Ant community patterns in highly fragmented Chaco forests of central Argentina

Abstract

The Chaco is the largest dry forest biome in South America and one of the regions most threatened by agricultural intensification. As a consequence, in several areas Chaco forests persist as forest remnants of different sizes embedded in an agricultural matrix. Ants are social insects that have key roles in ecosystem functioning, and the effects of this ongoing land use change process on ant communities are little known for this region. In the present study, we assessed the consequences of land use replacement by monocultures and forest fragmentation on ant communities. Particularly, we assessed whether patch size, patch isolation and edge effect affect species richness and composition of ground-dwelling ants in fragmented landscapes of Chaco forests. We collected ants by combining hand collecting and pitfall traps in 17 forest fragments and the surrounding matrix from two sites in C ordoba, Argentina. Patch size and patch isolation had no effect on ant richness; however, patch isolation and, to a lesser extent, patch size altered ant species composition. The ant community was not affected by edge but it was negatively affected by the crop matrix, which reduced richness and altered species composition. These results indicate that monoculture matrices severely affect ant communities in the Chaco forests, and that the effects of other indicators of habitat fragmentation (patch size and edge effect) are subtler and less relevant. In the present context of land use change, even small fragments could have an important value for the conservation of ant diversity.Abstract in Spanish is available with online material.

Vegetation structure and relative humidity drive the diurnal foraging activity of Malaysian giant ant workers in urban fragmented forests

“…Our findings are in line with Pereyra et al (2019), who suggested that even small forest fragments could have an important value for the conservation of ants. Ross et al (2018) found no detrimental effect of habitat fragmentation on ant diversity, although habitat fragment size was correlated with estimated species richness.…”

Diversity of ground‐dwelling ants across three severely threatened South American subtropical forests: are diversity patterns influenced by spatial or climatic variables?

“…The invasive ant W. auropunctata and the South American big-head ant P. obscurithorax (another known native ant species also invasive in the United States) were very common and indicator species of the Chaco forest. Interestingly, W. auropunctata was present, together with Brachymyrmex patagonicus Mayr, 1868 (another well-known invader), in all the Chaco forest fragments studied by Pereyra et al (2019), independently of fragment size and isolation, indicating that their dispersal is not limited in this context of land-use change. This species is considered as a disturbed habitat indicator because it is strongly associated with fragmented dry tropical forest edges in Brazil and Colombia (Majer & Delabie, 1999;Achury et al, 2008Achury et al, , 2012 and disturbed habitats both within its native and introduced range (Foucaud et al, 2009;Orivel et al, 2009;Chifflet et al, 2018).…”

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

“…Also, insects belonging to different taxa respond differentially to fragmentation. Additionally, fragmentation facilitates alien insects that can disrupt native insect diversity and community structure (Pereyra et al, 2019).…”

“…Additionally, fragmentation facilitates alien insects that can disrupt native insect diversity and community structure (Pereyra et al, 2019).…”