Artrópodes predadores generalistas em agroecossistemas com uso do fogo em estabelecimentos agrícolas familiares na Amazônia Oriental

Abstract

The shifting cultivation model of slash and burn practiced by Amazon family farmers bring their short-term benefits for their crops, however there is a series of changes in agricultural ecosystems. The arthropods can be strongly reduced their population affected by fire environments because aside from direct mortality caused by the heat of the flames, population changes may result from environmental changes. The aim of this study was to evaluate the use of fire in agro-ecosystems of family farming in the Eastern Amazon of generalist arthropod predators. The evaluations were performed at family farms in the city of Maraba, southeast Pará, with soil type trap traps. For the analysis of general arthropod predators in cut area with use of fire (Evaluation 1), three areas were used (converted area with use of fire, reference area and the area managed with the use of heat), where the arthropods in six sampled samplings depending on regional climatic seasonality (dry and rainy season). The dynamics of predatory arthropods (Evaluation 2) has been studied in three areas: farming area, transition area and the reference area. For all analyzes the collected arthropods underwent screening in the laboratory, separated into taxonomic groups and kept in ethanol at 70% in technical reserves of the Faculty of Agricultural Sciences of the Maraba Unifesspa. The communities of generalist arthropod predators were studied by the definition of abundance, the means were compared by Tukey test (p ≤ 0.05), still held the correlation Pearson tests between meteorological factors and arthropod predators and analysis Regression the same being realized with the Sigmaplot software (Version 11). In different areas managed with use of fire and the reference area were collected in total 344 arthropod predators. The carabids had higher average abundance in the managed area with use of fire, the dermapteras and spiders stood out in the area converted by the use of fire, spiders being the only influenced by meteorological factors. The staphylinid had higher averages in the areas that had the use of fire. The dynamics of the study were collected 572 arthropod predators, the most abundant was the Aranea taxon. The transition area was the most abundant, showing that in this environment there was a great movement of arthropods. In the reference area the abundance of spiders and dermapteras correlated with mean temperature, the carabids with precipitation. The spiders were the most abundant arthropods in general studied agro-ecosystems. The meteorological factors influence the abundance of generalist predators differently in each taxonomic group and in each managements situation of agro-ecosystems with use of fire. The total rainfall favored an increase abundance of generalist arthropod predators in areas with use of fire.