Observations of Natural Recruitment and Human Attempts at Mangrove Rehabilitation After Seismic (Tsunami and Earthquake) Events in Simeulue Island and Singkil Lagoon, Aceh, Indonesia - Post-Tsunami Hazard: Reconstruction and Restoration - page 308

It must be noted, that this pattern of subsidence and upward migration of mangroves
merits further study, as it provides an accelerated analogue of the anticipated effects
of sea level rise on mangrove distribution.

19.2 Methods

Ten, 20 m × 5 m vegetation plots were temporarily established shore-left in a
random stratifi ed design (Duke 2011 ). Within each 100 m 2 plot total counts of
trees (dbh > 2.5 cm, height > 130 cm, saplings (dbh < 2.5 cm, height > 100 cm) and
seedlings (height < 100 cm)) of each species were determined. Girth of each tree
was recorded using a tape measure and from this the cross-sectional area, or basal
area (BA), was calculated to give an indication of growth and dominance. Tree
height was recorded using an extendable height stick. Height of the fi rst ten saplings
and seedlings encountered were recorded.
A pair of sits (Teluk Dalam - Mercu Suar and Teupah Selatan) were monitored
twice at a 12 month interval. The relationship between average stem densities over
time for these two sites were examined with correlation analyses. Changes in
density between pre-rehabilitation survey and most current survey data per site were
analyzed with paired student T-tests using months since rehabilitation and average
densities as group factors at 95 % confi dence levels. The remaining four sites
were only measured once, and a rate of recruitment was calculated simply by
dividing the average stem density by the 7 years since the most recent major seismic
disturbance (March 2005).
In all, six sites were measured, four of which had not experienced any degree of
mangrove planting and two of which had been previously planted as part of the
earlier rehabilitation attempts:

Never planted

1. Teluk Dalam-Mercu Suar (TDMS)
2. Teupah Selatan (TS)
3. Singkil Lagoon 1 (SL1)
4. Singkil Lagoon 3 (SL3)

Previously planted

5. Teluk Dalam-Sambay (TDS)
6. Singkil Lagoon 2 (SL 2)

To better understand stakeholder perspectives, non-formal interviews, formal interviews
and focus group discussions were conducted with 200 villagers in partner villages
in Simeulue Island and Singkil, as well as government agents from District Level
Forestry Department, and Environmental Agency. Data was not analyzed, but
anecdotes are used below.