Estrutura das comunidades e nicho térmico de formigas em mosaicos campo-floresta no Sul do Brasil

Abstract

The niche theory is related to the community assemblage in spacetime. The specific habitat conditions of each ecosystem and its dynamic within time defines the community in terms of species composition and functional diversity. Grasslands and forests forms mosaics in southern Brazil since the last glacial era and differs between plants composition, humidity, and average temperature, being this last one of the most important factors impacting ant community. This work aimed to compare taxonomic composition and thermal niche between grassland and forest ants and compare different methods for sampling ants (pitfalls, tuna, and honey baits). The study was released in Reserva Particular do Patrimônio Natural Pró-mata (RPPN Pró-Mata/PUCRS). In total, 9 sample areas were established in two lines of 10x50m each, one in the forest and another in the grassland. Each line contained two intercalated pairs of pitfalls and bait traps. The average temperature was collected in different periods of the day to have the thermal niche of species in terms of activity. The taxonomic diversity was calculated using Simpson’s index and compared between habitats using analysis of variance. To evaluate the taxonomic composition of grasslands and forests we made a Principal Coordinates Analysis (PCoA) based on Bray-Curtis dissimilarity metrics with multivariate variance to test the detected patterns. Different ant species were affected by different ambiental filters over evolutionary time and we found (i) ant assemblage differs between grasslands and forests, (ii) greater thermal niche in species that occurs in both habitats and grassland exclusives and lower thermal niche in species occurring in forests.