Influência do monocultivo de pau-brasil (Paubrasilia echinata Lam E. Gagnon, H. C. Lima & G. P. Lewis, Fabaceae) na regeneração e fauna edáfica em área de Mata Atlântica de Pernambuco.

Abstract

Restoration processes of tropical forests can be conducted through the planting of native species in degraded areas caused by human activities, aiming for the gradual reconstruction of a dynamic and biodiverse ecosystem. However, little is known about the performance of a native species planted in a monocultural model for restoration purposes. Based on this principle, the objective of this research was to assess the influence of the monocultural system with Paubrasilia echinata on the regeneration flora and soil fauna in the understory of a Semideciduous Seasonal Forest environment in Pernambuco. For this purpose, two areas were selected: one in passive restoration with a plantation of Pau-Brasil aged over 50 years (BPB), and an adjacent Native Forest (MN) area used as a control area, both within a protected area of the Tapacurá Ecological Station, an advanced campus of UFRPE. A survey of natural regeneration and soil fauna was conducted as ecological indicators in both areas, with a total of 6 plots measuring 600m² each. For regeneration, tree individuals with a Circumference at Breast Height (CBH) of up to 15cm and a minimum height of 1m were measured, identified to the species level, and classified by origin, dispersal syndrome, and ecological groups. Richness was determined by the species list, and diversity was assessed using Shannon-Weaver Diversity Indices, Simpson's Dominance, and Pielou's Evenness. The species were analyzed both horizontally and in 3 height classes. To evaluate the soil fauna, pitfall traps were used, 9 in each area, the collected organisms were screened and identified, when possible, at order level. The analysis of the edaphic fauna was made through the ANAFAU program, which provides ecological indexes and information on the structure of the community. The results of the ecological indexes of the two indicators were compared by the Hutcheson t test in the PAST program. As a result, in natural regeneration the area of MN presented greater richness and higher values of diversity and equability, while the area of BPB presented higher dominance due to the superior and expressive presence of individuals in regeneration of the species. There was a significant statistical difference for the diversity and dominance of natural regeneration among the studied areas. In both areas it was observed a greater number of zoochoric species and highlight to the ecological group of early secondary. Only in the area of MN there were records of exotic species. Individuals were observed in the three height classes in both areas, being the MN with the highest number of species with this representation. Regarding the edaphic fauna, higher values of abundance in the BPB area and greater richness in the MN area were verified, and the soil fauna diversity was similar between the areas. The orders Collembola, Hymenoptera and Diptera were highlighted for the two areas. The order Orthoptera was found in greater abundance and frequency in the BPB area. Therefore, the monoculture of Brazilwood has been negatively influencing the stratum of natural regeneration in questions of plant diversity and has been affecting the proportion of some groups of soil fauna.