Threats to biodiversity. Environmental Systems and Sustainability

1. Significant ideas:
1) While global biodiversity is difficult to quantify, it is
decreasing rapidly due to human activity. Classification
of species conservation status can provide a useful tool
in the conservation of biodiversity
36.2% —or about 3,402,000 hectares—of Malawi is
forested.
Change in Forest Cover: Between 1990 and 2000,
Malawi lost an average of 32,900 hectares of forest
per year. The amounts to an average annual
deforestation rate of 0.84%. Between 2000 and
2005, the rate of forest change increased by 9.6% to
0.93% per annum

2. Big Questions:
1) To what extent have the solutions emerging from this
topic been directed at preventing environmental
impacts, limiting the extent of the environmental
impacts, or restoring systems in which environmental
impacts have already occurred?
2) How are the issues addressed in this topic of relevance
to sustainability or sustainable development.

3. Big Questions:
1) In what ways might the solutions explored in this topic
alter your predictions for the state of human societies
and the biosphere some decades from now?
2) What indicators can be taken to suggest that a species
is a threat from extinction?
3) How can the population of a species facing extinction
be restored?
4) development, and conservation in tropical biomes?

4. Big Questions:
1) What threats do biologically significant areas face and
how can the extent of the environmental impacts be
limited?
2) What issues arise when attempts are made to balance
conservation with economic development? What
conflicts exist between exploration, sustainable
development, and conservation in tropical biomes?

5. Understandings
Statement Guidance
3.3..U1 Estimates of the total number of species on Earth
vary considerably. They are based on
mathematical models, which are influenced by
classification issues and a lack of finance for
scientific research, resulting in many habitats and
groups being significantly under-recorded.
3.3.U2 The current rates of species loss are far greater
now than in the recent past, due to increased
human influence. The human activities that
cause species extinctions include habitat
destruction, introduction of invasive species,
pollution, overharvesting and hunting.
3.3.U3 The International Union of Conservation of
Nature (IUCN) publishes data in the “Red List of
Threatened Species” in several categories.
Factors used to determine the conservation
status of a species include: population size,
degree of specialization, distribution,
reproductive potential and behaviour, geographic
range and degree of fragmentation, quality of
habitat, trophic level, and the probability of
extinction.

6. Understandings
Statement Guidance
3.3..U4 Tropical biomes contain some of the most
globally biodiverse areas and their unsustainable
exploitation results in massive losses in
biodiversity and their ability to perform globally
important ecological services.
3.3.U5 Most tropical biomes occur in less economically
developed countries (LEDCs) and therefore there
is conflict between exploitation, sustainable
development and conservation.

7. Applications and Skills
Statement Guidance
3.3.A1 Discuss the case histories of three different
species: one that has become extinct due to
human activity, another that is critically
endangered, and a third species whose
conservation status has been improved by
intervention.
3.3.A2 Describe the threats to biodiversity from human
activity in a given natural area of biological
significance or conservation area.
3.3.A3 Evaluate the impact of human activity on the
biodiversity of tropical biomes.
3.3.A4 Discuss the conflict between exploitation,
sustainable development and conservation in
tropical biomes.

9. 3.3.U1 Estimates of the total number of species on Earth vary
considerably. They are based on mathematical models, which are
influenced by classification issues and a lack of finance for
scientific research, resulting in many habitats and groups being
significantly under-recorded.
Current estimates of the total number
of species on earth range anywhere
from 5 to 30 million, of which 1.8
million or so have ben formally
described

10. Only about 1.4-1.8
million are known to
science
Suggest why the percentage of identified species larger for
certain groups?
3.3.U1 Estimates of the total number of species on Earth vary
considerably. They are based on mathematical models, which are
influenced by classification issues and a lack of finance for
scientific research, resulting in many habitats and groups being
significantly under-recorded.

11. • Due to our lack of knowledge of how many
species there actually are it makes it very hard
to estimate extinction rates.
• 100 species per million species per year.
• 1000 times the background rate.
• 3 species per hour.
• Humans are responsible.
https://www.ted.com/talks/e_o_wilson_on_saving_life_on_earth?language=en
3.3.U1 Estimates of the total number of species on Earth vary
considerably. They are based on mathematical models, which are
influenced by classification issues and a lack of finance for
scientific research, resulting in many habitats and groups being
significantly under-recorded.

12. 3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting..
• In the past 500 years, we
know of approximately 1,000
species that have gone.
• The current amphibian
extinction rate may range
from 25,039 to 45,474. More
than 50 percent of the world's
primate species are at risk of
extinction.
• The current extinction rate is
about 100 species per million
species per year

13. 3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting
Based on the graphic, which has been the single most
significant cause of extinction over the past 500 years
https://animalextinctionincalifornia.weebly.com/why-animals-are-going-extinct.html

14. Factors that help maintain biodiversity
1. Complexity of the ecosystem
2. Stage of succession
3. Limiting factors
4. Inertia
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

15. • Two major causes
– Natural Causes (Non-Human)
– Human Causes
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

16. • Volcanic Eruptions
• Drought
• Meteors
• Glaciers and ice age
• Competition and Predation
Natural Causes (Non-Human)
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

17. • A-Agriculture Practices
• N-Natural hazards and disasters
• D-Disease spread
• H-Habitat destruction and
fragmentation
• I- Introduced species
• P-Pollution
• P-Population Growth
• O-Over exploitation
Human Causes (AND HIPPO)
Dodo Bird – Extinct
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

18. • Farming causes habitat loss
and reduces biodiversity
because of…
– Monoculture: Farming of
only one crop on a large
scale
• Pesticides: Often lethal to many
non-pest species
• Herbicides: Lethal to species
other than the weeds
Practices of Agriculture
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

19. Natural hazards and disasters
• Naturally occurring events that
may have a negative impact on
the environment
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

20. Spread of Disease
• Decreases biodiversity
• Diseases are usually
species-specific but if they
mutate they can infect
across the species barrier
– Swine flu (2010)
– Bird flu (since 2003)
– Foot and mouth disease
(2001)
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

21. Habitat Loss and Fragmentation
• Fragmentation: Large area divided up into
smaller areas
• Fragments separated by roads, power lines,
fields etc.
• Fragments act as ‘green’ islands
surrounded usually by urbanization
• Diseases can be passed between domestic
and wild species
• Degradation: reducing the quality of available habitat
• Ex. Logging, agriculture, sewage
• Loss: Disappearing of an entire habitat
• Ex. Paving natural area for building sites, converting
prairies to farmland or residential subdivisions
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

22. Introduction of Alien Species
Organisms that are living in an environment outside of its normal
range or natural environment
Sometimes it works:
• Potatoes brought from the Americas to
Europe
• Rubber trees form Amazon to South East
Asia
Sometimes it is a disaster:
• Rhododendrons, introduced into Europe
from Nepal , outcompete native plants
and are toxic
• Australia; cane toads, rabbits, foxes,
camels, blackberry etc.
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

23. Pollution
• Local pollution e.g. oil spills killing seabirds
• Environmental pollution e.g. emissions from factories and
transport lead to acid deposition or photochemical smog
• Run off of fertilizers into waterways
• Climate change alters weather patterns and shifts biomes
away from the equator
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

24. Population Growth
• http://www.worldometers.info/world-population/
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

25. Overexploitation
• Technology has allowed humans to become
better at catching, hunting and harvesting
• Chain saws instead of axes for timber
• Hunting fish using sonar and trawling nets
• Growing rural poverty means that many
humans living at subsistence level
overexploit the environment
3.3.U2 The current rate of species loss are far greater now than in
the recent past, due to increased human influence. The human
activities that cause species extinction include habitat destruction,
introduction of invasive species, pollution, overharvesting and
hunting

26. 3.3.A2 Describe the threats to biodiversity from human activity in a
given natural area of biological significance or conservation area
• You must identify natural areas by name – “coral reef” or “tropical rainforest” are too broad
to earn marks on the IB ESS exams. Consult the map below for some initial ideas to get your
started. Research one or two named areas as case studies and learn the details for your exam
http://www.grida.no/resources/6956

27. 3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories. Factors used to determine the conservation status of a
species include: population size, degree of specialization,
distribution, reproductive potential and behaviour, geographic
range and degree of fragmentation, quality of habitat, trophic
level, and the probability of extinction.
https://animalextinctionincalifornia.weebly.com/why-animals-are-going-extinct.html

28. • IUCN (International Union for Conservation
of Nature)
• Red list used to determine extinction risk
• Specific Aims:
– Provide system that can be applied consistently
– Improve evaluation of different factors which
affect the risk of extinction
3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories..

29. Criteria used to determine list
 Population size:
 Small population size easier to wipe out
 Degree of specialization
 More vulnerable due to reliance on a limited range of resources
 Geographic range and degree of fragmentation
 Intact habitats spread over larger geographic areas are less likely to be affected
 Trophic level
 Fewer apex predators and tertiary consumers to survive disturbances
 Distribution
 Widely distributed species more likely to survive
 Quality of habitat
 High quality habitats provide ample nutrients and energy pathways
 Probability of extinction
 Combinations of these factors make some species more vulnerable
 Reproductive potential and behavior
 High reproduction rate means more offspring
3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories..

30. Narrow geographic range
The Golden Lion Tamarin

31. Small population size
• Low genetic diversity
• Less variation so less resilient to change

32. Low population densities and large
territories
• Reduces chance of individuals meeting for
reproduction.
• Requires very large area to support few
organisms.
Giant Panda has a
range of 5km2

33. Few populations
• If there is only one population of a species
then that is their only chance of survival.
Lemurs are only found
on Madagascar (an
island of the coast of
Africa). There are often
only one or two groups
of each species.

34. A large body
• 10% rule means predators are rare.
• Usually large range, low population densities
and need lots of food.
• Compete with humans for food.
• Hunting trophies.
• Danger to humans

35. Low reproductive potential
• Reproducing slowly and infrequently means
populations take a long time to recover.
• Albatrosses produce one egg per pair per year
and take several years to become fecund.

36. Seasonal migrants
• Long hazardous journeys.
• Reliant on multiple habitats.
• Many salmon species swim upriver to
spawn.

37. Poor dispersers
• Species that cannot easily move to new
habitats.
• Plants rely on seed dispersal meaning they can
die out before it can move.
• Non-flying animals.
• Flightless birds of New Zealand.

38. Specialised feeder or niche
requirements.
• Single food source can be destroyed, meaning
you have no food.
• Koala bear and eucalyptus.

39. IUCN labels the threat of individual species’ extinction according to
the following categories
3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories..

41. • Extinct (Ex) – No reasonable doubt that
the last individual has died. Determined
after exhaustive surveys of animals known
range and expected habitats
• Endangered (E)- Survival is unlikely if
causal factors continue operating.
Drastically reduced populations and habitat
3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories..

42. • Critically Endangered (CR) –considered to
be facing an extremely high risk of extinction
in the wild.
• Vulnerable (V) – Near endangered if causal
factors continue. Numbers are abundant but
are under threat from serious factors
(overexploitation, habitat destruction)
3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories..

43. • Near Threatened(NT) – Small world
populations that are at risk. Unexpected
threat could easily cause a critical decline
(small geographic disturbance)
• Least Concern (LC) -
• Unknown (K) – Suspected to fit in one of
the above categories but there is a lack of
information
3.3.U3 The International Union of Conservation of Nature (IUCN)
publishes data in the “Red List of Threatened Species” in several
categories..

44. 3.3.A1 Discuss the case histories of three different species: one
that has become extinct due to human activity, another that is
critically endangered, and a third species whose conservation
status has been improved by intervention
• Include all of the following in your case history
– Name and description of the species
– Its ecological niche
– Pressures contributing to its IUCN threatened
status
– Factors related to its
• If extinct – the consequences of its disappearance
• If thratened or recovering – an evaluation of the
methods applied to combat its loss
https://www.weareteachers.com/quiz-endangered-species-knowledge/

45. 3.3.U4 Tropical biomes contain some of the most globally
bioiverse areas and their unsustainable exploitation results in
massive losses in biodiversity and their ability to perform globally
important ecological services

46. • Contain 50% of Earth’s known
species
• Most species have specialized niches
• Humans disrupt environment for
logging
• Changing one part of ecosystem
alters the entire web of relationships
• Breakdown of rainforest likely lead to
extinction of 10% worlds species in
25 years
• Regeneration rate is slow due to poor
soil quality (rapid year round
nutrient cycling depletes soil)
3.3.U4 Tropical biomes contain some of the most globally
bioiverse areas and their unsustainable exploitation results in
massive losses in biodiversity and their ability to perform globally
important ecological services

47. Here is a different perspective on
rainforest diversity. What do you
think is being communicated
here?
3.3.U4 Tropical biomes contain some of the most globally
bioiverse areas and their unsustainable exploitation results in
massive losses in biodiversity and their ability to perform globally
important ecological services

48. 3.3.U5 Most tropical biomes occur in less economically developed
countries (LEDCs) and therefore there is conflict between
exploitation, sustainable development and conservation

49. • Globally 2.4 (1 hectare) acres of rainforest have been destroyed
every second... it is the equivalent of two US football fields
• 149 acres (60 hectares) have been destroyed a minute
• Located within many developed
countries, meaning that it would face
more human disturbance
• Very complex structure with high
diversity
• Play an important role in reducing the
effects of global warming
• Having much economic value and
demands e.g. timber
• the rainforest needs a long time to
recover and, due to human destruction,
has poor soils
• The destruction of rainforest has been regard as a key mobiliser of the
environmental movement and green policy
3.3.A3 Evaluate the impact of human activity on the biodiversity of
tropical biomes

50. • Controlling the loss of biodiversity requires international legislation
• The willingness to participate in conservation initiatives varies from
country to country and is very dependent on economics, social and
political views.
• Most tropical biomes are located in LEDC and in the countries there
are conflicts between exploration of resources and sustainability
3.3.A4 Discuss the conflict between exploitation, sustainable
development and conservation in tropical biomes