Distribuição e características abióticas de bancos de Urochloa arrecta e Eichhornia azurea na bacia do rio Itanhaém, SP

• Autor(a) principal: Gonçalves, Dafner Cristina Vida [UNESP]
• Data de Publicação: 2016
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/155808; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2017-08-24/000889763.pdf
• topic: Ecologia aquatica; Ecossistemas aquáticos; Macrófitas aquáticas; Plantas invasoras; Biomassa vegetal; Eichhornia; Brasil; Itanhaem (SP); Itanhaém, Rio, Bacia (SP)

Urochloa arrecta is an aquatic macrophyte originally from Africa. It is known to affect tropical and subtropical areas due to its high regeneration potential and have shown high competitiveness against emerging species. Because that it have been considered an invasive exotic species that has been caused injuries to the Brazilian aquatic ecosystems. In recent years U. arrecta has expanded its occupation area in Itanhaém and places previously occupied by native species Eichhornia azurea. Both species have rooted/floating habit and has been observed that exotic species growth causes reduction of biodiversity and functional diversity of aquatic macrophytes in the region. In order to verify that the abiotic characteristics of that two species occurence places is similar and infer about the U. arrecta's expansion and E. azurea's reduction in the Itanhaém River basin, It were set a total of 30 sampling sites, among which 10 were located in monospecific banks of E. azurea, 10 in monospecific banks of U. arrecta and 10 in mixed banks. In each bank were obtained of abiotic variables values to dissolved O2, photosynthetically active radiation, different forms of nitrogen and phosphorus and also held biomass measurements. By applying a Principal Component Analysis (PCA) to appreciate the ordering of collection sites was observed that the abiotic characteristics from some sites are distinct because different rivers characteritics and its types of water and macrophyte banks are not distributed according to these characteristics. The exotic species, as well as native, occur in different types of water indicating that the two species have a wide tolerance to these abiotic characteristics. From the results we can infer that the distribution of the two species is related to other variables, such as the order of arrival in the colonization and probably the replacement of native species by exotic will continue to occur in the basin