Evaluating Biodiversity and
Vulnerability
Topic 4.2
4.2.1 Identify factors that lead to loss
of diversity…….
• You will be allocated a factor
from the list on the next few
pages…….describe and explain
(using real life examples) how
biodiversity is affected by your
factor:
By Kieran Harris, Fausti
Preysler, and Anil Daryanani
How do
Natural
Disasters
effect
Biodiversity?
Meteors:
 The
visible path of a meteoroid that
enters the Earth’s atmosphere.
 Meteors are otherwise known as
shooting stars or falling stars
 Destroys the land that each meteor
strikes
Meteors:
Cretaceous Period
 Meteor
wiped out all dinosaurs
 Burned down 50% of forests
 Caused excessive amounts of carbon to
enter the atmosphere killing most life
species on earth
 Aqua life much further down in the seas
survived as they were unaffected
 Turtles survived as well due to their slow
metabolisms and aquatic lifestyles
 No land animal larger than 23 kg survived
Drought:



A long period of no rain
Causes extreme heat and dryness
Effects on biodiversity
 Dries everything up, kills it all
 Plants dry up and die, leaving no shelter
for other living organisms like bugs, birds,
etc.
Drought:
 Example:



Dust Bowl
Caused by severe drought in the American
and Canadian prairie land in the 1930’s
Caused by severe drought, plus decades of
extensive farming without things such as
crop rotation
Nothing to keep soil in place, dried up,
turned into dust and blew away into many
cities
Volcanoes and
Animals:
 When
volcanoes erupt they release huge
amount of ash into the atmosphere, it also
spews out molten lava.
 The lava destroys the habitats of the
animals that are surrounding the volcano,
the animals that also live near the
volcano would die as well due to this.
Volcano’s and
Environments:
 The
trees and forests around the
volcano’s will be destroyed from the
magma that seeps down the mountain
side onto the ground and they also
release a great deal of soot into the air
which pollutes the atmosphere.
 Volcano’s can also effect the people
surrounding the volcano by destroying
homes, crops, and there livelihood.
Works Cited
Volcano Image:
http://www.indianchild.com/images/valcanoe2.jpg

Drought Image:
http://4.bp.blogspot.com/_hLV9xP2uHXs/TUtQZGMAhLI/AAAAAA
AABCA/NUvH87j6W0I/s1600/drought.jpg

Meteor Image:
http://www.pollsb.com/photos/o/217336huge_meteor_hit_earth_die_dinosaurs_did.jpg

Volcano information:
http://library.thinkquest.org/06aug/00886/index_files/Page307.htm

Habitat
degradation,
fragmentation
and loss.
• Ecosystem degradation
Look back at your work on deforestation,
desertification, leaching and salinization.
(topic 3.4)
Fragmentation definition:
The term habitat fragmentation includes five
discrete phenomena:
1. Reduction in the total area of the habitat
2. Decrease of the interior : edge ratio
3. Isolation of one habitat fragment from other
areas of habitat
4. Breaking up of one patch of habitat into several
smaller patches
5. Decrease in the average size of each patch of
habitat
http://en.wikipedia.org/wiki/Habitat_fragmentation
Ecosystem Fragmentation
Fragmentation and destruction
of Great Ape habitat in Central
Africa, from the GLOBIO and
GRASP projects
• Habitat fragmentation as the name
implies, describes the emergence of
discontinuities (fragmentation) in an
organism's preferred environment
(habitat), causing population
fragmentation.
• Habitat fragmentation can be caused
by geological processes that slowly
alter the layout of the physical
environment (suspected of being one
of the major causes of speciation), or
by human activity such as land
conversion, which can alter the
environment much faster and causes
extinctions of many species.
http://en.wikipedia.org/wiki/Habitat_fragmentation
Natural causes and effects
• Evidence of habitat destruction
through natural processes such as
volcanism, fire, and climate change is
found in the fossil record.[1] For
example, habitat fragmentation of
tropical rainforests in Euramerica 300
million years ago led to a great loss of
amphibian diversity, but
simultaneously the drier climate
spurred on a burst of diversity among
reptiles.[1]
http://en.wikipedia.org/wiki/Habitat_fragmentation
Human causes
• Habitat fragmentation is frequently caused by
humans when native vegetation is cleared for
human activities such as agriculture, rural
development, urbanization and the creation of
hydroelectric dams.
http://en.wikipedia.org/wiki/Habitat_fragmentation
• Habitats which were
once continuous
become divided into
separate fragments.
After intensive clearing,
the separate fragments
tend to be very small
islands isolated from
each other by
cropland, pasture,
pavement, or even
barren land. The latter
is often the result of
slash and burn farming
in tropical forests
http://en.wikipedia.org/wiki/Habitat_fragmentation
• In the wheat belt of central western New South
Wales, Australia, 90% of the native vegetation has
been cleared and over 99% of the tall grass prairie
of North America has been cleared, resulting in
extreme habitat fragmentation.
http://en.wikipedia.org/wiki/Habitat_fragmentation
Implications
• One of the major ways that habitat fragmentation affects
biodiversity is by reduction in the amount of available habitat
(such as rainforests, boreal forests, oceans, marshlands, etc.) for all
organisms in an ecological niche.
• Habitat fragmentation invariably involves some amount of habitat
destruction. Plants and other non- moving or slow moving
organisms in these areas are usually directly destroyed. Mobile
animals (especially birds and mammals) retreat into remnant
patches of habitat. This can lead to crowding effects and increased
competition.
• The remaining habitat fragments are smaller than the original
habitat. Species that can move between fragments may use more
than one fragment. Species which cannot move between
fragments must make do with what is available in the single
fragment in which they ended up. Since one of the major causes of
habitat destruction is agricultural development, habitat fragments
are rarely representative samples of the initial landscape.
http://en.wikipedia.org/wiki/Habitat_fragmentation
Farming Practices & Biodiversity
Monoculture, Pesticide
use, GMOs
Monoculture
• Monoculture is the practice of producing one
single crop over a wide area
– Monocultures often kill off all the biodiversity because
the crops are not used to having to share soil with
other plants and often kill of the competition
Pesticide Use
• Pesticides can be spread through the
air and water into areas which they
were not originally intended, harming
many other organisms than pests
– Some of these chemicals are toxic or
lethal to the organisms they make
contact with
– But some of the chemicals would also
not be considered directly toxic or lethal,
with effects sufficiently impairing
populations in these ways:
• Inability to recover from infectious disease
due to immunosuppression
• Inability to obtain sufficient food, effectively
avoid predators, or apply proper parenting
instincts due to neurotoxicological effects
• Development of abnormal sexual anatomy or
behavior due to hormone disruption
Genetically Modified Organisms
• Genetically modified organisms can
compromise biodiversity in these ways:
– Out-crossing: If GM plants pass their traits onto
their wild relatives, then those relatives could be
changed in a way that could change their
ecological role, which would potentially enable
them to out-compete other species
GMOs (continued…)
– New traits agreed upon by genetic engineering
could offer advantages that could lead to
widespread use of only a few crop varieties, but
this means a loss of cultivar biodiversity. (Cultivar
is a term used in plant breeding for the
differentiation of breeding lines) Reducing the
diversity of the cultivars found in agriculture could
lead to problems such as raised susceptibility to
widespread outbreaks of plant diseases and pests
• Using GMOs doesn’t necessarily mean reducing the
diversity of cultivars, but it is still a good idea to keep a
close eye on this
Sites to look at:
• Monoculture:
HERE :D & AND HERE
• Pesticides:
HELLO & HOW ARE YOU?
• GMOs:
BYE
Invasive species – Cane-toad and
rabbit, cats and goats
Invasive species affect on
biodiversity
 There are two ways for the invasive species to
affect biodiversity, out-competing and hybridizing
native species.
 The invasive species is one that lessens that
diversity by throwing off the natural balance
• Damage life forms effecting the ecosystem
Habitat destruction, such as forest clearing
 The more invasive species invading certain levels
of ecosystems, the biodiversity would be more
threatened
Australia - Rabbits
• Rabbits are an invasive species in Australia brought by
Europeans. Since rabbits reproduce very quickly, the
population of rabbits quickly increased.
• Native species of animals, such as the Rabbit-eared
Bandicoot or Bilby needs a constant supply of
carbohydrate-rich seeds and roots. The rabbits graze or
degrade vegetation that provides food and shelter for
them and other native animals. Rabbits grazing on
vegetation also cause erosion and removal topsoil, and
thus endangers some native vegetation. If rabbits
destroy or eat the native vegetation, the Bilby and
other native species are placed under greater pressure,
and thus the native species become endangered.
Australia - Rabbits
• Rabbits are an invasive species in Australia
brought by Europeans. Since rabbits
reproduce very quickly, the population of
rabbits quickly increased.
Australia - Rabbits
Native species of animals, such as the Rabbiteared Bandicoot or Bilby needs a constant supply
of carbohydrate-rich seeds and roots. The rabbits
graze or degrade vegetation that provides food
and shelter for them and other native animals.
Rabbits grazing on vegetation also cause erosion
and removal topsoil, and thus endangers some
native vegetation. If rabbits destroy or eat the
native vegetation, the Bilby and other native
species are placed under greater pressure, and
thus the native species become endangered.
Sources
http://www.environment.gov.au/biodiversity/in
vasive/ferals/index.html
• http://www.environment.gov.au/biodiversity/i
nvasive/ferals/index.html
• http://www.pbs.org/wgbh/nova/nature/impactinvasive-species.html
• http://curiosity.discovery.com/question/invasiv
e-species-affect-biodiversity
Kei and Christine
Pollution
and
Biodiversity
Biodiversity Decreasing
• The IUCN has reported that about 5,200 species of animals
currently are threatened with extinction, including:
* Close to
1,100 species of mammals, one-quarter of the total number of
mammals.
• Over 1,100 birds, 11% of the 9,600 known species of birds.
• Over 2,000 species of freshwater fish, 20% of the total number
identified.
• 253 species of reptiles, 20% of the total number surveyed.
• An estimated 124 species of amphibians, 25% of the total number
surveyed
• Plant species are not faring well, either. Of the 270,000 known
species of higher plants, 34,000 are endangered. In the US nearly
30% of the 16,000 known plant species are at risk of extinction.
View these statistics here: https://online.uas.alaska.edu/online/portfolio/CJOHNSON9/Courses/Fall2008/Introduction/Pollution__Life?behavior=UAS;
Pollution Increasing
• Since the industrial revolution in the 1800’s,
we’ve been relying on environmentally
detrimental methods of creating materials and
products.
• Factories and waste help our industrial
development but hinder our biodiversity
development.
How does one affect the other?
WATER
Toxic discharges
This includes metals, organic chemicals, and suspended sediments
usually found in industrial and municipal effluents that are
discharged directly into waterbodies. Toxic discharges can inversely
impact the biota (living organisms) in an ecosystem by killing them,
weakening them, or affecting their ability to carry out essential
biological functions (feeding, reproducing, etc.).
Bacterial contamination
For example, fecal coliforms that come from human waste are
found in municipal effluent discharges. Potable water is treated to
destroy fecal coliforms which can make people ill if ingested.
How does one affect the
other?
LAND
Area Pollution
Area pollution prevents a specific region from
having nutrient buildup, which is ultimately an
disadvantage to species such as lichen. But it
helps stimulate rapid growth of algae and
aquatic plants.
How does one affect the other?
AIR
Acid Rain
Acid precipitation is the air pollutant that has the most
significant impact on biodiversity in Canada. Despite
legislation aimed at reducing acid rain and acid loading, it is
predicted that we will lose fish, mollusk and amphibian
populations in thousands of lakes because they will not be
able to survive in acidified conditions. This is of particular
concern in the Canadian Shield region of Quebec, whose
countless lakes are sensitive to acidification because their
drainage basins cannot neutralize acid inputs the way they
can in more southern Quebec regions.
These information is mostly based on the St. Lawrence watershed in the
southwest and northeast of North America and Canada.
Read more at: http://redpath-museum.mcgill.ca/Qbp/3.Conservation/impacts.htm
Researchers say that pollution affects plant
diversity more than animal diversity
•
•
•
•
•
Air pollution affects lower life forms more than higher life forms. Plants are
generally more affected than animals on land.
Plants constantly take up atmospheric gases i.e. air everyday to sustain their
biological processes. Vegetation growing under optimum conditions is most
susceptible to air pollution. As air pollution is for the most part man-made, we are
the main source of this phenomenon. Pollution can be derived from two kinds of
sources namely, stationary and multiple point sources.
Multiple point sources are usually mobile and include automobiles and other
vehicles. The vehicles are the most important source of atmospheric pollutants as
they release carbon monoxide. This is followed by industrials sources which
release sulphur oxides, steam and electric power plants, space heating and lastly
refuse burning. Agricultural chemicals also form part of air pollution.
The uptake of pollutants depends on the concentration gradient between the
ambient air and the absorptive sites within the leaf. It also depends on the
conductance of the stomata. The toxic effect of a pollutant may thus be almost
directly related to the functioning of the stomata.
Because of the higher susceptibility of dying off as a result of pollution in plants,
their biodiversity is at a greater threat. But sometimes, the biodiversity of plants
can affect the biodiversity of animals as you’ll see in the next slide………..
Read more at: http://bcb705.blogspot.com/2007/03/air-pollution-lethal-injection.html
Example:
The Pollination Crisis
•
•
•
•
•
•
•
•
Since 2006, honeybee colonies in the United States have been suffering from a widespread
phenomenon known as colony collapse disorder (CCD), in which adult worker bees abandon an
otherwise-healthy hive.
Air pollution interferes with the ability of bees and other insects to follow the scent of flowers to
their source, undermining the essential process of pollination, a study by three University of
Virginia researchers suggests.
Their findings may help unlock part of the mystery surrounding the current pollination crisis that is
affecting a wide variety of crops.
Scientists already knew that scent-bearing hydrocarbon molecules released by flowers can be
destroyed when they come into contact with ozone and other pollutants.
Most bees have poor eyesight, which makes scent particularly important, the researchers wrote.
This phenomenon triggers a cycle, the authors noted, in which the pollinators have trouble finding
sufficient food, and as a result their populations decline. That, in turn, translates into decreased
pollination and keeps flowering plants, including many fruits and vegetables, from proliferating.
"We know that ozone levels continue to be high and go well beyond EPA standards for public
health," Tear said. "What's been pretty consistent is the more we look at air pollution's impacts on
natural resources, the more we find those impacts to be.”
Tear and his colleagues have recently completed a survey of how atmospheric pollution is affecting
biodiversity in the Eastern United States and concluded that high levels of ozone can decrease
forest growth by as much as 30 percent.
Read more at: http://www.washingtonpost.com/wp-dyn/content/article/2008/05/04/AR2008050401737.html
Hunting, collecting and Harvesting
Hunting
• Most extinction over the past several hundred years
are mainly due to over-harvesting for food, fashion,
and profit
• Commercial hunting, both legal and illegal (poaching),
is the principal threat.
• For Example Rhino Horns for $40,000 to $100,000 per
horn
• The pet and decorative-plant trade falls within this
commercial hunting category, and includes a mix of
legal and illegal activities. The annual trade is
estimated to be at least US $5 billion, with perhaps
one-quarter to one-third of it illegal.
Hunting (continued)
• “Sport or recreational hunting causes no
endangerment of species where it is well
regulated, and may help to bring back a
species from the edge of extinction. Many
wildlife managers view sport hunting as the
principal basis for protection of wildlife.”
• http://www.fathom.com/course/21701785/se
ssion2.html
Harvesting/Collecting
• Conversion of Forests into agriculture for harvesting – Lessens
habitat, which in turn lessens species diversity.
• Harvesting removes certain foods or areas of nutrition for animals
• Overharvesting any area is a direct threat to a biodiversity
• Habitat loss and overharvesting often occur simultaneously
“The problem with biological resource extraction is when
the rate of increase in demand for the resource far outstrips
the reproductive rate of the population - demand outstrips
supply”
http://redpath-museum.mcgill.ca/Qbp/3.Conservation/impacts.htm
Harvesting/Collecting
(continued)
• “The recent expansion of road networks into
previously remote tropical forests enables the
bush meat trade resulting in what some
conservationist describe as ‘empty forests’ as
more and more wild animals are shot for food.”
• Link to a table which shows the affects of overharvesting in
comparison with the other factors.
• http://www.fathom.com/course/21701785/session2.html
Overharvesting (3 points)
“The unsustainability of biological resource
extraction has, at its root, three main
problems
a) too many people want the resources,
b) the short-term profit goals of extractors
c) Lack of information about the ecology and
about the life-histories of the populations
being harvested.”
http://redpath-museum.mcgill.ca/Qbp/3.Conservation/impacts.htm