Transcript Madagascar Powerpoint

Madagascar
Gerald Durrell
described
Madagascar as being
'shaped like a badly made omelette lying off the east coast of
Africa but containing, as a properly made omelette should, a
wealth of good things inside it'.
This particular omelette is the size of France and Switzerland put
together.
Leaving the mainland
Madagascar was once sandwiched
between India and Africa. Then it split
from the mainland, between 100 and
180 million years ago, carrying with it
a wealth of wildlife from the African
continent.
Until 40 million years ago, before it
became too isolated, animals could
reach Madagascar by floating across
from the surrounding continents on
rafts of vegetation.
New species evolving
Once marooned on this young
island, the plants and animals
evolved over time into unique
species. Around 80% of all its
species are endemic, meaning that
they are found nowhere else in the
world.
Few large predators made it to the
island, so new species could evolve
to fill different niches. The aye-aye,
for example, evolved to take
advantage of the gap in the
insectivorous market. Its long, slim
finger enables it to hook out insect
larvae hiding in crevices in wood.
Lemurs – endemic primates
The aye-aye belongs to an endemic group of primates known
as the lemurs. There were over 40 species of primate adapted
for life throughout Madagascar. Since the arrival of humans
more than 10 species are now extinct.
The human population
Madagascar's wildlife treasure
chest is matched for uniqueness
by the variety of the people, the
first of whom settled on the
island in AD 500. It is now a
melting pot of colours and
creeds mainly from Africa, Asia
and Arabia, who have
themselves evolved new
cultures and traditions bearing
little resemblance to their
ancestral homes.
Agriculture – growing rice
A common need for land links together people and wildlife.
Traditionally, farming has been the source of human sustenance,
with rice being the most common source of food. Growing rice is a
way of life, and is integral to the local culture.
Rum is still sprinkled onto the
fields before many farmers
start their day's work as a
mark of respect for the
ancestors who first cultivated
rice hundreds of years ago.
Rice cultivation is the bridge
between the present-day
Malagasy population and
their 'ancestors'.
Reed beds under environmental pressure
Nowhere illustrates the conflict between humans and their
habitat better than around the largest freshwater lake on
Madagascar, Lac Alaotra.
As each successive year's
crops are planted by the
villagers of the 32 villages
encircling the lake, more of
the reed beds that grow in
the shallows are destroyed.
Pioneers and building materials
The villagers rely on the reed beds for building materials, and for
textiles such as those used in hats, bags and even sieves for
separating the rice from the silt and stones.
It is not only people
who benefit from
the reed beds; the
reeds represent the
pioneer community
in the area, being
some of the first
plants to take hold in
the marshy habitat.
Maintaining the lake habitat
The reeds act as giant sieves,
trapping mud and silt
washed down the rivers from
the deforested hillsides. This
makes the lake a sedimentfree home for fish and other
lake wildlife.
Without the reeds the lake becomes choked with sediment and
dries up, taking with it the fish that form a vital part of the
people's diet.
Adapted for reed life
Many other
species depend on
the reeds for
survival, including
a species of lemur
found only around
Lac Alaotra, the
Lac Alaotran gentle
lemur.
Clearly if the reeds go, then so does the
gentle lemur.
Human predators
The villagers also hunt the
lemur by burning the reeds
and driving the animals out
into the open where they are
caught and killed for food.
After all, where else can the
villagers turn for meat when
funds are low?
A threatened habitat
The biggest single
threat to the reed
beds is through the
loss of land to farming
as the area of waterthirsty rice steadily
swamps the lake.
This artificial 'ecosystem' of one plant species reduces the
opportunities for animals by providing few new niches to
colonise. The monoculture rice farms are unable to support the
variety of wildlife dependent on a varied reed-bed system for
food and shelter.