Human InteractionChapter 12

• “Sustainability” is a popular idea these days.

• What does “sustainability” in the ecosystem mean?

• What does “sustainability” in human communities mean?

WORK

TOGETHER

The term “ecological footprint” means:

1 2 3 4

25% 25%25%25%1. The ecological

services of a natural area.

2. The complete bio-capacity of Earth.

3. The land and water area needed to sustain humans.

4. The risk of a species to extinction.

Natural Communities• Natural, self-renewing communities

share several features:

• Stable populations at or below carrying capacity

• Biological diversity

• Recycling of all raw materials

• Reliance on sustainable energy (solar)

Human Communities

• How well does our community score on each of these four points?

• Stable populations at or below carrying capacity

• Biological diversity

• Recycling of all raw materials

• Reliance on sustainable energy

Human PopulationDate

Technical andcultural advances

Industrial andmedicaladvances

Agricultural advances

123

Billions Time to addeach billion(years)All of humanhistory

1312131433

1804

201219991987197419601927

1

234567*

*projected bubo

nic

plag

ue

billi

ons

of p

eopl

e

2012*

1830

1975

1960

1930

1987

19992006

We know that human population is increasing exponentially. Our resources are not.

Poll: The human species:

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33% 33%33%

1. Is approaching carrying capacity.

2. Has overshot carrying capacity.

3. Can never reach carrying capacity.

0

time

Consequences of exceeding K.

K(original)

K(reduced)

Populationovershootscarryingcapacity;environmentis damaged.

Extremedamage;populationdies out.

Low damage;resources recover,population fluctuates.

High damage;carrying capacitypermanently lowered.

The problem is, we don’t know for sure where we are on this graph.

Bear in mind that this is what “overshoots carrying capacity” looks like.

When resources are highly limited, most individuals have access to only a small share

of those resources.

developed countries

2006: 6.5 billion

popu

latio

n (b

illio

ns)

year

developing countries

Presently, populations in developing nations are increasing, while developed nations are

stabilizing.

Developing countries average: 1.4%

Wor

ld r

egio

ns

natural increase per year (percent)

Europe: –0.1%

N. America: 0.6%

Developed countries average: 0.3%

China: 0.6%

Asia (excluding China): 1.6%

Latin America/Caribbean: 1.6%

Africa: 2.2%

World average: 1.2%

Breakdown of population increases in different parts of the world.

femalemale

Population pyramids for Mexico

percent

Mexico 2007

femalemale

percent

Population pyramids for Sweden

Sweden 2007

High birth rates increase population,

but also provide many young people to

support their elderly relatives.

Low birth rates reduce or level off the population,

but leave less support for the aging segment of the

population.

U.S

. po

pula

tion

(in m

illio

ns)

year

Even with a modest 0.6%

increase in the population each year, the U.S.

shows exponential growth.

In which area of Earth is the human population growing the fastest?

1 2 3 4

25% 25%25%25%

1. North America2. Europe3. Africa4. Asia

On which continent are natural resources being used the

fastest?

1 2 3 4

25% 25%25%25%

1. North America2. Europe3. Asia4. Africa

While populations in developed nations are increasing slowly,

individuals in developed nations use many times the amount of

resources as individuals in developing nations.

What happens if developing nations adopt the U.S. lifestyle?

In some countries, such as the United States, population control is a highly controversial

issue.

This group promotes zero

population growth, birth control, and

social justice as means to

improve society.

This group rejects birth control, believes people should have as many children as possible, and

supports the rights of the individual.

In some developing

nations, women’s education

programs have taught women to read, write, and

run small businesses.

Where women are educated and

most people have meaningful work, birth rates slow down and the quality of life

improves.

Growth curves for the human population show that our species is

experiencing:

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25% 25%25%25%

1. Logistic growth2. S-shaped growth3. Exponential

growth4. Declining growth

Age structure diagrams show that human population is declining in which part of the

world?

1 2 3 4 5

20% 20% 20%20%20%

1. China2. Latin America3. United States4. Africa5. Europe

Humans affect natural populations

• We are living in the middle of a mass-extinction event, and we are the cause.

• We humans change our environment to meet our needs for food, shelter, and other resources. In doing so, we impact other species dramatically.

• The larger our population gets, the faster we use up limited resources.

Extinction Risks

• Specialization and resource partitioning increase diversity.

• However, the tradeoff is that organisms become more vulnerable to extinction if the environment drastically changes.

Localized Distribution

• By living in a limited area, a population avoids competition with other populations.

• The risk is that a natural disaster will destroy the limited habitat.

The Devil’s Hole Pupfish lives in a single waterhole

in Nevada.

Overspecialization• Organisms that

have specialized feeding habits reduce competition with other species.

• If the limited food source goes extinct, so does the species feeding on it.

Fender’s Blue Butterfly feeds only on Kinkaid’s

Lupine.

Interactions• Isolation reduces

competition and predation.

• If a new predator or competitor is introduced, a formerly isolated species may be hunted or out-competed to extinction.

Many Hawai’ian birds were driven to extinction by introduced predators.

Habitat Loss

• The greatest cause of extinction is habitat loss.

• Organisms with highly specialized habitat needs may avoid competition, but risk extinction if their habitat is threatened.

Tropical rain forests are being logged at an alarming rate, mostly for grazing cattle.

“HIPPO” and Extinctions

• Humans activity can contribute greatly to species extinction.

• The acronym “HIPPO” can help us remember the major contributors to human-caused extinctions.

Habitat destruction

Humans plow up land for farms and

housing developments, strip soil from

mountains to mine minerals, damage

ocean bottoms with deep-water

nets, and cut down forests for wood products. All of

these are habitats for wildlife.

H

Invasive Species

Humans have introduced

species into areas where they have

no natural predators.

Without natural controls, the

invasive species overpopulate

rapidly, crowing out native species.

Kudzu – there’s a house under there.

Ivy

Purple Loosestrife

Starling

I

Pollution

Debris, oil spills, and toxic chemicals pollute

waterways, air, and soil. Pesticides and herbicides used on

farms, lawns gardens, and golf courses

contribute to local pollution.

P

Population

Human population has increased

exponentially and is still climbing.

Large populations need large amounts of

resources, but at the same time

occupy land that might otherwise have supplied

resources.

P

Overharvest

Ancient bison in North American may have been hunted to extinction. The dodo,

the passenger pigeon, and the

Great Auk have all gone extinct due to

overhunting.

O

Of the five HIPPO factors, which causes extinctions the fastest?

1 2 3 4 5

20% 20% 20%20%20%

1. Habitat destruction

2. Invasive species3. Population

(human)4. Pollution5. Overharvest

So why don’t people…

• …simply stop polluting, reproducing excessively, and start using resources wisely?

• The “Tragedy of the Commons” scenario helps explain the human mindset that interferes with this “simple” solution.

Common Pool Resources

These are resource that:

1) are available in limited supply (either they do not renew, or

renew more slowly than they are being

used)

2) are openly available for use, and

3) it is costly to prevent people from using the resources.

When it comes to Common Pool

Resources:

It is in the community’s best

interest to control how the resource is used so that the resource will not be depleted and will be available

for all.

It is in the individual’s best interest to get as much of the resource

as possible.

Part of the problem is that nations all over the world have economies that rely on a linear system

of resource extraction and disposal. Our linear system relies on over-exploitation of common pool

resources.

Linear systems are not sustainable. Material

extraction MUST be tied to material recovery and re-

use, just like a natural ecosystem, to be

sustainable.

The current situation was no accident. In the

1950s, the U.S. made a deliberate move from

being a nation of producers to being a

nation of consumers in order to grow the

economy.

It has been estimated that if everyone in the world lived as people do in Western nations, we would need about 4 Earths to sustain us.

We don’t have these.We only

have this.

In 2013, Earth Overshoot Day fell on August 20 – the day when the

world has used as much of Earth’s resources as Earth can replace in

one year.

Victor Lebow, U.S. economist under Eisenhower.

This is the definition of “overshooting carrying

capacity.”

Is it hopeless?• Never in the history of the Earth has

one species had such an enormous effect.

• However, unlike other organisms, humans have choices about how they live and how they use resources.

• Our past decisions have gotten us into this mess. Our future decisions can solve the problem.

Lessons from Nature• Remember the features of a

renewable, self-sustaining natural community:

• Stable populations at or below carrying capacity

• Biological diversity

• Recycling of all raw materials

• Reliance on sustainable energy (solar)

Stable populations at or below carrying capacity

Humans, unlike other organisms, have the

ability to choose whether to reproduce or not. Some societies have

created laws to regulate populations. Others have relied on incentives, or have left the issue to

individual choice.

The issue becomes complex if a society depends on a large

number of young people to support the aged.

Okay, not like this.

What are some

unexpected effects of

small families?

Biological diversity

Preserving biological diversity in nature, in agriculture, and even

in our human communities is

becoming increasingly important.

Ecosystem services

Indirect, beneficial services• maintaining soil fertility• pollination• seed dispersal• waste decomposition• regulation of local climate• flood control• erosion control• pollution control• pest control• wildlife habitat• repository of genes

Directly used substances• food plants and animals• building materials• fiber and fabric materials• fuel• medicinal plants• oxygen replenishment

“Ecosystem services” are direct and indirect benefits humans receive from the

environment.

Humans have directly benefitted from biodiversity.

Drugs derived from plants and animals.

Andean Potatoes

Forest mushrooms

Tropical fruits

A diverse ecosystem yields a diversity of foods.

Natural rivers meander, creating a richly diverse wetland ecosystem.

Humans also benefit indirectly from intact, diverse ecosystems.

Channelizing rivers, reducing wetlands, and

cutting down trees along rivers changes the

ecosystem.

Loss of wetland diversity means loss of species. Sediments that would be deposited along the

river system and in islands around the

mouth of the river flows straight out to sea.

New Orleans was once protected by

the many islands in the Mississippi

Delta.

Much of the sediment that built those islands now

runs out to the sea. The islands have

eroded, leaving less protection against

hurricanes.

The term “ecosystem services” refers to:

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33% 33%33%

1. Direct and indirect benefits humans receive from the ecosystem.

2. How the ecosystem supplies our needs even when we extract resources at a high rate.

3. When humans do service projects to help restore ecosystems.

YellowstoneNational Park

On a large scale, National Parks, the wildlife refuge system, and public lands can contribute to the preservation of habitat and biodiversity.

transitionarea

Allows developments andtourism, as well as sustainablefishing, forestry and agriculture.

Allows experimental research,education, training, tourism,and low impact development.

Protected; may allowanimal monitoring andlow impact development.core

reserve

bufferzone

Biologists are studying how biological reserves can co-exist with human communities and

allow for multiple uses.

buffer zones

core reserve

core reserve

corridors

smallreserve

Connecting reserves with

wildlife corridors vastly increases

the value of individual reserves.

Animals can make use of a much larger area of land,

which benefits top carnivores that need large

territories.

Wildlife preserves in our current Wildlife Refuge system can be

considered:

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33% 33%33%

1. Corridors2. Core reserves3. Buffer zones

Routes that are maintained between preserved habitat are

called:

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25% 25%25%25%

1. Core zones2. Preserves3. Corridors4. Transits

Modern agriculture relies on vast monocultures of crop plants; the exact opposite of diversity. Monocultures are easier to harvest, but more vulnerable to

diseases and pests than mixed crops.

Sustainable agricultural practices help preserve topsoil, reduce the need for pesticides and

fertilizers, and can help support natural diversity as well.

Most sustainable agriculture is currently practiced on a small scale, but sustainably-

grown food can be found at farmer’s markets, “U-pick” farms, and from Community Supported

Agriculture (CSA) farms.

Permaculture and mixed-crop

agriculture supports a diverse soil food web,

which supports the crops. These methods

tend to be more labor-intensive.

A good place to buy sustainably grown food is:

1 2 3 4

25% 25%25%25%

1. McDonald’s2. A major grocery

store3. A farmer’s market4. A mall

Recycling of all raw materials

In nature, all materials are

recycled. Humans can also recycle raw materials. Making new products from recycled materials

uses much less energy than making products from raw

materials from nature. BUT

recycling only works if there is a market

for recycled products.

Besides recycling to conserve natural

resources, reusing items, repairing items, and

reducing overall consumption are

important: Reduce, Reuse, Repair, then

Recycle.

“Use it up, wear it out, make it do, or do

without”

Not buying stuff in the first place helps reduce material consumption and resource over-exploitation. When you shop for gifts or are thinking of what to do

with the weekend, think of “doing” rather than “consuming.”

Movie or concert tickets

Zoo or museum memberships

Take someone outdoors and do something fun.

Help someone with their cleaning or

gardening.

Reliance on sustainable energy

Wind, solar, and geothermal energy are available from nature in unlimited supply. Using these in a sustainable way means developing energy-harvesting methods that are

efficient, cost-effective, have a low

impact in nature, and produce far

more energy than the energy required

to manufacture them.

Harvest of renewable energy can be practiced on a

community-wide or individual basis.

New material technologies make alternative energy more reliable, accessible, and feasible. Solar glass and roof tiles, for example, integrate solar energy

collection into building design, turning entire structures into electricity generators.

And hey… Solar freakin’ roadways!

Real change requires more than just recycling your pop cans. Real change requires a change in

thinking – from “More is better” to “Better is better.” Better stuff rather than more stuff.

Better energy sources rather than more energy use. Better, more active living rather than more

shopping.

What can I do?You may hear: “It’s impossible to be a ‘locavore’ and eat only locally-grown

food. Give it up and just eat ‘regular’

food.”

But you can think, “I can eat some

locally-grown food. I can commit to

buying a pound of produce each week

at the farmer’s market.”

You may hear: “Organic food and recycled products are too expensive. You should save

money.”

But you can think, “I can save money lots of ways. And I

can buy some organic food and

recycled products.”

You may think: “I live in an

apartment. There’s no way I can install solar panels and go

solar.”

But you can think: “But hey, here’s this really

cool crowd-funded project for a green

company I’m interested in.”

You may hear: “Money talks.

Lobbyists have the money, and

politicians listen to them.”

But you can think: “I can write to my representatives, and join a group working on an

issue, until they DO hear us.”

There is always something you can do, no matter how small.

Lots of small actions add up to a big effect.

Do what you can, with what you have, where

you are, right now.

THIS project was started by a student in

college.

Jane Goodall

Jane Goodall makes the point that to save the environment, we must also help the people who

depend on that environment.

Jane Goodall talk on the TED site

• Discuss and list specific ways in which your community contributes to:

• Preservation of biodiversity

• Recycling materials (also, Reduce, Reuse, Repair)

• Using renewable energy

• Which of these have you participated in?

WORK

TOGETHER

Recap• Humans as a species have a huge

and devastating effect on biodiversity worldwide.

• The “Tragedy of the Commons” scenario pits long-term benefits to the community against short-term benefits to the individual.

• Humans can make conscious choices. We can choose to contribute or not contribute to environmental destruction.