Biodiversity Under Threat - Complete notes (Edexcel Geography)

Contains full notes from all text books and other sources, on arguments and case studies on Biodviersity under threat. 

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Page 1

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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…

Page 2

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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…

Page 3

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o 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…

Page 4

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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…

Page 5

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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…

Page 6

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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,…

Page 7

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2. 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…

Page 8

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o 34
hotspots
only
take
2.3%
of
land
surface.

- 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…

Page 9

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o 7,700
different
plant
species

! 70%
are
endemics.

o 7
planet
families
found
nowhere
else
on
earth

! Fynbos
plants
include:
Cape
reeds,
Poreas
and
Ericas.

! Adapted
to
the
warm
climate.

- Threatened

o Spread
of
alien
plants

! E.g.
Hakea
and
Australian
Acacia


o Commercial
forestry
using…

Page 10

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o 11,700
endemic
plant
species.

o 11
endemic
threatened
mammals

o 9
endemic
threatened
birds

- 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…

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