Perturbation of Ecological Systems

Dr. Debrah Fine

Ecology

• The study of how living things interact with each other and their non-living environment– From Greek “oikos,” meaning “home,” and “logy,”

meaning “knowledge.”

Lesson Overview

• I. Types of ecological interactions• II. Examples of human perturbation of

ecological systems– Australia– Hawaii– New Zealand

• III. What are humans doing now to perturb the ecosystem?

Types of Social Actions

Effect on organism 1

Effect on organism 2

Benefit Harm No Effect

Benefit Mutualism Predation or parasitism

Commensalism

Harm Predation or parasitism

Competition Amensalism

No Effect Commensalism Amensalism -

Lesson Overview

• I. Types of ecological interactions• II. Examples of human perturbation of

ecological systems– Australia– Hawaii– New Zealand

• III. What are humans doing now to perturb the ecosystem?

Rabbits in Australia

• In 1859, Thomas Austin imported and released 24 rabbits in Australia

• "The introduction of a few rabbits could do little harm and might provide a touch of home, in addition to a spot of hunting."

Population Surge

• Since there were few natural predators to rabbits in Australia, their population soared to an estimated 20 billion by the 1920’s

Why are rabbits such a nuisance?• Rabbits threaten native mammalian populations– Support fox and feral cat populations– Compete with similar sized native mammals for

shelter and food• Rabbits threaten native plants– Rabbits feed on seedlings and prevent regeneration

of native trees and shrubs

An Early Attempt at Containment

Myxoma Virus

Development of Resistance to Myxoma Virus

Resistant

Resistant

Hawaii: Mongoose

• Sugar cane farmers brought the mongoose to control the rat population

Hawaii: Mongoose

• No natural predators in Hawaii

Hawaii: Mongoose

• The mongoose did not control the rat population, but instead preys on native birds and bird eggs

New Zealand: Possum

• Possums were introduced in New Zealand to establish a fur trade

New Zealand: Possum

• No natural predators

New Zealand: Possum

• Spread bovine tuberculosis

• Damage crops and orchards

Lesson Overview

• I. Types of ecological interactions• II. Examples of human perturbation of

ecological systems– Australia– Hawaii– New Zealand

• III. What are humans doing now to perturb the ecosystem?

Humans and the Earth’s Ecosystem

Climate Change

Climate Change: What is a Greenhouse Gas?

A Map of the World

Population

Energy Consumption

Greenhouse Gas Emissions

What is a Carbon Footprint?

• Your carbon footprint is the sum of all emissions of CO2 (carbon dioxide), which were induced by your activities in a given time frame

Ways to Reduce Our Carbon Footprints

• Take public transportation, walk, ride a bicycle, carpool• Switch to bio-diesel or a hybrid car• Less air travel• Use energy efficient lightbulbs and appliances• Recycle and reuse stuff• Don’t be wasteful• Eat food grown locally• Eat less meat

– If your four-person family skips steak 1 day a week [for a year], it’s like taking your car off the road for almost 3 months