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1、Biol.Rev.(2007),82,pp.393423.393doi:10.1111/j.1469-185X.2007.00017.xEcologyofAustralia:theeffectsofnutrient-poorsoilsandintensefiresGordonH.Orians1,*andAntoniV.Milewski21DepartmentofBiology,Box351800,UniversityofWashington,Seattle,Washington98195,USA(E-mail:blackbrd@serv.net)2Per
2、cyFitzPatrickInstituteofAfricanOrnithology,UniversityofCapeTown,SouthAfrica(E-mail:milewski@rts.com.au).(Received15November2006;revised9February2007;accepted2May2007)ABSTRACTAustralia,theflattest,driest,andgeologicallyoldestvegetatedcontinent,hasauniquelyhighproportionofnutrient-
3、poorsoils.WedevelopaNutrient-Poverty/Intense-FireTheory,whichpostulatesthatmostanomalousfeaturesoforganismsandecosystemsofAustraliaaretheevolutionaryconsequencesofadaptationstonutrientpoverty,compoundedbyintensefirethattendstooccurasaresultofnutrientpoverty.Thefundamentaltenetoft
4、hetheoryisthatplantsgrowinginenvironmentswithplentifullightandperiodicadequatemoisture,butonsoilspoorinphosphorus,zinc,andotherindispensiblenutrients,cansynthesizecarbohydratesinexcessoftheamountthatcanbecombinedwith,orcatalyzedby,thesenutrientsformetabolismandproductionofnutrien
5、t-richfoliageandreproductivetissues.Theyusethisexpendableenergytoproducewell-defendedfoliage,largequantitiesoflignifiedtissues,andreadilydigestibleexudates.Rapidaccumulationofnutrient-poorbiomass,aresultoflowratesofherbivory,providesfuelforintensefire.Intensefireexacerbatesnutrie
6、ntpovertybyvolatilizingcertainmicronutrientscriticalforanimals.AnomalousfeaturesoforganismsofAustraliathatcanbeexplainedbythistheory,ratherthanbyclimateorphylogenetichistoryalone,includethefollowing:mostwoodyplantshavelong-lived,durablefoliage;plantsdefendtheirtissuesprimarilywit
7、hcarbon-richbutnutrient-poorcompounds;anunusuallyhighproportionofplantsprotectsseedsfromfireandgranivoresinsturdy,woodycapsulesorfollicles;plantsallocateunusuallylargeamountsofexpendableenergytoproductionofcarbon-basedexudates,suchasnectarandgums;anunusuallyhighproportionofplants
8、peciesispollinatedbyvertebratesthatavera
