1- Department of Forest Sciences, Faculty of Natural Resources, Tarbiat Modares University, Tehran, Iran
Abstract: (6031 Views)
We assessed the size and composition of the soil seed bank and above-ground vegetation
in 52 relevés representing a range of habitats within an old- growth, temperate deciduous
forest at Hyrcanian region, northern Iran. We identified 63 taxa in the seed bank, with an
average density of 4202 seeds/spores per m2 by seedling emergence method. Hypericum
androsaemum, Cardamine impatiens, and Rubus hyrcanus, with Athyrium flix- femina and
Pteris cretica as two ferns, were the most abundant species in the seed bank and spore
bank that made up to 92 % of the seeds/spores recorded in the soil seed bank. Totally, 107
species were recorded in the vegetation and soil seed bank of the study site, of which 33 %
were common in both seed bank and vegetation and 26 % and 41 % were found only in
the seed bank or in the vegetation, respectively. The dominant tree species with many
woody understory species found in the above- ground vegetation were absent from the
persistent soil seed bank. Jaccard’s similarity coefficient revealed that the correspondence
between the species in the vegetation and the same species in the seed bank were
consistently low (average of 24.3%) based on presence/absence data. Yates- corrected c
2
test showed that sites present significant differences (P<0.001) in seed bank and
vegetation species composition. DCA ordination of the above-ground vegetation and soil
seed bank flora displays a clear pattern, with two distinct groups on the basis of the
above-ground vegetation and soil seed bank floristic data. Our results explain the low
similarity between soil seed bank and vegetation of the Darkola oriental beech (Fagus
orientalis Lipsky) forest only to a limited extent, but confirm that most of the species of
the above-ground vegetation do not depend on the persistent soil seed bank. Therefore, it
may be concluded that the persistent soil seed bank is not capable of restoring the extant
vegetation of the studied site.
Received: 2011/01/19 | Accepted: 2011/01/19 | Published: 2011/01/19