4.2. Initial achievements of the restoration effort
It was observed that mangrove saplings transplanted in the
sheltered area have been securely protected from the wave action
by the defence structure (breakwater). Using coir logs, on the other
hand, seedlings are pre-grown in nursery and the roots are firmly
anchored in the coir, reducing the risk of being washed away by
waves. The restored mangroves are expected to trap natural
waterborne mangrove propagules (provided by the adjacent
natural mangroves) that will contribute to further expansion of the
new mangrove stands.
Approximately 30% of the original saplings survived as of the
last date of monitoring, February 2009 (Fig. 7). This survival rate
eight months after initial restoration indicates that the restoration
project achieved a moderate degree of success. The result is very
encouraging since mangrove restoration efforts on eroding shorelines
exposed to wave action are not often successful (Riley and
Kent, 1999).
As illustrated in Fig. 7, 27.1% of mangrove saplings had died
during the first month of being transplanted to the site. The reason
for this early mortality could be that conditions (e.g. salinity, sun
exposure, wave energy, inundation regime, etc) in the nursery are
not generally the same as in the restoration site. This could cause
stress when transplanting the seedlings nurtured in a nursery to
the restoration site (Gilman and Ellison, 2007). However, as
described in Section 3.3, the conditions of the project site were not
appropriate to plant seedlings/propagules directly in the site.
Approximately 70% mortality of mangrove saplings during eight
months, from July 2008 to February 2009, could be attributed to