ALPINE NEWTS (TRITURUS-ALPESTRIS) AS TOP PREDATORS IN A HIGH-ALTITUDEKARST LAKE - DAILY FOOD-CONSUMPTION AND IMPACT ON THE COPEPOD ARCTODIAPTOMUS-ALPINUS

1. Population dynamics and feeding ecology of adult and larval alpine newts (Triturus alpestris, Laurenti) were investigated in a high-altit ude karst lake to estimate their feeding pressure on the copepod Arcto diaptomus alpinus (Imhof). Estimates of population size for reproducin g adults ranged from 666 to 864 individuals in the lake during July an d August. Total abundance of larvae before the onset of ice cover vari ed considerably between 4400 and 25400 individuals in different years. 2. Arctodiaptomus alpinus was an important prey item for adult and la rval alpine newts. During the second half of their aquatic period, adu lt newts moved to deeper water where the copepod reached its highest d ensities near the sediment. Adults and larvae exhibited no periodic fe eding pattern. The feeding rhythm was more synchronized among the larv ae than among the adults. 3. Daily food consumption, estimated using t he Elliott and Persson (1978) model, reached 4-21 mg dry biomass in ad ults. The daily ration of larvae was about 7% of body dry weight in th e temperature range 6-11 degrees C. Compared to published estimates of daily food consumption in salmonid fishes, the feeding pressure of ne wts appears low.