Generally, A. marina benefits more than other species from the
growth of mudflats and is considered as a pioneer species in these
environments. This was also observed by Weiss (1972) in S and SW
Madagascar. We noticed in Zone A (Fig. 4) the spontaneous
expansion of a mangrove forest in a region where human pressure
was very low: the mangrove area increased from 1315 ha to
1394 ha between 1951 and 2000, i.e. a mean increase of
1.7 ha year1 over 49 years. As shown in Fig. 4, nearly five-sixths
of the area occupied by water in 1951 had been invaded by
mangrove forest in 2000. It can also be seen (Fig. 4) that 90% and
50% of the two mudflats in 1951 (to the west and to the north of
Ankilifaly, respectively) had been invaded by A. marina and/or Rh.
mucronata by 2000.