Announcements – Oct 11, 2006
Exam # 2 one week from today
(on October 18th)
Gone for Decades, Jaguars
Steal Back to the Southwest
Oct 10, 2006
Using the same clandestine routes as drug smugglers, male jaguars are crossing
into the United States from Mexico . Four of the elusive cats have been
photographed in the last decade — one as recently as last February — in the
formidable, rugged mountain ranges of southeastern Arizona and southwestern
New Mexico.
Of course, if the Border Patrol built an effective barrier in the mountains where
jaguars cross into the United States, “it’d be all over,” said Jon Schwedler of the
Northern Jaguar Project. “You could kiss the jaguar goodbye.”
Audubon Society Seafood Ratings
Green –
Yellow – some
Red – severe
abundant, well concern over
overfishing, poor
managed
status, manag. management
Farmed mussels
and clams
Alaska salmon
Troll caught
Mahimahi
U.S. farmed Tilapia
Pole/troll caught
yellowfin,
bigeye, albacore
tuna
Longline caught
Mahimahi
Pacific cod
Rainbow trout
Maine lobster
Squid (calamari)
Canned tuna
Atlantic cod
Shrimp
Atlantic flounders and
soles
Sharks
Farmed salmon
Orange Roughy
Chilean seabass
(toothfish)
http://www.audubon.org/campaign/lo/seafood/seafood_wallet.pdf
Is Aquaculture the answer?
•
•
•
Aquaculture - breeding and raising of fish and
shellfish for food
Rapidly increasing industry
Provides 1/4 world’s marine fisheries
Aquaculture
• Arguments for aquaculture
– 1. Not depleting natural fish stocks
– 2. No bycatch
– 3. More efficient
• Problems
– 1. Still depleting natural fish populations
• Feeds often include fishmeal from wild populations
• 2-5 kg wild fish to produce 1 kg raised fish
– especially problematic for carnivores fish (e.g. salmon)
Aquaculture
• Problems (cont.)
– 2. Fish wastes
• aquatic pollution, disease spread
– 3. Genetic diversity
• raised fish escape and breed with wild fish
• reduces genetic diversity
• can cause migration problems
– 4. Can still be bycatch
• if wild fish used to stock pens/ponds
• Milkfish in Philippines
– 85% of fry collected NOT milkfish
Aquaculture
•
Problems (cont.)
–
5. Habitat destruction - loss of mangroves, coastal wetlands
habitats
•
•
•
•
•
•
provide nursery habitat for fish/shellfish
protect coast from storms
help control floods
trap sediments
filter and clean water of excess nutrients
Solutions?
–
Reduce fishmeal in feeds, raise more herbivorous fish (e.g.
Tilapia), regulations on building new facilities
Coral Reefs
• One of most diverse and productive
ecosystems
• Support at least 1/3 marine fish
• Protect coasts from storms
• Uptake carbon
Threats to Coral Reefs
• Most threatened marine habitat
• Major problems include:
– 1. Trawling and dynamite fishing - breaks up
reefs
Threats to Coral Reefs
2. “Bleaching” - death/loss of algae
• Triggered by stress
– elevated temperatures
– pollutants
• Frequency and severity have increased in the
last decade
Threats to Coral Reefs
•
Problems (cont.)
–
3. Runoff
•
–
4. Aquarium industry
•
–
sediments, pollutants
collect best coral, animals
5. Global warming
•
•
rising sea levels - corals need shallow water
rising temperatures
–
•
corals exist in very narrow temperature range
Solutions - creating marine reserves, control
development, regulate collecting
Why should I care about coral reefs?
•
Tourism
–
Countries w/reefs get about 50% of their GNP from reef
activities
•
Beach protection from waves
•
Medical uses
–
•
AZT, 50% of cancer research, bone-grafting
Biodiversity
–
1% of ocean floor houses 25% of marine species
Points to know
1)
2)
3)
4)
5)
6)
What is channelization? Why is it done and what problems can it cause?
What can be the problems with dams and flood control? How do they affect
sediment & water flows, fish migration, and floodplains?
What is a wetland and how much has been lost in the U.S.? What
ecosystem services do they provide?
Why is oceanic fishing important (2 reasons)? Name 3 reasons for
overfishing. What does the bluefin tuna example tell us about the effects
politics & conflict of interests on fishing policies?
What are the pros and cons of aquaculture?
Why should you care about the destruction of coral reefs?
Agriculture I
Lecture Objectives:
1) Where do we get our food?
2) What are the environmental costs of
industrial livestock production?
3) What are the relative costs and benefits of
different approaches to agriculture?
Approaches to Agriculture
– Agriculture: Farming. Growing crops and
animals for food or feed.
The earliest agricultural sites (10,000 - 12,000 years ago):
Nile Valley
Zagros Mountains in Iran
Anatolia (modern Turkey)
northern Syria
Jordan River valley
Mesopotamia
Agricultural revolution led to:
Development of permanent societies
Technological advances
Animal domestication
Nutrition and Food Supplies
• Malthus (1798) predicted that we would outstrip our food
supplies
• World food supplies have more than kept up
– 1950 - 2.5 billion people - average daily diet was less than
2,000 calories/person.
– 2001 - 6.0 billion people - world food supply can provide
more than 2,500 calories/person.
• Problems with global food distribution
Nutrition
The most common
dietary problem in
wealthy countries
is over-nutrition.
In NA and
Europe, average
daily caloric
intake is 3,500
calories.
In US, obesity linked to 400,000 deaths/year in 2000
Obesity could overtake tobacco as leading cause of
preventable death in 2005!!
Nutrition
• Sub-Saharan Africa has not kept food
production up to pace of population growth.
– 30 of 40 countries have decreasing per capita food
production over the past two decades
• Collapse of Soviet Union also led to significant
collapse in food production.
Will this trend continue and be enough to feed another 2
or 3 billion people?
Chronic Hunger and Food Security
About 1 in 5 people in the developing world are
considered chronically hungry.
– 200 million children
• Can lead to permanently stunted growth, mental
retardation, and other developmental disorders.
• Infectious diseases can kill poorly nourished
individuals
– Poverty is the greatest threat to food security (The
ability to obtain sufficient food on a daily basis).
• 11.1% of household in US have do not have
regular food security
Risk of Inadequate Nutrition
Famines
• Famines are characterized by large-scale food
shortages, massive starvation, social
disruption, and economic chaos.
– Environmental conditions are immediate trigger,
but politics and economics are often underlying
problems.
• Arbitrary political boundaries block historic
access to refuge areas.
Some Famine Death Tolls
Estimated
Dead
Year
Place
1840s
Ireland
500,000 –
1 Million
1930s
Ukraine
7 Million
1958-1961
China
30 Million
1980’s
Ethiopia
1.2 Million
Major Food Sources
Three crops deliver majority of world’s nutrients:
Wheat, Rice and Corn
•Potatoes, barley, oats and rye are staples in cool, moist
climates.
•Cassava, sweet potatoes, and other roots and tubers are
staples in warm wet climates.
•Soy is important in many Asian cultures.
Wheat
Rice
Corn
Seafood
• Worldwide - 25% of animal protein
• Since 1989, 13/17 major fisheries have
declined or become commercially inviable.
• Between 1970-1990, number and average
vessel size of world fishing fleet doubled.
– Now have twice the capacity needed to extract
total annual sustainable harvest.
Meat and Dairy
• Meat and dairy products distribution highly
inequitable.
– More developed countries make up 20% of world
population, but consume 80% of meat and dairy
production.
– 90% of grain grown in NA is used to feed livestock.
Meat
It takes 16 kg of grain and soybeans fed to beef cattle
in feedlots to produce about 1 kg of edible beef.
Our ability to
produce enough
food to feed the
world’s growing
population is
directly tied to the
amount of meat
consumed!!
(environmental
argument for
vegetarianism)
Protein
Food
Protein (g)
Sirloin Steak (4 oz)
32
Chicken (4 oz)
37
Tofu (4 oz)
12
(soy)
Cooked beans (1 cup)
13 - 18
Cooked grains (1 cup)
12 - 28
Environmental Problems of Industrial
Livestock Production
Environmental Problems of Industrial Livestock
Production
Pollution
Environmental Problems of Industrial Livestock
Production
Overuse of antibiotics
Photo courtesy of Farm Sanctuary
Social/Political Problems of Industrial
Livestock & Crop Production
Since 1950, number of farmers in industrialized
nations has dropped by up to 80%
In the US, farmers over 65 outnumber farmers under
35 by 3 to 1.
A family farm today must be 4x bigger than the same
farm in 1950 to make ends meet
Much of the farming industry controlled by “Big Ag”
ConAgra, ADM, Monsanto-Cargill
Agricultural Approaches
1) “Slash-and-burn”
2) Labor-intensive
3) Mechanized
“Slash-and-Burn” Agriculture
Usually conducted in areas with nutrient poor soils
(e.g., tropical forests)
Cut & burn existing vegetation to provide nutrients,
use land for brief period, then move to new patch
• land can be slow to recover
Usually plant polycultures (more than 1 species)
• advantages: species benefit one another, avoid
insect/fungal pests
Only sustainable in low population densities
Labor-Intensive Agriculture
• Intense form of agriculture using human
and animal labor to grow crops
• Typical farming practice until Industrial
Revolution
• Still practiced today when:
1. Growing site won’t allow machines
Mountain regions, small, oddly-shaped plots
2. Type of crop requires careful handling
Rice planting, harvesting fruits
3. Economic conditions poor, human labor
cheap
Mechanized Agriculture
• Requires large areas of land
• Found in areas with good soils, and necessary
money and land
– US, Europe, USSR, South America
• Usually monocultures (one crop)
• Labor reduction in the United States:
– 1913: Required average of 135 hours of labor to
produce 2,500 kg of corn.
– 1980: Required average of 15 hours.
Mechanized Agriculture
Benefits
– Reduced labor
– Increased yields (per area)
Mechanized Agriculture
Biological Problems
– Fields left bare, leads to erosion
– Organic matter often removed
– Planting only 1 or 2 crops
• Depleted nutrients
• Insect/Fungal problems
– Genetic similarity in crops
• Insect/Fungal problems
– Increased energy usage
– Increased reliance on fertilizers &
pesticides
Energy
• Farming in industrialized countries is highly
energy-intensive.
– Between 1920-1980, energy use rose directly with
mechanization of agriculture
– US food system consumes 16% of our total energy
use. Buy locally!
– Most foods require more energy to produce,
process, and transport than we yield from them!!!
Fossil Fuel Use
• Takes 5.5 tons of fossil fuel to produce 1.1
tons of fertilizer.
• Developed world is dependent on oil to
produce energy to manufacture pesticides.
Points to Know
1. What is the most common dietary problem in wealthy
countries? In poor countries?
2. What is a famine? What conditions can lead to famines?
3. What three crops provide most of the world’s nutrition?
4. How is meat consumption related to the Earth’s carrying
capacity?
5. What are the characteristics of the three agricultural
approaches?
6. What are the benefits and problems of mechanized
agriculture?