Biodiversity Under Threat - Complete notes (Edexcel Geography)

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Biodiversity
Under
Threat
Defining
biodiversity
Definition
- The
term
biodiversity
is
a
buzzword
­
a
shortened
version
of
`biological
diversity'
- "Biodiversity
means
the
variability
among
living
organisms
from
all
sources
­
terrestrial,
marine,
and
aquatic
ecosystems
and
the
ecological
complexes
of
which
they
are
part:
this
includes
diversity
within
species
(genetic
diversity),
between
species
(species
diversity)
and
diversity
between
ecosystems
(ecosystem
diversity)"
o (UN
Convention
of
Biological
Diversity
1992
Rio
Summit)
- Importance
o "At
least
40
per
cent
of
the
world's
economy
and
80
per
cent
of
the
needs
of
the
poor
are
derived
from
biological
resources.
In
addition,
the
richer
the
diversity
of
life,
the
greater
the
opportunity
for
medical
discoveries,
economic
development,
and
adaptive
responses
to
such
new
challenges
as
climate
change"
! (Convention
on
Biological
Diversity)
- Destruction
and
degradation
o Destruction
of
biodiversity
­
is
its
complete
removal.
o Degradation
of
biodiversity
­
is
no
decrease
in
the
area
covered
by
biodiversity,
but
a
decrease
in
the
quality.
Types
- Genetic
Diversity
o This
is
the
range
of
genes
found
within
a
particular
species.
Genetic
biodiversity
often
determines
the
degree
of
resistance
to
pests
and
diseases.
o Areas
of
analysis
! Biomes,
bioregions,
landscapes,
ecosystems,
habitats,
Niches,
populations.
o Example
! Genetic
variability
among
populations
or
individuals
can
determine
the
degree
of
resistance
to
pests
and
diseases.
! A
broad
gene
pool
is
vital
to
combat
diseases
and
climate
change.
! Agro-ecosystems
have
been
reduced
by
plant
breeding
to
artificial
monocultures
(genetic
erosion).
o Advantages
! A
good
general
measure
of
biodiversity.
On
a
basic
level
areas
can
be
compared.
! Sometimes
better
if
a
range
of
indicator
species
of
specified,
ones
that
suggest
a
richer
system
if
they
are
present.
! Better
to
use
taxonomic
diversity
e.g.
If
an
island
has
one
rodent,
two
birds
and
one
lizard
species,
then
it
is
more
diverse
than
an
island
with
four
bird
species
on
it.
o Disadvantages

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Take
care
when
assessing
area
as
larger
areas
tend
to
be
more
diverse.
You
need
to
compare
like
with
like.
! Many
species
as
yet
undiscovered
are
likely
to
be
microscopic.
Might
skew
a
biodiversity
index
based
on
species
numbers.
! Species
richness
does
not
cover
the
distribution
of
the
species
or
the
interactions
between
species.
- Species
Diversity
o This
is
the
variety
of
plant/animal
species
in
a
given
area
(habitat);
it
is
a
measure
of
species
richness
i.e.
the
number
of
different
organisms.…read more

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Disadvantages
! Difficult
to
know
where
to
place
the
boundaries
for
the
area
under
investigation.
Sand
dunes
may
merge
into
sea
meadow
and
then
into
Carr
woodland.
! Need
a
consistent
set
of
criteria
to
demarcate
an
ecosystem.
Then
numbers
and
distribution
of
the
ecosystems
can
be
compared
within
a
region.
Influences
on
Biodiversity
- Limiting
factors
are
what
determines
biodiversity.
- An
absence
of
limiting
factors
leads
to
high
levels
of
primary
productivity
and
the
energy
produced
leads
to
high
levels
of
biodiversity.…read more

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Biodiversity
can
be
low
because
the
climate
is
too
dry
(deserts)
and/or
too
cold
(polar
and
tundra
regions).
Climatic
extremes
usually
have
low
biodiversity
because
there
are
not
enough
food
sources
to
support
large
populations
and
often
only
specialised
organisms
can
survive.
! NPP
is
the
suns
energy
minus
respiration
· Tropical
rainforest
o Mean
NPP:
2220
g/m^2/yr
o Mean
biomass:
45kg/m^2
· Savannah
o Mean
NPP:
900g/m^2/yr
o Mean
Biomass:
4kg/m^2
· Tundra
o Mean
NPP:
140g/m^2/yr
o Mean
Biomass:
0.…read more

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Natural
disaster
e.g.
hurricanes,
volcanoes,
tsunamis
on
both
land
and
ocean
ecosystems,
· E.g.
Asian
tsunami
2004
destroyed
some
mangrove
forests.
o NOTE:
Can
move
factors
around
a
bit,
in
terms
of
categories.
! Also,
other
things
of
slight
note
in
book.
Human
factors
- Direct
o Levels
of
protection/management
o Direct
actions
exploiting
flora
and
fauna
! Hunting,
fishing
and
over-harvesting
o Use
of
fertilisers,
pest
control
methods
and
irrigation
practices.
o Clearance
for
agriculture
leading
to
deforestation
and
soil
erosion.…read more

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Distribution
of
biodiversity
- Biodiversity
is
strongly
correlated
with
latitude,
the
highest
amount
of
biodiversity
occurring
in
tropical
regions.
- The
top
5
countries
with
the
highest
diversity
index
are
located
around
the
equator
or
the
tropics
(see
lower
down).
o Areas
with
tropical
rainforest
in
South
and
Central
America,
Madagascar,
Malaysia
and
Indonesia
showing
high
species
richness.
o Greatest
biodiversity
in
tropical
rainforests
! Only
about
7%
of
the
planet's
surface.
! Have
highest
biodiversity
index.
! E.g.
Brazil
biodiverse,
contains
Amazon
rainforest.…read more

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Qatar
­
0.189
3. Kuwait
­
0.224
4. Libya
­
0.240
5. Ireland
­
0.279
Biodiversity
of
100km^2
of
rainforest
- 60
species
of
amphibian
- 1,500
species
of
flowering
plants
- 750
species
- 400
types
of
birds
- 150
butterfly
species
- 100
kinds
of
reptile
Biodiversity
Hotspots
- Biodiversity
Hotspots
are
areas
that
are
very
biodiverse,
but
threatened.
o British
ecologist
Norman
Myers
defined
the
Biodiversity
Hotspot
Concept
in
1988
as
a
tool
to
assess
conservation
priorities.…read more

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Conservation
International
also
identified
11
marine
hotspots.
o 11
Marine
hotspots
! 25%
of
the
world's
coral
reefs
! 34%
of
restricted
range
endemic
species
! But
cover
only
0.02%
of
the
oceans.
o Most
of
these
marine
hotspots
are
adjacent
to
terrestrial
hotspots.
! They
often
experience
land-based
threats
of
pollution,
over-
fishing
and
tourism
development.
· E.g.
Coral
Triangle
(Indonesia,
Philippines,
and
Papua
New
Guinea),
which
was
subdivided
into
three
hotspots:
Indonesia,
Sundaland
and
Wallacea.…read more

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Fynbos
plants
include:
Cape
reeds,
Poreas
and
Ericas.
! Adapted
to
the
warm
climate.
- Threatened
o Spread
of
alien
plants
! E.g.…read more

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Threats
o Deforestation
! Only
5%
of
original
forest
cover
is
left.
o Human
expansion
! Densely
populated
! Tourism
o Agriculture
! Cut
down
trees
The
value
of
Ecosystems
- Ecosystems
have
value
in
several
ways
o Provisioning
services
(goods)
! Products
derived
directly
from
the
ecosystem.
· They
can
be
sustainable
o E.g.
Fruit
and
nuts
· They
can
be
unsustainable
o E.g.
Hardwood
timber
! Food,
Water,
raw
materials,
medical
resources...
! They
tend
to
be
of
economic
value.…read more

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