Quantitative estimation of Hyalella curvispina Shoemaker population (Amphipoda) in aquatic vegetation of northeastern argentinian ponds

MARÍA EUGENIA GALASSI; MARÍA CELESTE FRANCESCHINI; ALICIA POI DE NEIFF

Mendoza, Argentina

Congreso; II Reunión Binacional de Ecología; 2004

Asociación Argentina de Ecología y Sociedad de Ecología de Chile

Quantitative comparisons were made of the accuracy of different sampling nets (962 cm 707 and two techniques for extracting Hyalella curvispina from plants. The number of individuals per area and per unit of plant biomass and the biomass were estimated in a permanent pond during an annual cycle.  Seasonal samplings to test the spatial distribution of H. curvispina were done at 13 water bodies of northeastern Argentina populated by different macrophytes. Smaller number of replicate samples for a given level of precision is required using a net of 960 cm2 and Berlesse funnels. Mean abundance of the population in the permanent pond vegetated by Pistia stratiotes L. reach to 3200 m-2 and 18785 individuals per plant biomass during spring samplings with an air temperature between 22?24°C and high photoperiod. Biomass varied between 0.20 and 1.95 g.m-2. Sampling date and electric conductivity explained population variations.