Distribuição longitudinal de adultos de Odonata em riachos no Cerrado: uma hipótese ecofisiológica

• Ano de defesa: 2006
• Autor(a) principal: Batista, Joana Darc
• Orientador(a): Marco Junior, Paulo de
• Banca de defesa: Resende, Daniela Chaves , Sperber, Carlos Frankl
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Entomologia
• Departamento: Ciência entomológica; Tecnologia entomológica
• País: BR
• Palavras-chave em Português: Odonata; Termorregulação; Riqueza de espécies; Continuum fluvial; Largura do canal; Mato Grosso; Ecologia dos rios; Libélula
• Palavras-chave em Inglês: Odonata; Thermoregulation; Species richness; River continuum; Channel width; Mato Grosso; River ecology
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::ZOOLOGIA::ZOOLOGIA APLICADA::CONSERVACAO DAS ESPECIES ANIMAIS
• Link de acesso: http://locus.ufv.br/handle/123456789/3999

The longitudinal distribution of adult Odonata was examined in streams of different channel width in the Pindaíba River Basin, in the municipalities of Barra do Garças and Nova Xavantina. The general purpose was to evaluate the existence of environmental gradients that affect the longitudinal distribution of Odonata, and to establish testable predictions to this predator group regarding the River Continuum Concept. Two hypotheses were tested: (1) increasing channel width longitudinally along the basin causes an increase of light input, and, assuming restraints and distinct abilities, there would be a decrease of Zygoptera and increase of Anisoptera species richness. (2) Dragonflies are affected by the gradient generated through river continuum mechanisms, increasing species richness in medium-sized streams. I sampled 19 sites in rivers and streams from 1st to 6th orders, and in each site I sample once in the dry and once in the rainy seasons. Quantitative survey was conducted through scan method in fixed areas, counting visually on Odonata adults along 100 meters of the waterbody, divided into 20 stretches of 5 meters each. Channel width and depth measures were taken at the beginning, middle, and end of each 20-meter region. A total of 549 individuals were collected, distributed in one family, 13 genera and 17 species of Anisoptera, and six families, 15 genera and 30 species of Zygoptera. The abundance and proportion of Zygoptera species decrease while Anisoptera increase with channel width and mean depth of rivers and streams. The channel width was considered the best predictor of Odonata species distribution. The distribution of Odonata, species richness, did not corroborate the hypotheses of higher species richness in the middle courses of streams. The results obtained in this study confirm the thermoregulation hypothesis as a determining factor in the distribution of Odonata species in the system.