Troncos caídos na serrapilheira de mata: “microhabitats” que promovem diversidade

Abstract

There is a lack of information around a great number of discrete and ephemeral microhabitats like trunks, debris, carrion, fruits and shelters under rocks. Some studies have elucidated the aforementioned as important sights for the invertebrate biodiversity maintenance. To help understand the functioning of the communities structures present in these environments, data on the invertebrates associated with fallen trunks within an urban forest were evaluated. The physical-chemical parameters, such as the bark roughness, the volume of the particulate organic matter, moist and the organic matter present in the wood were also measured. 12 fragments of 4 fallen trunks were studied, where it was sampled a total of 3016 individuals distributed among 128 morphospecies of the orders Nematoda, Oligochaeta, Tardigrada, Isopoda, Paurododa, Symphyla, Polyxenida, Diplopoda, Acari, Araneae, Opiliones, Pseudoescorpiones, Protura, Collembola, Blattaria, Ensifera, Dermaptera, Isoptra, Embioptera, Psocoptera, Thysanoptera, Heteroptera, Homoptera, Coleoptera, Lepidoptera, Diptera and Hymenoptera. The species richness related negatively and significantly to the heartwood diameter (Rs = -0,84; p<0,00), to the heartwood length of the fallen trunks (Rs = -0,84; p<0,00), the volume of particulate wood (Rs = -0,87; p<0,02) and to the percentage of organic matter present in the particulate wood (Rs = -0,81; p<0,04). The richness also related significantly and positively to the bark roughness (R² = 0,78; p<0,02). Due to the presence of a mosaic of conditions in the decomposing trunks present in the litterfall, the fallen trunks can shelter a great diversity of invertebrate fauna and, therefore, being important factors in promoting and maintaining the diversity in the forest soil.