Is β‐diversity of Amazonian ant and dung beetles communities elevated at rainforest edges?

Abstract

Aim Thousands of kilometres of rainforest edges are created every year through forest fragmentation, but we have little knowledge of the impacts of edges on spatial patterns of species turnover and nestedness components of β‐diversity. Location A quasi‐experimental landscape in the north‐east Brazilian Amazon. Methods We sampled dung beetles and ants using a sampling design based on a fractal series of equilateral triangles that naturally allows examination at multiple spatial scales. We sampled two edge types (primary‐secondary and primary‐Eucalyptus forest) and three control sites immersed in primary, secondary and Eucalyptus forest. We measured β‐diversity between communities across the primary forest‐matrix edge and within communities at up to 1 km from the forest edge. We examined β‐diversity at multiple scales by partitioning the dissimilarity matrix into fractal orders representing inter‐point distances of ~32, ~100, ~316 and ~1,000 m and into turnover and nestedness components. Results Turnover but not nestedness was greater across the primary‐Eucalyptus forest than primary‐secondary forest edge. There was spillover of species across edges in both directions. Across edges and within controls, turnover was the main driver of β‐diversity. Within community, β‐diversity was increased for dung beetles at large scales (~300–1,000 m) at both edge types. This increase, however, was driven by elevated nestedness. Levels of β‐diversity were affected even ~300 m into habitat interiors, but appeared to be at control levels by 1 km. Main conclusions The effects of edges on the spatial dynamics of community composition penetrated far beyond the typical distances at which forest structure and microclimate are altered. This indicates that for a significant proportion of Amazonian communities, the underlying processes determining diversity may be impacted by deforestation.

Biodiversity in tropical plantations is influenced by surrounding native vegetation but not yield: A case study with dung beetles in Amazonia

“…Our results provide strong support for the important role of landscape context in contributing to the biodiversity of plantations, as the extent of native forests in the area surrounding the Eucalyptus plantations was associated with higher taxonomic and functional diversity of dung beetles in the plantations (Figures 4b and c). A greater coverage of native forests may enhance spillover (Gray et al 2014, Marsh et al 2018 and increased movement of forest species through the plantation. It is possible that some of the sampled individuals of native forest species are only foraging in managed sites, which may not necessarily indicate suitable plantation conditions if these individuals cannot sustain populations or perform key functions within the plantations.…”

A preliminary checklist of soil ants (Hymenoptera: Formicidae) of Colombian Amazon

“…The study done by Ryder Wilkie et al 2010, which is recognised as the most complete work on ant diversity in the Amazon region, recorded at the Tiputini Reserve in Ecuador 66 genera and more than 300 species between subsoil and canopy. The high diversity reported in our work was certainly the effect of the broad area sampled (which includes three river basins) and the wide range of altitude included (Marsh et al 2018). …”

Habitat quality and edge area of fragments determine insect diversity in a heavily used landscape: Implications for forest landscape restoration

“…The insect diversity and functional groups in the forest fragments of Attappady are driven by the edge area rather than the extent of the fragment area. Although, the theory of island biogeography suggests that habitat area and habitat isolation drive species richness and diversity of insect communities, the edge area has a greater effect on the species diversity and functional groups of insects in the terrestrial ecosystems (González et al, 2018; Marsh et al, 2018; Sobrinho et al, 2003). This study also confirms that smaller fragments (with relatively larger edges) support higher insect diversity, while providing little or no evidence of a positive effect of the fragment area (Magura et al, 2017).…”