The size and composition of soil seed‐banks in remnant patches of three structural rainforest types in North Queensland

Abstract

under deciduou.s forests because they would he e.xposed annually to conditions .suitable for iiermination. Third, ehronie disturbanee by cattle and pii^s produces sites suitable for the establishment of rapidly maturing herbs, and possibly disperses their seeds into the forest. AbstractThe size and species composition of the .soil seed-bank in a remnant pateh of each of three slructwally and floristically distinct rainforests (Complex Mesophyll \ 'ine Forest. Complex Notophyll Vine Forest and Semi-Fvergreen Vine Thicket) were a.ssessed. Seeds of 94 speeies germinated from 12 surface soil samples collected from each site. .All three seed-banks were composed mostly of herbs charactertstic of roadsides and agricultural land, and pioneer rainforest trees and shrubs. .Agglomerative classifications indieated that the seed-bank samples from each rainforest remnant had a characteristic speeies eomposition and eould be distinguished reliably from seed-bank samples drawn from other sites. Seeds of species present in the.standing forest were poorly represented in the seed-banks except for one long-lived pioneer tree. Dendrocnide photinophylla, at one site. The seed-bank from the seasonally dry vine thicket was significantly larger (4000 .seeds m~^) than those from the two moister sites (400-600 seeds m~-. contained more seeds of roadside and agrieultural herbs, and fewer seeds of rainforest pioneer and seeondary shrubs and trees. We suggest three explanations for the different seed-bank structure observed in the seasonally dry forest site. First, with inerea.sed deciduousness in rainforests, seed-banks are increasingly subjeet to invasion and domination by seeds of rapidly maturing herbs. Second, long-lived seeds that germinate in canopy gaps would be less likely to accumulate

Avaliação do potencial da transposição da serapilheira e do banco de sementes do solo para restauração florestal em áreas degradadas

“…Transposição da serapilheira e do banco de sementes do solo, Viçosa, MG. P = espécie pioneira; St = espécie secundária tardia; Si = espécie secundária inicial; Sc = espécie não classificada. Segundo Hopkins et al (1990), a situação de dominância das espécies herbáceas é comum em trabalhos com banco de sementes de comunidades florestais fragmentadas e cercadas de vegetação antropizada (pastos, culturas agrícolas, etc.). Alguns fatores, como mecanismos eficientes de dispersão, tamanho e dormência das sementes destas espécies colaboram para este padrão (GARWOOD, 1989).…”

Densidade e composição florística do banco de sementes de um trecho de floresta estacional semidecidual no campus da Universidade Federal de Viçosa, Viçosa, MG

“…O predomínio de sementes de espécies arbustivoarbóreas pioneiras no banco é comumente relatado na literatura (BAIDER et al, 1999;ENRIGHT, 1985;LAWTON;PUTZ, 1988;HOPKINS et al, 1990). …”

The seed bank of a gallery forest in Southeastern Brazil

“…Fifty-seven species belonging to 45 genera and 25 families were identified in the rainy season samples, whereas 87 species from 66 genera and 34 families were found in the dry season samples. The woody species found in the soil seed bank were mainly those that regenerated only in large gaps, mainly through the seed bank (Cecropia pachystachya, Croton floribundus, C. urucurana, Helicteris brevispira and Trema micrantha) (Table 1).A low density of woody species compared to herbaceous species has been reported in previous studies (Young et al, 1987;Quintana-Ascencio et al, 1996;Dupuy and Chazdon, 1998;Grombone-Guaratini and Rodrigues, 2002), and might be reflecting the degree of perturbation and fragmentation since weeds became common components of the seed bank when the forest got fragmented or surrounded by non-natural vegetation Hopkins et al, 1990;Poiani and Dixon, 1995;Dalling and Denslow, 1998).…”