Complimentary biodiversity measures applied to zooplankton in a recovering floodplain lake
Sodré, Elder de Oliveira; Figueiredo-Barros, Marcos Paulo; Roland, Fábio; Esteves, Francisco de Assis; Bozelli, Reinaldo Luiz
published: Nov 1, 2017
published online: Oct 23, 2017
manuscript accepted: Sep 21, 2017
manuscript received: May 18, 2017
ArtNo. ESP141019004001, Price: 29.00 €
Abstract Different biodiversity measures are necessary to understand response of freshwater communities to environmental change. This is especially true for the Amazon region that experiences increasing threats to its ecosystems, which already show clear signs of loss of structure and functions. Aquatic ecosystems are particularly threatened by large-scale power generation, mining and agriculture ventures. Our objectives were to assess the recovery of a floodplain lake from the impact of bauxite tailings and the flood pulse effect on it. We used several indices of diversity as a tool to understand the recovering process in the zooplankton community of an Amazonian floodplain lake (Batata Lake) impacted by bauxite tailings during the 1980s. Zooplankton was sampled 4 times per year in two sampling stages: during seven years in the 1990s and for one year in 2012 –13. In the second sampling stage, environmental variables were also measured and related to biotic indices. Zooplankton community was characterized in terms of total densities, functional groups, richness, and the functional indices of richness, evenness and dispersion. Impacted and non-impacted areas of the lake displayed similar seasonal and long-term patterns. Seasonally-associated flood pulses tended to increase densities in periods of high water and increase species richness and functional richness in periods of low water. However, in years of extreme drought, there was a loss of functionality manifested as a reduced functional dispersion index and functional group composition. Seasonal water level variations are the major biodiversity driver in these systems, and its effects become stronger in years of extreme droughts. The combined use of taxonomic and functional measures helped explain different aspects of biodiversity.