Site 2 (28°22′38.12″S; 32°25′23.60″E) was chosen as the freshwater seepage site, where dredge spoil was deposited in the past (Fig. 1). This site had the oldest mangroves sampled in this study, as they were established in the 1960s. Stands of A. marina and B. gymnorrhiza occurred at Site 2 (also known as the Black Pipe or Shark Basin site). Phragmites australis and A. aureum were densely interspersed within the old Bruguiera stands (Quadrat 2) and the Avicennia stands (Quadrats 3 and 4) were sparsely interspersed with P. australis only. The sediment that occurred in the Bruguiera stands (Quadrats 1 and 2)was also much drier when compared to the Avicennia stands (Quadrats 3 and 4) that were waterlogged and covered in a dense mat of pneumatophores. This site was characterised as the freshwater site as both the sediment and porewater salinity were very low.