Assembling an ant community: species functional traits reflect environmental filtering

Abstract

Species should only persist in local communities if they have functional traits that are compatible with habitat-speciWc environmental conditions. Consequently, pronounced regional environmental gradients should produce environmental Wltering, or a trait-based spatial segregation of species. It is critical to quantify the links between species' functional traits and their environment in order to reveal the relative importance of this process to community assembly and promote understanding of the impacts of ongoing environmental changes. We investigated this relationship using epigaeic ants in an environmentally heterogeneous region of Florida. We found evidence for environmental Wltering as environmental conditions such as groundcover, surface temperature, vapor pressure deWcit, and plant diversity were strongly correlated with assemblage composition. Certain species traits appeared particularly important to persistence: (1) ants in environments with less groundcover have relatively longer legs but do not diVer in size, (2) ants in hotter environments exhibit greater thermal tolerances, and (3) ants in hotter and drier environments do not exhibit greater desiccation resistance. These Wndings show surface complexity and temperature may interact with morphology and physiology to impact the spatial distribution of ants and underscore the importance of climate change. Climate warming is predicted to alter assemblage composition, competitive dynamics, and consequently impact ecosystem processes. We suggest environmental Wlters acting at regional scales, as shown here, act in tandem with more frequently studied local-scale competitive interactions to delimit ant community assemblages.

Edge effects decrease ant-derived benefits to seedlings in a neotropical savanna

“…Moreover, a lower residence time of O. chelifer colonies may also decrease benefits provided by these aggressive ants through protection against insect herbivory to seedlings (see Passos and Oliveira 2004). More exposed sandy soils at edges of cerrado may reach extreme temperatures, possibly over the thermal tolerance of these ants (Wiescher et al 2012). Thus, although ant nests seem to be safe sites for seedling establishment in the interior of cerrado, this potentially beneficial effect disappears near edges.…”

“…Indeed, water stress is among the main mechanisms promoting seedling mortality worldwide (Moles and Westoby 2004). Environmental conditions may also filter the local ant assemblage following physiological, morphological, or behavioral traits of the ants better adapted to the harsh conditions found at edges (Wiescher et al 2012). Furthermore, other factors not directly related to microclimate such as resource availability, competition, and predation risk may also influence the diversity and activity of ants, thus influencing the ant species likely to interact with fallen fruits of Erythroxylum at edges.…”

“…behave mainly as seed predators and may decrease plant recruitment (Ferreira et al 2011; but see Leal and Oliveira 1998;Christianini and Oliveira 2009). Edge effects may influence the outcome of ant-plant interactions since changes in environmental conditions may have a great influence in the diversity and activity patterns of ants (Crist 2009;Wiescher et al 2012;see Brandão et al 2011, for example, in the cerrado). Antprovided benefits to seedlings may depend on the level of nutrient enrichment near the ant nest, which in turn is correlated with the residence time of the ant colony (Hughes 1990).…”

Morphological structure of ant assemblages in tropical and temperate forests

“…Among the arthropods, ants are an ideal taxonomic group for investigating relationships between morphology, traits, and assemblage structure because they (i) are abundant, comprising the dominant fraction of animal biomass in most terrestrial ecosystems (Wilson and Hölldobler, 2005), (ii) perform a range of important ecosystems functions (Del Toro et al 2012), (iii) exhibit a very large morphological diversity at very small scales (Silva and Brandão 2010), and (iv) vary in composition along environmental gradients (Gotelli and Ellison 2002). In addition, many studies have shown that ant species have specific traits that are correlated with environmental conditions (Wiescher et al 2012), macro-or microhabitat structure (Kaspari and Weiser 1999, Gibb and Parr 2010, Yates et al 2014) and resource exploitation (Retana et al 2015). Finally, recent research with stable isotopes has identified 5 morphological space occupied by temperate and tropical ant assemblages.…”

Relations between the design and management of Senegalese orchards and ant diversity and community composition

“…This was unlike those of type (4) in the locality of Notto, which grew fruits for the export market and displayed higher intensification levels (Ndiaye et al, 2012). The weak or non-existent technical interventions in type (1) and type (2) orchards were conductive to high leaf litter levels, no pesticide use and no fertilizer inputs that influenced ant diversity, ant richness or ant community structure, as reported by other studies demonstrating the sensitivity of ants to environmental conditions (Peck et al, 1998;New, 2000;Hernández-Ruiz and Castaño-Meneses, 2006;Torchote et al, 2010;Chen et al, 2011;Wiescher et al, 2012;Bernadou et al, 2013). For the group (A) orchards, one ecological factor able to influence the ant community was the vegetation stratum which determines the amount of leaf litter (Perfecto and Snelling, 1995;Ellison et al, 2002;Boulton et al, 2005), depending on whether or not there was orchard cleaning.…”