Distribuição das espécies de Odonata e o padrão de diversidade beta encontrado entre riachos na Amazônia Central

• Autor(a) principal: Juen, Leandro
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4001
• topic: Odonata; Diversidade beta; Conservação; Riqueza de espécies; Libélula; Biogeografia; Odonata; Beta diversity; Conservation; Species richness; Biogeography; CNPQ::CIENCIAS BIOLOGICAS::ZOOLOGIA::ZOOLOGIA APLICADA::CONSERVACAO DAS ESPECIES ANIMAIS

The Amazon region has the largest drainage basin of the world, which is constituted by a diversity of waterbodies, and almost all of them are resulting from the junction of small streams ( igarapés ) that drain the forest. The igarapés present acid, nutrient-poor waters, and their food chains are dependent on allochthonous materials provided by the forest that fall into the igarapé, as pollen, flowers, fruits, leaves, branches, insects and spiders. In spite of that, the Terra-Firme system in the Amazon is recognized as the ecosystem of higher species diversity on the planet. This work aimed to describe the distribution and the beta diversity pattern of the species comprising the Odonata communities present in the Adolfo Ducke Forest Reserve river basins. It also objectives to provide information about determining factors of the fauna similarity among sites, in order to select viable units for Odonata conservation. Samples were carried out in 24 igarapés (eleven of 1st, eight of 2nd and five of 3rd order) distributed in four river basins, and in each basin it was conducted samples in six igarapés. The samples constituted on visual counting of adult individuals of Odonata present in 100 meters along each waterbody, divided into 20 stretches of 5 meters. The sampling time constituted of one hour duration on average. The total fauna of Odonata founded in the Ducke Reserve was of 17 species observed and 23 (± 4,77) estimated. The cluster analysis of the abiotic data demonstrated high similarity among the igarapés. The microdrainage basins were compared in relation to species richness and they were similar statistically, and the same result was also obtained for beta diversity. The low value of beta diversity index demonstrated high fauna similarity among the igarapés. The relationship of beta diversity between the environmental data and the distance among the igarapés was highly non-significant. The low values of beta diversity index may be attributed to the high similarity of the environment, which presented small variation in the abiotic data, and also to the distance scale of this study, which may be small enough to not represent a barrier to Odonata dispersion. Another factor that may have contributed to these values is the occurrence of a long period of environmental stability in the Amazon that allowed the species distribution in the environment, even those with low dispersion capacity. The basic environmental variables (channel width and depth) were related to species richness increase. These results are important to species conservation, and indicate the necessity of including intermediate-size streams, with higher variation in depth and channel width, to be used as one selection criteria in the choice of environmental protection areas.