Two-Decade Remaining Effects of Bauxite Tailings on the Fish Taxonomic Structure of a Clear-Water Floodplain Lake in Central Amazon (Batata Lake, Pará State, Brazil)

Abstract

In recent decades, anthropic disturbances have led to major changes in biological communities. Batata Lake (Oriximiná, Pará State, Brazil) is located in the flood area of the right bank of Trombetas River and received effluents rich in mineral waste due to near mining activities in the 80's, which led to the siltation of 30% of its area and numerous local impacts. We monitored about to 20 years the ichthyofauna of Batata Lake and we assessed if there is still remaining effects of the siltation by bauxite tailings in the affected area. We sampled in Silted and Non-Silted areas in the filling period of 1991 to 2015, using a set of gillnets with mesh sizes between 15 to 70 mm. Differences in taxonomic structure (estimated richness, Simpson's dominance and Shannon's diversity) and in community composition among Silted and Non-Silted areas were evaluated with multivariate analysis, considering year as covariate. We sampled 10,435 individuals classified in 141 species. Only 41 species represented 90% of total abundance, which we considered the numerically dominant fishes in the lake. Among taxonomic indices, only estimated richness exhibited a significant trend through time; high estimated richness in the Silted area during the first years of monitoring and posterior decreasing. This negative slope was highly affected by a single point in 1992, so we considered it a particular case in time and not a real temporal trend. Significant changes in community composition occurred among areas by differentiation in species abundance, and not by species loss. These results show that siltation effects in Batata Lake did not express itself as a loss of biodiversity, but in the reconfiguration of the community composition according to species niche.

Influences of multiple anthropogenic disturbances coupled with a tailings dam rupture on spatiotemporal variation in fish assemblages of a tropical river

“…Nonetheless, there are many dam‐free river reaches up‐ and downriver of Baguari, many of which are >100 km long and in which migratory fishes can reproduce (Santos et al, 2012). Another factor that helps explain the absence of differences between River and Dam phases for both native and non‐native species richness was the previous extirpation of sensitive species (Alves et al, 2007; Gomes et al, 2020; Ruschi, 1965; Vieira, 2009) and the prior occurrences of resistant non‐native species (Bueno et al, 2021; Magurran, 2013; Soares et al, 2017). These factors may explain the absence of differences between River and Dam temporal phases, but not the absence of expected differences between Dam and Rupture.…”

From virus to igapó forest: a systematic review of 35 years monitoring of an Amazonian Lake impacted by bauxite tailings (Batata Lake)

“…Studies on the omnivorous catfish Auchenipterichthys longimanus indicated a potential disperser of forest seeds with distinct germination and dormancy patterns in the lake (Mannheimer et al, 2003). Since this opportunistic fruit-eater is the most abundant fish species in the silted area, the authors considered that this catfish has also been playing a role in the regeneration process of the igapó forest (Soares et al, 2017).…”

“…Despite the extensive information on the effects of bauxite tailings on the Batata ecosystem structure and function, the long-term quantification trends remain incomplete (Soares et al, 2017;Sodré et al, 2017, Huszar et al 2022. Many questions were raised throughout the research project and are still under investigation.…”

Phytoplankton Biomass Increases in a Silt-Impacted Area in an Amazonian Flood-Plain Lake Over 15 Years

“…Most studies on phytoplankton using time series have focused on oligotrophication or eutrophication (Straile 2000, Bürgi & Stadelmann 2002, hydrologic fluctuations (Reynolds et al 2012), and recently, global climate changes (Havens et al 2019). Considering the Batata Lake, only a few studies performed long-term analyses, mainly for fish (Soares et al 2017) and zooplankton communities (Carneiro et al 2002, Garrido et al 2003, Bozelli et al 2009, Sodré et al 2017.…”