Distribution and diversity of macrobenthos community in the seagrass ecosystem of Merambong Shoal, Johor, Malaysia
Merambong Shoal seagrass bed is heavily impacted by reclamation activities that has been ongoing since 2014. A monitoring survey was conducted to monitor the diversity and distribution of macrobenthos community structure in this seagrass bed along with its interaction with sediment and macrophyte...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/98805/1/FP%202021%2055%20-%20IR.pdf |
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| Summary: | Merambong Shoal seagrass bed is heavily impacted by reclamation activities
that has been ongoing since 2014. A monitoring survey was conducted to
monitor the diversity and distribution of macrobenthos community structure in
this seagrass bed along with its interaction with sediment and macrophytes
composition in relation to possible environmental disturbance or habitat
alteration caused by the reclamation activities. Three 200 m transects were laid
across the Merambong North Stations (MNS) while another two were placed in
the Merambong South Stations (MSS). Macrobenthos sediment samples were
collected bi-monthly from five transects on the seagrass bed using PVC hand
corer from December 2015 to June 2018. Macrophytes composition data was
also collected from December 2016 to June 2018 using the same transects.
Results showed that there was obvious decline in monthly mean density (6.6 –
14.6 ind per m2) and alteration in the composition of macrobenthos dominant
groups inhabiting the seagrass bed compared to other previous studies in the
same area. There was also spatial difference in where MNS was recorded to
have lower macrobenthos abundance (6.6 – 7.0 ind per m2) as in comparison to
MSS (10.6 – 14.6 ind per m2). As according to Bray-Curtis similarity analysis the
reclamation activities might also even created two distinctively different structure
of macrobenthos communities originated from one shoal. It was recorded that
there was significant difference (p<0.05) in silt percentage between different
transects where T1, T2 and T3 were found to have higher silt percentage (2.10%
- 3.01%) than T4 and T5 (0.96% - 1.12%) suggesting higher sedimentation in
this part of the shoal. The reclamation activities have also resulted in spatial
differentiation in macrophytes composition between different transects around
the seagrass bed. MNS was mainly dominated by opportunistic macroalgae Ulva
reticulata while MSS continued to contain higher abundance of seagrass cover.
It was recorded that there is significant correlation (p< 0.05) between abundance
of major macrobenthos groups abundance with sediment and macrophytes
composition. Signs of recovery in the seagrass ecosystem were observed after the excavation of the sand causeway separating MNS and MSS, starting August
2017 onwards where seagrass was observed to recolonize MNS area directly
replacing the Ulva reticulata invasion. These results concluded that the
reclamation activities might have damaging effects on macrobenthos community
in Merambong Shoal which also significantly altered its community structure. |
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