I
t’s a widely accepted view that the best relationships take
time. My love affair with Australia’s mangrove ecosystems
grew slowly, following a number of very uncomfortable first
dates. I survived clouds of Lane Cove sand flies, submersion in
some bottomless Hinchinbrook mud, and various tribulations in
tropical Queensland to eventually see exoticism even in these
maligned places. Now, four decades on, my wonder at mangroves
just keeps growing. While anglers have acknowledged the critical
benefits mangrove stands have for coastal fisheries, particularly
as nurseries for juvenile barramundi, mud crabs and mangrove
jack, the wider view of mangroves as places that are best avoided
remains. And while Moreton Bay might be nationally renowned
for its cultural and natural heritage, few embrace the idea that
mangroves are an integral part of that heritage. So, how do I
reconcile my view with an often contrary public perception in
order to preserve and protect this special flora?
At first glance
Mangroves consist of about 80 plant species worldwide, all
of which provide habitat, structure and biomass, often with
locally distinctive features. My research has established that
Australia has at least 47 species – more than half of those found
globally. Only one species (Avicennia integra) is endemic to
Australia; most occur widely, broadly distributed by water-borne
propagules. The mix of species in particular mangrove stands,
while bringing distinctive features and functioning, is often
unexpectedly diverse. Some 10 billion species of bacteria can be
Far from being ‘just one plant’,
mangroves form an ecological entity
just like a rainforest.
Blood-hungry biting bugs. Flesh-craving crocs. Oozy, smelly mud. Rotten, decaying detritus and slime.
Ankle-twisting roots. It’s fair to say that the mental images that flicker to mind when most people think
about mangroves are less than romantic. Even for mangrove researcher Norm Duke, it wasn’t exactly
love at first ‘bite’ when he began studying this vital coastal flora. Now, much of his role is convincing
the public to fall in love with these plant communities, which act as vital ‘coastal kidneys’.
ECOLOGICA
found in a handful of mud from some north Queensland mangrove
forests, and many thousands of species depend on mangroves as
habitat or for their role in keeping waters sediment-free.
Despite the relatively small number of actual mangrove plant
species, they belong to at least 20 higher plant families, making
them unusual and genetically diverse. Epiphytes such as lichen
and mosses, as well as ferns, trees, shrubs, palms, grasses
and climbers, make up the mangrove habitat – far from being
‘only one plant’, mangroves form an ecological entity just like
a rainforest in character and biomass. These ancient habitats
evolved over more than 50 million years, and their diversity
suggests a lineage of multiple origins. Sometimes, mangrove
species within a habitat may even be more closely related to
upland relatives than to each other, making it hard to determine
which plants are mangroves and which are not. Usually,
identification comes down to physiological tolerances and
specific adaptations for that habitat niche. As a result, identifying
species requires plenty of field observations, examining a range
of characteristics from flowers, fruits and foliage. Often that
means spending a lot of time knee-deep in muck and suffering
more than the odd bite from gnats and green ants.Photo: Gary Sheehy
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LOVE
WHY MANGROVES DESERVE OUR ADMIRATION
Wildlife Australia | 29