Is the stage of development of Eichhornia azurea crucial in macroinvertebrates community?

Abstract

Eichhornia azurea (Sw.) Kunth is an aquatic macrophyte frequently observed in lentic systems that can be colonized with a very rich and abundant macroinvertebrates community. This is because of the habitat complexity observed in its root's morphology and architecture which can be affected by seasonal variation of environmental factors of the lake. Thus, two questions can be considered: 1) There is a difference on the composition, taxa richness and abundance of macroinvertebrate community according of E. azurea rhizome and roots development stage? 2) Besides to plant's phenology, environmental variables and study period can be influence the colonization? The present project aims to answer these questions, considering the complexity levels of roots that the plants present according to its development, to the location and position of roots (from pelagic zone ’ to fixation point on littoral zone) and, to seasonal influence. The selected environment to answer these two questions is the Lake Barbosa, a marginal lake to Paranapanema River near its mouth site into Jurumirim reservoir. Quarterly samplings (from April, 2013 to January, 2014) will be made at least three different E. azurea stands. In each stand, five samples will be collect in a sequence from apical part of the floating plant to the site of fixing of macrophyte in the sediment, beginning with the 2th visible root system of E. azurea. In each sampling of the temporal scale, macroinvertebrate community attributes (composition, taxa richness and abundance) will be determine in each plant and stand (in this case the five samples of root system distributed by the rhizome); the complexity level of roots system will be measured and, the relationships with environmental variables will be assessed.