Composição da macrofauna de solos sobre a influência da variabilidade climática em Cabaceiras - PB.

Abstract

The Brazilian semiarid region has a hot and dry tropical climate, rainfall variability and seasonality. This seasonality directly affects the soil and the macrofauna in it. The present study aims to analyze the macrofauna composition of soils under the influence of climate variability in CabaceirasPB. As procedures, 3 distinct areas were selected in different phases of regeneration. Macrofauna collection was performed by pitfall traps. Eight traps were placed in the preserved area, nine (9) in regenerating area, Caatinga shrub and four (4) in exposed or degraded soil physiognomy. These traps were repeated in the three sampling periods, totaling 63 traps all with 70% alcohol solution and detergent for a period of 5 days. Samples were performed in the dry period of 2017, 2018 and wet period of 2019. All individuals were manually accounted for and separated into taxonomic level of class and order through specialized literature. All organisms found were fixed in 70% alcohol, except for earthworms, which were fixed in 92.8% alcohol, and later identified in large and quantified taxonomic groups. For the frequency and dominance analysis, the Shannon diversity method of hierarchization of species was used. To reinforce the accuracy of the tests mentioned, a normality (ShapiroWilk) and variance homogeneity (Bartlett) test was performed. Analysis of variance (ANOVA) was performed using software R 2.10.1. The results show 16 taxonomic groups (order level), with 5,457 soil macrofauna animals in the municipality of CabaceirasPB, with an abundance of 418 individuals in the dry period (2017), 1,018 in the dry period of 2018 and 4,021 individuals. in the rainy season of 2019. The taxonomic groups Formicidae, Lycosidae and Tenebrionidae were the most abundant in shrub and tree fragments in the three periods analyzed. For all periods and all fragments the family formicidae was the most significant, with the largest abundance of individuals, followed by Tenebrionidae and Lycosidae. Tukey test revealed that in the dry period of 2017 there was no significant difference in species abundance among the three sampled areas. In the rainy season of 2019, there was a significant difference in the number of individuals collected in the referred sampling units, and the degraded area had smaller number of collected organisms in relation to the other sampled areas. Variability in number of individuals and species is directly associated with precipitation, which in turn is a result of existing climate variability.