Densidade de Iscas e variáveis ambientais influenciando a dominância nas comunidades de formigas em Florestas de Terra Firme, Amazônia Central, Manaus (AM)

Abstract

Ants are present in most ecosystems and have been widely used to answer ecological questions in many different environments. This is because ant communities and populations are species rich and widely distributed. Dominance is a concept strongly related with richness, diversity, and relative abundance of species. The quality of the available resources directly affects the diversity patterns and consequently the dominance in ecological communities. In this work I evaluate the effects of resource gradients on dominance patterns (numerical and behavioral) and community richness in ant faunas from upland tropical rainforests ( terra firme ) nearby Manaus, Central Amazon. The influence of the volume, litter patchiness, soil moisture, and temperature upon these patterns was also investigated. The sampling consisted of 28 transects (100 m each) with bait density varying from 1 to 4 baits at each 10 m, and 27 transects (200 m each) with bait density varying from 0,5 to 2 baits each 20 m. Resource density have negative influence over behavioral dominance on longer transects (200 m), while in 100 m transects this effect was not found, probably due to environmental saturation with offered resources. The sampled numerical dominance and total richness were not affected by resource density. However, in transects with more bait density, a larger proportion of subdominant species were sampled. Environmental variables were sampled along 10 m intervals in smaller transects, and along 20 m intervals in longer transects. Because of the higher sampling detail, models of environmental variables generated by multiple regression analyses were only significant in the smaller transects. Behavioral and numerical dominance relationships were better explained by variables like litter volume and patchiness. In places with higher litter volume and patchiness, less baits were dominated (numerical and behaviorally). Soil moisture and temperature did not have significant influence on ant dominance patterns.