Hyalella Smith, 1874 (Crustacea, Amphipoda, Dogielinotidae) em áreas úmidas do Rio Grande do Sul, Brasil

• Ano de defesa: 2011
• Autor(a) principal: Rodrigues, Stella Gomes
• Orientador(a): Bueno, Alessandra Angélica de Pádua
• Banca de defesa: Ferreira, Rodrigo Lopes, Araujo, Paula Beatriz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: UNIVERSIDADE FEDERAL DE LAVRAS
• Programa de Pós-Graduação: DBI - Departamento de Biologia
• País: BRASIL
• Palavras-chave em Português: Áreas úmidas; Hyalella; Biodiversidade; Aspectos populacionais; Wetlands; Biodiversity; Population aspects
• Área do conhecimento CNPq: CNPQ_NÃO_INFORMADO
• Link de acesso: https://repositorio.ufla.br/handle/1/3526

Wetlands are abundant ecosystems that occur on all continents of the planet. They are highly productive and have a rich variety of species. Many of these species are of endemic origin. However, the urban development and agricultural expansion have caused the extinction of more than half of these areas on the planet. Within South America half of the total wetland area is situated in Brazil, with concentration mainly in the south. The state of Rio Grande do Sul (RS) has the highest number of wetlands in Brazil. It is estimated that over 90% of these areas have already been eliminated by soy and rice agriculture. Despite the rich biodiversity, there has not been much ecological research in this area. Crustaceans belong to the most abundant invertebrate in these habitats, as well as the genus Hyalella, which is an important element in food chains of freshwater ecosystems. However, nothing is known about the group in wetlands. Thus, the aim of this study was to identify the species of Hyalella that occur in wetlands of RS, studying population aspects and geographical distribution. Possible factors influencing species richness, abundance and distribution patterns were analyzed as well. Physical characteristics of the environment such as altitude and size of the area, along with collections realized in 146 wetlands, were taken into consideration during this study. Three species that have already occurred in the state of RS, and one only known in Argentina, were found. Additionally, eight morphospecies were identified. One of them had troglomorphic traits. Significant differences were observed between the body size of species. The positive correlation between the length of the cephalothorax (CC) and the total length was discovered, as well as positive relationship between the CC of ovigerous females and number of eggs in the pouch. The sexual ratio favored males in all species and population structure was bimodal. The watershed region of Uruguay and the geomorphological province of plateau had the highest species richness. There was a higher occurrence of species in permanent areas with herbaceous or emergent vegetation. The results obtained by this research represent the first information about the population and ecology of the Hyalella species that occur in wetlands of RS. More research is needed in order to preserve these endangered ecosystems.