Sonneratia,　a　critical　genus　within　tropical　and　subtropical　coastal　mangrove　forests　in　the　Indo-West　Pacific　biogeographic　region,　includes　Sonneratia　×　hainanensis,　Sonneratia　×　gulngai,　and　Sonneratia　ovata,　which　are　rare　and　endangered　mangrove　plants　on　Hainan　Island,　China.　Despite　its　conservation　significance,　there　has　been　a　lack　of　comprehensive　scientific　study　on　the　population　status　and　endangerment　mechanisms　of　this　genus.　In　this　study,　using　the　multiple　methods　like　diameter　at　the　breast　height　(DBH,　acquiring　from　the　field)　instead　of　age　classes,　calculation　in　the　quantity　between　each　pair　of　adjacent　DBH　classes　(laboratory　analysis,　the　same　below),　static　life　table　compilation,　population　prediction,　and　artificial　pollination,　we　investigated　the　population　structures,　dynamics,　and　flowering　traits　of　these　above-mentioned　three　endangered　Sonneratia　plants.　Our　findings　revealed　that　S.　×　hainanensis　and　S.　×　gulngai　populations　had　a　critical　deficiency　in　young　individuals,　indicating　poor　self-renewal　capacity　and　a　likely　population　decline　in　the　future.　In　contrast,　S.　ovata　showed　a　high　proportion　of　young　individuals,　suggesting　a　potential　for　population　increase.　This　divergence　in　population　dynamics　correlates　with　differences　in　flowering　traits　among　the　mangroves.　S.　ovata　exhibited　the　highest　pollen　viability,　fruit　set　rate,　and　average　seed　count　per　fruit.　Consequently,　our　study　suggests　that　the　flowering　traits　of　these　Sonneratia　plants　are　pivotal　to　their　conservation　status.　To　address　the　current　population　challenges,　we　recommend　the　promotion　of　artificial　pollination,　the　preservation　of　ex　situ　germplasm　resources,　and　the　enhancement　of　in　situ　conservation　efforts.　Additionally,　strict　measures　should　be　implemented　to　prevent　anthropogenic　deforestation　and　habitat　destruction　and　long-term　conservation　education.　These　strategies　are　essential　for　the　sustainable　conservation　and　management　of　endangered　Sonneratia　plants.　©　2025　The　Authors