Nature isn't outside of us, it is modified by humans
- Crosby shows this goes way
back
- new proposals for geoengineering such as the idea of putting sulfur in the atmosphere
- is there something wrong with this idea? If so, what?
- don't know what is going to happen
- might create an imbalance in nature
- could be catastrophic if it doesn't work
- creating the symptoms and not the cause
- there is some level of meddling that is too much: "playing God"--tricky argument to make because line changes
- technology often has
unpredictable side effects+watch out for scale (big interventions are
riskier than small ones)
- beware of the technological fix--we don't have to worry because technology can solve our problems
- we are nervous about
interfering with nature
- Europeans dispaced the native people
- changed the ecosystem to look more like Europe
- how did they displace the natives--why is South Africa majority black but the U.S. is not majority indian?
- European diseases killed
off indigenous people in the Americas in large numbers (chapter 9)
- disease was a bigger
problem for Europeans in Africa, particularly in the tropics (chapter
6)
- more Europeans migrated
to the Americas (partly because they feared diseases in tropical areas
and so fewer migrated say to Africa)
- Europeans had a bigger technological advantage in North America--Africans had iron
- Europeans brought their whole ecosystem with them--why was European agriculture so successful in (some but not all) new places? And it wasn't just that what farmers planted grew--many plants spread faster than European settlement.
- you need a similar climate
- European plants took over in North America, not in Africa--this is the focus today
- how could European plants so successfully go wild--you can't say because they were better
- you have native plants that are well adapted to the environment--why can European plants out-compete them?
- quick answer--because the
Europeans changed the environment
What is a weed?
- it doesn't matter whether
the plant is undesirable
- weeds are the plants that
spread without human cultivation (eg. dandelions spread by wind-born
seeds)
- weeds grow where the soil is disturbed--trees cut down, domestic animals eat native plants, etc.
- European plants succeeded
because they were adapted to growing in the disturbed soil the
Europeans created
broad-leaved plantain
- 54-66% of the vegetation in California consists of European species
- clover and bluegrass spread faster than European settlers
- by 1920 only 20% of the vegetation of the pampa of Argentina was native plants
- non-native species are present in such large numbers in North America that they are a problem for anyone restoring ecosystems
Europeans plants were at first mostly brought on purpose (and weeds came with the crops):
- Europeans planted the crops they knew
- they wanted familiar foods and other products
- that was what there was a market for in Europe
- Johny Appleseed--planted apple seeds in the wild--produced apples not good to eat but you could make alcohol from them
- why is he a children's hero?
- he is doing something to benefit future generations
- he is transforming nature to make it friendlier to humans
- he is trying to make
North America look more like Europe
- they wanted a familiar-looking landscape around them
- they brought their own ornamental plants too
- and honeybees to polinate
their crops
- European plants spread in the neo-Europes, plants from the neo-Europes did not spread (except where cultivated) in Europe
- why is it not the same in
both directions
- were European plants better? no--they were adapted to the European environment
- the European environment involved:
- lots of
agriculture--usually plowed every year
- no undisturbed wild land left
- lots of grazing animals
on the land that wasn't planted in crops
- the European plants were
better suited to an environment disturbed by humans and their animals
- plants in the Americas
weren't evolved to survive heavy grazing, so cattle and sheep displaced
native plants
- European plants had evolved
to live in land disturbed by agriculture--weeds--they like the
environment when whatever was growing there has been removed and the
soil is exposed
- they were plants that like
to grow where the soil has been disturbed by
- agriculture
- deforestation--cutting
down trees lets in more sun and opens up the soil
- pigs (and cattle and sheep)
damage done by feral hogs
- the plants of the Americas and Australia prefered undisturbed environments, which were rare in Europe
- a few plants from the
Americans became important as crops
in Europe
- most important what we call corn, known in Europe as maize (in Europe "corn" is a general term for any kind of grain)
- also potatoes and
tomatoes (which were thought at first to be poisonous)
- peanuts and manioc became important in Africa and sweet potatoes in Asia
- crops were a fairly even exchange, unlike plants in the wild
- few plants from the
neo-Europes could do well in the disturbed environment of Europe
- is this saying European plants were better?
- no, but they were better adapted for living on land disturbed by agriculture
- the ability to spread
quickly is most useful when the land is disturbed
- consider French explorers in the Pacific in the 1790s
- when they arrived someplace new they would plant a garden of European plants as a scientific experiment and leave European animals
- they were interested in adaptation (which they called acclimitization)
- the plants did not do
well in the absences of settlers
- European plants were adapted to live alongside of farming and grazing
- European plants succeeded because they were adapted to the conditions that Europeans created
- the Europeans changed the environment in ways that favored their plants
- Europeans were able to
change nature on a very large scale