6GEO3 Unit 3 Contested PlanetTopic 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 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.
CONTENTS 1.Defining biodiversity 2. Biodiversity threats 3. Managing biodiversityClick on the information icon to jump to that section.Click on the home button to return to this contents page
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 livingmaterial on the planet’s surface•Biome – a global scale ecosysteme.g. tropical forest•Biomass - the total weight of livingmatter per unit area (dry)
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 andnutrient 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.
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 Earths land surface. Each hotspot has already lost at least 70% of its natural vegetation. Over 50% of the world’s plantspecies 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 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
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
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
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 cycleClimate change may affect precipitation, runoff, decay rate and weathering rateAlien species can disrupt the food web, changing the balance of predators and preyEutrophication drastically increases available nutrients
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
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 “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
Organisations and campaigners IGOs Individuals NGOs GovernmentUNESCO, UNEP Sting, Al Gore, Greenpeace, UK (local and David WWF national) AttenboroughDifferent arms of the Certain individual Some NGOs, like WWF Government policy isUN are responsible for campaigners have the or The Nature crucial to ecosystemsCITES, World Heritage ability to reach a Conservancy help conservation andSites and helped with global audience and manage conserved preservation ofthe Millennium push for change. areas. biodiversity.Ecosystem Assessment. Other like GovernmentsGlobal treaties, Greenpeace, campaign implement and policescientific research and to keep issues in the treaties like CITES andmonitoring are media, and lobby set up and runimportant aspects of governments and IGOs National Parks andtheir work. 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 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.
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
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 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.