Conclusion

• Be sure you have clear justifiable objectives for control….not just because you think it will work!

• Be sure you have data on collateral effects from control efforts

• Be aware that you are embarking on a long term commitment.

• DON’T enter into it lightly!!

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Ok, it is justified

• How do you do it?• First is by manipulating mortality: killing them!• Humane considerations need to be taken into

account (often difficult to do). Even the most obviously deleterious species will have defenders.

• The worse thing to do is make a sport of it!

Your set to kill

• What should be the appropriate control strategy?

• Return to harvest strategies: the one that was most prone to overharvest?

• Fixed quota harvest!• Saw earlier that even if you have a stable

population, can remove enough to cause overharvesting.

That is what you want!

• You want to exceed the maximum sustained yield!

• Add to that the instability of populations, a fixed quota harvest, set to overharvest would provide the maximum control and could even cause the population to go extinct.

Again, trick is how many

• Because you can overharvest anywhere on the curve, setting the target kill then affects the time it takes to reach eradication.

Examples

• Setting the kill rate of feral goats in a New Zealand park at 90%, each year would lead to eradication in 12 years.

• If it was only 50% it would take 50 years!

Other factors?

• Again, easy to say we will kill certain number of animals/year but… as mentioned, the less there are, the harder they are to get!

• Adjust to hunting pressure• Adjust habitat to hard to get to places,• Adjust behavior: cows in Mexico.• Judas goats

Besides hunting them?• Poisons!• Whole storehouse of chemical poisons have been used

on “pest” species.• Most famous:• 1) Warfarin on rodents, blood thinner, literally bleed to

death.• Strychnine: used on wolves, coyotes, and anything else

that eat carrion.• 1080: Sodium fluoroacetate is an organic compound

and an organofluorine compound that is a well known metabolic poison. Tasteless and odorless, perfect!

• M-44 or Coyote getter: exploding device that expels cyanide into the mouth of the animal that bites it.

• Many others

Historic use

• Used indiscriminately, spread over 1,000s of km sq.

• Helped exterminate the wolf in the west.• Not so effective on coyotes!• Along with reducing populations of hundreds

of other species!• Many are persistent and animal that dies from

them will kill others that eat on them!

Current use

• Much more controlled, many banned• Still use M-44s for “target” operations• Needless to say more environmental

problems related to their use than any benefits.

Besides hunting or poisoning them?

• Biological controls• Effective against insects but less so against

vertebrate wildlife.• Showcase is Myxoma against rabbits in

Australia.• Still not 100 %, rabbits developed immunity

and Myxoma reduced virulence (not evolutionarily advantageous to kill ALL your hosts! About 20% of previous highs.

Other forms?

• So finding a biological agent is not so great but…

• If you can’t augment mortality, try the other end and reduce natality!

• Controlling fertility• One way is to introduce sterile males!• Screwworms in southeast US.

Flood the market!

• Flood the market with sterile males and females (if they only mate once) will not be successfully inseminated.

• Again, useful for insects but more problematic for vertebrate pests!

• Unless you can sterilize them at a distance, e.g. chemicals OR use contraceptives.

But… can they be effective?

• List of 17 characteristics of an ideal chemosterilant program for rodents!

• Highlights• Orally effective and at low doses• Permanent or long-lasting and effective both

sexes• At least genus specific and inexpensive• Highly palatable and biodegradable

More!

• No acquired tolerance or genetic resistance!• Humane: no stressful symptoms• Sufficiently stable• NOT translocated into plants, especially

crops!!• Is it possible???• Do we want to go this route???

Is it possible?

• A lot depends on breeding systems of species.• Usually will not be controlled by action against

only males.• If breeding by dominant female suppresses

subordinate females, sterilization programs could actually INCREASE productivity unless you sterilize a sufficient number.

• Even without breeding system considerations, often reduced litter production can result in increased fertility of the females that are not sterilized or receive the contraceptive!

• In rabbits in Australia, female sterility had to reach 80% or more for a decline to occur!

• Last note: again, long term commitment unless you can cause extinction!

Others?

• Immunocontraception• Causing an increase in antibodies that hinder

reproductive processes.• Has been used in elephants, horses, white-

tailed deer, and seals.

• Must be injected and often more than once in less than one year, and repeated yearly!

Effectiveness?

• Obviously only on small populations that are easy to catch!

• Other: genetic engineering!• Tie a gene that can disrupt reproduction to a

low virulent virus (e.g. Myxoma for rabbits).• Problems with this!!!

Other than killing them or reducing reproduction?

• Indirect methods:• 1)Exclusions: fences (Farmer Brown and Peter

Rabbit!), chemical repellents• Can be small scale or large: Australia built a

dingo proof fence spanning 8614 km!!• Keeps out other species too!!• Environmental costs high.

More?

• Sonic deterrents: alarm calls, ultrasonic sounds, etc

- Unfortunately, not very effective

• Habitat and food manipulation - found could reduce red squirrel damage on young

pines by air dropping sun flower seeds!- Other examples: some have been effective, others

not so. Mixed results.

Summary

• Control operations rarely meet the necessary criteria

• 1) when benefits exceed the costs• 2) when “pest” species is in fact the cause of

the perceived problem• 3) when control has an acceptable impact on

non-target species.

Summary

• Most clearly justifiable for exotic species• Less so for natives: Often are not pests in that

there are a lot of them, perceived as such because using a resource we want.

• Should we be disrupting ecosystem structure: reducing predators, or medium to small mammals .

Summary

• Control methods far from species specific and usually a lot of collateral damage is done.

• Lastly…• Considering managing and controlling wildlife

species we have to ask ourselves….

Is this the way it should be?

• If all we want is to “ranch” a single species, ok.• Lets manage them like cattle and control their

predators/competitors• But is that all we want?• Is that what is good for the ecosystems that

support these desired species?

What should our management goals be?

• Sacrificing keystone species and ecosystem health for one single focused use of the ecosystem.

• Remember it is the intact ecosystem that best supports the species we desire: Alaska/Africa

• Not saying we should discontinue hunting, just that it should not be the only focus in resource management.

Original views

• America has always used the utilization of natural resources, in this case wildlife, as the focus of its resource management

• But is one species management the only vision America had?

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Remember

• Started with a point in time: concern about our wildlife resources, theoretically could have gone in an infinite number of different directions.

• What other directions were there??• Return to history

Return to the past

• Said concern started with Massive abuses of natural resources

• Concern grew from this and led to 3 different perspectives on how to manage resources.

A look at the past

• Resource Conservation Ethic. - resources to be used but just need to control

the use.• Romantic Transcendental Conservation Ethic - Nature has other uses than just economic gain. - Advocated protection of large pristine areas

A look at the past

• Evolutionary-ecological land ethic - based on ecological awareness - Nature more than collection of parts - cannot discard some based on usefulness - Also, not a temple to be worshipped

A look at the past

• Evolutionary-ecological land ethic -Complicated, interconnected, functional - result of long term evolutionary change - We can use the system but not alter basic structure

A look at the past

• Which of the three dominated?

• Resource conservation ethic most attuned with growing country and economy.

• No Brainer!!• This is what we have been talking about.• Still believe nature was to be used, just not

abused, sort of….

A look at the past

• Tried to use what we wanted wisely

• Still discarded what we did not want or need.• Time when we eliminated wolves from lower

48• “range management” use for cows

A look at the past

• Extraction not only function of ecosystems

• Other aesthetic, non extracting recreational, supportive roles.

• We needed clean water, air, recreational areas, open spaces, wilderness.

• Survival depended on functioning ecosystems.

A look at the past

• This awakening a mixture of the two ethics:

• Romantic-conservation- save for inherent value

Evolutionary-ecological – we need all the parts!

A look at the past

• Started talking about ecosystem integrity, biodiversity, keystone species, etc.

• Saw natural systems as dynamic entities where change essential part of system

• Changed from managing elements of the system to managing processes.

-fire management rather than fire suppression.

Today

• All the past laid the foundation for the next logical step:

• Ecosystem Management as opposed to resource management

Ecosystem management

• What is it

• Not as easy as it may seem. Books give no less than 14 definitions!!!

• Here are some of them.

“Ecosystem management is not just about science nor is it simply an extension of traditional resource management; it offers a fundamental reframing of how humans may work with nature”

Ecosystem management integrates scientific knowledge of ecological relationships within a complex sociopolitical and values framework toward the general goal of protecting native ecosystem integrity over the long term

R. E. Grumbine

Ecosystem management is a concept of natural resources management wherein national forest activities are considered within the context of economic, ecological, and social interactions within a defined area or region over both short and long term

An Assessment of Forest Ecosystem Health in the Southwest

Ecosystem approach = promoting ecological integrity while allowing human use on a sustainable basis

S. L. Yaffee

Another

• Approach to maintaining or restoring the composition, structure, and function of natural and modified ecosystems for long term sustainability

• Based on Collaboratively developed vision of the desired future conditions, integrating ecological, socioeconomic , and institutional perspectives

• Applied in geographical framework defined by natural ecological boundaries.

Common factors

• Large scale• System wide perspectives• Emphasis on composition and processes• Integration across various spatial temporal

scales• Participation of stakeholders/consensus

decision making.

Dominant Themes in Ecosystem Management

• Adaptive management

• Goals set by human values

• Hierarchical context• Recognition of

ecological boundaries

• Ecological integrity

• Research anddata collection

• Monitoring

• Interagency cooperation

• Organizational change

• Humans as ecosystem

components

What are these things?

• These are the “parts” necessary for an ecosystem management plan.

• Structural framework, not just definition but a visual image of what it is.

• But what are its goals?

Fundamental Goals of Ecosystem Management

• To mange ecosystems so as to

assure sustainability

• To maintain ecological integrity of the

system (i.e., healthy ecosystems)

Sustainability

• Maintenance of the potential of ecosystems to produce the same quantity and quality of goods and services in perpetuity

Ecosystem Goods and Services

Ecosystem “goods”

• Food

• Construction materials

• Medicinal plants

• Wild genes for domestic plants and animals

• Tourism and recreation

Ecosystem Services

• Maintaining hydrological cycles

• Regulating climate• Cleansing water and air

•Pollinating crops and other impt. plants

• Generating and maintaining soils

• Storing and cycling essential nutrients

• Absorbing and detoxifying pollutants

• Provide beauty, inspiration and research

Guiding Principles for Sustainability

Must maintain the physical and biological elements of productivity including:

1. No net loss of productivity

2. No accelerate loss of genetic potential

Fundamental Goals of Ecosystem Management

• To mange ecosystems so as to assure sustainability

• To maintain ecological integrity of the system (i.e., healthy ecosystems)

How to Maintain Ecological Integrity

• Accommodate human use

• Maintain viable populations

• Ecosystem representation

• Maintain ecological processes

• Protect evolutionary potential

Terminology

• Resilience

• Biotic Integrity

• Adaptive Management

• Disturbance

• Indicators

How do we do it?

• Integration of ecological understanding and socioeconomic perspectives and values

• Attempt to reconcile human interests and needs with natural resource protection.

Conflict common!

• Resolution requires perspectives from:

1) Ecologists2) Diverse interest groups3) Government agencies.

Three components

• Ecological.

• Socioeconomic.

• Institutional.

Three arenas in which we need to work.

Three Contexts

• Different view points

• Different possession of fact.

• Different capacities to pursue or prohibit actions.

Three context model

• Core of ecosystem management structure

• Simple obvious solutions not universal

• Challenge to blend perspectives.

Visual conception

• Circles representing each• Overlap in 4 areas. A, B,C,D.• Gives us idea of how each interact.

Zone A: Regulatory authority

• Ecologists feed info to agencies• Policy made based on info.• Legal right to do so.• Typical structure in past.

Zone B: social obligations.

• Socioeconomic and Institutional.• No ecology• Socioeconomic responsibilities of agencies.- Equal opportunities, etc.

Zone C: Zone of influence.

• People via groups influence• Informal, interpersonal relationships• Trout Unlimited, Nature Conservancy.• Voluntary, private lands.

Ecosystem management stresses

-Partnerships of all stake holders

-Conflict low if knowledge high

-Conflict high if knowledge low.

-Adaptive management.

• So, need considerations on various levels

• Last three lectures on three different considerations of ecosystem management

• 1) biological: populations• 2) institutional: adaptive management• 3) society: the human dimension

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