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
1.Defining biodiversity2. Biodiversity threats3. Managing biodiversity
CONTENTS
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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.
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)
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.
The isolation of islands limits human influence – at least until recently
Decay and nutrient cycling
are rapid in tropical soils
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 richnessHigh 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.
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.
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.
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
Tourism development; trampling, erosion;
urbanisation and associated pollution; increased risk of
wildfires
Overfishing and harmful forms of fishing e.g.
dynamite and cyanide
Siltation from runoff; increased risk of alien
invasive species
Runoff from farms and urban areas;
eutrophication and heavy metals in rivers, lakes and
seas
Mining, ranching and overgrazing, road building
leading to ecosystem fragmentation
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
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!
• 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
Successful invaders tend to be:Capable of rapid reproduction
Able to disperseRapid 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
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”
“What a great photo, but the car parking could be better”
“What do we want? National
Park! When do we want it? Now!”
“Keep the forest, we’ll build the
hotel on this side of the lake”
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 speciesRaising money for Pandas, Tigers and Chimps is relatively easy, but how important are they at a global level?
KEYSTONE speciesSpecies such as Bees, the pollinators of numerous plants, are crucial but hard to ‘sell’ to a wary public
HOTSPOTSHotspots 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
ECOREGIONSEcoregions 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
Conservation and
Development areas
‘Paper Parks’
Zoos and Gene Banks
Sustainable Management
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
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 lip-service to sustainability. Continued degradation of biodiversity
Policy FirstA greater balance between human and ecological wellbeing, but humans are put first by short-termist policymakers and ecosystems are protected when possible and expedient
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.
Sustainability First Equal weight is given to human and ecological wellbeing , and thinking is long-term to gradually recover lost ecological ground