Tipos e Agentes Dispersores de 26 Espécies Arbóreas Oriundas da Regeneração Natural em Áreas Mineradas na Amazônia, Porto Trombetas, Oriximiná, Pará

Abstract

Species have evolved to conduct seeds or fruits to areas of preferential establishment, through biotic or abiotic factors. The interaction between fauna and vegetation is of fundamental importance in the process of recovery of degraded areas. In the National Forest of Saracá-Taquera/Ibama, in Porto Trombetas, Oriximiná, Pará, the Mineração Rio do Norte (MRN) promotes the extraction of bauxite since 1979. After mining, it is necessary to restore the forest landscape. In 2001, natural regeneration was monitored in MRN's annual forest restoration areas. Every arboreal individual with total height of 1.5 m was registered, identified and measured the DBH (trunk diameter at 1.3 m from the ground) and total height. Measurements are made every two years in permanent plots. The objective of this study was to conduct a survey of dispersal agents in areas of forest restoration after bauxite mining of 26 tree species from natural regeneration. The great majority of species were dispersed by animals (90%), followed by balochoric dispersion (7%) and wind dispersion (3%). Vismia latifolia (Choisy) was the species that had the largest number of individuals (323); it has zoochoric dispersion (characteristic of tropical forests), with birds as dispersing agents, which contributed greatly to seed dispersal, since they are animals of relatively light body volume, with ease of movement. Next was Bellucia grossularioides ((L.)Triana), with 234 individuals, which also have zoochoric dispersal. In last place was Sclerolobium paniculatum (Mart.ex.Tul Benth.), with an occurrence of 10 individuals in the permanent plots of natural regeneration, with dispersal by wind. As known, natural dispersion is a very important process also for the recovery of degraded areas. In the process of forest restoration in areas degraded by mining, the dispersion by animals was what most facilitated the process of natural regeneration of tree species, followed by ballocoria and wind dispersion.