Biodiversity Strategy - Gosford City Council - NSW Government

considered. This is true for all riparian and emergent vegetation.
Although mangroves are protected under NSW Fisheries legislation, they are now considered to
be opportunistic. They have become particularly prolific around creek deltas where mud is
accumulating. Their ability to trap and accumulate sediments has resulted has seen their
expansion into creeks and other waterways, limiting or denying navigation of marine craft. They
are also encroaching into and displacing saltmarsh habitats. This has become an issue of
particular concern because saltmarsh habitats have already been considerably reduced in the
area as a result of urban expansion.
Saltmarshes
Saltmarshes play a similar water filtration role to that outlined for mangroves. Biofilms
associated with emergent vegetation and root systems are extremely effective in binding
contaminants. The high density of saltmarsh plants makes them excellent pollutant filtration
systems. Stormwater flows to these systems slow, facilitating the removal of sediments,
particulate matter and dissolved contaminants. The habitat is poorly conserved in NSW as
continuously more is cleared for development.
In Gosford, the frontal levee of the saltmarsh is typically dominated by Sporobolus viginicus, but
where drift litter accumulates Suaeda australis, Tetragonia tetragonioides and Sesuvium
portulacastrum can also be abundant (Figure 6.3). Casuarina glauca is found higher on the
levees. Sarcocornia quinqueflora occurs in the depression landward of the levee, together with
Triglochin striata and Samolus repens, in the wetter patches. Dense rush, Jucus kraussii, or
sedge, Baumea juncea, comprise the mid-marsh community. Fringing the pools are Phragmites
australis, Schoenoplectus litoralis and Schoenoplectus validus, while Ruppia and the alga
Lampromthamnion papulosum may be abundant within the pools. Scattered through this zone
are isolated Casuarina glauca and mangroves.
Figure 6.2 Avicennia marina, seedlings and pneumatophores (Peter Freewater)
Biodiversity - Technical Report Page 132