EFICIÊNCIA DE ISCAS NA COLETA DE ARTRÓPODES ENCONTRADOS NO MEIO SUBTERRÂNEO SUPERFICIAL EM FORMAÇÃO FERRÍFERA NA AMAZÔNIA BRASILEIRA

EFFICIENCY OF BAIT TO COLLECT ARTHROPODS IN THE SUB-SUPERFICIAL HABITAT IN THE BRAZILIAN AMAZON FOREST IRON FORMATION

Abstract

The Brazilian legislation concerning the determination of conservation areas of the national speleological heritage uses, among other information, surveys of the biological parameters found in caves, since these places represent direct access to the underground environment. This practice is recurrent in environmental licensing procedures for mining projects. In the mineralogical province of Carajás there is one of the largest deposits of iron ore in the world and this iron formation has several caves distributed in the landscape. In order to improve indirect survey techniques which direct access is impossible, in other words, in habitats such as the superficial underground environment - MSS, this work intended to evaluate the effect of using baits in traps on the efficiency of these traps in capturing arthropods that occupy these environments in one of the plateaus of the iron formation. The richness and composition of the fauna contained in the MSS captured by traps inserted in boreholes containing different baits were tested: standard bait, consisting of sterilized local leaf litter; and enriched bait, composed of the same litter plus animal protein (ground bovine liver). Although invertebrates belonging to four phyla were collected (Annelida, Mollusca, Plathyhelminthes and Arthropoda), only arthropods were considered, as they were more abundant in the samples. The total sampling of underground arthropods resulted in the collection of 66 taxa, distributed in 5 Classes and 13 Orders. When analyzing the effect of different baits on species richness, it was observed no significant difference regarding the type of bait, however some groups such as Acari and Araneae were more abundant in traps with standard bait. Species composition, on the other hand, was affected by different types of baits.