information:extraction, linguistic:paraphrasing
Mangroves and salt marsh

Mudflats exist along the shoreline of the Royal National Park which is substantial enough to sustain a simplistic system of mangrove woodlands especially along the Port Hacking Estuary with the occasional clump of stunted tree on the seaward coastline in sheltered coves. Vegetation in the mangroves consists almost exclusively of the grey mangrove (Avicennia marina var. australasica) growing up to 4m as well as the river mangrove (Aegiceras corniculatum) which is usually only found on the shoreward edge of mangrove woods or in the brackish end of the Port Hacking Estuary.

These mangroves are important nursery grounds for nearly all major angling fish including yellowfin bream (Acanthopagrus australis), flat-tail sea-mullet (Liza argentea), luderick (Girella tricuspidata) and sand whiting (Sillago ciliata) which are caught in adjoining waters as adults, mangroves also provide rich organic matter to the Port Hacking Estuary by fixing carbon into the river system through the addition of leaves into the thick rich black mud. Many crustacean and mollusc species rely on mangroves as a source of food whether by providing foraging through leaf litter, mud or direct predation of the mangrove trees and seeds. Soldier crabs (Mictyris longicarpus), semaphore crab (Heloecius cordiformis), blue swimmer crabs (Portunus pelagicus) and hermit crabs (Pagurus sinuatus) also call the mangroves home. A more casual visitor to the mangroves at high tide is the eastern sea garfish (Hyporhamphus australis) which scoots around just an inch from the surface and is virtually invisible unless viewed through a snorkel.

Dozens of different bird species may be seen foraging in the rich mudflats in and around mangrove flats many of these birds being threatened with extinction and protected by international agreements. Commonly seen bird species include Eastern curlews (Numenius madagascariensis), striated herons (Butorides striatus), brown honeyeaters (Lichmera indistincta), little egrets (Egretta garzetta), royal spoonbills (Platalea regia), white-faced grey herons (Egretta novaehollandiae), Australasian little bitterns (Ixobrychus dubius), pied oystercatchers (Haematopus longirostris), Australasian pelican (Pelecanus conspicillatus), sacred ibis (Threskiornis moluccus), chestnut teal (Anas castanea) and azure kingfishers (Alcedo azurea).