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Unit 3 Environmental Science Area of Study 2: Diversity in the Biosphere


Unit 3 Environmental Science Area of Study 2: Diversity in the Biosphere Assessment of biodiversity Measuring the species richness or diversity of a particular area ... – PowerPoint PPT presentation

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Title: Unit 3 Environmental Science Area of Study 2: Diversity in the Biosphere

Unit 3 Environmental ScienceArea of Study 2
Diversity in the Biosphere
Overview of presentation
  • How to prepare for the exam
  • The format of the midyear exam
  • How to respond in the mid-year exam
  • Content to cover for Area of Study 2 Diversity
    in the Biosphere

How to prepare for the midyear exam
  • Summarise notes
  • study design
  • text
  • class notes
  • SACs
  • Age article http//education.theage.com.au/cmspag
  • glossary of terms
  • Past exam papers 2005 onwards
  • VAEE trial exams
  • Prepare what to take to exam pen, grey lead
    pencils, eraser, pens, scientific calculator

Term Definition
Analyse Break down something to its components and work out how it operates
Assess Make a judgement about or measure an outcome or value
Classify Place in an appropriate category/group
Compare Describe the similarities and differences
Contrast Describe the differences
Define State the meaning or identify the essential qualities of a term
Demonstrate Show by using examples
Describe Give an account of what something is like
Discuss Examine something by sifting through the information, showing both sides of an argument/issue or the advantages and disadvantages of a particular solution
Evaluate Judge something - weigh up the advantages and disadvantages of something, or measure its value or worth judge whether, on balance, there are more pros or cons
Examine Similar to discuss sift through the issue and describe the different sides of an issue in some detail
Explain Provide a reason why/how something is as it is
Identify Briefly name or state the feature, factor or component
Interpret Translate the meaning or implications within data or text
Outline Summarize the main points/elements
Predict Suggest what may happen in a given scenario/situation
Quantify Use a numerical measure
Recommend State what you think is the best option/alternative in a given situation
State A brief answer in response to a given situation
Suggest Present an hypothesis or make a proposition
The format of the midyear exam
  • The exam totals 90 marks.
  • There will be a Question and Answer Book
    consisting of two sections Section A is the
    multiple choice section and is worth 20/90 marks,
    and Section B has short answer questions and is
    worth 70/90 of the marks.
  • There is a separate answer sheet for the multiple
    choice questions .
  •  The mid-year examination will contribute 33 to
    the Study Score for Unit 3 Unit 3 SACs
    contribute 17.
  • No marks are deducted for wrong answers.

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How to respond in the midyear exam
  • Use the reading time to read through the
    questions carefully and have a good look at the
    data provided.
  • Read the question carefully all the way through
  • Stop and think before you write - plan
  • Tailor your response to the scenario that has
    been posed refer to details of this scenario in
    your response
  • Ensure you have met all the requirements of the
  • Be concise use dot points and do not rewrite the
  • Show all your workings for questions that require
  • If you are asked to give a specific number of
    responses, give the number requested
  • If you are asked to evaluate or give an opinion,
    be decisive
  • Back up your contention with facts and figures
  • Watch the time 90 marks in 90 minutes

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

  • Biodiversity is the variety of living organisms
    plants, animals and microorganisms in a
    particular area, country, ecosystem or on Earth.
  • It includes the variety of species, the variety
    within species, and the variety of different
    habitats and ecosystems within a region.

  • The diversity of species on earth has changed
    over time.
  • New species have evolved in response to changes
    in the environment and some species have become

  • Evolution, migration and extinctions have
    occurred throughout time.

The rate of species loss has increased in
historic times, a phenomenon known as accelerated
extinction. Current rates of loss are 100 1000
times the historic background levels. (UN
meeting on Convention on Biological Diversity,
Processes that allow evolutionary change
  • mutation
  • migration
  • natural selectionSelection for a particular,
    advantageous trait, which then affects the genes
    passed onto the next generation
  • genetic drift
  • Random events, that affect the proportion of
    individuals with a particular trait passing on
    their genes to the next generation, is known as
    genetic drift.

Species and population
  • A species is the most definitive classification
    level or taxon (or group of organisms) that are
    genetically so similar that they can interbreed
    and reproduce fertile offspring.
  • A population is a group of individuals of a
    particular species which share a particular
    habitat in a particular area.

Habitat and range
A habitat is the type of environment the taxon is
adapted to. It may be an area with a very
specific environment, or the taxon may have a
very general habitat.
A range is the location of its geographic area of
habitat inhabited by a taxon. It may be
continuous, or populations of the species may be
isolated or separate but interacting, so forming
a metapopulation. A small area of native
vegetation is deemed a remnant.
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A population
  • Where populations are isolated from each other,
    there is no gene flow between the two
  • Over time, the genotype of different populations
    diverge and they may eventually form a subspecies
    or a new species.

An ecosystem
  • An ecosystem is a community of interdependent
    species of plants, animals and microorganisms
    (the biotic component) occupying a certain area,
    together with the soil and other abiotic
    components of the environment.

An ecosystem

The diversity of abiotic features on Earth has
lead to the development of many different types
of ecosystem. Within each ecosystem is a
diversity of habitats.
An ecosystem
  • Within an ecosystem there is a complex web of
    relationships between different species and with
    their physical environment.
  • Each species has its particular niche.
  • A community is a set of populations of plants
    and animals living and closely interacting in a
    common habitat over a shared range.

An ecosystem
  • A trophic level consists of all the species of
    that ecosystem that compete for food.

An ecosystem
  • Relationships between individuals of different
    species can be
  • competition
  • predation
  • symbiosis live together on an intimate
  • - parasitism parasite benefits, but
    detrimental to the host
  • - commensalism one benefits other no harm or
  • - mutualism both benefit

The sea anemone benefits from the clownfish
because it can feed on scraps of food left by the
clownfish. The clownfish benefits by being
protected from predators by the stinging cells in
the anemones tentacles. The mucus coating on the
clown fishs skin contains a chemical inhibitor
that prevents the discharge of stinging cells in
the tentacles
  • The small remora fish scavenges on leftover bits
    of food after the reef shark has fed. The shark
    is neither helped nor harmed by the presence of
    these fish

  • The host is a reef fish. The tick-like creatures
    called isopods attach to the hosts skin and
    gills and obtain their nutrients from the fishs
    blood. A isopods only survive while they are
    attached to the reef fish or until the reef fish

Types of biodiversity
  • There are three types of biodiversity
  • species diversity
  • genetic diversity
  • ecosystem diversity

Species diversity
Species diversity is the variety of species in a
particular ecosystem or area. Species diversity
is the number of species in an area, that is the
species richness, and the abundance of each

Species diversity
  • Rarity
  • Three components can contribute to the rarity of
    a species
  • very low population density or small population
  • restricted geographic range
  • a highly specific habitat requires a narrow set
    of ecological requirements to survive
  • A species only needs to display one of these
    characteristics to be considered rare.
  • Endemism
  • Endemic species are restricted to one particular
  • Regions of the world with particularly high
    levels of biodiversity are called biodiversity
    hot spots.

Genetic diversity
  • Genetic diversity is the range of genetic
    material contained in the alleles of a taxon or
    ecosystem. It usually refers to variation in
    genetic information between individuals of the
    same population or species, but can also be used
    to refer to the genetic diversity between related
  • Because it is difficult to measure the genetic
    variation of a taxon, appearance (phenotype)
    rather than their genes (genotype) is often used
    to measure genetic diversity.
  • These happy face spiders (Theridion grallator)
    look different, but since they can interbreed
    they are considered the same species.

Genetic diversity
  • Genetic diversity plays an important role in
    adaptability and survival of a population or
    species. Populations that have very little
    genetic variation are at a great risk.
  • The sources of genetic variation are
  • mutations
  • variations in habitat eg a mosaic of different
    aged vegetation.
  • gene flow the movement of genes from one
    population to another.
  • sexual reproduction this
  • genetic shuffling is an important source
  • of genetic variation.

Ecosystem diversity

Ecosystem diversity refers to the variety of
different habitats and ecosystems within a given
2010 exam
  • Q.14
  • The Southern Bent-wing Bat roosts and breeds
    only in caves and mineshafts in southeastern
    South Australia and southwestern Victoria.
  • This means that the species
  • a. has a wide variety of habitats.
  • b. is at risk of genetic swamping.
  • c. is endemic to this region of Australia.
  • d. needs demographic variation to occur to
    maintain population size.

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

Importance of preserving biodiversity
  • Benefits for humans
  • biological resource
  • ecosystem services
  • social benefits

Importance of preserving biodiversity
  • A species may be a potential biological resource
    in the future or for future generations, such as
  • food
  • medicines and pharmaceuticals
  • fibres or other materials
  • ornamental plants and pets
  • breeding stock for use in agriculture.

Biological resources
  • Rubber is from the latex tree, linen from flax,
    rope from hemp, cotton from cotton, wool from
    sheep and goats, silk from silkworms. Honey,
    beeswax, rattan, wicker, bamboo, timber,
    perfumes, spices and herbs are all from plants
    and animals
  • Approximately 20 of prescription drugs are
    derived from plants.
  • The venom of certain snakes is the basis for
    substances which enables blood clots to form

Wheat, maize and rice supply one half of the
worlds food, and 90 of the world's food is
derived from only 15 species of plants out of
80,000 potentially edible plants
Ecosystem services
  • Ecosystem services ecosystems provide humans
    with many natural services including
  • energy transfers
  • waste treatment
  • clean air and water
  • climate stability
  • soil formation and maintenance
  • pollination or seed dispersal
  • natural predators of pest species
  • the cycling of nutrients, minerals and gases.

Ecosystem services
Leguminous plants, such as clover, lupines and
alfalfa, have a symbiotic relationship with
Rhizobia bacteria in the nodules in their root
systems. This allows these plants to fix
nitrogen from the atmosphere and release this
essential element to other plants when it dies
and decays in the soil.
Social benefits of biodiversity
  • Social benefits educational, scientific,
    cultural, spiritual, aesthetic, tourist and
    recreational value.

Social benefits of biodiversity
Many native species are a part of our cultural
heritage and an important source of tourism.
Tourism from the Great Barrier Reef contributes
over 800 million per annum, which is additional
to its value for commercial fisheries.
Benefits of biodiversity to humans
  • Estimates of various benefits of biodiversity to
    humans (US trillion)
  • Soil formation 17.1
  • Recreation 3.0
  • Nutrient cycling 2.3
  • Water regulation and supply 2.3
  • Climate regulation (temperature and
    precipitation) 1.8
  • Habitat 1.4
  • Flood and storm protection 1.1
  • Food and raw materials production 0.8
  • Genetic resources 0.8
  • Atmospheric gas balance 0.7
  • Pollination 0.4
  • All other services 1.6
  • Total value of biodiversity benefits to humans
    US 33.3 trillion
  • source Adapted from R. Costanza et al., The
    Value of the Worlds Ecosystem Services and
    Natural Capital, Nature, Vol. 387 (1997), p.

2008 exam
  • Q 5e
  • Discuss the reasons for maintaining biodiversity
    in our world for human health and wellbeing.
    Include some examples in your answer. (4 marks)

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

Threats to biodiversity
  • Biodiversity can be reduced through
  • habitat destruction or modification
  • introduced species
  • over-exploitation of biological resources
  • economic and scientific threats to genetic
  • the flow-on effect of changes to other species
    within the ecosystem
  • reduced population size

Habitat destruction or modification
  • Habitat destruction and modification may
    precipitates the loss of species which are form
    and depend upon that habitat
  • habitat destruction resulting from clearing of
    natural habitat for agriculture, urbanisation or
    other landuse.
  • degradation results from the deterioration of the
    quality of the habitat due to pollution, erosion,
    salinity or over-use.
  • habitat change resulting from events such as
    change in fire regime, extreme weather events,
    tectonic activity and climate change.
  • fragmentation of the habitat, where the clearance
    of pockets of vegetation leave a series of
    fragments of intact habitat. If the pockets of
    remnant vegetation are isolated and too small to
    support viable populations of species, or if the
    fragments are not connected, the impact can be

Habitat destruction or modification
  • Deforestation and increased road-building in the
    Amazon rainforest are a significant concern
    because of increased human encroachment upon wild

Introduced species
  • An introduced, or exotic species is one which
    has been deliberately or accidentally imported
    into a region.
  • These species may become a pest or weed to
    indigenous species by
  • occupying the same niche as an indigenous species
    within the ecosystem, competing for resources
    such as food or space
  • preying on indigenous species within the
  • poisonous to indigenous species
  • degrading or modifying the habitat to the
    detriment of the indigenous species.

Over-exploitation of biological resources
  • Over-exploitation results from harvesting
    biological resources at an unsustainable rate.
  • Some examples of species which have been
    over-exploited include
  • the deforestation of land in the Amazon forest
    for timber and agricultural land
  • harvesting whales for their meat and oil
  • slaughtering seals for their furs and oil
  • hunting elephants and for the ivory in their
  • hunting rhinoceros for the use of their horn for
    to produce aphrodisiacs
  • over-fishing of Atlantic salmon as a source of
  • felling the trees of Easter Island by the
    original inhabitants to transport their carved
    status to the coastline

Economic and scientific threats to genetic
  • The manipulation of species commonly used by
    humans through crop breeding, animal husbandry
    and genetic modification have developed
    domesticated species and hybrids which are quite
    different genetically from their original, wild
    ancestors, and has created a much narrower gene
    pool. This has lead to the loss of some genetic
    diversity and lowered resilience to threats, such
    as diseases, plagues and extreme weather events.
  • Today, 80 of our food is sources from 20 kinds
    of plants worldwide, and much of our meat is
    sources from a few species of animal.
  • eg the Irish potato famine of 1847, where the
    potato blight wiped out virtually all potato
    crops in Ireland, as they were bred from a very
    small number of ancestor plants (brought back
    from the Americas) that did not have resistance
    to this disease.

The flow-on effect of changes to other species
within the ecosystem
  • Because species within an ecosystem are
    interdependent, loss or weakening of one species
    can have a flow on effect upon the other species
    it interacts with.
  • This could be the impact of the loss or
    weakening of a species which
  • is a food source
  • provides a vital component to the niche habitat
  • assists with a plants pollination or seed
  • is a predator, competitor or has a symbiotic
    relationship with the species.

Reduced population size
Threats may not lead to the extinction of
species, but may significantly reduce population
size. This in itself becomes a threat as the
population becomes vulnerability to a cascade of
genetic, demographic and environmental factors.
  • All the animals shown above suffer from low
    population size. Scientists estimate that about
    1000 Kemps Ridley sea turtles (left), 300 right
    whales (centre) and 65 northern hairy-nosed
    wombats (right) survive in the wild.

Reduced population size
  • Very small populations pose a number of dangers
  • greater vulnerability to genetic drift
  • inbreeding depression
  • low genetic variation, because the gene pool is
    greatly reduced
  • possibility of genetic swamping
  • demographic variation

Vulnerability to genetic drift
  • Small populations are more susceptible to
    genetic drift, that is, that random chance events
    will reduce the frequency of particular alleles,
    which could be alleles for characteristics which
    confer an advantage to the next generation.

Inbreeding depression
  • In any population there may be alleles for a
    deleterious trait. In a large population, there
    is a low probability an individual will wind up
    with both alleles for the deleterious trait. In a
    small population, where mating between two
    individuals with similar genotype is inevitable,
    there is a greater chance an individual will have
    two alleles for such a trait, and that that
    disadvantageous trait will be expressed.
  • Inbreeding over a number of generations can lead
    to the genetic weakening of the population at a
    whole, a phenomenon called inbreeding depression.

A small number of adders (Vipera berus)
experienced inbreeding depression when farming
activities in Sweden isolated them from other
adder populations. Higher proportions of
stillborn and deformed offspring were born in the
isolated population than in the larger
populations. When researchers introduced adders
from other populations - an example of
outbreeding - the isolated population recovered
and produced a higher proportion of viable
Low Genetic Variation
  • Genetic variation allows species to adapt and
    evolve in response to changing environmental
    conditions. For example, if a population is
    exposed to a new disease, natural selection will
    confer advantage to individuals with genes for
    resistance to the disease - if they exist in the
  • Cheetah (left) populations have low amounts of
    genetic variation, while lion (right) populations
    typically have higher amounts. The lion in more
    likely to be resilient to any threats.
  • In a small population there will be less genetic

Low Genetic Variation
  • As an endangered species dwindles, it loses
    genetic variation - and even if the species
    rebounds, its level of genetic variation will
    not. Genetic variation will only slowly be
    restored through the accumulation of mutations,
    migration and genetic shuffling over many
  • For this reason, an endangered species with low
    genetic variation may risk extinction long after
    its population size has recovered.

Genetic swamping
  • If two isolated populations of a species are
    reunited through a habitat change or
    reintroduction program, the genetic diversity of
    the smaller population may be lost in the
    process. This is genetic swamping, where the
    event may lead to the dilution or loss of
    potentially advantageous alleles it contained.

Demographic variation
  • In any population there is natural variation in
    population dynamics the birth rates, death
    rates, sex ratio, migration etc. Normally, this
    does not have a significant impact on the long
    term viability of the population as a whole, but
    where the population is very small, this natural
    demographic variation can have deleterious
    effects on the whole population.
  • eg a species of bird may vary in the number of
    eggs laid in the breeding system. If the
    population reaches very small numbers and then
    has a year where the number of eggs laid is
    within its normal variability, but at its lowest
    value within that range, its risk of extinction
    may rise.

2008 exam
  • Q 14. Two previously isolated populations of a
    particular species come into contact and breed
    with each other. One of the populations is much
    larger than the other.
  • A potential consequence for the smaller
    population may be
  • a. genetic drift
  • b. genetic swamping
  • c. inbreeding
  • d. demographic variation

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

Assessment of biodiversity
  • Measuring the species richness or diversity of a
    particular area is usually done by surveys and
    monitoring by
  • counting the species and numbers of individuals
  • sight and count individuals eg spotlighting
  • capture (and possibly tag) and release the
  • electronic surveillance
  • indirect evidence of the species, eg scats,
  • recordings of sightings by field naturalists
  • assessing of randomly selected sample quadrats or
  • species present
  • relative abundance
  • Other aspects may also be investigated weight,
    health, signs of breeding.
  • Genetic diversity can be conducted through
    genetic research, or from observing variation on

Assessment of biodiversity
  • This data can then be used to assess
  • The numerical methods for measuring biodiversity
  • species richness the number of species in a
    region the more species, the greater the
    richness. Does not take into account of the
    number of individuals of each species present.
  • species diversity the number of different
    species and the number of individuals of each
    species (ie each species relative abundance)
  • species evenness the degree of similarity of
    population size for each of the species the more
    similar the abundance of each species the greater
    the evenness. A higher level of biodiversity
    exists when species of similar trophic levels
    have high species evenness.
  • endemism the number of endemic species (that
    only occur in one region)
  • rarity the number of rare species.

Assessment of biodiversity
  • Two indices which are commonly used to measure
    the species diversity of a region
  • Simpsons Diversity Index (D) index which takes
    into account the species richness and the
    abundance of each species.
  • Shannon-Weiner Diversity Index (H) index which
    takes into account species richness and abundance
    of each species within a habitat, but is
    increased by having high species evenness
  • Other indices can be created to measure species
  • You will be given the formula for index in exam.

Assessment of biodiversity
  • In measuring biodiversity, it is common to
    collect two or more sets of data for comparison
    or change over time.
  • 2010 exam

Assessment of biodiversity
  • But there is natural variability in the data
    collected within an ecosystems because
  • variation over space the natural and random
    variation in the distribution of species within
    its range
  • variation over time eg diurnal changes,
    seasonal changes, lunar and tidal movements,
    breeding periods etc
  • demographic variations natural variations in
    birth rate, death rate, sex ratio.
  • Because ecological systems show a high level of
    natural variability it is necessary to determine
    whether there is a significant difference or
    change between two sets of data.

Statistical analysis can be used to determine
whether there has been significant difference or
change. This can be achieved by checking if the
difference or change falls within the known level
of variation.
Assessment of biodiversity
  • The more data, the more reliable the analysis.

2006 exam
  • Q10 Species diversity is best measured by
  • a. the total number of species
  • b. the total number of individuals
  • c. the number of species and the relative
    abundance of each
  • d. the number of different ecosystems available
    in the habitat
  • Q 11 Genetic diversity in best assessed by
  • a. small variations within a species
  • b. the risk of extinction of the species
  • c. the relative abundance of the species
  • d. the number of different species in the

2006 exam
  • Q 16. A scientist monitors a population of
    possums for six years.
  • Which conclusion best supports the above data
  • a. The population is stable
  • b. The population is steadily increasing
  • c. An exotic competitor was removed in 2002
  • d. A predator was introduced into the habitat
    in 2003.

Year 2000 2001 2002 2003 2004 2005
Population 44 42 45 40 43 44

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

Conservation of biodiversity
  • Preservation protect the biosphere in its
    natural state.
  • (Ecologically) sustainable development the use
    of biological resources in a way and at a rate
    that does not limit its availability to future
    generations (ie intergenerational equity).
  • Precautionary principle where there is a threat
    of serious or irreversible damage to the
    environment by a proposed activity, the lack of
    full scientific certainty about the possible
    impacts should not be used as a reason to

Conservation of biodiversity
  • When planning conservation strategies,
    biodiversity needs to be considered at the
  • gene level
  • population level
  • species level
  • ecosystem or habitat level
  • The most effective conservation occurs when all
    are considered together.

Conservation of biodiversity
  • Methods of managing biodiversity include
  • risk assessment evaluating the level of threat
    the species, population or ecosystem is exposed
  • evaluating the risk of potential developments
  • protecting individual species or specific
    populations of a species
  • maintaining or rehabilitating the habitat
  • pest control
  • relocation and reintroduction programs
  • sustainable use of biological resources

Risk assessment
  • Risk of extinction (ER) involves the use of data
    to determine either
  • the probability of extinction of the species for
    a given period,
  • eg ER 80 (0.8) in the next 10 years.
  • the carrying capacity of the habitat and how a
    known amount of habitat loss is likely to impact
    upon population numbers within a given period,
    ie ER 10 (or 0.1) in next 5 years if scenario x
  • Risk of extinction requires the following data
  • demographic data on the species
  • current population numbers and the rate of
    population loss
  • the amount of habitat area (territory) required
    by each individual of the species
  • the amount of remaining habitat and its quality.
  • Risk assessment can also be determined by
    ascertaining the minimum viable population
    required for the species to survive.

2010 exam
  • Q. 13
  • The probability (calculated risk) of extinction
    of this Southern Bent-wing Bat population over
    the next fifteen years is estimated to be 0.70. A
    larger population in a second separate cave
    system has a probability of extinction estimated
    to be 0.20 over the same period.
  • Which of the following best gives the
    probability of extinction of both populations in
    the next fifteen years?
  • a. 0.14
  • b. 0.27
  • c. 0.50
  • d. 0.97

Risk assessment
  • Population Viability Analysis (PVA) is a tool
    used to assist in determining the level of risk
    and the appropriate management strategies to
    conserve a species or population.
  • It uses computer-based ecological modelling and
    the information used in risk assessment.
  • It uses this information to predict the likely
    outcome, for the species or population, of
    various scenario, and
  • ranks the management options available, and
  • identifies where further research is needed.

2005 exam
  • Q.4e
  • Outline a scientific process for evaluating the
    threats to the species.
  • (1 mark)
  • Population Viability Analysis (PVA)
  • Risk of extinction (ER)

Risk assessment
  • Assigning conservation status classifies the
    level of risk confronting a taxon.
  • The International Union for the Conservation of
    Nature (IUCN) has devised a system to award
    conservation status redlist.
  • The criteria used include
  • the population size and the observed population
    change over time
  • the total number of mature adults
  • the extent of the species range (geographic
  • the probability of extinction in the wild over a
    designated number of years or generations.
  • Commonwealth and state government use a similar
    process to assign conservation status.

conservation status definition risk of extinction
Extinct no reasonable doubt the last individual has died
Extinct in wild survives only in cultivation or captivity or naturalised community
Critically endangered extreme high risk of extinction in the wild in the immediate future ER 50 within 10 years or 3 generations
Endangered very high risk of extinction in the wild in the near future ER 20 within 20 years or 5 generations
Vulnerable high risk of extinction in the wild in the medium-term future ER 10 within 100 years
Conservation dependent part of a conservation program, the cessation of which would result in the taxon moving into one of the above categories
Data deficient
Low risk
Not evaluated
2007 exam
  • Q 17
  • In Victoria, the conservation status of the
    Striped Legless Lizard is endangered, while the
    Swamp Skink is regarded as vulnerable
  • This means the Striped Legless Lizard
  • a. is in competition with the Swamp Skink
  • b. will survive for longer than the Swamp Skink
  • c. has a population size smaller than the Swamp
  • d. is at greater risk of extinction than the
    Swamp Skink

Evaluating the risk of potential developments
  • Environmental Impact Assessment (EIA) is the
    assessment of environmental impact of a major
    development before it proceeds. It is an example
    of the precautionary principle in action.
  • It may not prevent development from proceeding,
    even if environmental degradation is predicted to
    occur, if the potential social and economic or
    other environmental benefits are deemed to
    outweigh the potential losses.
  • An EIA involves
  • synthesis of existing information on native
    species and the region
  • additional research conducted by experts
  • considers alternative designs and locations
  • includes risk assessment techniques
  • allows for community consultation and input
  • arranges for ongoing monitoring if the project
    does proceed
  • attempts to balance environmental, social and
    economic considerations.

Evaluating the risk of potential developments
  • An EIA is required when the proposal
  • requires the clearing over 10ha of native
  • is deemed to be likely to affect endangered
  • is proposed for a region of high conservation
  • is not authorised under any existing forest
    management plan
  • may eventually involve the loss of significant
    proportion of an species habitat
  • is located within a wetland listed under the
    Ramsar Convention
  • may have an extensive or major impact on an
    aquatic, estuarine or marine ecosystem
  • may have an extensive or major impact on human
  • has potential carbon emissions exceeding 200 000

Protecting individual species or specific
populations of a species
  • International level
  • Convention on International Trade in Endangered
    Species of Wild Fauna and Flora (CITES) 1992
  • Ensures that the international trade in
    biological resources does not pose a threat or
    contribute to the decline or possible extinction
    of any species
  • Ramsar Convention 1983
  • Conservation of wetland habitats and paths used
    by migratory birds
  • Convention on Biological Diversity 1992
  • National level
  • National Strategy for the Conservation of
    Australias Biological Diversity 1996
  • Environmental Protection and Biodiversity
    Conservation Act 1999
  • State level
  • Victorian Flora and Fauna Guarantee Act 1988
  • Provides legal protection and a Recovery Plan
    for species and ecosystems which have been
    identified as being threatened.

Flora Fauna Guarantee Act (1988)
  • It involves a process of investigation and
  • If a species is found to be in need to
    protection, it is listed as threatened and an
    Action Statement is produced which
  • identifies threats to the species and designates
    its conservation status
  • confers legal protection for the species
    authorities must prosecute those who injure or
    cause the loss of individuals of the species
  • establishes a management plan (Recovery Plan) for
    its conservation
  • assigns responsibility to government agencies and
  • establishes ongoing monitoring
  • arranges for review of their status from time to
  • Members of the public, including experts, can
    nominate a species or Victorian population they
    believe is at risk of extinction.

Protecting and rehabilitating habitat
  • Conservation reserves national parks,
    conservation reserves, multi-use reserves
  • Reducing vegetation clearance
  • Habitat rehabilitation revegetation, replanting,
    erosion repair, address contamination and
  • Habitat maintenance prevention of degradation
    control burning to produce a mosaic of different
    aged habitats, fencing to obstruct pests, erosion
    prevention, etc
  • Creating or preserving wildlife corridors which
    link fragments of remnant vegetation
  • promoting gene flow and genetic diversity
  • the ability for individuals to migrate in
    response to environmental change

Pest control
  • The control of pest animals, weeds or diseases
    can be achieved by
  • culling or relocating pests and weed
  • erecting fences to keep out pests, methods of
    preventing seeds and diseases from entering
  • introducing natural predators to the pest

Translocation and reintroduction programs
  • Native species may over-breed and be at risk of
    exceeding their habitats carrying capacity.
    Translocation can overcome this problem.
  • Individuals from one population may be
    translocated to another region where population
    numbers are low or have died out.
  • Species may be propagated in herbaria or bred
    through a captive breeding program zoos or
    sanctuaries, and reintroduced back into the wild.
  • The problems associated with these strategies
    can be reduced by
  • carefully staged transitions in reintroductions
  • tracking the parentage of individuals in the
    program (pedigree books) to reduce inbreeding
  • outbreeding
  • - swap individuals between different breeding
  • - add individuals from the wild to the program
    from time to time
  • - releases of some captive bred individuals to
    the wild populations
  • genetic testing and monitoring of their phenotype

Sustainable use of biological resources
  • The concept of conservation and sustainable
    development does not preclude the harvesting of
    use of a species or region, but they must be used
    in a way that ensures it is available for future
  • This can be achieved through
  • Ecotourism allowing tourist use of the site but
    in a way which causes least possible degradation
    to the site and has an environmental educative
  • Sustainable harvesting of biological resources
    resources, such as trees and fish, are harvested
    or used at a rate which minimises impact and
    ensure the resource is maintained into the long
    term future.

2005 exam
  • Q. 10. Which one of the following management
    strategies is likely to increase genetic
    diversity in a population of a species?
  • a. wildlife corridors connecting different
  • b. culling some animals to allow more access to
  • c. fencing their breeding habitat to exclude
  • d. removal of some pairs for a captive breeding
    program and reintroduction to this habitat

Evaluating efforts to protect biodiversity
  • Requires research, surveying and/or monitoring to
  • Has the genetic diversity increased?
  • Have the species/population bred in the wild?
  • Has the health of individuals been maintained?
  • Has the range of the species/population expanded?
  • Have pest species declined?
  • Has habitat quality improved?
  • Has species abundance or diversity been
    maintained or increased?

Overview of Area of Study 2 Diversity in the
  • What is biodiversity?
  • Why is it important?
  • What are the threats to biodiversity?
  • How is biodiversity assessed?
  • How is biodiversity maintained and protected?
  • Examination of a selected endangered species and
    its management.

Your endangered species
  • a description of the animal and its survival
    needs its original range, habitat and other
  • the current geographic locations of the remaining
    populations and a history of its population
    decline, including the threats that have caused
    its decline and current population numbers
  • the species conservation status, what this
    status means in terms of level of threat and its
    risk of extinction, and the reasons why it has
    been awarded this status
  • strategies set out in the Action Statement to
    conserve the species and the stakeholders
    involved in the species conservation and their
  • evaluation of the strategies implemented to
    conserve the species
  • a detailed description of a remaining population
    of the species
  • the habitat it provides
  • the threats that exist in this population
  • strategies which have been implemented to protect
    this population
  • monitoring used to evaluate the strategies
  • an evaluation of how the population is being
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