also that many farm animals could live in the wild without human care
the Europeans radically transformed the ecosystem into an ecosystem dominated by European plants and animals
the argument made for plants doesn't work for animals
Pigs
- feral hogs
in South Carolina
- source of meat, and you don't need to feed them
- even in Europe often lived free in the woods
- so they were well-prepared
to live without human care
- they root and disturb the
soil (feral
pig video)
- had a particular impact in forest areas and swamps
- why weren't there native
animals that competed and predators that killed the pigs
- Spanish cattle were already
less dependent on human care, they released them in the southwest and
south America to live in the wild
- could fend for themselves
on an open range, climate was suitable
- not many predators--wolves
(other predators had died out with the extinction of the megafauna)
- more successful than
buffalo/bison
- how could cattle brought
from somewhere else out-compete the buffalo?
- because of
hunting--wiping out the buffalo made room for cattle (buffalo
slaughter video)
- probably other reasons
- in South America there was an empty niche left by the extinction of the megafauna
- both grazing animals and predators
- nothing had yet appeared to take their place
- so European animals who
took those ecological niches had little competition and few predators
- had gone extinct
in North America about 10,000 years ago along with the megafauna
- brought back by the
Europeans, particularly the Spanish
- multiplied and spread in the wild
- consider not just the
ecological issues but the cultural role of horses
- there were wild horses in
the southwest by the mid 1500s, but indians did not use them much until
a successful Pueblo
Indian revolt in 1680 put horses in the hands of Indians who had
worked for the Spanish and learned to use them, who then traded them
with other Indians
- Indians changed their culture to use horses--the horse and the gun altered the balance between tribes and made the tribes of the great plains much more mobile
- horses made the Indians much more successful in hunting buffalo, making room for cattle
- the Indians of the Great Plains got the horse in the 1700s and weren't badly hit by European diseases until the early 1800s.
- should we remove wild horses? management, argument for native status
- the horse is an animal that is present only because the Europeans brought them
- they aren't exactly non-native because they were once there
- in Holland they are reintroducing wild horses and cattle to natural areas
- this is seen as a way
to restore the ecosystem
- some people argue to restore the ecosystem we should remove the horses--
- why not--they were
present so they have the right to be there
- are they really causing a problem? (some ranchers think so)
- similar story of the
reintroduction of wolves in the Yellowstone area
- horses are an important part of our image of the wild west--that is the ecosystem that is historically meaningful to us
- should we invent a new
ecosystem?
- why were imported species more successful than local ones?--same question as weeds
- because of the extinction
of the megafauna:
- lack of predators
- the ecosystem had empty
niches they could fill--this is imporant, think about why
- they were adapted to live in situations modified by human beings
- in the midlands the ecosystem had widely spaced trees with grass, suitable for free range cattle, created by the indians starting fires
- Crosby does not make
diseases part of the story--the competing animals weren't there in the
first place
- there were no honeybees (or other bees that were large-scale pollinators) in North America when the Europeans arrived
- produced sugar and wax,
pollinate crops
- bringing in a new kind of pollinator changes the ecosystem for plants dramatically
- honeybees are currently declining and that causes major problems
- 90% of apple tree
pollination is by honeybees
- Europeans reshaped the
whole ecosystem to the one they were used to--were able to because
their plants and animals had an advantage
- native birds that nest on the ground can be wiped out by rats, some reptiles too
- a particularly dramatic example in a more isolated setting: 3/4 of Hawaii's native bird species are extinct
- in Hawaii mongooses
were
brought in to control the rats and instead nearly wiped out a native
goose
- native species went on the
decline because of imported animals