Transcript Support and guidance - Unit 3, topic 3: Biodiversity Under

6GEO3 Unit 3 Contested Planet
Topic 3: Biodiversity under Threat
What is this topic about?
• Biodiversity under Threat is
the third of the ‘resources’
topics
• It examines the nature of
biological resources,
essentially plants and
animals, and how people use
and conserve them
• The earth’s biosphere
represents a critical part of
the planet as a life support
system
• How humans act towards the
biosphere reveals a great deal
about their priorities,
attitudes and understanding.
Biodiversity’s future?
An endangered Kangaroo in San
Diego Zoo
CONTENTS
1.Defining biodiversity
2. Biodiversity threats
3. Managing biodiversity
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1. Defining biodiversity
• Biodiversity can be defined in a
number of ways
• High levels of biodiversity might be
seen as ‘healthy’ because narrow
genetic diversity means species are
vulnerable to disease
• Species diversity is the most commonly
used definition.
Genetic
Diversity.
The genetic
variability
within one
species.
Biodiversity
Bio…?
•Biodiversity – the variety of genes,
species and ecosystems in an area.
•Biosphere – the thin veneer of living
material on the planet’s surface
•Biome – a global scale ecosystem
e.g. tropical forest
•Biomass - the total weight of living
matter per unit area (dry)
Ecosystem
Diversity.
The range of
different
ecosystems,
habitats and
niches in an
area.
Species
Diversity.
The number
of different
species
within an
area.
Influences on biodiversity
• Biodiversity is high on large, high, tropical (low latitude) islands –
Madagascar, Sumatra and Java are good examples
Lack of factors to limit
growth: lots of light,
warmth and rain
promote growth
Altitude produces a range of
ecological zones, each with its
own species
Islands are isolated, so
evolution goes its own
way producing new
unique species and
varieties; this is called
endemism.
Decay and
nutrient cycling
are rapid in
tropical soils
The isolation of islands
limits human influence
– at least until recently
Large areas can support
large numbers of
species in complex food
chains, with space for
top carnivores.
Today, humans factors are important –
how protected is an area? Does poverty
force people to destroy ecosystems?
How widespread is deforestation and
the need for new farmland? How fast is
population growing? Do people care
about biodiversity?
Global biodiversity
• Due to several 100 years of intense
human activity the global pattern of
biodiversity is no longer ‘natural’.
• Humans can have both positive and
negative influences on biodiversity
• Norman Myers coined the terms
‘biodiversity hotspot’
• Hotspots are areas with:
High species richness
High levels of endemism (uniqueness)
Facing severe human threats
• Biodiversity hotspots (see map, next
slide) are often tropical areas,
islands and highlands –but also areas
in the developing world where
poverty leads to ecosystem
destruction.
Negative
Positive
Biodiversity hotspots
Combined area covers only 2.3% of the Earth's land
surface. Each hotspot has already lost at least 70% of
its natural vegetation. Over 50% of the world’s plant
species and 42% of all terrestrial vertebrate species
are endemic to the 34 biodiversity hotspots.
The value of ecosystems
• Ecosystems have value
• In some cases, a financial value can be
calculated – income from timber or tourism
• Much of the value of ecosystems cannot easily
be calculated in monetary terms
• Healthy, biodiverse ecosystems are essential
for maintaining human wellbeing
You need to be able to assess
the value of ecosystem services
with reference to one global
ecosystem (biome) e.g. coral
reef, tropical forests, or
temperate grasslands etc.
Regulating services
Atmospheric gases
Flood regulation
Disease regulation
Water Purification
Goods (provisioning services)
Food (hunting and gathering; farming)
Fresh Water supply
Wood and fibre
Fuel wood
Ecosystem
services
Cultural services
Aesthetic value
Spiritual value
Educational value
Recreation and Leisure
2. Biodiversity threats
• Biodiveristy hotspots are by
definition areas which are
under threat
• In some areas, threats are so
great that extinction is
occurring
• These areas can be seen on
the map to the right
(compare to map on slide 7)
• Cold environments tend to
be fragile and lack resilience
• Small islands have low
populations of species, and
have high endemism
• Forests are simply too
resource rich to be left alone
in many cases.
Global threats
• Globally there are a number of trends which threaten ecosystems and
biodiversity
Global Threat and its consequences
Global Warming
•Rising sea levels threaten coastal ecosystems (coral,
mangroves, estuaries)
•Rising ocean temperatures threaten coral through
bleaching
•Shifts in climate zones will stress biomes; migration
patterns will be altered; some biomes (tundra,
montane forest) may be wiped out.
Desertification
•A widespread and complex problem, some 10-20% of
dryland ecosystems are already degraded; grasslands
are very vulnerable
•Overgrazing, climate change, poor farming practice
and population pressure all contribute
•Once soil is eroded, ecosystem recovery is very
difficult
Poverty and food
insecurity
Population pressure, poverty and the need to produce
food are leading to unsustainable use of ecosystems
worldwide
Overfishing, deforestation, conversion of ecosystems
into farmland are all major causes of ecosystem and
biodiversity loss
Local threats
• In small scale areas, local threats can be numerous and represent a
severe threat to ecosystems and biodiversity.
Localised deforestation;
clearance for farming
and urbanisation
Mining, ranching and
overgrazing, road building
leading to ecosystem
fragmentation
Tourism development;
trampling, erosion;
urbanisation and associated
pollution; increased risk of
wildfires
Runoff from farms and
urban areas; eutrophication
and heavy metals in rivers,
lakes and seas
Overfishing and harmful
forms of fishing e.g.
dynamite and cyanide
Siltation from runoff;
increased risk of alien
invasive species
Ecosystem processes
• Functioning ecosystems have a
continual flow of nutrients
(top) and energy (bottom)
through them
• These systems are selfregulating, but prone to
human disruption:
Deforestation or over fishing
depletes the biomass store in
the nutrient cycle
Climate change may affect
precipitation, runoff, decay
rate and weathering rate
Alien species can disrupt the food
web, changing the balance of
predators and prey
Eutrophication drastically
increases available nutrients
Alien invasive species
• Our globalised world has increased
the threat from alien invasive
species
• These are species which move out
of their natural habitat and colonise
new areas, as a result of human
activity
• Such species don’t move because
they want to find a better place to
live!
Successful invaders tend to be:
Capable of rapid reproduction
Able to disperse
Rapid growing
Tolerate a range of environmental conditions
Able to eat a wide range of foods
Species such as rats, goats, the Chinese
Mitten crab and Zebra Mussel are successful,
and highly destructive, aliens
• Some aliens are introduced deliberately,
perhaps as a food source, predator or
ornamental species, but then escape into
the wild and have unintended
consequences
• Other aliens are accidental introductions
Ecosystem destruction
• Pristine ecosystems are rare today
• Highly developed countries tend
to have few of them, although
they may use their wealth to
protect, conserve and restore
ecosystems
• Wealth, and leisure time, tend to
mean people have positive
attitudes to the environment
• In NICs and RICs (see graph)
threats to ecosystems tend to be
severe, as ecosystems are used as
resources and there is limited
money for conservation
• In less developed countries, yet to
industrialise, ecosystem may not
be exploited yet – but for how
long?
3. Managing biodiversity
• Given that 6.5 billion humans cannot
stop ‘using’ ecosystems, is there are
safe way to use them?
• A certain level of use (yield) is
sustainable – be it logging, fishing,
hunting etc.
• This level is the Maximum
Sustainable Yield for a species /
ecosystem – the level at which
utilisation by humans does not lead
to long term decline in species
numbers
• In reality, taking the MSY leaves no
room for error (or climate change,
disease etc)
• The Optimum Yield is lower, and
safer in terms of long term
sustainability.
Players
• Different players have
conflicting views on
biodiversity and ecosystems
• One player may have quite
complex views e.g. wanting
to protect the rainforest but
still use its products
• Some players view
ecosystems as a resource to
be exploited, but this could
be out of necessity
(subsistence) as well as for
profit (TNCs)
• Other players may be much
more conservation minded
and focus on the ecological
and aesthetic value of
biodiversity
“First, get rid of
them tree, then its
perfect cattle
country”
“Keep the forest,
we’ll build the
hotel on this side
of the lake”
“What a great photo,
but the car parking
could be better”
“What do we want?
National Park!
When do we want
it? Now!”
Organisations and campaigners
IGOs
Individuals
NGOs
Government
UNESCO, UNEP
Sting, Al Gore,
David
Attenborough
Greenpeace,
WWF
UK (local and
national)
Different arms of the
UN are responsible for
CITES, World Heritage
Sites and helped with
the Millennium
Ecosystem Assessment.
Global treaties,
scientific research and
monitoring are
important aspects of
their work.
Certain individual
campaigners have the
ability to reach a
global audience and
push for change.
Some NGOs, like WWF
or The Nature
Conservancy help
manage conserved
areas.
Other like
Greenpeace, campaign
to keep issues in the
media, and lobby
governments and IGOs
Government policy is
crucial to ecosystems
conservation and
preservation of
biodiversity.
Governments
implement and police
treaties like CITES and
set up and run
National Parks and
other conservation
areas.
What to conserve?
• There is not, and never will be, a limitless pot of money for conservation.
• Decisions have to be taken about what should be conserved , but these
decisions are difficult to make
ICONIC species
Raising money for Pandas, Tigers and
Chimps is relatively easy, but how
important are they at a global level?
KEYSTONE species
Species such as Bees, the pollinators of
numerous plants, are crucial but hard to
‘sell’ to a wary public
HOTSPOTS
Hotspots are clearly under threat and
very biodiverse; they would yield a lot
of conversation per $ spent, but many
areas (like the Arctic) are not
biodiverse enough to qualify
ECOREGIONS
Ecoregions are large areas, like
Amazonia; conserving them would
achieve a great deal, but would be
expensive and difficult to police and
monitor. Ecoregions do fit the ‘Single
Large’ rather than ‘several small’ model
which would allow species to shift due to
climate change.
Management strategies
• Ecosystems and biodiversity can be managed in a range of different
ways
• There is a spectrum of different management strategies
• Some are sustainable as they balance ecological and human needs
Scientific
Preserve
with no
access for
public
Wildlife
Parks and
Nature
Reserves
National
Parks;
extractive
reserves
Conservati
on and
Developm
ent areas
Sustainable Management
‘Paper
Parks’
Zoos and
Gene
Banks
Biosphere reserves
• One of the most common form of
conservation management is the
UNESCO Biosphere reserve model
• Biosphere reserves use the
principle of zoning to conserve
core ecological areas, whilst
allowing some economic
development – such as ecotourism or managed hunting or
logging
• Educating local people to
conserve resources for future
generations is important
• Biosphere reserves usually have
scientific research and
monitoring activities too
• Famous locations such as the
Galapagos and Komodo NP use
elements of the biosphere
reserve model
Biodiversity futures
• 2010 is the UN International Year of Biodiversity
• This alone shows how important biodiversity is to the
planet’s future.
• UNEPs GEO-4 Project (2007) identifies 4 possible futures for
biodiversity and ecosystems (below)
• There are some difficult choices to be made!
Markets First
Profit driven future, playing lipservice to sustainability. Continued
degradation of biodiversity
Security First
‘Me First’ – the focus is on maintaining
the wealth of the few in a very unequal
world; IGOs like the UN are viewed
with suspicion; the environment is
there to be exploited.
Policy First
A greater balance between human and
ecological wellbeing, but humans are
put first by short-termist policymakers
and ecosystems are protected when
possible and expedient
Sustainability First
Equal weight is given to human and
ecological wellbeing , and thinking is
long-term to gradually recover lost
ecological ground