1. TRANSPLANTED SEAGRASS BED MONITORING

Monitoring Requirements

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.

Monitoring Equipment

1.2 Equipment used for monitoring included a 50x50 cm quadrat, measuring ruler, digital camera and handheld GPS.

Monitoring Location

1.3 Monitoring was conducted at the 4 locations (A, B, C and D) on the intertidal flats at Pak Nai.

Monitoring Methodology

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.

Results and Observations

1.6 The thirteenth quarterly survey to monitor the seagrass transplantation sites (A, B, C and D) was conducted on 13 December 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 recent visit, seagrass was observed at three transplantation sites - Site A, B and D.

Site A

1.8 About 30% coverage of seagrass found in the transplantation site was reported in the last monitoring survey. During recent survey, transplantation site and the adjacent area were observed to be densely covered by seagrass. The coverage of seagrass substantially increased to about 80%.

Site C

1.9 It was reported that a cluster of grass was found occupying 40% of the transplantation site and no seagrass was observed in the last monitoring report. During recent survey, grass on the transplantation site was found extend the coverage to about 60%. No seagrass was found within the transplantation site but seagrass was observed sparsely present on the adjacent mudflat area. Grass invasion increased the competition for resources such as light and nutrients, transplantation site was therefore less favourable for the growth of seagrass. It was considered that seagrass spread to the area adjacent to the transplantation site for lower competition.

Sites B and D

1.10 During recent survey, about 70% coverage of seagrass was recorded on the mudflats of the transplantation sites. Unlike the recent finding, seagrass was rarely detected in these sites since the relocation of seed-containing sediment plugs, though mudflats at these areas were identified as seagrass-supporting in the EIA report. The presence of seagrass might be due to the change of biotic or abiotic condition within the transplantation sites and the mudflat habitat became more favourable for the growth of seagrass.

Conclusions

1.11 Monitoring of relocated sediment plugs was conducted at 4 locations on the Pak Nai intertidal flats on 13 December 2006. In the recent survey, seagrass was observed on the mudflat at Site A, B and D. At Site A, the coverage of seagrass was about 80%. At Site C, it was considered that seagrass responded to the unfavourable biotic condition and spread to the area adjacent to the transplantation site. At Sites B and D, there was about 70% coverage of seagrass recorded on the mudflats.