230 likes | 244 Views
B I O D I V ERSI T Y A N D C O N S E R V A T I ON. BIOD IVERS I T Y A N D C ON SE R V A T I ON. Biodiversity : the term biodiversity refers to the totality of genes, species, and ecosystems of a region. Types of biodiversity described by Edward Wilson:
E N D
BIODIVERSITYANDCONSERVATION • Biodiversity:thetermbiodiversityreferstothetotalityofgenes,species,andecosystemsofaregion. • TypesofbiodiversitydescribedbyEdwardWilson: • Geneticdiversity:Asinglespeciesmightshowhighdiversityatthegeneticleveloveritsdistributionalrange. • MedicinalplantRauwolfiavomitoriaofHimalayanrangeproducesactive • chemicalreserpineshowsgeneticvariation. • Indiahasmorethan50000differentstrainofrice. • 1000varietiesofmango. • • Speciesdiversity:differentspeciesofasingleanimallikefrog. • Ecologicaldiversity:diversityintheecosystemlevellikedesert,rainforest,mangroves,coralreef,wetlands,estuariesetc.
HowmanyspeciesarethereonEarthandHowmanyinIndia? • AccordingtoIUCN(2004),1.5millionofplantsandanimalsareinourbiosphere. • RobertMayplacesglobalspeciesdiversityatabout7 millions. • Morethan70percentofallthespeciesrecordedareanimals. • Allplantsconstituteabout22percent. • Amonganimalsinsectsconstitute70percent. • India has only 2.4 percent of the world’s land area; its share ofglobalspeciesdiversityisimpressive8.1percent. • Indiaisconsideredoneofthemegadiversitycountriesoftheworld.
Patternof Biodiversity • Latitudinalgradients: • Speciesdiversitydecreasesaswemoveawayfromtheequatortowards • thepole. • Tropic(23.5oNto23.5oS)harborsmorespeciesthantemperateandpole • ThelargelytropicalAmazonianrainforestinSouthAmericahasthegreatestbiodiversityonearth: • 40,000speciesofplants. • 3000speciesoffishes. • 1300ofbirds. • 427amphibians • 378reptiles • Morethan1,25,000invertebrates.
Whytropicalrainforesthasgreater biodiversity: • Unliketemperateregionssubjectedtofrequentglaciationsinthepast,tropicallatitudeshaveremainedrelativelyundisturbedformillionsofyearsandthus,hadalongevolutionarytimeforspeciesdiversification. • Tropicalenvironments.Unliketemperateones,arelessseasonal,relativelymoreconstantandpredictable,promotesnichespecializationandleadtogreaterspeciesdiversity. • Thereismoresolarenergyavailableinthetropics,whichcontributetohigherproductivity.
Speciesarearelationship: • ALEXANDERVONHUMBOLDTobservedwithinaregionspeciesrichnessincreasedwithincreasingexploredareabutonlyuptoalimit. • Therelationbetweenspeciesrichnessandareaforawidevarietyoftaxaturnsouttobearectangularhyperbola. • OnalogarithmicscaletherelationshipisastraightlinedescribebytheequationLogS=logC+ZlogA • WhereS=speciesrichness,A=Area,Z=slopeoftheline(regressioncoefficient),C=Y-intercept
ImportanceofspeciesdiversitytotheEcosystem: • Communitywithmorespeciesgenerallytendstobemorestablethanthosewithlessspecies. • Astablecommunityshouldnotshowtoomuchvariationinproductivityfromyeartoyear;itmustberesistantorresilienttooccasionaldisturbances(naturalorman-made) • Stablecommunitymustberesistanttoinvasionbyalien • species. • David Tillman’s long-termfieldexperimentfindsthat: • Plotswithmorespeciesshowedlessyeartoyearvariationin • biomass • Increaseddiversitycontributedtohigherproductivity.
LossofBiodiversity: • TheIUCNRedList(2004)documentstheextinctionof784species. • Recentextinctionincludes: • Dodo(Mauritius). • Quake(Africa) • Thylacine(Australia) • Stiller’s cow (Russia) • Threesubspeciesoftiger(Bali,Java,Caspian). • Sincetheoriginanddiversificationoflifeonearththerewerefive episodesofmassextinctionofspecies. • ThesixthmassExtinctionsinprogressnow.
Howthe’sixth Extinction’is different fromthe • previousfiveextinctions. • Thecurrentextinctionrateis100to1000timesfaster. • Allothersarepre-humanperiod,thisoneisanthropogenic.
Effectofbiodiversityloss: • Declineinplantproduction. • Loweredresistancetoenvironmentalperturbationssuchasdrought. • Increasedvariabilityincertainecosystemprocessessuchasplantproductivity,wateruse,andpestanddiseasecycle.
Causesofbiodiversityloss: • Thepresentlossisallduetohumanactivity(anthropogenic) • Therearefourmajorcauses“The Evil Quartet” areasfollows: • 1.Habitatlossandfragmentation • 2.Over-exploitation: • 3.Alienspeciesinvasion: • 4.Co-extinction:
Habitatlossandfragmentation: • Mostimportantcausedrivinganimalsandplantstoextinct. • Thetropicalrainforestreducedto6%from14% • ofearthlandsurface. • TheAmazonianrainforestiscalledas‘lungsoftheplanetǮis being cut cleared for cultivating soya beans. • Degradationofmanyhabitatbypollutionisalsothreatensthelossofdiversity. • Largeareasarebrokenintofigmentsalsothecause • ofdiversityloss.
Over-exploitation: • When Ǯneedǯ turns to Ǯgreedǯ it leads to over-exploitationofnaturalresources. • Manyspeciesextinctionsinthelast500yearsȋStillerǯs cow, passenger pigeonsȌ were due to over-exploitation. • Manymarinefishpopulationsaroundtheworld • areoverharvested.
Alienspeciesinvasion: • Thealienspeciesbecameinvasiveandcausedeclineorextinctionofindigenousspecies. • NileperchintroducedintoLakeVictoriaineastAfricaledtoextinctionof200speciesofcichlidfishinthelake. • Parthenium,(carrotgrass),Lantana,andwaterhyacinth(Eichornia)posedathreadtoindigenousspecies. • AfricancatfishClariasgariepinusforaquaculturepurposedisposingathreattoindigenouscatfishesinourrivers.
Co-extinction: • Whenaspeciesbecomesextinct,theplantandanimalspeciesassociatedwithitanobligatorywayalsobecomeextinct. • ExtinctionofHostspeciesleadstoextinctionof • theparasitealso. • Co-evolvedplant-pollinatormutualismwhereextinctionofoneinvariablyleadtotheextinctionoftheother.
BIODIVERSITYCONSERVATION: • Reasonforconservationbiodiversityisgroupedintothreecategories. • Narrowlyutilitarian. • Broadlyutilitarian • Ethical
Narrowlyutilitarian: • Humanderivecountlessdirecteconomicbenefitsfromnature- • Food(cereals,pulses,fruits),firewood,fiber,constructionmaterial. • Industrialproducts(tannins,lubricants,dyes,resins, • perfumes) • Productsofmedicinalimportance. • Bioprospecting:exploringmoleculargeneticandspecies-leveldiversityforproductsofeconomicimportance.
BroadlyUtilitarian • Amazonianforestalongproduce20%ofoxygenduringphotosynthesis. • Pollinatorlayer:bees,bumblebees,birdsandbatthatpollinatetheplantwithoutwhichseedcannotbeproducedbyplants. • Aestheticpleasurewegetfromthebiodiversity.
Howdoweconservebiodiversity? • Insituconservation: • Whenweconserveandprotectthewholeecosystem,itsbiodiversityatalllevelisprotected– wesavetheentireforesttosavethetiger.Thisapproachiscalledinsitu(onsite)conservation. • Biodiversityhotspot:regionswithveryhighlevelsofspeciesrichnessandhighdegreeofendemism.(speciesconfinedtothatregionandnotfoundanywhereelse) • Hotspotinbiodiversityisalsoregionsofacceleratedhabitatloss. • Outof34hotspotintheworld,threehotspotlocatedinIndia: • WesternGhatsandSrilanka. • Indo-Burma. • Himalaya.
Otherprotectedareaunderinsituconservationsare: • 14biospherereserve • 90nationalpark • 448wildlifesanctuary • • Sacredgroves:tractofforestweresetaside,andallthetreesandwildlifewithinwereveneratedandgiventotalprotection
Exsituconservation • Threatenedanimalsandplantsaretakenoutfromtheirnaturalhabitatandplacedinspecialsettingwheretheycanbeprotectedandgivenspecialcare. • ZoologicalPark. • Botanicalgarden • Wildlifesafari. • Conservationofgametebycryopreservation. • Geneticstrainsarepreservedinseedbank.
ConventiononBiodiversity: • “The earth Summit” held in Rio de Jeneiroin1992calleduponallnationstotakeappropriatemeasuresforconservationofbiodiversityandsustainableutilizationofitsbenefits. • WorldSummitonSustainabledevelopmentheldin2002inJohannesburg,SouthAfrica,190countriespledgedtheircommitmenttoachieveby2010asignificantreductioninthecurrentrateofbiodiversitylossatglobal,regionalandlocallevel.