The salt marshes of the Northern shores of Leisure Isle, particularly those of Kingfisher Creek show the well-developed zonation typical of the Knysna salt marshes i.e. upper, middle and lower marsh. These zones occur in response to the tidal flooding experienced by the marsh vegetation as a result of differing heights above mean sea level.
Small creeks penetrate into the upper marsh in some areas of Kingfisher Creek with the result that some of the zones are mixed and the vegetation has a mosaic effect. A similar situation applies in Steenbok Nature Park as a result of the construction, many years ago, of the sea wall.
The salt marshes play an important roll in the ecology of the estuary. Briefly they are a habitat for many estuarine species including crabs, mud prawn and worms, all of which occur along the Northern Shores. The Zostera (Eelgrass) beds are a nursery for many juvenile fish species and provide protection and feeding grounds for the endangered Knysna seahorse. They are also a feeding, breeding and nesting site for many bird species.
The upper marsh provides an important site for the degradation of suspended animal and plant material during spring high tides this material is deposited on the upper marsh where it decomposes. It is imperative that these ecologically sensitive but highly functional areas be nurtured and protected.
We wish to thank Bronwen Marais for writing this introduction and for her invaluable assistance in identifying the different species. We also thank Professor Brian Allanson for arranging for us to have access to the Salt Marsh Field herbarium of the Knysna Basin Project which facilitated the identification process.