This document provides an overview of the topic of biodiversity under threat. It begins by defining key terms like biodiversity, biosphere, biome, and biomass. It then discusses factors that influence biodiversity like island isolation and tropical climates. Global threats to biodiversity are explored such as habitat loss and invasive species. Specific threats include deforestation, overfishing, pollution, and mining. The document examines ecosystem processes and managing biodiversity through approaches like biosphere reserves and protected areas. It concludes by considering different futures for biodiversity conservation.

1. 6GEO3 Unit 3 Contested Planet
Topic 3: Biodiversity under Threat

2. 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 Biodiversity’s future?
the planet as a life support An endangered Kangaroo in San
system Diego Zoo
• How humans act towards the
biosphere reveals a great
deal about their priorities,
attitudes and understanding.

3. CONTENTS
1.Defining biodiversity
2. Biodiversity threats
3. Managing biodiversity
Click on the information icon to jump to that section.
Click on the home button to return to this contents page

4. 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.
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)

5. Influences on biodiversity
• Biodiversity is high on large, high, tropical (low latitude) islands –
Madagascar, Sumatra and Java are good examples
Islands are isolated, so
Lack of factors to limit Altitude produces a range of evolution goes its own
growth: lots of light, ecological zones, each with its way producing new
warmth and rain own species unique species and
promote growth varieties; this is called
endemism.
Decay and
nutrient cycling
are rapid in
tropical soils
Today, humans factors are important –
how protected is an area? Does poverty
force people to destroy ecosystems?
The isolation of islands Large areas can How widespread is deforestation and
limits human influence support large numbers the need for new farmland? How fast is
– at least until recently of species in complex population growing? Do people care
food chains, with about biodiversity?
space for top
carnivores.

6. 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.

7. 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.

8. The value of ecosystems
• Ecosystems have value
• In some cases, a financial value can be
You need to be able to assess
calculated – income from timber or tourism
the value of ecosystem services
• Much of the value of ecosystems cannot easily with reference to one global
be calculated in monetary terms ecosystem (biome) e.g. coral
reef, tropical forests, or
• Healthy, biodiverse ecosystems are essential temperate grasslands etc.
for maintaining human wellbeing

9. 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.

10. Global threats
• Globally there are a number of trends which threaten ecosystems and
biodiversity

11. Local threats
• In small scale areas, local threats can be numerous and represent a
severe threat to ecosystems and biodiversity.
Tourism development; Overfishing and harmful
Localised deforestation; trampling, erosion;
clearance for farming forms of fishing e.g.
urbanisation and associated dynamite and cyanide
and urbanisation pollution; increased risk of
wildfires
Runoff from farms and Siltation from runoff;
Mining, ranching and urban areas; increased risk of alien
overgrazing, road building eutrophication and heavy invasive species
leading to ecosystem metals in rivers, lakes and
fragmentation seas

12. Ecosystem processes
• Functioning ecosystems have a
continual flow of nutrients
(top) and energy (bottom)
through them
• These systems are self-
regulating, 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

13. Alien invasive species
• Our globalised world has increased Successful invaders tend to be:
the threat from alien invasive Capable of rapid reproduction
Able to disperse
species Rapid growing
• These are species which move out Tolerate a range of environmental
of their natural habitat and colonise conditions
Able to eat a wide range of foods
new areas, as a result of human
activity Species such as rats, goats, the Chinese
Mitten crab and Zebra Mussel are successful,
• Such species don’t move because
and highly destructive, aliens
they want to find a better place to
live!
• 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

14. 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?

15. 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.

16. Players
• Different players have “First, get rid of
them tree, then its “What a great photo,
conflicting views on perfect cattle but the car parking
biodiversity and ecosystems country” could be better”
• 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 “Keep the forest, “What do we
we’ll build the want? National
and focus on the ecological Park! When do we
hotel on this side
and aesthetic value of of the lake” want it? Now!”
biodiversity

17. Organisations and campaigners
IGOs Individuals NGOs Government
UNESCO, UNEP Sting, Al Gore, Greenpeace, UK (local and
David WWF national)
Attenborough
Different arms of the Certain individual Some NGOs, like WWF Government policy is
UN are responsible for campaigners have the or The Nature crucial to ecosystems
CITES, World Heritage ability to reach a Conservancy help conservation and
Sites and helped with global audience and manage conserved preservation of
the Millennium push for change. areas. biodiversity.
Ecosystem Assessment. Other like Governments
Global treaties, Greenpeace, campaign implement and police
scientific research and to keep issues in the treaties like CITES and
monitoring are media, and lobby set up and run
important aspects of governments and IGOs National Parks and
their work. other conservation
areas.

18. 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 KEYSTONE species
Raising money for Pandas, Tigers and Species such as Bees, the pollinators of
Chimps is relatively easy, but how numerous plants, are crucial but hard to
important are they at a global level? ‘sell’ to a wary public
HOTSPOTS ECOREGIONS
Hotspots are clearly under threat and Ecoregions are large areas, like
very biodiverse; they would yield a lot Amazonia; conserving them would
of conversation per $ spent, but many achieve a great deal, but would be
areas (like the Arctic) are not expensive and difficult to police and
biodiverse enough to qualify monitor. Ecoregions do fit the ‘Single
Large’ rather than ‘several small’ model
which would allow species to shift due to
climate change.

19. 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
Wildlife ‘Paper
Scientific
Preserve Parks National Conservati Parks’
Parks; on and
with no and extractive Developm
access for Nature Zoos and
reserves ent areas
public Reserves Gene
Banks
Sustainable Management

20. 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 eco-
tourism 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

21. 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 Policy First
Profit driven future, playing lip- A greater balance between human and
service to sustainability. Continued ecological wellbeing, but humans are
degradation of biodiversity put first by short-termist policymakers
and ecosystems are protected when
possible and expedient
Security First Sustainability First
‘Me First’ – the focus is on maintaining Equal weight is given to human and
the wealth of the few in a very unequal ecological wellbeing , and thinking is
world; IGOs like the UN are viewed with long-term to gradually recover lost
suspicion; the environment is there to ecological ground
be exploited.