Chuva de sementes, banco de sementes do solo e deposição de serapilheira como bioindicadores ambientais no bioma Mata Atlântica, Teresópolis, RJ

Abstract

The aim of this study was to quantify seasonal litterfall and the patterns of the seed bank and the seed rain in a pristine Atlantic Forest in order to contribute to proposals of environmental indicators. In a National Park located at Teresopolis, RJ, one hectare was divided in 20 plots 25 x 20 m where 20 traps (0,25 m2), were centered in order to sample litter and seed rain. Monthly, from March 2004 to February of 2005, all deposited material was collected and separated in leaves, branches, reproductive material and others. Soil samples in each plot area (4 replications by plot) were collected monthly (0,25 m2, 0,05 deep) and placed in a nursery and a green house. Along 430 days seed emergency (viable seeds) were counted and seedling were measured and removed. The annual litterfall was 5597,32 ± 125,50 kg.ha-1, with dominance of leaf-fraction, which represented 60,9% of total arrived material; the reproductive material contributed with 19,8% being the second fraction more representative in relation to total litterfall. The deposition revealed sazonal in the area. The density of deposited propagules was 28.303, from which 93 morph-species, distributed in 34 identified families and of these 12 genus identified 14 species and 8 that were only identified by morph-traits. The species and families more representative in seed rain were Arecaceae (Palmae), with Euterpe edulis Mart., Melastomataceae by Miconia budlejoides Triana, and Vochysiaceae by Vochysia saldanhana Warm.. The seed rain species diversity calculated by Shannon-Wiener (H´ = 2,185 nats.ind¯¹), Pielou s evenness index (J´ = 0,4667) and Margaleff s richness index (d = 10,44), were low when compared to others studies in Atlantic Forest. Also seed bank diversity (H´ = 3,076 nats.ind¯¹), evenness (J´ = 0,9134) and richness (d = 5,236) were lower than expected to a pristine Atlantic Forest. The number of viable seeds 1142 however only 210 emerged as seedlings. Seed rain and seed bank was a available tool to evaluate forest conservation and their potential regeneration; despite litterfall can be considered also as an useful bioindicator, it needs to be associated to others parameters. Though, seed rain and bank associated to litterfall were valid parameters to formulate biological indicators.