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Natural regeneration in a Caatinga fragment under different disturbance levels

This work was carried out on the border between the municipalities of Areia and Remígio, in the state of Paraíba, where some remnants of hypoxerophytic caatinga were encountered. The objective was to observe modes of natural regeneration in areas with different levels of anthropogenic disturbance. Three areas (I, II, III) with decreasing levels of disturbance were chosen. Five sample units from each area were chosen for plotting. Four size classes were established in order to stratify the specimens under study: class 1 -- specimens ranging from 0.10 to 0.29 m in height; class 2 -- specimens ranging from 0.30 to 1.49 m in height; class 3 -- specimens ranging from 1.5 to 3 m in height, and class 4 -- specimens more than 3 m tall, but having a diameter of less than 3 cm at the base. The total density was in the range of 5000 specimens per ha-1. Twenty-six species of trees belonging to seventeen families were identified. 60% of the samples belonged to the Euphorbiaceae and Mimosaceae families. Croton sonderianus Muell. Arg. demonstrated the highest rate of natural regeneration in regions I and II, while in region III, the species with the highest rate of natural regeneration was Thiloa glaucocarpa (Mart.) Eichl. Most of the trees belonged to the smaller size categories. Only area III, the best preserved of all, contained specimens belonging to all four size categories. The greatest impact due to anthropogenic disturbances was detected in area I. The least impact was observed in area III, as proved by the richness of the forest and the predominance and distribution of plants in the previously defined size categories.

Natural regeneration; caatinga; anthropogenic disturbance; dry forest


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