1.1
Monitoring of the relocated
seagrass bed (Halophila beccarii) for
survival and growth at Pak Nai was required to be conducted quarterly during
the construction phase of the Project as specified in Section 6.2.3
of the EM&A Manual.
1.2
Equipment used for monitoring
included a 50x50cm
quadrat, measuring ruler, digital camera and handheld GPS.
1.3
Monitoring was conducted at the
4 locations (A, B, C and D) on the intertidal flats at Pak Nai.
1.4
Sediment plugs on the
intertidal flats at Pak Nai were relocated using visual markers that had been
placed at each location at the time of transplantation,
and using GPS. Care was taken not to
disturb each site by avoiding trampling.
1.5
At each location (dimensions of
1.5 x 1.5m), monitoring was conducted by our ecologist to
measure presence/absence of seagrasses and seagrass cover. Monitoring also included observations on seed
germination, leaf size and general
condition of any seagrass present.
1.6
The eleventh quarterly survey
to monitor the seagrass transplantation sites (A,
B, C and D) was conducted on 20th
September 2006 following relocation of sediment plugs in September 2003. A photographic record of each transplantation
site is presented in Figure 1.2.
1.7
During the monitoring visit, no seagrass was observed at any transplantation
sites.
Site A
1.8
Seagrasses were considered to
have spread from the transplantation seagrass bed into the adjacent area and
the mudflat did not detect any presence of seagrass in the last two monitoring
surveys. During the recent survey, about 30% coverage of seagrass was found in the
transplantation site. In addition, the seagrass was found close to the
transplantation site in the recent survey. It was considered that the seagrass spread from
the adjacent area to the transplantation site.
Site C
1.9
During the December 2004 survey, a small number of about half a dozen seagrass
leaves were found at the edge of the transplantation site in one of the
corners. In the survey in March 2006, coverage was about 50% of the transplantation
site. For the recent survey, the mudflat did not detect any presence of
seagrass. In addition, a cluster of grasses were found growing, from about 10% in the last survey to about 40% in the
recent survey, and occupying the
seagrass transplantation site area. It
was considered that the invasion of the grasses changes the condition of the
transplantation site. Due to the changes
of biotic condition, the
transplantation site might become unfavourable for the growth of the seagrass, which would respond to the unfavourable condition. Based on the observation in the previous
surveys, it was expected that the seagrass
has spread into the area adjacent to the transplantation site.
Sites B and D
1.10
Similar to the previous surveys, no seagrass was detected in transplantation sites
B and D by close observation of the mud surface. At sites B and D,
no seagrass plants were present growing on the sediment previously identified
as supporting seagrass in the EIA report. Although the transplanted sediment may contain
seeds derived from previously existing seagrasses growing on the sediment, monitoring observations revealed no evidence of
germination since the previous monitoring survey.
1.11
Monitoring of relocated
sediment plugs was conducted at 4 locations on the Pak Nai intertidal flats on 20th
September 2006. In the recent survey, seagrass was only observed on the mudflat at Site
A. At Site A,
it was considered that the seagrasses have spread from the adjacent area to the
transplantation site. At Site C, it was considered that the seagrass has spread
into the area adjacent to the transplantation site because it responded to the unfavourable
condition. At the two other locations
(Sites B and D) monitoring observations indicated that there was no evidence of
seed germination despite the possibility that the relocated sediment may
contain seeds deposited by seagrasses living on it that had since disappeared.