Announcements – Oct 11, 2006

Exam # 2 one week from today (on October 18th)

Gone for Decades, JaguarsSteal 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 RatingsGreen –

abundant, well managedFarmed mussels

and clamsAlaska salmonTroll caught

MahimahiU.S. farmed TilapiaPole/troll caught

yellowfin, bigeye, albacore tuna

Yellow – some concern over status, manag.Longline caught

MahimahiPacific codRainbow troutMaine lobsterSquid (calamari)Canned tuna

Red – severe overfishing, poor managementAtlantic codShrimpAtlantic flounders and

solesSharksFarmed salmonOrange RoughyChilean 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

• sediments, pollutants

– 4. Aquarium industry• 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 know1) What is channelization? Why is it done and what problems can it cause?

2) What can be the problems with dams and flood control? How do they affect sediment & water flows, fish migration, and floodplains?

3) What is a wetland and how much has been lost in the U.S.? What ecosystem services do they provide?

4) 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?

5) What are the pros and cons of aquaculture?

6) Why should you care about the destruction of coral reefs?

Lecture Objectives:

Agriculture I

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 ValleyZagros Mountains in IranAnatolia (modern Turkey)northern SyriaJordan River valleyMesopotamia

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

Year PlaceEstimated

Dead

1840s Ireland 500,000 – 1 Million

1930s Ukraine 7 Million

1958-1961 China 30 Million

1980’s Ethiopia 1.2 Million

Major Food SourcesThree 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.

MeatIt 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)

Tofu (4 oz) 12 (soy)

Chicken (4 oz) 37

Sirloin Steak (4 oz) 32

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” AgricultureUsually 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 machinesMountain regions, small, oddly-shaped plots

2. Type of crop requires careful handlingRice 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 AgricultureBenefits

– Reduced labor

– Increased yields (per area)

Mechanized AgricultureBiological 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?