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Animals of the
mangroves
Mangrove forests form the interface between marine and
terrestrial environments. Consequently, animals from both these environments can be found in
the mangroves. Few animals use mangroves as their only habitat. Some live primarily in the
mangroves, while others move in and out of the mangroves seasonally, at different stages of
their life cycle or even depending on the tide.
Saltwater crocodiles are one of the most
infamous inhabitants of mangrove areas. They do not generally nest in mangroves but are found
nesting in vegetation fringing mangrove areas and vegetation where rivers adjoin coastal flood
plains. On the rising tide these reptiles come into the mangroves to feed. Juvenile
crocodiles feed on crabs, prawns, mudskippers and other small fish. As they mature their diet
changes to include large mud crabs, birds and mammals.
Sea snakes are common visitors to
mangrove forests as are terrestrial snakes. Pythons tend to be occasional visitors to the
mangroves, while the Little File Snake, the Mangrove Snake and the White-bellied Mangrove Snake
tend to use the mangroves as their primary habitat. The Mangrove Monitor and the Rusty Monitor,
which feed on insects, fish, crabs and sometimes birds, also use the mangroves as their primary
habitat.
Mudskippers are one of the few animals which are restricted to mangrove environments.
They burrow into the soil and can swim like fish, but, using their pectoral fins, can also climb
tree roots and move across the soil. In contrast, most other fish species which inhabit
mangrove creeks are also found in the coastal seas, entering the mangroves during a particular
stage of their life cycle. For example, Barramundi spawn and spend their juvenile phase in
mangrove creeks. Sea Mullet also inhabit the mangroves as juveniles. The availability of food
and protection from predation are important factors influencing fish migration into, and out of,
mangrove environments.
Crustaceans (sea lice, barnacles, shrimps, prawns and crabs) are
abundant in mangrove forests. One of the most distinctive crustaceans is the Mud Lobster which
builds large mud towers at the entrance to its burrow. Pistol Shrimps are responsible for the
loud clicks you can often hear in mangrove forests. There are also around 60 species of crabs
which inhabit the mangroves. Some crabs are predominantly leaf eaters while others feed mainly
on algae and detritus on the soil surface, scooping the material into their mouthparts and
discarding the inedible material as round pellets. One of the most conspicuous species is the
Fiddler Crab which has an enlarged orange claw. Molluscs, like the Common Mud Whelk and the
Mangrove Oyster, are often visible on the muddy soil around the base of mangrove trees. In
addition to these largely surface dwellers is a fauna associated with rotting wood such as
Shipworms, which are not really worms but highly adapted bivalve molluscs.
Many species of birds also
depend seasonally on mangrove environments for food and shelter. Honeyeaters and lorikeets
visit the mangroves for nectar during the plant flowering season. Other species, such as the
Torresian Imperial Pigeon, inhabit the mangroves during breeding. Mangroves are important
habitats during annual migrations and can become important refuges during
droughts and when adjacent terrestrial forest is destroyed. Water
birds that visit the mangroves on a more regular basis include the Jabiru, egrets and the
Mangrove Heron while the Mangrove Robin, White-breasted Whistler, Mangrove Honeyeater and
Mangrove Kingfisher are woodland birds that are considered mangrove specialists.
Flying foxes
(fruit bats) often form large colonies in the mangroves and can be seen roosting during the day.
Other mammals are not often seen in mangroves, however, wallabies, rats, possums and bandicoots
visit the mangroves, as do feral pigs, cattle and water buffalo.
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