What humans have
done that has affected
the Galapagos islands
Habitat disturbance
Increased pollution, building & convertionof
land for agriculture have caused destruction
and fragmentation of habitats
Forests of Scalesia trees and shrubs have
been almost eradicated on Santa Cruz & San
Cristobal for agricultural land
Exponential increase of human population
increases demands on water, energy &
sanitation services which authorities struggle to
meet.
More waste pollution
produced and oil demands
have increased
Over-exploitation of resources
In C19 whaling boats & fur -
traders took up residence,
harvesting whales & seals to
sell internationly
Species were harvested faster than
they could replenish themselves
Giant tortoises were take as they could
survive on little food whilst in ships for long
periods of time, before being killed & eaten
This lead to plummeting
number of tortoises
(over 200K in less than
1/2C
Depletion of sea
cucumber populations
has a drastic effect on
under-water ecology.
International market of shark fin has led to
150K sharks each year around the islands
(includes 14 species listed as endangered)
Introduced species
Species such as: goats, cats, fruits & vegetable plants
were deliberately brought to the islands. Other
species like insects were carried accidently.
These species out-competed local species, alien species
can eat native species & destroy native species' habitats,
and bring diseases such as: avian malaria & bird flu
Goats
Most damaging species to Galapagos
ecosystem as it eats Galapagos rock purslane
It out-competes the giant
tortoise for grazing, trampling &
feeding on their food supply &
changes the habitat to reduce the
number of tortoise nesting site
On Northern Isabella island the goat
has also transformed forest into
grassland, leading to soil erosion
Cats
Hunt species like lava lizard & young iguanas
Red quinine tree
The red quinine also out competes native Scalesia trees
The Cacaotillo shrub has almost been eradicated from Santa Cruz
On Santa Cruz the red quinine tree is aggressively
invasive. Occupying high lands, spreads rapidly, has wind
dispersed seeds. Highland ecosystem has changed from
low shrub & grassland to closed forest canopy