Something is lost and something is gained: loss and replacement of species and functional groups in ant communities at fragmented forests

Abstract

Context Small fragments of natural habitats with an increased proportion of edges are common landscape traits following agricultural expansion. Consequences of habitat fragmentation are widely documented. However, functional and mechanistic approaches are still needed in order to understand these changes. Objectives We studied habitat loss and edge effects on ant communities, addressing changes in species and functional group diversity, and the relative importance of b-diversity components. Methods In an endangered Neotropical forest, we sampled ants in edge and interior habitats using pitfall traps, during three summers (28 sites). We calculated taxonomic, phylogenetic and functional diversity and partitioned taxonomic and functional b-diversity into replacement and loss/gain components. Results We found more species and functional groups at edge than interior habitats, and four species were edge indicators. Habitat loss negatively affected total abundance and that of particular functional groups (fungus-growers and cryptic species) but had a positive effect on taxonomic, phylogenetic and functional diversity as well as abundance of opportunists and predators. Species and functional group replacement drove b-diversity, being linked to habitat loss. However, interactions between habitat loss and edges explained the loss/gain of taxonomic and functional composition. Conclusions Fragmentation led to enriched ant communities at edges, possibly resulting from a higher influx of matrix species as edges become pervasive. This highlights the need to assess the spillover between habitats to understand its influence. Moreover, species replacement and the decrease of functional groups due to habitat loss could have an impact on ecosystem processes in which ants play an important role.

Effects of habitat loss on three insect assemblages in modified ecosystems of foothills of the Colombian Orinoquia

“…In this way, these generalist species may be displacing specialist species, since they have a greater tolerance to extreme conditions and are more efficient in the use of the remaining resources as a consequences of habitat loss (Sanabria-Blandón & de Ulloa, 2011). The simplification of ant assemblages due to habitat loss has been documented previously (Dias et al, 2008;González et al, 2018). However, the presence of monocultures and trees in pastures, can provide greater habitat heterogeneity and, therefore, an increase in the number of species, due to an increase in feeding sites and nesting sites (Bernardes et al, 2020;Dias et al, 2008;Rivera et al, 2008).…”

Road preference of ants in a Japanese warm temperate forest and its implications for the regeneration of myrmecochorous sedges

“…A previous study that examined the seed dispersal behavior of ants in relation to forest roads has reported the avoidance of roads by the ant Aphaenogaster rudis (Warren et al, 2015), an opposite pattern to ours. The difference is not surprising considering the wide variety of responses by ant species to the edge effect along roadsides reported across the world (Gonz alez et al, 2018;Mitchell et al, 2002;Pereyra et al, 2015;Sobrinho & Schoereder, 2007). Inconsistencies between studies even for the same ant species (Banschbach et al, 2012;Mitchell et al, 2002;Ness & Morin, 2008;Warren et al, 2015) suggest that the roadside response of an ant species can be context-dependent.…”

Effects of Habitat Conversion on Ant Functional Groups: A Global Review

“…Fungus-growers ants form a peculiar FG, with habits associated with fungal gardening, for which they use residues from arthropods and carcasses and/or live or dead plant material to grow their symbiotic fungus or yeast (Delabie et al, 2000;Mehdiabadi & Schultz, 2010). Forest habitat loss has been related to decreased abundance of this group in Argentina (González et al, 2018). The impacts of habitat conversion in fungus-growers FGs probably occurred because some land uses, with intensive management, in addition to homogenizing the habitat, affect strongly the ant fauna through the use of pesticides and soil preparation with effects on the structure of the nests, as well as the availability of the organic substrate for cultivation of the fungus (Lobry de Bruyn, 1999;Queiroz et al, 2012;Nickele et al, 2013).…”