Tesis
A comunidade de invertebrados bentônicos nos reservatórios de Promissão, Nova Avanhandava e Três Irmãos (Baixo Rio Tietê - SP)
Fecha
2006-02-23Registro en:
FRANÇA, Roberta Sebastiany. A comunidade de invertebrados bentônicos nos reservatórios de Promissão, Nova Avanhandava e Três Irmãos (Baixo Rio Tietê - SP).. 2006. 165 f. Dissertação (Mestrado em Ciências Biológicas) - Universidade Federal de São Carlos, São Carlos, 2006.
Autor
França, Roberta Sebastiany
Institución
Resumen
The aim of the present study was to characterize the benthic community of Promissão,
Nova Avanhandava and Três Irmãos reservoirs, in relation to the composition of taxa,
population densities and also to verify the occurrence of exotics mollusks in this reservoir
system. Moreover, it aimed to evaluate possible relations between the physical and
chemical characteristics of the water and of the sediment and the structure of the
community considering the spatial (upper, middle and lower portions of each reservoir) and
temporal scales (dry and rainy periods). Sampling was carried out through November 2002
(rainy period) and August 2003 (dry period). Sediment samples for the analyses of the
benthic community were obtained using a van Veen grab. The benthic communities of
Promissão, Nova Avanhandava and Três Irmãos Reservoirs, were represented, in the rainy
period, for a total of 24, 23 and 15 taxa, and in the dry period, for a total of 25, 25 and 17
taxa, respectively. In both sampling periods, and in all reservoirs, there were representatives
of Phylum Arthropoda, Annelida, Mollusca and Platyhelminthes. Only in Nova
Avanhandava Reservoir the occurrence of individuals belonging to the Phylum Crustacea
were registered. The main groups in the benthic communities were Mollusca, Oligochaeta
and Chironomidae. Amongst the Mollusca, three exotic species were found: Melanoides
tuberculata, Corbicula fluminea and Helisoma sp. M. tuberculata was the most abundant
species, corresponding to more than 60 % of the total individuals. C. fluminea and
Helisoma sp were less abundant and they did not register in all the portions of the
reservoirs. Among the representatives of the Oligochaeta, the species Branchiura sowerbyi
was the most abundant and unique, occurring in all reservoirs and periods sampled, being
registered with a maximum abundance of 6 %, during the rainy period in the upper portion
of Promissão Reservoir. Chironomidae had the highest species richness, and Coelotanypus
sp was the most abundant taxon, in all the reservoirs studied. The highest diversity of
taxons was found in Promissão Reservoir. It is possible that eutrophication have favored
the primary production, the survival and the establishment of certain species. The low
values of uniformity found in all three reservoirs and in both periods of sampling reflects
the presence of highly dominant species, as it is the case of M. tuberculata. The present
study evidenced the high capacity of invasion of this species, which is widely distributed in
all the reservoirs, evidencing the necessity of control or erradication of these exotic and
invasive species in the reservoirs.