrichment does not necessarily lead toa positive effect on herbivorous populations. Invertebrate predation effects depend on the lake and type of predator, whilevertebrate predation does control crustacean populations. The characteristic low species richness of top predators is likely tochange following the introduction of exotic salmonids. The benthic food web is quite distinctive with a slow rate of decayingorganic matter and easily altered by the introduction of exotic tree species.Key wordsbenthos, food web interactions, plankton, South Andes lakes