Changes in Epigaeic Ant Assemblage Structure in the Amazon during Successional Processes after Bauxite Mining

Abstract

Environmental impact studies often involve monitoring and using bioindicators to evaluate the restoration stage of impacted areas. We aimed to assess ant assemblages’ response to the ecological succession of previously disturbed areas in the Brazilian Amazon. We sampled epigeic ant assemblages in five bauxite mining areas, representing different restoration stages, and compared them with two pristine areas. We also compared trends in species richness at the same mine site investigated 14 years earlier. Ten pitfall traps and four Winkler samples of litter were taken along a 100-m transect in each area. We expected that ant species richness would increase with the amelioration in habitat condition (i.e., environmental surrogates of ecological succession, including litter depth, soil penetrability, the circumference of trees, the distance of trees to adjacent trees, and percentage of ground cover). We also compared the efficacy of both sampling methods. Due to more significant sampling effort, pitfall traps captured more ant species than Winkler sacks. However, Winkler samples’ addition allowed the collection of more cryptic species than by pitfall traps alone. We sampled a total of 129 ant species, with increases in ant species richness in more mature rehabilitation. Nevertheless, similarity analysis indicated a significant difference between ant assemblages of rehabilitated areas and pristine ones. Assemblages differed mainly by the presence of specialist and rare species, found only in pristine plots. Rehabilitated areas exhibited a significant increase in tree circumference as they reached more ecologically advanced stages, which contributed to increasing ant species richness. These trends and comparison with the earlier study indicate that although there are favorable increases in ant species richness, in terms of species composition, rehabilitated areas were far from achieving an ant assemblage composition or environmental status that closely resembles pristine areas.

Linking disturbances in neotropical landscapes with ecosystem functional traits: A preliminary assessment using epigaeic and leaf‐litter ant communities

“…The preliminary results presented here, indicating a cutback in the functional spectrum matching the gradient of disturbance, corroborates this idea. The trends observed here concur with other works focusing on the Amazon (Fernandes et al, 2021; Fontenele & Schmidt, 2021), other Brazilian biomes (Leal et al, 2012; Martello et al, 2018), but also other regions of the world (González et al, 2018). We found that dissimilar patterns and responses were displayed by specific versus generalist functional traits, for example, specialised traits were particularly eroded in assemblages of disturbed ecosystems while generalist traits seem unscathed.…”

The Smallest “Miner” of the Animal Kingdom and Its Importance for Raw Materials Exploitation

“…The ant population in areas where human mining is present has been used as a biological indicator of environmental remediation in many studies [40][41][42][43][44] based on the population and the number of species that thrive in the area of mining operations relative to the native species in the area (in the upper part of Figure 8). Special traps are placed in the mine under consideration to measure the ant population, and these are compared with corresponding traps in a reference site from an area without human intervention.…”

“…Ottonetti et al [43] suggested suitable ant species for biomarkers in restored Mediterranean mines. • The same technique was used by Fernandes et al [44] to study the evolution of bauxite mine reclamation in the Amazon. • The study of Khazin et al [45] uses two inhabitant species of ants as bioindicators:…”

“…The same technique was used by Fernandes et al [44] to study the evolution of bauxite mine reclamation in the Amazon. …”