Forest complexity drives dung beetle assemblages along an edge‐interior gradient in the southwest Amazon rainforest

Abstract

1. The habitat heterogeneity hypothesis predicts that heterogeneous habitats may provide more niches and diverse ways of exploiting environmental resources, thereby allowing more species to coexist, persist and diversify. 2. We aimed to investigate how an edge‐interior gradient related to forest complexity influences species composition, abundance and richness of dung beetles in the western Amazon rainforest. We expected dung beetle abundance and richness to increase along the forest edge‐interior gradient, in accordance with the habitat heterogeneity hypothesis. We also expected strong changes in species composition driven by species turnover in the forest interior and nestedness along the forest edges. We sampled dung beetles using baited pitfall traps across an edge‐interior gradient. We also assessed the variation in forest features along the edge‐interior gradient to identify changes in forest complexity. 3. Both species richness and abundance of dung beetles increased along the forest edge‐interior, following the gradient of forest complexity. The Sorensen dissimilarity of dung beetle assemblages was higher among sampling units placed near the forest edge, although neither turnover, nor nestedness was different between the extremes of the forest edge‐interior gradient. There was a clear compositional change along the edge‐interior gradient mostly driven by species turnover. Individual indicator value analysis revealed that species were strongly associated with the forest interior conditions. 4. The simplification of the Amazon rainforest near clearings causes compositional changes in dung beetle assemblages. These changes are characterised by species‐poor and low‐abundance assemblages and may impair dung beetle ecological functions and therefore forest recovery.

Not all dung beetles feed on dung: Scarabaeinae (Coleoptera: Scarabaeidae) attracted to different carrion types in contrasting habitats at Brazilian Amazon

“…Recent ecological studies using vertebrate carrion and dung to attract dung beetles in the Brazilian Amazon showed high diversity and abundance of necrophagous and copro‐necrophagous species ( see Beiroz et al, 2018; Bitencourt et al, 2020; Ratcliffe, 2013; Silva et al, 2014). For these studies, Silva et al (2014) and Beiroz et al (2018) sampled dung beetles using rotten cattle spleen, while Ratcliffe (2013) used rotten fish and Bitencourt et al (2020) used rotten chicken. This demonstrates that there is no standardized carrion type to sample dung beetles in the Amazonian landscapes, and we believe that such trend also occurs in other tropical ecosystems.…”

Chapter 19: Drivers and ecological impacts of deforestation and forest degradation

“…It is not only the flora that is directly impacted by edge effects; both vertebrate and invertebrate fauna also experience considerable compositional and functional shifts, with some species thriving while others decline (Bitencourt et al 2020;Santos-Filho et al 2012). Overall, generalist species are favored by edge habitats, while specialists become restricted to the forest core.…”