Squirrel Wars

Watch the news item called Squirrel Wars UK.

While you watch answer the following questions

1. The news item concerns two species of squirrels, what are they?


2. Which one was introduced?


3. What is the origin of the introduced squirrel?


4. What is the problem that the dominant species is causing?


5. What is the solution?


6. What is the best way to catch a grey squirrel?


7. What is done with the carcasses?


8. Who is buying the meat and what class of people do you think it appeals to?


9. What is the RSPCA's (Royal Society for the Prevention of Cruelty to Animals) position on the culling of the grey squirrel?


10. Do you agree or disagree with the RSPCA - explain your answer.

Biodiversity Summary

Ecology by Charles Krebs
Chapter 22
Summary

This chapter is concerned with giving you the basics about biodiversity.


Measurement of Biodiversity

The first section deals with defining and measuring it. Biodiversity is measured in three basic ways:

a) Species richness - the number of species in an area
b) Heterogeneity - the releative abundance of different species.

Most communities which have small numbers of species tend to contain relatively few common species and many rare species; that is, most species a rare.

If we were to graph this we would get a "hollow curve". This pattern occurs when there are a small number of species in a community and one environmental factor is dominant. The model predicts that "the greatest number of species would have minimal abundance", however as it is typical in ecology every rule has numerous exceptions.

There are many examples in which the pattern of abundance in a community doesn't fit the "hollow curve" but the "bell shaped curve" otherwise known as the "normal distribution" or "log-normal" curve. Here the majority of species are of moderate abundance, and there are both a minority of very rare and very common species.


Biodiversity Gradients

There are biodiversity trends. The one investigated throughout the chapter is the trend that biodiversity increases as one moves towards the equator. This is referred to as the "...one of the great patterns found in community ecology." (p456).

This apears to be true for many plant and animal species such as forest trees in Malaysia compared to Michigan, or ants in Brazil compared to Alaska. But there are many exceptions to this trend. For example, in Australia there are more marsupial species to be found in arid regions than in tropical ones.
In North American mammals one investigator has identified five diversity gradients including the north-south trend.

Possible Factors Responsible for Diversity Gradients

1) History

More time for evolutionary radiation

Tropics are free of severe changes such as glaciation and species can radiate without disturbance creating greater diversity than in cold areas. In other words, in the absence of disturbance we can say that tropical areas are more mature than temperate or polar regions.

Ecological and Evolutionary Time

This can explain diversity changes. Ecological time involves the time needed for a species to colonize a vacant niche.

Evolutionary time involves the time needed for an organism to evolve to fill a vacant niche. Also, in general, evidence suggests that the number of species increases over evolutionary time. Rates of extinction tends to be lower in the tropics and higher in the colder areas.

2) Spatial Heterogeneity

The more complex and heterogeneous the environment the more diverse the flora and fauna tends to be, and complexity increases towards the tropics.

Topographical relief affects diversity. This is the case for North American mammals. This is because:

a) it produces a variety of habitats

b) it creates isolated populations which generates speciations

This pattern does not work for birds or trees nor does it work for oceanic commnities either.

3) Competition

Interspecific competition drives natural selection in the tropics but it is the severity of the environment that drives it at the poles.

In the tropics numerous different species live alongside each other and to survive they must avoid competing with one another. They do so my becoming very specialized.

Niche breadth/length and overlap

The more species there are in a community the narrower their niches are. This is because of Gause's hypothesis which states that "...two similar species rarely occupy the same niche, but will displace one another..."

Where there is overlap, that is where niches of organisms cross over, competition is avoided by sharing resources. The example of species of Anolis lizards in the Caribean is given. Here they eat the same types of insects but will select prey of a certain size so as to avoid competition with other lizards.

Competition is a certain factor in determining biodiversity in animals but less so in plants.

4) Predation

Predation increases biodiversity

The example of a rock pool is given. Here Pisaster, a starfish, was removed from a pool. It was noticed that fierce competition for resources resulted and led to some species disappearing.

Predator and prey species are more abundant in the tropics, and prey populations are kept low. This means that if there are less prey species there is less competition them. Less competition may allow for a greater variety of prey species and consequently a greater variety of predators - well so the argument goes.

5) Climate and Climatic Variability

Climatic stability leads to greater variety. This is due to a lack of calamity and other disturbance and this gives species greater evolutionary time to radiate. See the section on disturbance for an alternative view.

Species-energy-richness model

Species diversity is limited by available energy (measured in terms of evapotranspiration which is a product of temperature and solar radiation). This is consistent for trees, British birds and N.American vertebrates.

6) Productivity

One would expect that highly productive areas would have high biodiversity. I presume this refers to production of biomass although it's not stated in the text. Nevertheless, evidence does not support this idea, in fact high productivity leads to reduced biodiversity.

7) Disturbance

The absence of disturbance leads to competitive exclusion. Disturbance leads to extinction if it occurs frequently enough.

Intermediate disturbance hypothesis

Communities if left alone should tend towards equilibrium in which species are selected by interspecific competition, and generally competition may reduce diversity. But equilibrium is prevented by various factors such as predation, catastrophies etc. Increasing disturbance of this kind tends to stimulate biodiversity.

Ecological succession

Distubance of a forest will lead to regrowth in which colonizing varieties will estabish and change the diversity until the forest has recovered.

However there are many exceptions to these models in which disturbance reduces biodiversity. (Note you need to balance this section with 'evolutionary time' above which suggests a lack of disturbance increases biodversity)

Conclusion

No single factor can account for biodiversity, but a combination of several. It has to be noted that ecology is often case specific; that is, what is true for one instance cannot necessarily be extrapolate to others

Non-Technical Solutions and Lao-tse

Tick-Tack-Toe or Noughts and Crosses

1. Play five games of tic-tack-toe with your partner.
2. Who won?
3. If no-one won, explain why?
4. When the game is stale mated what can you do to resolve the problem so that someone can win?
5. It is said that the game has “no technical solution”. What do you think this means? Can you think of any global or environmental problems that are like this?

Reading Comprehension
Extract 1

Now read an extract from an article that explains defines “no technical solution” and compare your answers with it. Once you have completed reading it, answer the questions that follow.

At the end of a thoughtful article on the future of nuclear war, J.B. Wiesner and H.F. York concluded that: "Both sides in the arms race are…confronted by the dilemma of steadily increasing military power and steadily decreasing national security. It is our considered professional judgment that this dilemma has no technical solution. If the great powers continue to look for solutions in the area of science and technology only, the result will be to worsen the situation.''
I would like to focus your attention not on the subject of the article (national security in a nuclear world) but on the kind of conclusion they reached, namely that there is no technical solution to the problem…A technical solution may be defined as one that requires a change only in the techniques of the natural sciences, demanding little or nothing in the way of change in human values or ideas of morality. …
…Consider the problem, "How can I win the game of tick-tack-toe?" It is well known that I cannot, if I assume (in keeping with the conventions of game theory) that my opponent understands the game perfectly. Put another way, there is no "technical solution" to the problem. I can win only by giving a radical meaning to the word "win." I can hit my opponent over the head; or I can falsify the records. Every way in which I "win" involves, in some sense, an abandonment of the game, as we intuitively understand it. (I can also, of course, openly abandon the game -- refuse to play it. This is what most adults do.)

From : "The Tragedy of the Commons," Garrett Hardin, Science, 162(1968):1243-1248

Questions
1. What is a “technical solution” to a problem?
2. In relation to the nuclear arms race what will happen if countries look for technical solutions?
3. What is required to have a “non-technical solution” to a problem?
4. According to the author how can you “win” at tick-tack-toe?

You have been reading from the article called the Tragedy of the Commons by Garrett Hardin published in the journal Science in 1968. It is predominantly concerned with rising population and its impact on the environment. The article claims that global problems are often caused by one particular aspect of human behaviour: ‘The Tragedy of the Commons’. This can be translated as the individual placing their rights over those of the community, in other words it is an “every man for himself” attitude. In the following passages you will explore this concept and how Garrett Hardin believes it can be controlled.

Extract 2: “The Greatest Good for the Greatest Number”

Population, as Malthus said, naturally tends to grow "geometrically," or, as we would now say, exponentially. In a finite world this means that the per-capita share of the world's goods must decrease. Is ours a finite world?
A fair defense can be put forward for the view that the world is infinite or that we do not know that it is not. But, in terms of the practical problems that we must face in the next few generations with the foreseeable technology, it is clear that we will greatly increase human misery if we do not, during the immediate future, assume that the world available to the terrestrial human population is finite. "Space" is no escape.
A finite world can support only a finite population; therefore, population growth must eventually equal zero. (The case of perpetual wide fluctuations above and below zero is a trivial variant that need not be discussed.) When this condition is met, what will be the situation of mankind? Specifically, can Bentham's goal of "the greatest good for the greatest number" be realized? …
….To live, any organism must have a source of energy (for example, food). This energy is utilized for two purposes: mere maintenance and work. For man maintenance of life requires about 1600 kilocalories a day ("maintenance calories"). Anything that he does over and above merely staying alive will be defined as work, and is supported by "work calories" which he takes in. Work calories are used not only for what we call work in common speech; they are also required for all forms of enjoyment, from swimming and automobile racing to playing music and writing poetry. If our goal is to maximize population it is obvious what we must do: We must make the work calories per person approach as close to zero as possible. No gourmet meals, no vacations, no sports, no music, no literature, no art…I think that everyone will grant, without argument or proof, that maximizing population does not maximize goods. Bentham's goal is impossible.
…The optimum population is, then, less than the maximum. The difficulty of defining the optimum is enormous; so far as I know, no one has seriously tackled this problem. Reaching an acceptable and stable solution will surely require more than one generation of hard analytical work -- and much persuasion.
We want the maximum good per person; but what is good? To one person it is wilderness, to another it is ski lodges for thousands. To one it is estuaries to nourish ducks for hunters to shoot; to another it is factory land. Comparing one good with another is, we usually say, impossible because goods are incommensurable. Incommensurables cannot be compared.
Theoretically this may be true; but in real life incommensurables are commensurable. Only a criterion of judgment and a system of weighting are needed. In nature the criterion is survival. Is it better for a species to be small and hideable, or large and powerful? Natural selection commensurates the incommensurables. The compromise achieved depends on a natural weighting of the values of the variables…
…Has any cultural group solved this practical problem at the present time, even on an intuitive level? One simple fact proves that none has: there is no prosperous population in the world today that has, and has had for some time, a growth rate of zero. Any people that has intuitively identified its optimum point will soon reach it, after which its growth rate becomes and remains zero.

Questions
1. According to Malthus populations grow geometrically. Give a synonym for ‘geometrical growth’.
2. What is ‘per-capita’?
3. What is the consequence of seeing the world as limitless?
4. Although it is not stated explicitly in the text why is going to other planets not a solution to problems of population growth?
5.What is Bentham’s goal?
6. Why does Hardin think that Bentham’s goal is unachievable?
7. What is the optimum human population?
8.To have an optimum population requires that everyone has a minimum quantity of goods to be satisfied. How can you determine what would be acceptable for everyone, as everyone has different tastes?
9. According to Hardin has any prosperous society achieved optimum population?.


The following excerpt deals with how this attitude has become entrenched in modern economic thinking. For Hardin it is due to an interpretation of the writings of eighteenth century thinker Adam Smith. Now read the text below and answer the questions.

Extract 3: Adam Smith and the Invisible Hand

In economic affairs, The Wealth of Nations (1776) [by Adam Smith] popularized the "invisible hand," the idea that an individual who "intends only his own gain," is, as it were, "led by an invisible hand to promote…the public interest." Adam Smith did not assert that this was invariably true, and perhaps neither did any of his followers. But he contributed to a dominant tendency of thought that has ever since interfered with positive action based on rational analysis, namely, the tendency to assume that decisions reached individually will, in fact, be the best decisions for an entire society. …

Questions
1. Paraphrase ‘…the individual who “intends only his own gain,”..’
2. Paraphrase ‘…"led by an invisible hand”…”
3. Paraphrase ‘…the public interest…’
4. Did Adam Smith believe his idea of the invisible hand was true in all cases?
5. What was Smith’s major influence on our way of thinking?


Extract 4 Tragedy of Freedom in a Commons

…The tragedy of the commons develops in this way. Picture a pasture open to all [called ‘the commons’]. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. Such an arrangement may work reasonably satisfactorily for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below the carrying capacity of the land. Finally, however, comes the day of reckoning, that is, the day when the long-desired goal of social stability becomes a reality. At this point, the inherent logic of the commons remorselessly generates tragedy. [20]
As a rational being, each herdsman seeks to maximize his gain. Explicitly or implicitly, more or less consciously, he asks, "What is the utility to me of adding one more animal to my herd?" This utility has one negative and one positive component. [21]
1. The positive component is a function of the increment of one animal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly + 1. [22]
2. The negative component is a function of the additional overgrazing created by one more animal. Since, however, the effects of overgrazing are shared by all the herdsmen, the negative utility for any particular decision ­making herdsman is only a fraction of - 1. [23]
Adding together the component partial utilities, the rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another.... But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit -- in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all. [24]
Some would say that this is a platitude. Would that it were! In a sense, it was learned thousands of years ago, but natural selection favors the forces of psychological denial. The individual benefits as an individual from his ability to deny the truth even though society as a whole, of which he is a part, suffers. Education can counteract the natural tendency to do the wrong thing, but the inexorable succession of generations requires that the basis for this knowledge be constantly refreshed. [25]

Questions

1) What are the commons? Paragraph 20.

2) Each herdsman will try to increase to a maximum their number of cattle. On what conditions can this situation continue for along time? Paragraph 20

3) What happens when “social stability” arrives with an end of tribal wars, poaching and disease have been controlled? Paragraph 20.

4) What are the consequences of a farmer adding more cattle to the commons? Paragraph 21-24.

5) What is the result when everyone pursues their own best interests? Paragraph 24.

6) Paraphrase the concept of the tragedy of the commons.

7) Talk about the sources of the Aral Sea as a commons.



A Non-Technical Solution: Education

As you have discovered a solution exists through education; the transmission of of knowledge and wisdom. Read an extract from the ancient Chinese philosophical text the Tao Te Ching by Lao Tse (6-4th Century BCE) then answer the questions that follow.

http://en.wikipedia.org/wiki/Lao_tse

22. Futility of Contention

To yield is to be preserved whole.
To be bent is to become straight.
To be hollow is to be filled.
To be tattered is to be renewed.
To be in want is to possess.
To have plenty is to be confused.

Therefore the Sage embraces the One,
And becomes the model of the world.
He does not reveal himself,
And is therefore luminous.
He does not justify himself,
And is therefore far-famed.
He does not boast of himself,
And therefore people give him credit.
He does not pride himself,
And is therefore the chief among men.
Is it not indeed true, as the ancients say,
"To yield is to be preserved whole?"
Thus he is preserved and the world does him homage.

http://www.galilean-library.org/tao.html
Tao Te Ching by Lao Tse (6C-4C BCE, Before the Common Era)
Questions


1) Read the following definitions from the Webster’s Online Dictionary and choose one that best describes the poem by Lao tse.

A) Contradiction
A proposition, statement, or phrase that asserts or implies both the truth and falsity of something. Logical incongruity. A situation in which inherent factors, actions, or propositions are inconsistent or contrary to one another

B) Metaphor
A figure of speech in which a word or phrase literally denoting one kind of object or idea is used in place of another to suggest a likeness or analogy between them (as in drowning in money); broadly : figurative language

C) Paradox:
A statement that is seemingly contradictory or opposed to common sense and yet is perhaps true

D) Simile:
A figure of speech comparing two unlike things that is often introduced by like or as (as in cheeks like roses)

2) Read the first part of the poem again and say what message you think the poet is trying to convey to you.

3) Read the second part of the poem again and say who the poet is talking about. Then say what his message is to that person.

Conservation in the Future

Here you will find summaries of the six essays on the future of conservation biology that feature in the text book Principles of Conservation Biology, Second Edition by Meffe, G.K., Ronald, C. et al

Essay 19A
The Post-modern World by Frederick Ferré

The Modern World emerged from the seventeenth century. It is characterised by 3 features:

1) The quantitative (that which can be measured) is more important than the qualitative (that which is subject to taste – subjective)
2) Reductionism –breaking problems into smaller parts for analysis
3) Rejection of a final cause in Nature – that is, a rejection of the idea that things happen for divine purpose

Problems with modernism

1) People are very subjective and values orientated. Ignoring what people consider to be good or bad just because it cannot be quantified leads to unhappiness.
2) Reductionism leads to excessive specialization in professions. The earth is a system made up of numerous parts. Understanding one part is not possible without understanding the whole.
3) Nature has no goal or final cause, but people feel they have a reason to live. This argument puts people outside Nature.

The Post-modern Way of Thinking

It is a blend of the quantitative and the qualitative. In ecology we have to be able to distinguish a healthy ecosystem from a damaged one. This requires both value judgement and measurements.
Ecology is interested in how the world functions as an integrated system and how each part functions.
It shows that we are connected to Nature
The post-modern way of thinking validates our desire for quality and our need to make value judgement

Essay 19B
Conservation Biology in the 21st Century
David Ehrenfeld

4 resources needed for Conservation Biology

1) Money
2) Social Stability
3) Environmental Awareness
4) Specialized knowledge of plants and animals

1) Money

Conservation biology would cease when the resources that create wealth dry up. The discipline is dependant on donations from wealthy companies and governments as well as from individuals.


2) Social and Economic Stability

When people are preoccupied by their own survival they don’t think about Nature.

3) Environmental Awareness

If people do not know anything about threatened animals and plants they are not very likely to want to protect them. Deep feelings about Nature only come when people experience it. The modern world we tend to have less and less contact with Nature making it difficult to convince people to contribute money to save certain species.

4) Specialized knowledge

We need to know what species exist in order to know if they are threatened and in need of protection. Focus in biology is towards molecular biology and not towards taxonomy.


Strategy for success

Minimise costs of research in conservation biology because money is scarce.
Use flexible research methods – this will save research money – that is, use methods that can be adapted to many projects
Study taxonomy
Conservation jobs are often short term contracts. Have an alternative job, so that you can support yourself and your family when your contract runs out.
Get local communities involved. They should be motivated to support and run the project when you are gone.
In your projects include a monitoring system to measure project progress


Essay 19C
The Importance of Communicating with the Public
Laura Tangley


Publicity helps conservation projects. Publish your research projects in popular magazines. This will increase public awareness and help attract funding.

In your articles use photos and drawings so people can see the organism you are working on.

Explain using plain and simple language – avoid jargon

Talk about your interests with friends

Invite people to visit your study site.

Show animals and plants that have charisma and or ecological importance. Charismatic species are usually large vertebrates such as bears, elephants and owls for example. ‘Keystone species’ are species on which the ecosystem depends, such as top level predators or herbivores.


Essay 19D
Opportunities for Creative Conservation
By T.E.Lovejoy

Challenges bring about creativity. For example, save biodiversity by finding creative uses for it – one way has been to argue that biodiversity is an indicator of pollution. Streams that are polluted have low biodiversity.

Local people must be involved in conservation projects for them to be effective.
Most conservation problems are created by landowners deciding things on their own for themselves. They are unaware of greater consequences of their actions.

Encourage co-operation by encouraging collective decision making. A landowner may lose control over their land but gain partial control of others.

Assign monetary value to ecosystem services – this should ensure their protection.

Ecosystem services are the things that ecosystems provide for people that we take fro granted, such as pollination, absorption of pollution by plants, water cycle, nutrient cycles etc.


Example of the Debt for Nature Swap

A rich NGO such as WWF or Greenpeace could take over part of poor country’s external debt. The NGO then becomes the creditor. The poor country or debtor continues to make repayments but to the NGO. The NGO uses the money to fund conservation projects in the country using local currency and labour. This occurred in 1987 in Bolivia with the WWF. (Check out the link to find out more: Debt for Nature Swap)


Carbon Tax

Carbon taxes will encourage the reduction in the use of goods and services that require fossil fuels.


Essay 19E
The Bottom Line - Human Population Control
Paul R. Ehrlich

People need ecosystems to survive so why are we destroying them? Human population growth is responsible for much destruction of Nature. The impact of poulation can be expressed in the following equation:

I = P x A x T

"Overall impact (I) is a function of population size (P), times the per capita level of affluence (A), times the environmental disruptiveness of the technologies used (T)." Meffe et al (1997) p.659

Obviously A & T are difficult to measure so the best approximation of AxT is per capita energy use. Total impact of a society is measured as total energy use.

The impact of populations has been increasing steadily. the global population ioncreases by 95 million people per year.

The human population is in competition with resources of other animals. The human population is exploiting or destroying around 40% of 'terrestrial net primary production'.

The author claims that for the conservation biologist the priority should be in working for the reduction in population growth, consumption, and for the promotion of enviromentally friendly technologies.

Basically all other conservation efforts are a waste of time unless population growth cannot be stopped.

In poor countries population can be reduced in the following ways:

1) Education
2) Human rights
3) Equal opportunities for men and women
4) Adequate health care for women and children

Economic systems should reject models that promote perpetual growth.
Conservation biologists can help assign monetary value to ecosystem services so that politicians will consider them when making decisions.
The costs of fossil fuel use should be internalised; that is, the cost of repairing the damage caused by them should be built into the price we pay for them. This would make environmentally friendly, ie low carbon producing technologies more competitive.


Essay 19F
Commons Problems in Conservation Biology
Bobbi S. Low

Introduction

The Tragedy of the Commons by Garrett Hardin was an influential article published in the journal Science in 1968. It is predominantly concerned with rising population and its impact on the environment. The article claims that global problems are often caused by one particular aspect of human behaviour: the individual placing their rights over those of the community, in other words it is an “every man for himself” attitude.

Garrett gives the example of cattle farmers overgrazing publicly owned pasture known as ‘the commons’ simply because there was no legal restriction to stop them. They all overgraze because the more grass for their cattle means more productivity and more profits. Of course, as the pasture is limited and none of the farmers will exercise restraint it soon becomes exhausted. Environmental issues that involve an abuse of a public resource (such as land, air, water or the oceans) resulting from this kind of attitude are referred now to as “commons problems”. The article by Bobbi Low deals with them .

Conservation Commons Problems

Low identifies two types of public resources

a) open access – owned by no-one and disappear quickly
b) commons – owned by a specific group and protected by outsiders

Two types of commons

a) Stiglerian - “benefits are concentrated but costs dispersed” (I presume it is named after the economist G. Stigler although this is not mentioned in the article – not very helpful). This is the case described by Garrett.
b) Olsonian – benefits are dispersed but costs concentrated – the author gives the example of a nuclear power plant located near a town. The country as a whole benefits from the electricity and are exposed to minimum risks, but the local residents around the power station suffer the ill effects. This is summed up as NIMBY or “not in my back yard”. (Again I don't know who the Olson of Olsonian is, Low does not give the reference).

Resources managed as commons for centuries and always involve cheating.
Cheating occurs because it’s profitable.

Solutions:
a) Local control.

The resource is often destroyed for short term profit.

b) Government control

Regulations are expensive and not always effective.


c) Private ownership

Only works if owners don’t want to sell to the highest bidder – i.e. “get mine and get out”


Characteristics of Successful Commons

a) Social & Political Characteristics

Small, cohesive, ‘kinship-based’ groups with stable membership

b) Ecological Characteristics

Subsistence based

c) Political Characteristics

Isolated from large markets

Costs of cheating in this case is more social if the individual is caught.

d) Organizational Conditions

- Clearly defined boundaries
- Collective choice arrangement – each member has a voice in decisions
- Monitor and catch cheats
- Graduated punishments – that is, the punishment reflects the severity of the offense
- Conflict –resolution mechanisms

Successful examples are often small areas and communities e.g. Swiss mountain villages, villages in Japan, irrigation communities in Philippines. Large scale commons such as affecting whaling are more difficult to manage due to:

· difficulties monitoring large areas
· difficulties keeping out outsiders


Solutions to large scale commons problems probably lie in communication and interaction with stake holders. The greater the communication the greater the chance that members will sanction cheats.



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