Efeitos da variação do lençol freático em assembleias de formigas (hymenoptera: formicidae) que vivem na serapilheira na Reserva Adolpho Ducke, Manaus, AM

Abstract

Disturbances can affect richness and abundance patterns of species, but little is known about the effects of natural disturbances compared to human disturbance. This study evaluated the effects of groundwater level (natural disturbance) on behavioral response, richness and abundance of ants species that inhabit the leaf litter of tropical forests. Data were collected in the Adolpho Ducke forest Reserve in Manaus / Amazonas in 2014, along ten riparian plots using sardine baits and litter sampled by Winkler method. Data collection was conducted in the rainy season (March) when the water table was shallow and during dry season (September) when the water table was deeper. Abundance of dominant ants, monopolization of food resources, richness and occurrence of ants living in the litter accumulated at the base of stem less palms and in the litter adjacent to it. The results obtained indicate that the number of baits monopolized during the period with sallow water table was approximately 3 times larger than the number of monopolized bait when the water table was deeper at the litter adjacent to the palm. The number of occurrence of dominant species during the period with sallow water table were approximately 2.5 times higher when the water table level was deeper in litter adjacent to stem less palms. For the results of the samples collected in the mini- Winkler the average difference in the number of species sampled in the adjacent litter the palm between the period with shallow and deep groundwater was approximately 10 species. In other words, on average, 10 species of ants were more collected when the water table was deep. The results demonstrate the occurrence of ants living in the litter adjacent to the palm period deep groundwater is approximately 1.5 times less than the occurrence of species of ants when the surface was ground water. As for the result of the experiment colonization and nesting the colonization rate was higher in the 6 months in the area adjacent the palm in the deep groundwater period, however, the period that the groundwater was closer to the surface, it was observed that there was a decline in the foundation of ant nests. In all analyzes the results obtained for the samples taken in the accumulated litter at the base of stem less palms (habitat with relative little influence of the water table level) remained stable. Together, our results suggest that the groundwater level can act as a disturbance to ant assemblages.