Estrato lenhoso e mesofauna edáfica em área de caatinga em processo de recuperação.

Abstract

Anthropic pressure in the Caatinga intensified after the Portuguese colonization of Brazil, characterized at first by the exploitation of natural resources, the monoculture of sugar cane, and extensive ranching. Subsistence agriculture, ranching and the extraction of wood and firewood are currently practiced in the biome, and are considered to be the main factor of Caatinga degradation. Together with slash and burning, the recurrent clear cutting of forests and the adversities of the climate negatively affect the biome and cause the social discrepancies that characterize the region. The combined effect of these factors disrupts the fragile environmental balance of the region, reduces fauna and flora diversity, impacts on water resources, and contributes to compaction, erosion and salinization of soils. Currently, most of the Caatinga areas are in initial or intermediate stage of secondary succession and or in the process of desertification, however, it is possible that most of this vegetation can be recovered and explored in a sustainable way. Recovery of degraded areas depends on the use of ecological principles and silvicultural practices, the knowledge of the causes of degradation and the characteristics of fauna and flora. Environmental recovery can be based on natural regeneration, nucleating techniques or seedling planting. The regeneration process of a degraded area can take its natural course after ceasing the factors causing degradation, such as overgrazing, forest fires and the recurrent cutting and removal of biomass. Seedling planting of pioneer woody species is an alternative for revegetation of degraded Caatinga areas. Despite the high costs, seedling planting can accelerate the recovery of degraded areas, since stavlishment of thesse trees is facilitated and, in turn, the established trees can provide the conditions for the establishment of other species in the herbaceous and tree-shrub strata. Ecosystem status can be assessed by its edaphic fauna because these organisms are adapted to survive, reproduce and carry out ecological interactions under specific environmental conditions, characterizing what is known as bioindicators. The presence and abundance of these organisms are directly influenced by the vegetation cover of the area, the quantity and quality of organic matter, the availability of water, and soil pH and nutrients.