Effects of habitat complexity on the nutrient status and algal structure of periphyton: an observational and experimental study

Abstract

In lentic ecosystems, the complexity of habitat is an environmental factor that can directly influence community structure, but this influence is little known about periphyton. This research project aims to assess the influence of habitat complexity on the nutrient status and algal community structure in periphyton through an observational and experimental (Lago das Ninféias, PEFI, São Paulo). The observational study will include assessing the seasonal changes of structure and nutrient status in parts of the littoral zone with the presence and absence of macrophytes (n = 3). This design will evaluate the influence of habitat complexity on periphyton in natural conditions, as well as the variation of limnological conditions, especially resources availability. The factor complexity of habitat will be isolated in the experimental study. The glass slides are used as substrate for colonization. The experimental study will be conducted in open mesocosms (n = 5), where the periphyton will be subjected to different structural complexities of habitat (control, with no structural complexity, low structural complexity, structural complexity medium, high structural complexity, n = 5). Sampling of substrates will be random. This proposal will contribute information for the project "Influence of spatial heterogeneity on the structure and nutrient status (N, P, C) of periphyton, phytoplankton and metaphyton in Ninféias Reservoir (PEFI, São Paulo) (Fapesp: 2009/52253-4) completed in February 2012. This study will validate some hypotheses about the complexity of habitat. Specifically, the project aims to answer the following questions: i) the increasing complexity of habitat has a positive effect on nutrient status and growth of periphyton biomass, ii) the increasing complexity of habitat has a positive effect on diversity and density algal.