drone on about trees:
You can create an enjoyable walk where the visitors leave with a
better understanding of mangroves without even giving a single name
of a tree or mentioning a single medicinal use. It can get boring
if you only talk about individual tree species. People more readily
absorb information about the mangroves as a system, and the role
the entire system plays in our daily lives. Sprinkle interesting
facts about individual species. Don't overdose.
What are mangroves?
Mangroves are trees that can grow in the sea!
high do you think the tide gets in this mangrove forest?
Point out the change in colour on tree roots and trunks.
Let's look at some of the challenges facing mangrove trees.
in salt water twice a day
- Stand in
which is soft, unstable and poor in oxygen.
It is tough
to live in the sea and stand in mud all your life.
you had to stay submerged in shallow water twice a day, how would
you breathe? Yes, you might snorkel and breathe through
a tube. You might breathe through an air tank. Mangrove trees
have breathing roots! And can store air in their roots too. How
many different kinds of roots can you see?
is very little freshwater to drink! How would you cope?
Yes, mangrove trees can get rid of the salt from seawater. Some
deposit the salt on their leaves. See the salt crystals on this
But this is hard work to remove the salt, so mangroves prevent
water loss (thick, waxy or hairy leaves, feel it).
soil is very soft, how would you stay upright?
Yes, some mangroves have stilt and prop roots. Others have shallow
horizontal roots that form a kind of raft.
it's tough to be an adult tree in the sea, it's even harder for
a seedling or baby tree. In many mangrove, the fruits stay on the
mama tree and become long seedlings while still hanging onto her!
By the time they drop off, they are in a much better position to
survive in the sea.
Don't step on mangroves!
are important to the ecosystem
- The pointy
things on the ground are breathing roots of the mangrove trees.
Don't step on them or break them.
- Many small
animals hide among mangrove roots. You will squash them if you
step on them.
- Some animals
can eat mangrove leaves, Can you see any animals that might
eat mangrove leaves? Yes, crabs do! (See tree
- Dead and
decaying mangrove leaves also wash out into the seagrass meadows
and coral reefs where they feed other creatures there.
- The mangrove
roots provide hiding places for animals in the water.
- The mangrove
branches provide hiding places for birds and land animals.
- Some animals
that can live in between water and land are also found here (mudskippers,
- The mat of
roots provide firm ground for small burrowing animals (fiddler
see if we can find some of these animals?
chain: These small animals are in turn eaten by bigger animals.
Some of them swim in from deeper waters at high tide and we don't
see them now at low tide.
Eat or Not?" While we can't eat mangroves, some of our
favourite food depends on mangroves.
many of you like durians? Durian lovers must also love
the Sonneratia trees.
One way to tell the story with questions:
do you think pollinates the durian flowers? If no
one guesses right away, give them some clues: the durian flower
looks like a pom-pom, it's white and it blooms at night. Eventually
someone will guess bats.
them that these bats only drink nectar and eat pollen. They
don't eat fruits, they don't eat insects.
often does the durian tree flower?
Eventually they will realise once or twice a year. Emphasise
bats can't rely only on durian for their only food. Infact,
other trees like Sonneratia that bloom more regularly allow
a larger population of these bats to survive. With more bats,
more durians are likely to be pollinated.
are YOUR favourite seafood? Let's see if we can find them here
in this mangrove? Young
live in the mangroves before going into deeper waters as they
grow up where they are caught by fishermen. So to get good fishing,
it's important to have good mangroves nearby.
- The shrimp
industry can be bad for mangroves. This is quite a depressing
story, and usually only the more nature-oriented visitor can sit
through the long story.
myths to dispel
are not smelly because they are full of dead decaying things.
In fact, this 'Fart of Life' is a sign of a healthy mangrove.
More details of this story in the general
write up on mangroves.
are NOT wasted land. They provide shelter and food to
a wide variety of animals, many of which are among our favourite
seafood. These animals are part of the food chain in ecosystems
nearby. They stabilise sediments and keep the water clear for
seagrasses and coral reefs to develop nearby. Without mangroves,
other coastal ecosystems nearby can be severely affected.
- If we had
to build a system to do all the things that mangroves do for us
for free, it would cost a lot of money. Just imagine paying people
to pollinate the durians if we lost the bats that do the job for
us for free.
Don't step on the mangroves
If you HAVE to walk through a stretch of mangroves, choose
a route with few breathing roots and where the ground is not
soft. Ask the visitors to follow in your footsteps. Tell them
to keep to a single file to minimise the damage to the ground.
Don't pick off leaves, flowers or propagules! To give
visitors a closer look, use whatever are already broken off
or washed up on the shore.
Don't throw things at plants or animals in the mangroves!
Pointing things out to visitors from a boardwalk can
be tricky. If you just say "There!" you will inevitably
get the response "Where?!". Describe what they should
look for (size, colour, shape), use a prominent and distinctive
landmark (don't say "next to the brown leaf" when
there are 200 brown leaves on the ground). Using the landmark
say "2 o'clock from" etc.
Visiting the mangroves at low tide is great! You can
see the roots, mudlobster mounds, and lots of animals are
active on the ground.
Visiting the mangroves at high tide is great! The animals
are crowded on tree trunks (tree climbing crabs) and roots
(mudskippers). Snails gather at the high water mark. And fishes
and other aquatic animals are busy in the water.