etude des parametres influençant la reussite de restauration des mangroves dans la baie des assassins, aire marine protegee velondriake (région sud-ouest de madagascar)

Abstract

This study was carried out from August 2021 to November 2021, with the main purpose
to investigate the parameters influencing the success of mangrove restoration in the Bay of
Assassins. Three species (Rhizophora mucronata, Ceriops tagal and Bruguiera gymnorrhiza)
were planted. The data on mangrove survival rate of these species between 2015 to 2020 was
taken into account. Within more than 70 replanted mangrove degraded areas, 20 sites were
chosen to carry out this study. A countdown was conducted to identify the tide and season of
the planting. Other factors (salinity, site location, frequency of inundation and substrate type)
were collected in the field.
The mean survival rate of the replanted mangrove in the Bay of Assassins is 82.2±20%.
There was no significant difference between the survival rate in neap and spring tides (p =
0.907). The planting season (rainy and warm season, dry and cool season) was not among the
factors influencing the survival rate (p = 0.848). Three types of substrates were identified
including sandy, sandy-muddy and muddy. For that, the survival rate ranged between
56.32±5.21% to 92.55±7.2%. Thus, the difference between the type of substrate has no
significant influence on the survival rate (p = 0.223). The salinity of the sites varied from
17.5±4.2‰ to 60.5±23.1‰. The influence of salinity on the survival rate was not significant
(p= 0.131), although there was a low positive correlation (r = 0.263).
KEYWORDS: mangroves, restoration, plantation, survival rate, factors, Bay of Assassins