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Biodiversity• Biodiversity is the variety of life onEarth,• it includes all organisms, species, andpopulations;• the genetic variation among these; andtheir complex assemblages ofcommunities and ecosystems.
Levels of biodiversity1. Genetic diversity is all the different genescontained in all the living species includingindividual plants, animals, fungi, andmicroorganisms.2. Species diversity is all the different species, aswell as the differences within and betweendifferent specie3. Ecosystem diversity is all the different habitats,biological communities and ecological processes,as well as variation within individual ecosystems.
Causes of Biodiversity LossAccording to most sources, the major directcauses of human-induced biodiversity lossare1. land-use change (the fragmentation,degradation or loss of habitats)2. pollution (air and water)3. the over-exploitation of natural resources4. the introduction of non-native (alien orexotic) species5. climate change-induced biodiversity
LAND USE CHANGESChanges in landscape due to such activities asagriculture, urban expansion and transportationinfrastructure are generally major causes of theloss of biodiversity.1. Agricultural expansion: (growing food)• Agricultural expansion in the demand forcompensating meat• Increased the level of land use change,converting forests into grazing land.
2. Agricultural expansion: the case ofbiofuelsBiofuels which are produced from non-foodfeedstock are known as lignocellulosic material.E.g. wood, wood residues, grass, straw and fastgrowing trees. It is important to note that directand indirect causes of biodiversity losses frombiofuel production.
1. Direct land use changes biodiversity loss from degradation of highconservation value areas (rainforests andpeat lands). use of pesticides, genetically modified crops (endangerwildlife and biodiversity)2. Displacement effects (also known as“indirect land use changes or “leakageeffects”).
3. Infrastructure development• The impact of infrastructural developmentincludes:– the direct effects on wildlife by disturbance andavoidance– increased hunting activities– Small scale settlements along roads.1. Africa commercial logging and timberproduction2. In Latin America and the Caribbean, theconstruction of dams, oil and gas pipelines andnew settlements can be seen as a cause ofdeforestation.
4. Deforestation• 31% of the Earth’s land surface,• Contain more than 1/2 of all terrestrial animaland plant species (mostly in the tropics)• Account for more than two-thirds of net primaryproduction on land (solar energy to plant matter)• Despite policy efforts on reducing deforestation,around 13 million hectares of forests continueto be lost annually.
Causes of Deforestation• including conversion for agricultural uses,infrastructure development, wood extraction,agricultural product prices, and a complex set ofadditional institutional• high deforestation rates in Comoros, Burundi, Togoand Mauritania• The total size of the deforested area in Brazil andIndonesia is almost 200 times as large as the areadestroyed in the three countries that experience thehighest deforestation rate.
Tropical Rainforest Deforestation• hosts half of all global biodiversity• direct cause of biodiversity loss due to theassociated loss of natural habitat.• second largest source of anthropogenicgreenhouse gas emissions• contributes significantly to increasingsedimentation in surrounding coastal areas.• In South East Asia, sediments reduce coralgrowth in one of the most important biodiversityhot spots.
• Brazil, which is estimated to havearound 55,000 species of flora, amountingto some 22% of the world’s total• India has about 46,000 and some 81,000animal species (amounting to some 8% ofthe world’s biodiversity), are also undervarious pressures, from corporateglobalization, deforestation, etc.
Native bananas, palms, climbingplants and epiphytes and manyinvertebrates and birds Epiphytes (lichens, mosses, ferns andorchids) use trees for attachmentpurposes only, and do no hurt theirhost Forest floor is filled with herbs,herbivores and carnivores, insects
Tropical RainforestSouthAmericaAfricaIndiaCentralAmerica IndonesiaAlmost all rain forests lie near the equator.
POLLUTION1. Fresh Water pollution• Heated water from nuclear power stations forexample and microorganisms from untreatedwaste cause serious water pollution.• Several coastal zones in South- East Asia, forinstance, have developed eutrophication rapidlyresulting in pollution of along others chemicalwaste and this may seriously affect tropical coralreefs.
2. Marine pollution from oil spills• An approximate 400 gallons of oil a day havebeen released into the ocean that poses asignificant threat to wildlife• toxic and sub-lethal effects on plankton, seabirddrowning or body heat loss following fouling ofplumage by oil
Marine Zones Affected by oil• Open waters are generally considered as lesssensitive to oil spill damage, are typically not usedas habitats, spawning or breeding grounds.• Coastal waters are the most biologically diversemarine environments1. Seabirds breeding and feeding in coastal areasare faced with a high rate of mortality.2. Benthic organisms are usually heavily damaged,as are fish spawning areas and coastal andseabed vegetation.
• Polar region, more specifically offshore sub-Arctic and Arctic areas temporarily orpermanently covered with sea ice, are subject toan increasing amount of oil and gas explorationand sea transport activities.• Due to the slow growth and decay processtypical for arctic environments, biodegradationas well as recovery and re-growth of oiledcoastal areas is greatly delayed.
UNSUSTAINABLE NATURALRESOURCE USE1. Fisheries• 90 % of all large fish have disappeared fromthe world’s oceans in the past half century, thedevastating result of industrial fishing.• In the last decade, in the north Atlantic region,commercial fish populations of cod, hake, havefallen by as much as 95%,
Bluefin tuna (sushi)• Bluefin tuna disappeared from Danish marinewaters in the 1960s. Now the species couldbecome depleted throughout the northeastAtlantic and Mediterranean.Common cockle• The common cockle is a species of ediblesaltwater clams, a marine bivalve mollusc. It iscommercially overfished in the Netherlandsand the British Isles.• Declined over 50%
2. Miningi) Impacts on Fresh water biodiversity• Minerals that may be present either in the coal orassociated rocks, which causes degradation ofwater quality.• Particulate matter resulting from mining activitieshas been shown to be detrimental to local fishpopulations.• Decreased densities of macro invertebrate- andbenthic invertebrate populations have beenassociated with increased suspended solids.
• Enhanced sedimentation inhibits spawningand the development of fish eggs and larvae,as well as smothering benthic fauna (faunathat inhabit the bottom/beds of rivers andlakes).• high turbidity may impair the passage of light,• E.g. Australian miner spilt approximately 100million litres of cyanide-contaminated waterinto Romanian rivers that killed over onemillion kilograms of fish in Hungary.
ii) Impacts on marine biodiversityIn many coastal areas oil and gas companiesextract huge quantities of gas and oil, forinstance in the North Sea.In South East Asia, several oil companies extractoil from or in the vicinity of the for biodiversity.Coral reefs can be threatened by oil spills.
CLIMATE CHANGE1) Biodiversity is threatened by human-inducedclimate change.2) of the main threats to biodiversity in the CoralTriangle and widely reported as the cause ofcoral bleaching.3) desertification may increase in some areascausing species vulnerable to extinction.4) Climate change has also been implicated in thedecline of amphibians in tropical forests.
INVASIVE ALIEN SPECIES• Invasive species have been cited as being thesecond most important threat to global biodiversityloss, after land use change.• More than 80 species have been introduced to theNorth Sea.• These species have an impact on other speciesand sometimes reduce the numbers of indigenousspecies.
Over view of some endangeredspecies• The International Union for Conservation ofNature (IUCN) notes that many species arethreatened with extinction. In addition,• At threat of extinction are– 1 out of 8 birds– 1 out of 4 mammals– 1 out of 4 conifers– 1 out of 3 amphibians– 6 out of 7 marine turtles
• 75% of genetic diversity of agricultural crops hasbeen lost• 75% of the world’s fisheries are fully or overexploited• Up to 70% of the world’s known species riskextinction if the global temperatures rise by morethan 3.5°C• 1/3rd of reef-building corals around the world arethreatened with extinction• Over 350 million people suffer from severe waterscarcity
Biodiversity ConservationProtected areas are an essential part ofconservation programs. To be successful, sites forprotected areas need to be carefully chosen,ensuring that all regional ecosystems are wellrepresented.Market tools, such as direct payments for ecosystemservices or transfers of ownership rights to privateindividuals, can provide economic incentives toconserve biodiversity and to use ecosystemservices sustainably
Prevention and early intervention have proven tobe the most successful and cost-effective way oftackling invasive speciesBiodiversity must be integrated into theagriculture, fishery, and forestry sectorsStrong institutions at all levels are essential tosupport biodiversity conservation and thesustainable use of ecosystems.
Informing all of society about the benefits ofconserving biodiversity, and explicitly consideringtrade-offs between different options in anintegrated way, helps maximize the benefits tosociety.Ecosystem restoration is generally far moreexpensive than protecting the original ecosystem,but is becoming increasingly important as moreareas become degraded.