A characteristic macrobenthic community within the recently proclaimed uThukela Marine Protected Area, South Africa

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Abstract Summary

Marine benthic habitats, and the organisms that reside there, are vulnerable to direct habitat destruction and indirect anthropogenic activities such as pollution or freshwater flow reduction to habitats that require coastal connectivity. To reduce threats to these and other important ecosystems, they should be conserved through the establishment of Marine Protected Areas (MPAs). This study occurred within the uThukela Marine Protected Area, one of 20 new MPAs recently promulgated in the South African MPA network. This unique system is off the largest river on the east coast and its ecosystem attributes are significantly reliant on river outflow. The project aim is to contribute to the baseline information of this MPA through expanding our knowledge of the macrobenthic community and the abiotic factors influencing community distribution. Replicated benthic grab samples were collected along coast-perpendicular transects on the uThukela shelf, representing distance from shore and increasing depth. Numbers of taxa (identified to the lowest taxonomic level possible), abundances, and functional traits were noted. Multivariate analyses determined that uThukela shelf macroinvertebrates represent many different taxa but in low abundances. Communities are primarily distributed according to sediment grain sizes, and exhibit trait differences in the different sediment habitats. Polychaetes (mainly facultative detritivores) constitute 50% of the macrobenthic community abundance on the uThukela shelf, with crustaceans and molluscs also appearing in high abundances. These detritivores rely on organic matter and muddy substrates deposited on to the shelf by the uThukela river, but adaptive feeding behaviour allows dietary shifts when conditions do not favour optimal deposition. Macrobenthic communities are vital in the functional success of any marine ecosystem; particularly the uThukela system where previous studies have indicated macrobenthos as the most significant functional trophic compartment. These findings originate from recent samples collected prior to the protection of uThukela, thereby contributing to uThukela MPA baseline information.

Abstract ID :
Submission Type
Oral Presentation
Submission Topic
Management of protected areas and buffer zones

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