Occupation of artificial microhabitats by soil invertebrates in a forest fragment in Southern Brazil

Abstract

The degradation of the soil system and loss of organic layer can cause a decrease in the biodiversity of soil fauna, directly affecting its functional characteristics. Strategies that aim at ecological restoration of degraded areas, must take into account the heterogeneous nature of original systems, especially in the soil surface. The general objective of this study was to investigate the importance of cryptic microhabitats for soil invertebrate communities, through the introduction of artificial structures (mud tiles) on the litter fall. The study area consisted of native forest fragment in Triunfo, RS, Brazil, in which 40 mud tiles were distributed. Every quarter, for a year, 10 tiles were surveyed and 10 litter samples (control group) were collect. A total of 1025 individuals were found distributed in 17 taxonomic groups of invertebrates under the tiles and 935 individuals in 13 groups in the litter fall (control). It was verified that ants and harvestman had been more abundant under tiles than in the control. The abundance of spiders and molluscs was not significantly different between treatments. There were larger amounts of beetle, woodlice and immature insects in the litter fall samples. The mean richness of taxa was larger below the tile and a trend of finding more herbivores and omnivores below these structures was observed. The mud tiles, in this experiment, had fulfilled its task to supply basic information on the importance of cryptic microhabitats for the invertebrate fauna. More research needs to be conducted to clarify and establish the influence of spatial heterogeneity on the dynamics on the soil-litter system for restoring degraded areas.

Key words: invertebrates, microhabitat, litter fall, restoration.