PowerPoint Presentation
3.3 Threats to BiodiversitySignificant Ideas:
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.Kenya 2015 - To discourage poaching and trade in
ivory, fires are set to 15 tons of elephant tusks at a World
Wildlife Day event. 25 years since ivory trade was banned, new
demand from emerging markets (such as China) threatens Africas
elephants and rhinos.
Knowledge and Understanding I3.3 U1Estimates 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. [The total
number of classified species is a small fraction of the estimated
total of species, and it continues to rise. Estimates of extinction
rates as a consequence are also varied, but current extinction
rates are thought to be between 100 and 10,000 times greater than
background rates.]3.3 U2The 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 U3The 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.
Knowledge and Understanding II3.3 U4Tropical 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
U5Most tropical biomes occur in less economically developed
countries (LEDCs) and therefore there is conflict between
exploitation, sustainable development and conservation.
Applications & Skills3.3 A1Discuss 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. [Case studies of three species should be carried out.
In each case, the ecological, sociopolitical or economic pressures
that are impacting on the species should be explored. The species
ecological roles and the possible consequences of their
disappearance should be considered.]3.3 A2Describe the threats to
biodiversity from human activity in a given natural area of
biological significance or conservation area.3.3 A3Evaluate the
impact of human activity on the biodiversity of tropical biomes.3.3
A4Discuss the conflict between exploitation, sustainable
development and conservation in tropical biomes.
Tree of life1.8 million species have been described but
estimates range from 8 100 million species.
Estimates of global species numbers are based on mathematical
models.
Lack of exploration of the deep sea and rainforest canopies,
means that knowledge of the total number of species on Earth is
poorly understood.
This estimate is broken down as follows: animals: 7.77 million
(12% known)fungi: 0.61 million (7% known)plants: 0.30 million (70%
known)other species: 0.07 million
Of the total 1.8 million described species (excluding microbes):
3/4 are invertebrates.1/2 are insects (beetles are the most
successful group, found in all ecosystems except oceans)1% of
species are vertebrates (yet this is the group that conservation
initiatives are often focused on)
Most described species are larger, more appealing groups (e.g.
those with fur or feathers or flowers e.g. mammals, birds,
flowering plantsSmaller species that are more difficult to
identify/study are less represented, including the most
species-diverse groups on the planet (insects, spiders, bacteria,
fungi, etc.). Funds for research is limited, so specimens from
remote regions of the Earth are significantly under-recorded.
Estimations of total species numbers (and current extinction rates)
are therefore based on limited data.
Extinction is a natural process.
Mammals species lifespan is 1 million years.Anthropods species
lifespan is 10 million years ++3.2 Review
Background rate of extinction is 100 species/million
species/year
3.2 Review
Current rate of extinction is 1000x higher, (3 species/hour) and
due to human activities
3.2 Review
A biodiversity hotspot is a region with a high level of
biodiversity. They contain large numbers of endemic species
(species not found anywhere else).
Measures of biodiversity are essential in identifying areas that
should be protected against damaging human activities.3.1 ReviewUp
to 50% of animals and plants are in one of 30 hotspots which make
up 2% of the land on earth.These areas are very vulnerable to
habitat loss, disproportionately impacting endemic species
Threats to BiodiversityNatural CausesGravitational attraction of
other planets causes Earths orbit to fluctuate over a cycle of
~100,000 years
The Earths tilt on its axis changes by approximately 2.4o over a
period of 41,000 years.Threats to BiodiversityNatural Causes
Threats to BiodiversityNatural CausesPlate tectonics alter
energy and matter flows, along with changing biomes due to breakup
and formation of new landmasses 3.2 Review
Changes in the orbit of the Earth and its tilt, plus tectonic
movement, have led to repeated long-term cold periods (ice
ages)Threats to BiodiversityNatural Causes
1816 - (Year Without a Summer) a volcanic winter event caused by
the eruption of Mount Tambora in Indonesia. The eruption caused a
dust plume that reduced sunlight over large areas of the globe,
reducing surface temperatures. Average global temperatures to
decrease by 0.40.7 C, resulting in major food shortages across the
Northern Hemisphere and Asia due to crop failure. Threats to
BiodiversityNatural Causes
Forest fires
Threats to BiodiversityNatural CausesWildfires destroy 5 million
acres of land in USA every year
Threats to BiodiversityNatural Causes2007 A flooding of the
Yangtze River in China displaced 14 million people
Threats to BiodiversityNatural Causes2010 5.9 earthquake hit
Port-au-Prince, Haiti, killing 300,000 people. This death-toll was
higher than expected as Haiti had been hit by two hurricanes
previously, and were underprepared.
Threats to BiodiversityLoss of HabitatThe Mediterranean has only
10% of the original forest cover.
Lycian Way, Turkey, has some of the last untouched regions.
Threats to BiodiversityLoss of HabitatExcept for a small
protected area, there will be no moist forest remaining in
Madagascar by 2020.
Lemurs (like this ring-tailed lemur) are endemic, and likely to
become extinct.
Threats to BiodiversityFragmentationFragmentation of habitats
through roads, towns, factories, power lines, train rails,
pipelines and fields leads to islands within disturbed
ecosystems
Threats to BiodiversityFragmentationEdge Effect results in
variation of abiotic factors (temperature, light, humidity),
risking pests and human contact, which can spread diseases and
competition.
Threats to BiodiversityFragmentationEdge Effect results in
variation of abiotic factors (temperature, light, humidity),
risking pests and human contact, which can spread diseases and
competition.
Disturbance generally will decrease biodiversity, but there are
exceptions.
Describe the relationship show in the abundance graph.
Deduce the edge effect upon biodiversity in Araucaria
forests.
Suggest a reason why both abundance and richness is greatest at
the forest edge.
Suggest a reason why abundance and richness decrease after 100 m
from the forest edge.The graphs show changes in plant community
diversity and composition across an edge between Araucaria forest
and pasture in South BrazilImpact of edge effect on
biodiversity
Threats to BiodiversityPollutionFertilizer run-off into Lake
Erie has caused severe eutrophication and toxic chemicals to
bioaccumlate.
Threats to BiodiversityPollutionDeepwater Horizon oil spill
disaster in 2010 leaked 4.9 million barrels impacting both local
and global pollution, resulting in immediate die-offs and dolphins
and tuna dying of heart-defects at 6x the normal rate.
How Alien Species can be Introduced to a New Niche:Accidental
IntroductionIntentional IntroductionPest Control IntroductionZebra
MusselsBrought in ballast water from the Caspian &
Mediterranean Seas, invading N. American LakesJapanese
KnotweedBrought in to Europe from Asia because it looked like
bamboo but it literally grew everywhere. Today houses with knotweed
growing sometimes cannot even be sold.Cane ToadFrom S.America, it
was brought to Australia to reduce beetle infestations. It is now
an invasive species.
Threats to BiodiversityAlien Species
Competitive Exclusion Principle: Two species cannot occupy the
same niche in a community, as there will be competition for the
same resources. When one species has even the slightest advantage
or edge over another then the one with the advantage will
dominate.Advantages can come in different forms for example:High
reproductive rateLarger size / more aggressiveFaster / more
efficient foragerAbsence of predatorInvasive species often lack a
predator, due to being in a foreign environment. In the case of
invasive plants this can mean an absence of suitable
herbivores.Threats to BiodiversityAlien Species
Threats to BiodiversityAlien SpeciesKudzu is native to Japan but
in the US it is an invasive species. It causes environmental and
ecological damage through "interference competition", meaning it
outcompetes native flora by blocking their access to light by
growing over them and shading them with its leaves. Native plants
may then die as a result. Above is a house completely covered
kudzu.
Cane Toads: Introduced on Purpose, Invasive by Accident
Threats to BiodiversityAlien Species
Threats to BiodiversitySpread of Disease
2003 Avian Flu is adapted to both birds and humans, and H5N1
spread through Asia to Europe and Africa
There can be more than one producer in a food web, and consumers
can occupy multiple trophic levels (positions in a chain) A food
web is a diagram that shows how food chains are linked together
into more complex feeding relationships within a
communityMaintaining BiodiversityComplexity of EcosystemComplex
foodwebs are more resilient to the loss of one species, as others
will fill the gaps, and occupy that niche.2.2 Review
Maintaining BiodiversityInertiaInertia is the ability of an
ecosystem to resist change, which is important when considering
which systems to conserve/will recover.
Each stage of succession is more stable than earlier seral
stages.
The climax seral stage is in equilibrium.2.4 ReviewMaintaining
BiodiversityStage of SuccessionCommunities in early stages of
succession are more vulnerable to biodiversity loss, due to more
openness of matter and energy flows.
Abiotic Factors affecting
species:PlantsAnimalstemperaturewaterlight
(intensity/wavelength)breeding sitessoil pHfood supply soil
salinity territory mineral nutrient availability
2.1 ReviewMaintaining BiodiversityLimiting FactorsChanges in
limiting factors may increase competition/more challenging to get
resources to survive. If there are few limiting factors in a
system, then the system is more likely to manage if one factor
becomes limiting
Corals live in very nutrient poor waters and most coral species
have limits of tolerance of approximately 20oC. Photosynthesis
pathways are impaired at temperatures above 30oC therefore for most
corals the upper limit of tolerance is 30oCFavia pallida (hard
coral) with signs of bleaching2.1 ReviewRisk of ExtinctionNarrow
Geographical Range
Giant pandas have such specialized niches that small changes in
their habitats can be disastrous.
Their realized and fundamental niches are essentially the
same.2.1 ReviewRisk of ExtinctionSpecialized Feeders/Niche
Requirements
2.3 ReviewRisk of ExtinctionBody Size90% of energy is lost as
move up a trophic level: there are few predators, which need large
territories (to gather enough food), low population densities (not
enough energy to support more), and often complete with humans/are
hunted
Monocultures, like farming, reduce genetic diversity in a
population, which means that the entire species can be wiped out by
a new pathogen, as can occur with blights of wheat and rice.Factors
that Affect Resilience: Genetic Diversity1.3 ReviewRisk of
ExtinctionLow Genetic DiversityIf individuals are not able to find
one another due to fragmentation of a habitat, or habitat loss
limits access to energy/nutrients, then less likely to survive
Risk of ExtinctionLow Reproductive PotentialWhales, like other
K-strategists, take years to reach reproductive maturity and
reproduce infrequently, making them vulnerable to extinction due to
low population numbers.
Risk of ExtinctionValue to HumansOverhunting can eradicate a
species quickly, such as bison in N. America, cod in N. Atlantic
Ocean, or the pangolin.Pangolins are threatened by hunting (for
their meat and scales), heavy deforestation of their natural
habitats, and are the most trafficked mammal in the world .Of the
eight species of pangolin, 4 are listed as vulnerable, 2 are listed
as endangered, and 2 are listed as critically endangered on the
International Union for Conservation of Nature (IUCN) Red List of
Threatened Species.
International Union for the Conservation of Nature and Natural
Resources (IUCN) was founded in 1948 by the United Nations,
involving 181 governments, 800 NGOs, and 10,000 scientists. They
monitor the worlds species through the Red List, and supports the
Millennium Ecosystem Assessment (1.4), and determines the
conservation status of a species based on:
Population sizeDegree of specializationDistributionReproductive
potential and behaviourGeographic range & degree of
fragmentationQuality of habitatTrophic levelProbability of
extinction
Through these, they will classify an organism based on 8 levels
of extinction probability:
The list includes about 40, 000 species and 40% of these are
listed as threatened.
PodcastDiscuss the case histories of three different species:
one that has become extinct due to human activityanother that is
critically endangeredthird species whose conservation status has
been improved by intervention.
In each case, the ecological, sociopolitical or economic
pressures that are impacting on the species should be explored. The
species ecological roles and the possible consequences of their
disappearance should be considered.
Podcasts should be no more than 3 minutes long, with an
introduction of who you are, and a musical intro/outro
Amazon Case Study
Tropical deforestation in the Brazilian Amazon threatens to wipe
out the most biologically diverse ecosystems on Earth, replacing
them with degraded pastureland. There are a number of complicated,
interacting factors leading to the rapid destruction of tropical
forests, most of which are underscored by the economic value of
different land use options.
In this case study, students examine the issue from the
perspective of three dominant stakeholders in the region: a peasant
farmer, a logger, and an environmentalist. Using data and
techniques for valuing ecosystems, students determine how each of
these stakeholders values a hypothetical five-hectare plot of
tropical rainforest in the Amazon.
Objectives:
Understand the political, cultural, and economic history leading
to tropical deforestation in Amazonia.Understand issues facing the
major stakeholders in the Amazon.Understand the concern for such a
large loss in biodiversity.Understand the concepts of market and
non-market valuation of ecosystems, benefit-cost analysis, and
opportunity cost.Perform a benefit-cost analysis of clearing a plot
of tropical forest in the Amazon, from the perspective of a peasant
farmer, logger, and a conservation organization. Critically
evaluate economic vs. ethical valuation of ecosystemsAppreciate the
political, social, economic, and ecological complexity of tropical
deforestation.Appreciate how difficult decisions must be made in
the face of limited or nonexistent data.
Before class:
Read all three subsections of the case, Introduction,
Background, and The Problem
Consider three perspectives (a peasant farmer, a logger, and an
environmentalist) through these questions:
Who are the stakeholders involved in Amazonian deforestation,
and what are the issues facing them?
What does opportunity cost mean and how does it apply to the
valuation of land uses in this case?
How does the new view of ecological economics differ from
traditional economic views?
How is willingness to pay being used to value ecosystems? What
would you be willing to pay to ensure the protection of at least
10% of remaining tropical forests? A random 5-hectare plot in the
middle of the Amazon forest?
Using data presented in the case study, fill in the data tables
showing how a farmer, a logger, and an environmentalist values
tropical forests.
In Class:
30 minutes Group DiscussionFocus on comparing notes and putting
together a common set of data tables using the data presented in
the case (and any other information you may already know). NB: you
are valuing a single, 5-hectare forest in a 1-2 year time period,
and not the whole Amazon or tropical forests in general. By the
end, you should have come up with a written strategy of land use
and an associated data table of ecosystem values.
30 minutes - Class Discussion Which land use option is most
valuable, and how might this affect land use in theAmazon?"
