Relationship of land use and composition of aquatic insects from four watersheds of São Paulo State

Author(s)

Kathia Cristhina Sonoda

• Document type: Doctoral Thesis
• Press: Piracicaba. , ilustrações.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2005-06-30

Examining board members

Carlos Alberto Vettorazzi; Glaucia Maria Bovi Ambrosano; Hilton Thadeu Zarate do Couto; Claudio Gilberto Froehlich; Mônica Luisa Kuhlmann

• Advisor: Carlos Alberto Vettorazzi; Susana Trivinho Strixino
• Field of knowledge: Biological Sciences - Ecology
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca Central da Escola Superior de Agricultura Luiz de Queiroz; ESALQ-BC/t595.705; S699r

Abstract

1. To evaluate differences in the aquatic insects communities of four watersheds from the State of São Paulo showing different degrees of human occupation, relating them to the landuses and terrain slope of the watershed and the 50m’s buffer zone upstream of the sample sites as well as in relation to the chemical and physical water variables. 2. To evaluate alterations in the aquatic insects communities living in places showing presence/absence of riparian forest. The data were based on samples of aquatic insects collected with artificial substrates baskets; the exposure time was 44 days between August and October/2002. The watersheds studied were Alto Paranapanema, Peixe, Aguapeí and São José dos Dourados. For the first study, six samples were taken from each river and the fauna was identified and counted, Chironomidae were identified until genus level while the other insects, until family. To analyze the results, total and percentage numbers of individuals and taxons were used, as well as some community indexes, diversity, richness, evenness and total number of Ephemeroptera, Plecoptera and Trichoptera. For the remote sensing methods, information about the watersheds and the 50m’s buffer zone upstream the sample sites were generated from digital maps. The landuses and terrain slope of those areas were calculated. Pearson’s correlation index, analysis of variance and analysis of correspondence were used for the statistical analyses. For the second study, samples from Aguapeí and São José dos Dourados rivers were taken. The faunas were identified in the same levels following the other study. As result of the first study, thirty-one families were identified. Elmidae, Leptohyphidae, Leptophlebiidae, Chironomidae, Simuliidae and Hydropsychidae showed numeric dominance. Ten out 19 chemical and physical variables tested were able to characterize the rivers. The land uses were characteristic of some rivers as well. Study 2. In that study, the samples from forest showed fewer numbers of individuals and taxons, although the statistical analysis showed that, in fact, the greatest richness was associated to places where the forest was present. Both studies permitted us to make the inference that the forest immediately adjacent to the sample site is the most important factor for that fauna. The highest numbers of individuals and taxons from rivers with greatest impacted watersheds may be related to the presence of a better preserved riparian forest surrounding the rivers. Until the present study, little was known about the entomological aquatic fauna of those rivers; new taxons were found increasing the knowledge about the diversity of the State. Other studies are necessary to confirm about the local influence of riparian forest on the insect’s aquatic community. (AU)

• FAPESP's process: 00/14242-6 - Relationship between the different uses of the surrounding land and the composition of aquatic insects from five hydrographic basins in the State of São Paulo
• Grantee: Kathia Cristhina Sonoda
• Support Opportunities: Scholarships in Brazil - Doctorate