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.

Positive Negative

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

• 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.

• 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 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 Tourism development; trampling, erosion; urbanisation and associated pollution; increased risk of wildfires Overfishing and harmful forms of fishing e.g. dynamite and cyanide Mining, ranching and overgrazing, road building leading to ecosystem fragmentation Runoff from farms and urban areas; eutrophication and heavy metals in rivers, lakes and seas 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 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!

• •

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 ( hunting etc.

yield ) is sustainable – be it logging, fishing, This level is the numbers

Maximum Sustainable Yield

for a species / ecosystem – the level at which utilisation by humans does not lead to long term decline in species In reality, taking the disease etc)

MSY

leaves no room for error (or climate change, The

Optimum Yield

sustainability.

is lower, and safer in terms of long term

• • • •

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

UNESCO, UNEP

Individuals

Sting, Al Gore, David Attenborough WWF

NGOs

Greenpeace,

Government

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

‘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 allowing some to conserve core ecological areas, whilst economic development tourism or managed hunting or logging – such as eco 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

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