Early vegetation recovery of a burned Mediterranean forest in relation to post-fire management strategies

TheriskofwildfiresintheMediterraneanregionisexpectedtoincreasewithclimatechange.Fireisoneofthemaindriversofplantdiversityandcomposition,triggeringsuccessionprocessesthatvaryaccordingtothefireregimeandspecies’regenerationtraits.Humanmanagementcanmodulatetheseprocessestopromotetherecoveryoftheburnedsoil-vegetationsystem,throughtheapplicationofpracticessuchassalvagelogging.Effectsofthesemanagementshavebeenstudiedmostlyforconiferousforests,withcontrastingresults,whilelittleisknownabouttheresponsesofevergreenbroadleavedwoodlands.Here,weanalysedthe34-monthrecoveryprocessesofaQuercusilexforestandanadjacentPinuspinasterstandincentralItalywithrespecttotheirdiversity,compositionandplantfire-relatedtraits,inrelationtothreedifferentmanagementstrategiesappliedafterfire.Thesewere:(1)nointervention(NT),(2)salvageloggingandmulching(SMandSMPforthepinestand),(3)salvagelogging,mulchinganderosioncontrolmeasures(e.g.fascinesforhillslopestabilization;EC).Overall,theincreaseofpost-firevegetationcoverwasnegativelyaffectedbySMandECtreatments,whiletheireffectsonγ-andα-diversitywerepositive.Speciesdiversitywassignificantlylowerinpinethaninbroadleavedplotsandcompositionaldifferencesassociatedwithforesttypeweresignificant.Abundanceofwoodyspecieswashigherintheunsalvagedsites,exceptforafewspecies(e.g.Q.ilex),whileherbaceousplantswerenotaffected.Speciescompositioninmanagedplotswasdifferentfromcontrolplotsafter10and22months,whiledifferencesdecreasedafter34months.Effectsofmanagementstrategiesonthefrequencyofresproutersaswellasontheproportionofspecieswithpersistentvstransientsoilseedbankwereminor;thesetraitsweremainlydrivenbyforesttype.Ourfindingssuggestthatnon-treatmentisthebestpost-firemanagementstrategyforafastrecoveryofwoodyspeciesintypicalMediterraneanbroadleavedforests.However,theECstrategypromotedahighdiversitylevel,whilenotapparentlyalteringspeciescompositioncomparedwiththenaturalpost-firesuccessionprocess.