The Influence Of Aerial Root/belowground Root Structure On The Vertical Accretion And Elevation Change Of Mangroves

Surface elevation changes and sedimentation in mangrove ecosystems are the hot issues in the coasts that facing global climate changes and the rising sea levels.The study aimed to reveal the influence of different mangrove communities with different aerial root structure and belowground fine root biomass on the intertidal surface elevation.The Surface elevation table-Marker horizon(SET-MH)system and Shallow-SET method were used to monitor elevation changes and sedimentation in the Dongzhaigang mangroves at Hainan Province and the Futian Mangroves at Guangdong Province.The in-situ aboveground aerial root and belowground fine root investigation methods combing root cores and ingrowth bags were used.Sample plots of Kandelia obovata community(with plank roots),Sonneratia apetala community(with pneumatophores),Avicennia marina community(with pneumatophores),Rhizophora stylosa(with prop roots),Bruguiera sexangula(with knee roots)were included.The main findings of this study are as the followings.1.IUn Dongzhaigang Mangrove,the surface elevation change rates(SEC rates)in mangroves ranged from 3.24 mm/a to 9.98 mm/a,and in mudflat was-20.48 mm/a.The vertical accretion rates(VA rates)in mangroves varied from 26.18 mm/a to 35.23 mm/a,and was 58.31 mm/a in mudflat.The root zone expansion change of mangrove community ranged from 0.13 mm/a to 1.06 mm/a,and was-1.64 mm/a in mudflat.The Shallow subsidence rates(SS rate)of mangrove communities ranged from 12.70 mm/a to 33.02 mm/a,and was 78.79 mm/a in mudflat.2.In Futian Mangrove,the SEC rates of mangrove communities were found ranged from 4.52 mm/a to 29.35 mm/a,and was-24.00 mm/a in mudflat.The VA rate of mangrove communities varied from 18.90 mm/a to 63.98 mm/a,and was 50.27 mm/a in mudflat.The root zone expansion change of mangrove community ranged from-5.38 mm/a to-0.61 mm/a.The SS rates of mangroves ranged from 5.69 mm/a to 9.21 mm/a,and was 74.27 mm/a in mudflat.3.In Futian Mangroves,the SEC,VA and SS rates of the S.apetala community showed no significant differences before and after destroyed.4.In Dongzhaigang Mangroves,the fine root biomass of mangrove communities ranged from 27.56±3.54 t/hn2 to 41.63±6.26 t/hm2 with method of root cores.The fine root productivity of mangrove communities ranged from 4.5±0.71 t/hm2/a to 8.62± 0.98 t/hm2/a with ingrowth bag methods;with 12.03%to 25.44%fine root turnover rates.In Futian Mangrove,the fine root biomass of mangrove communities ranged from 9.22 ±1.18 t/hm2 to 46.20 ±9.12 t/hm2.The fine root productivity ranged from 23.60±3.33 t/hm2/a to 42.17±23.63 t/hn2/a,with 116%to 267%fine roots turnover rates.