Abstract

GALIZZI, María Celeste  and  MARCHESE, Mercedes. DECOMPOSITION AND INVERTEBRATE COLONIZATION OF Tessaria integrifolia (Asteraceae) LEAVES IN A SECONDARY CHANNEL OF THE MIDDLE PARANÁ RIVER. INCI [online]. 2007, vol.32, n.8, pp.535-540. ISSN 0378-1844.

The decomposition of leaf litter of Tessaria integrifolia and its colonization by invertebrates were studied in the Tiradero Viejo River. Leaves were collected at abscission and 6g dry weight and were placed in nylon bags with 5 mm mesh net. Samplings were carried out between May and September 2002 and three replicates were collected after 7, 14, 28, 56 and 112 days. The decay coefficient calculated over 112 days of decomposition was 0.0143d^-1. Invertebrate densities increased with the progressive decomposition of the leaves, reaching the maximum at 56 days (395 individuals/g of leaves dry weight). The highest species richness (43) and Shannon’s index (4.24) were obtained at 28 days of leaf decomposition. Colonization of decomposing leaves was dominated by oligochaetes (Pristina leidyi, P. aequiseta, Dero multibranchiata), chironomids (Polypedilum spp., Phanopsectra sp.) and mussels (Limnoperna fortunei). Gatherers-collector were dominant during the first time, the filterers increasing at the end of the colonization experiment and the shredders were more constant over time but scarce.

Keywords : Descomposición de Hojas; Grupos Funcionales; Invertebrados Bénticos; Tessaria integrifolia.