Annual and Seasonal Changes in the Structure of Litter-Dwelling Ant Assemblages (Hymenoptera: Formicidae) in Atlantic Semideciduous Forests

Abstract

We surveyed ant fauna in the leaf litter in an Atlantic Semideciduous forest in the State Park of Rio Doce (PERD). The work aimed to produce basic information about habitat effects on diversity, as well as about how the ant fauna in a such buffered forest habitat, as the litter layer, could respond the climate variation in a short and long term. We sampled two years in two distinct forest physiognomies, which respond to different geomorphologic backgrounds, in dry and rainy seasons. Species composition, richness and abundance of these forests were distinct. However, both forests hosted similar numbers of rare and specialized, habitat demanding species, thus suggesting both are similarly well preserved, despite distinct physiognomies. However, the lower and more open forest was, more susceptible to dry season effects, showing a steeper decline in species numbers in such season, but similar numbers in the wet seasons. The pattern varied between years, which corroborates the hypothesis of a strongly variable community in response to subtle climatic variation among years. The present results are baselines for future long term monitoring projects, and could support protocols for early warnings of global climatic changes effects on biodiversity.

Seasonality of Epigaeic Ant Communities in a Brazilian Atlantic Rainforest

“…Our results corroborate Castro et al, (2012) who also did not found a relationship between ant species richness and seasonality in a degraded area. The lack of correlation observed in the present study may be explained by environmental degradation, which makes the environments simpler (Vasconcelos et al, 2006;Sobrinho & Schoereder, 2007), and increases the competition and abundance of generalistic species (Schoereder et al, 2004).…”

“…For example, Castro et al, (2012) did not observe variations in the structure of ant assemblages in an impacted area, but only between different areas. In this study, we assessed temporal variations in ant assemblages that live in the soil-litter interface in the Cicuta Forest.…”

“…The ant richness found in the Cicuta Forest is high compared to other forest remnants (Veiga-Ferreira et al, 2005;Castro et al, 2012;Vargas et al, 2013). The assemblage composition of ants is highly generalist, but also we can found a high occurrence of rare species (33%).…”

“…It is well known that variations in rainfall intensity affect temperature and humidity, and so influence ecosystem productivity (Kaspari, 2001). Therefore, rainfall seasonality is expected to lead to variations in the activity, abundance, and species richness and composition of ants (Coelho & Ribeiro, 2006;Almeida et al, 2007;Castro et al, 2012). Indeed, rainfall may affect ant assemblages in two ways, by altering microclimate at a local scale or ecosystem productivity at a regional scale (Castilho et al, 2011;Castro et al, 2012).…”

Ants as indicators of environmental change and ecosystem processes

“…Season was an abiotic factor that also influenced the incidence and species richness of ants, with higher ant incidence during the drier season. This typical finding (Basu, 1997;El Keroumi et al, 2012; but also see Castro et al, 2012) might be attributed to higher foraging activity at higher temperatures (Medeiros et al, 2014), seasonal changes in the brood cycle, or availability of nest sites or food (Levings, 1983). However, in our study, higher ant activity did not seem to translate into higher predation in the herbal and shrub layers, but might be instead limited to ground-foraging activity (see subsection 4.3).…”