Ecología trófica de un Lago de Varzea (Amazonas, Colombia)

Abstract

The ichthyofauna of the Amazon River is the most diverse of the freshwater ecosystems of the world, which is the product of evolutionary processes, the generation of diverse habitats, speciation processes and multiple ecological relationships, yet to be understood in order to arrive at an adequate management of this resource by human populations that since time immemorial have been using it both for its consumption, as for other uses with different criteria and valuations. However, for the Colombian Amazonian region, problems have arisen during the last decades due to anthropic action that are affecting the survival and proper functioning of the ecological processes of aquatic ecosystems and the organisms that inhabit them, especially fish. In this sense, this doctoral thesis has focused on analyzing the trophic ecology of the ichthyofauna of the Yahuarcaca lakes in the Colombian Amazon through the use of different methods. Initially the changes in the composition, life histories and trophic guilds of the assemblages collected in the years 1999, 2004, 2005 and 2010 were analyzed, registering changes in the composition of the species and richness, but in general at the management level of the resources, no changes were evidenced. Regarding the analysis of the trophic guilds, during the high and low water seasons in the 2010 period, there were changes in the composition between the guilds and variations in the amplitude of the trophic niche of the species analyzed, evidencing the differential use of the food resources consumed by the fish fauna. Finally, with the compilation of data product of scientific collections and records of local fishermen it was possible to describe the trophic network of the ichthyofauna during the high and low water seasons, proposing the benefit of this type of initiatives to establish agreements for the management of the resources Amazonian fishing boats in Colombia. The results of this thesis emphasize the high complexity of processes involved in the permanence and use of resources differentially by the ichthyofauna of this floodplain throughout the hydrological cycle, which can only be understood through the application of different methodologies, among which the use of local ecological knowledge as a primary source of data stands out. The methodology used can be applied to other ecosystems of the floodplains that sustain a large part of the ichthyofauna of the neotropical rivers.