HR: 1330h
AN: NB33D-03    [Abstracts]
TI: Community Structure of Chironomidae (Midges) in Two Brazilian Rivers in Relation to Contrasting Land Uses
AU: * Sonoda, K C
EM: kcsonoda@esalq.usp.br
AF: Rural Engeneering Dpartement. "Luiz de Queiroz" Agricultural College, University of Sao Paulo, Av. Padua Dias, 11, Piracicaba, SP 13418900 Brazil
AU: Matthaei, C
EM: christoph.matthaei@stonebow.otago.nz
AF: Department of Zoology, Universitu of Otago, 85 Union Place West, PO Box 56, Dunedin, New Zealand
AU: Vettorazzi, C A
EM: cavettor@esalq.usp.br
AF: Rural Engeneering Dpartement. "Luiz de Queiroz" Agricultural College, University of Sao Paulo, Av. Padua Dias, 11, Piracicaba, SP 13418900 Brazil
AU: Trivinho-Strixino, S
EM: strixino@power.ufscar.br
AF: Federal University of Sao Carlos, Washington Luis Road, KM 235, Sao Carlos, SP 13565905 Brazil
AB: We investigated whether the conversion of riparian land use from indigenous forest to pasture is associated with changes in midge community composition in two South Brasilian rivers. Our study was conducted in the main rivers (Sao Jose dos Dourados 6th order; Aguapei 7th order) of two catchments in Sao Paulo State. Both catchments are dominated by agricultural ecosystems but retain substantial patches of native riparian forest in certain areas. Replicated artificial substrates (baskets filled with clay rocks) were exposed in forested and pasture reaches in both rivers. Both land uses had to be present for at least 500m along both river banks, and the riparian forest had to be at least 50m wide. In each river, six baskets per reach type were sampled after a colonization period of 44 days, and all Chironomidae in these samples were sorted and identified to genus level (a total of 3399 individuals belonging to 28 different taxa). As expected, land use affected midge communities. Total midge density was significantly higher in pasture reaches than in forested reaches. By contrast, midge taxon richness was higher at the forested reaches. These results show the importance of native riparian forests for preserving aquatic biodiversity in Brasilian rivers.
DE: 9300 INFORMATION RELATED TO GEOGRAPHIC REGION
DE: 9360 South America
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly