Understanding the Importance of Seed Banks in Ecosystems

SEED
 BANK
 
Seed bank 
is the 
reservoir 
of viable 
seeds or
vegetative 
propagules.
 
2 types 
of seed
 
bank:
Soil seed bank
Arial seed
 
bank
 
T
y
p
e
s
 
o
f
 
S
e
e
d
 
B
a
n
k
s
-
T
h
o
m
p
s
o
n
 
a
n
d
 
G
r
i
m
e
 
(
1
9
7
9
)
2
 
t
y
p
e
s
:
A)
Arial seed
 
bank.
B)
Soil seed
 
bank.
T
r
a
n
s
i
e
n
t
:
 
p
e
r
s
i
s
t
 
<
 
1
 
y
r
P
e
r
s
i
s
t
e
n
t
:
 
p
e
r
s
i
s
t
 
>
 
1
 
y
r
i.
Short term persistant_1 to 5
 
yrs
ii.
Long 
term-more 
than 5 
yrs 
(
Chenopodium album-40 to
1600
)
A 
species 
forming no soil 
seed bank 
at 
all (except 
the
 
dry
season between ripening and 
the 
first autumnal rains) is
Agrostemma 
githago 
(Corncockle), which is a 
formerly
widespread cereal
 
weed
 
Which 
species 
form 
large,
persistent
 
SB?
 
Disturbance
 
spp
Ann
u
als/biennials
Small-seeded
 
spp
 
Ref: 
seed bank and its 
perspective 
by 
Junling 
Ma 
• Zhimin Liu • 
Dehui Zeng
 
 
Soil 
seed
 
bank
 
The 
soil 
seed bank 
is the 
natural
storage 
of seeds, 
often dormant, 
within
the 
soil of 
most
 
ecosystems.
The 
study 
of soil seed 
banks 
started 
in
1859 
when
 
Charles 
Darwin
 
observed
the 
emergence 
of seedlings 
using 
soil
samples 
from 
the 
bottom 
of 
a
 
lake.
The 
first 
scientific 
paper 
on 
the 
subject
was 
published 
in 1882 and 
reported 
on
the 
occurrence 
of seeds 
at 
different 
soil
depths.
 
Living seeds 
have 
been 
found 
in or on the 
soil
for 
different 
durations 
,different 
seasons 
, 
at
different 
depths 
(buried –light-germinate)
(Duvel, 
1902;
Grundy 
et al.
, 
2003; 
Benvenuti, 
2007), 
in 
different 
quantities
and in 
different states 
of dormancy or
procession 
to 
germination 
(Baskin and
 
Baskin,1998)
 
 
In 
agro 
ecosystem,the 
soil seed bank 
is closely
associated 
to 
weed
 
studies
a.
Weed 
control
 
programmes
b.
SCMP-Rational use 
of
 
Herbicides
 
Seeds of 
several 
plant 
species 
hardly ever enter
the 
soil but 
persist 
at 
its 
surface 
or 
in the 
litter
for 
many years, prominent examples are 
the
large 
and 
hard 
fruits of 
Medicago 
and 
Neurada
,
which 
contain 
dozens 
of seeds 
and 
can give 
rise
to 
several 
plants over 
several
 years.
 
Plants 
differ 
in 
the 
duration 
their 
seeds remain 
in
the 
soil 
and 
even 
within 
a 
species 
and 
among
seeds 
of 
the 
same 
cohort there 
is 
variability 
in
the 
time 
they 
spend in 
the 
soil seed
 
bank.
 
Seed
 
longevity:
 
Longevity of seeds 
is 
very 
variable 
and 
depends 
on
many 
factors; 
few 
species 
exceed 
100
 
years.
 
 
In 
typical soils 
the 
longevity of seeds 
can 
range
from 
nearly 
zero 
(germinating 
immediately 
when
reaching the soil or 
even 
before) to 
several 
hundred
years.
 
Some of the 
oldest 
still-viable seeds 
were 
those 
of
Lotus
 
(
Nelumbo 
nucifera
) 
found 
buried 
in the 
soil 
of
a 
pond; these seeds 
were 
estimated 
by 
carbon
dating
 
to 
be 
1,040 
years
 
old.
 
Density:
 
The mortality 
of 
seeds in 
the 
soil 
is 
one of 
the 
key
factors 
for 
the 
persistence 
and 
density fluctuation,
especially 
for 
annual
 
plants.
 
Studies 
on 
the 
genetic structure 
of 
Androsace
septentrionalis
 
populations.
 
There are 
indications that mutations 
are 
more
important 
for 
species 
forming 
a 
persistent 
seed 
bank
compared 
to 
those 
with only 
transient
 
seeds.
 
The 
increase 
of species richness 
in a 
plant community
due 
to 
a 
species-rich 
and 
abundant 
soil seed bank 
is
known 
as the 
storage
 
effect
.
 
Associated 
ecosystem
 
processes
 
The 
term 
soil 
diaspore 
bank 
can 
be used 
to 
include
non-flowering 
plants 
such 
as 
ferns 
and
 
bryophytes.
 
In 
addition 
to 
seeds, 
many 
plants 
have 
vegetative
propagules 
to 
facilitate 
forming 
new 
plants,
migration 
into 
new 
ground, 
or 
reestablishment after
being top-killed. These 
propagules 
are 
collectively
called 
the 
soil bud bank, 
which 
includes 
dormant
and 
adventitious 
buds on 
stolons, 
rhizomes, 
and
roots.
 
Arial seed
 
bank
 
A 
canopy 
seed bank 
or 
aerial 
seed bank 
is 
the 
aggregate 
of
viable 
seed 
stored 
by
 
a
 
plant
 
in its
 
canopy
 
Canopy seed
banks 
occur 
in 
plants 
that postpone 
seed 
release 
for 
some
reason.
 
It is 
often 
associated 
with 
serotiny
, 
the 
tendency 
of some
plants 
to 
store 
seed 
in a 
cone
 
(e.g. in the 
genus 
Pinus
) 
or
woody 
fruits 
(e.g. in the 
genus 
Banksia
), 
until 
seed 
release 
is
triggered by 
the 
passage 
of 
a
 
wildfire
.
 
It also 
occurs 
in 
plants that 
colonise 
areas 
of shifting sands
such 
as 
sand dunes
. 
In 
such cases, 
the 
seed 
is 
held 
in 
the
canopy even 
if the 
canopy becomes 
buried; 
thus 
the 
seed 
is
anchored 
in 
place 
until good 
germination 
conditions
 
occur.
 
Seed 
bank-Conservative 
of 
genetic
 
diversity
 
Role 
in genetic 
diversity 
and 
natural 
restoration 
as 
well
as 
to recover endangered 
plant 
species. 
(
Red 
data 
books
document)
 
 
Coleanthus subtilis- 
today 
highly endangered 
or 
extinct
plant
 species.
 
One 
characteristic 
of such 
plants 
is 
their 
capacity 
to
survive 
in the 
soil seed bank 
during unsuitable
conditions
.
 
Due 
to 
the 
longevity 
of seeds, 
those 
species 
remain
present 
for
 
decades
 
Reference: 
K.G. BERNHARDT 
& E. ULBEL 
University 
of 
Natural Resources 
and Applied 
Life 
Sciences,
Department 
of 
Integrative 
biology, 
Gregor-Mendel-Strasse 
33, 
1180 
Vienna,
 
Austria
 
Environment
 
Re-Constituting 
natural environment 
of 
many 
ecosystems 
(by
wildfire, 
catastrophic 
weather 
timber 
harvesting 
is 
largely due
to 
the 
soil seed 
bank)agricultural
 
operations.
 
Forest 
ecosystems 
and 
wetlands 
contain 
a 
number of
specialized plant 
species 
forming 
persistent 
soil seed
 
banks.
 
Before 
the 
advent 
of herbicides 
a 
good 
example 
of 
a 
persistent
seed bank species, 
Papaver 
rhoeas
, sometimes 
was 
so
abundant 
in 
agricultural 
fields 
in 
Europe that 
it 
could 
be
mistaken for 
a
 
crop.
 
The 
absence 
of 
a 
soil seed bank 
impedes the 
establishment
 
of
vegetation 
during 
primary succession
, 
while 
presence 
of 
a
well-stocked 
soil seed bank permits 
rapid 
development 
of
species-rich 
ecosystems 
during 
secondary
 
succession
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Seed banks, categorized into soil and aerial types, serve as essential reservoirs for viable seeds and propagules. Soil seed banks are natural storage areas for seeds within ecosystems and play a crucial role in plant regeneration. They can persist for varying durations, influencing plant diversity and weed management. Species like Agrostemma githago and Medicago have distinct behaviors in seed persistence. The longevity of seeds varies widely, with some species capable of lasting over 100 years.


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  1. SEED BANK Seed bank is the reservoir of viable seeds or vegetative propagules. 2 types of seed bank: Soil seed bank Arial seed bank

  2. Types of Seed Banks-Thompson and Grime (1979) 2 types: A)Arial seed bank. B)Soil seed bank. Transient: persist < 1 yr Persistent: persist > 1 yr i. Short term persistant_1 to 5 yrs ii. Long term-more than 5 yrs (Chenopodium album-40 to 1600) A species forming no soil seed bank at all (except the dry season between ripening and the first autumnal rains) is Agrostemma githago (Corncockle), which is a formerly widespread cereal weed

  3. Which species form large, persistent SB? Disturbance spp Annuals/biennials Small-seeded spp

  4. Ref: seed bank and its perspective by Junling Ma Zhimin Liu Dehui Zeng

  5. Soil seed bank The soil seed bank is the natural storage of seeds, often dormant, within the soil of most ecosystems. The study of soil seed banks started in 1859 when Charles Darwin observed the emergence of seedlings using soil samples from the bottom of a lake. The first scientific paper on the subject was published in 1882 and reported on the occurrence of seeds at different soil depths.

  6. Living seeds have been found in or on the soil for different durations ,different seasons , at different depths (buried light-germinate)(Duvel, 1902; Grundy et al., 2003; Benvenuti, 2007), in different quantities and in different states of dormancy or procession to germination (Baskin and Baskin,1998) In agro ecosystem,the soil seed bank is closely associated to weed studies a. Weed control programmes b. SCMP-Rational use of Herbicides

  7. Seeds of several plant species hardly ever enter the soil but persist at its surface or in the litter for many years, prominent examples are the large and hard fruits of Medicago and Neurada, which contain dozens of seeds and can give rise to several plants over several years. Plants differ in the duration their seeds remain in the soil and even within a species and among seeds of the same cohort there is variability in the time they spend in the soil seedbank.

  8. Seed longevity: Longevity of seeds is very variable and depends on many factors; few species exceed 100 years. In typical soils the longevity of seeds can range from nearly zero (germinating immediately when reaching the soil or even before) to several hundred years. Some of the oldest still-viable seeds were those of Lotus (Nelumbo nucifera) found buried in the soil of a pond; these seeds were estimated by carbon dating to be 1,040 years old.

  9. Density: The mortality of seeds in the soil is one of the key factors for the persistence and density fluctuation, especially for annual plants. Studies on the genetic structure of Androsace septentrionalis populations. There are indications that mutations are more important for species forming a persistent seed bank compared to those with only transient seeds. The increase of species richness in a plant community due to a species-rich and abundant soil seed bank is known as the storageeffect.

  10. Associated ecosystem processes The term soil diaspore bank can be used to include non-flowering plants such as ferns and bryophytes. In addition to seeds, many plants have vegetative propagules to facilitate forming new plants, migration into new ground, or reestablishment after being top-killed. These propagules are collectively called the soil bud bank, which includes dormant and adventitious buds on stolons, rhizomes, and roots.

  11. Arial seed bank A canopy seed bank or aerial seed bank is the aggregate of viable seed stored by a plant in its canopy Canopy seed banks occur in plants that postpone seed release for some reason. It is often associated with serotiny, the tendency of some plants to store seed in a cone (e.g. in the genus Pinus) or woody fruits (e.g. in the genus Banksia), until seed release is triggered by the passage of a wildfire. It also occurs in plants that colonise areas of shifting sands such as sand dunes. In such cases, the seed is held in the canopy even if the canopy becomes buried; thus the seed is anchored in place until good germination conditions occur.

  12. Seed bank-Conservative of genetic diversity Role in genetic diversity and natural restoration as well as to recover endangered plant species. (Red data books document) Coleanthus subtilis- today highly endangered or extinct plant species. One characteristic of such plants is their capacity to survive in the soil seed bank during unsuitable conditions. Due to the longevity of seeds, those species remain present for decades Reference: K.G. BERNHARDT & E. ULBEL University of Natural Resources and Applied Life Sciences, Department of Integrative biology, Gregor-Mendel-Strasse 33, 1180 Vienna, Austria

  13. Environment Re-Constituting natural environment of many ecosystems (by wildfire, catastrophic weather timber harvesting is largely due to the soil seed bank)agricultural operations. Forest ecosystems and wetlands contain a number of specialized plant species forming persistent soil seedbanks. Before the advent of herbicides a good example of a persistent seed bank species, Papaver rhoeas, sometimes was so abundant in agricultural fields in Europe that it could be mistaken for a crop. The absence of a soil seed bank impedes the establishmentof vegetation during primary succession, while presence of a well-stocked soil seed bank permits rapid development of species-rich ecosystems during secondarysuccession

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