Effects of increasing structural complexity on the main energy source for macroinvertebrates and on their trophic position in simplified streams

• Grant number: 12/07115-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): June 01, 2012
• Effective date (End): May 31, 2013
• Field of knowledge: Biological Sciences - Zoology - Applied Zoology
• Principal Investigator: Lilian Casatti
• Grantee: Marina Reghini Vanderlei
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil

Abstract

Stream ecosystems are strongly related to the surrounding landscape, with energy flows between the land-water ecotone. These interactions are frequently mediated by the riparian forest and disturbances on this vegetation not only affect food webs of the aquatic systems, but also disrupt channel structure, negatively changing stream equilibrium. The processing dynamics of the organic matter provided by this zone is an important component of ecosystem structure and functioning due to their incorporation on aquatic food webs as an allochthonous energy source. In this context, the aquatic macroinvertebrates play an important role in the food webs as organic matter consumers and carbon assimilators. Nowadays, enhanced environmental degradation has been negatively interfering in different ecosystems by decreasing local diversity along with rates of ecological processes. Since changes in these processes can lead to greater environmental instability, making it fragile, restoration actions in impacted streams are of fundamental importance. Hence, the present study aims to investigate if the experimental increment with wood and leaf-packs in degraded streams can lead to a change in the main energy source for macroinvertebrate communities and to evaluate if these increments can lead to a raise on each taxa trophic position using stable isotope analysis of ´13C e ´15N. Therefore, the present work will contribute to a better understanding of these ecological processes. (AU)