Analyse Phytoécologique de la Flore Ligneuse de la Haute Sangha (République du Congo)

[摘要] PhytoecologicalanalysisofthewoodyfloraofHighSangha(RepublicofCongo).ThefloraoftheHighSangha,justlikethatofCongoasawhole,developsinthecorridorofthe“SanghaRiver”ofGuineo-Congolianarea.Stillbadlyknown,itisstudiedaccordingtoaNorth-easternSouth-westernfloristicgradient,correspondingtoaphytogeographicaldistributionextendingfromtheAtlanticelement(Nigero-Cameroono-Gabonese)totheCameroono-Congoleseelement.OnbothsideoftheSanghaRiver,thesurfaceofstudyissubdividedinthreesectorswhosecentralzoneisthefloristicjunctionbetweenSouth-westandtheNorth-East.Theinventoryoftheindividualsofdbh≥10cmcounts387speciesofwhich12marktheSouth-westernsector,18fortheNorth-easternsectorandsixforthecentralsector.Theverticaldistributiondistinguishesthreelayersfromunequalimportance,ofwhichthepercentageofspeciesoscillatesfrom24to42%.Floristicdiversity,interpretedbytheindicesofbiologicaldiversityofShannon(6.51à7.89)andSimpson(0.96à0.99),ofthecorrelationsofsimilarityofJaccard(31to38%)andofSørensen(62to76%)authenticatesthefloristicchangethroughoutgradientofstudy,withoutanydominanceoftaxa.TheweakestindicesofbiologicaldiversitycharacterizetheCentralsector.Thefloristiccompositionofthethreesectors,concomitantly,showsareductioninthenumberofindividualsforcertainspecies,andconcerningsomeothersanextinctionoftheirsurfaceofdistribution,asapproachingormovingawayfromtheSanghaRiver.Theecologicalcharacteristicsoftheflorashow77%ofsarcochoresand88%ofmesophylles.Theecologicalvalenceandtheabundance-dominanceratioshowthat72%ofspeciesareubiquistsandtheirdensityliesbetweenthreeandfiveindividuals/ha.

[学科分类] 植物学

[关键词] Republic of Congo;floristic diversity;ecological indices;Guineo-Congolian region;High Sangha;phytoecology;République du Congo;diversité floristique;indices écologiques;région Guinéo-Congolaise;Haute Sangha;phytoécologie