Ecological status and role of the Mfolozi–Msunduzi estuarine system within the iSimangaliso Wetland Park, a World Heritage Site on the south-east coast of South Africa

Abstract

The original structure and functioning of the historical Mfolozi–St Lucia estuarine system are described and anthropogenic impacts, which resulted in the Mfolozi and Msunduzi rivers being separated from the St Lucia Estuary and having their own combined mouth to the sea, are detailed. An overview is provided of the current ecological status of three major faunal groups, zooplankton, benthos and fish, present in the Mfolozi–Msunduzi estuarine system, a system upon which, until recently, virtually no scientific research had been conducted. Currently, decreased rainfall and extended closure of the St Lucia mouth have resulted in this system being under major ecosystem stress. Management options, both short- and long-term, related to reconnecting the Mfolozi–Msunduzi to a common mouth with St Lucia are considered. These include the re-establishment of sediment-filtering swamps in the lower reaches of the Mfolozi and Msunduzi rivers, as well as the construction of levees that would protect the bulk of the adjacent land on which sugar cane is farmed. Concern is expressed regarding potential problems that may arise as a result of the reconnection of the two systems.

Keywords:

• anthropogenic impacts
• benthos
• drought
• estuary
• fish
• management
• marine environment
• mouth closure
• zooplankton