My place in the mud
A colourful garden is my happy place: flowers all year round, with a mix of natives and hardy perennials. That’s why the drab, olive-green of the monochromed local mangroves has been slow to attract my attention. I have lived or worked on the Mornington Peninsula in Victoria, Australia for twenty-five years. I have walked the Hastings foreshore countless times; Warringine Park and the Bittern Coastal Wetland Boardwalk feel like my front yard. Wanders and rambles, buckets and bikes with grandchildren, husband jogging, rehab walking after surgery. Little ones afraid to fall off the boards in case something lurks underneath in the dank swamp.
When the grandchildren were small, we loved to go to Jacks Beach when the tide was out, equipped with gumboots, towels and snacks. Down across the sand we would creep in the gluggy mud. Then it was a game: how far can we walk without water or mud getting inside our boots or sinking and screaming for help? It felt a little dangerous and not something they were usually allowed to do, but as they grew older and more confident, we could wade right out to where the mangroves ended, and the sea took over. We would get quite close to the old wooden piles from an ancient pier, rotted but surviving the salt and waves. The children cautiously skirted the holes in the mud, wondering what creatures might emerge from them. Confirming their apprehension, tiny crabs scuttled in their sideways fashion as we squelched towards them.
I explained that these plants were mangroves, and that the pencil-sized upright growths were their roots seeking oxygen. They found little sprouted seedlings floating in their green split pockets and we began to explore. The mangroves at Jacks Beach are relatively small but were taller than the children and felt shadowy and threatening; we tried to teach them to respect the environment. When Covid lockdowns penned us into a small radius in Melbourne, Jacks Beach was fortuitously included in my area and walks down there saved my sanity through that nightmare.
In my Geography studies at Melbourne University in the sixties (yes, last century), we did some field work at Corner Inlet, to the east of the ‘neck’ of Wilson’s Promontory. Squelching then, as we do now, we waded through the mudflats, mapping the vegetation of the coastal tidal area and the mangrove swamps. We learnt how to record and sketch the vegetation profile along an imaginary line, to be drawn and later researched from our photos, hoping to accurately capture the ecosystem that we had explored and documented. No internet then.
I particularly enjoyed hand drawing the swamp vegetation, using pens on tracing parchment, followed by research and detailed labelling of species. Computers and mobile phones had not even been imagined, but the wetlands had always been in this remote corner and were already ancient. That excursion is a long time ago, but I have retained a sense of relationship with mangrove swamps, despite the mystery they encapsulate. Even as a youthful uni student, eco-geography appealed to my view of the environment and its interaction with human development – my sense of place.
I make a return visit to Corner Inlet some sixty years later. I have changed more than the mangroves have in that time; my university days are a blurred memory. At Foster Beach Recreation Reserve, the tide is high, with news reporting that the evening tide will be the highest in a decade. The tips of the smaller plants are barely holding their tops above water, and many have been inundated; no roots to be seen.
At the fishing hamlet of Port Franklin, the view of the wetlands across the Franklin River estuary from the viewing platform is breathtaking. Unbroken armies of mangroves as far as I can see; swooping and feeding birds always on the move and rainclouds threatening yet more water on a soggy landscape.
The nature reserve offers a boardwalk, and I become lost in the five-metre-high dense mangroves, set off by yellow grasses, all waving in synchrony in the whipping wind. They seem to be healthy, showing off more flower buds than the Hastings plants. The mud below is pock-marked and exposed as I walk out but has become animated with swirling, sparkling water from a racing tide when I walk back. The red-tipped samphire that is always the neighbour of mangroves looks well drenched, and I suck on a tasty, briny tip which explains why this plant has become di rigeur in hatted restaurants.
Technically, Miller’s Landing on the south shore is the location of the earth’s absolute southern growth of mangroves, but the whole of Corner Inlet, with its warm, sheltered water is rimmed with these adaptive, adventurous plants. Together with the Western Port groves, the southern march of the mangroves comes to an end in this part of our country; further south is all cold ocean.
Some years after my first discoveries in Gippsland, I lived in the Indonesian province to the north of Australia: West Papua, as it is called now. It was, and still is, an undeveloped land of jungles, mountains and coastal wetlands; I lived, worked and gave birth there over a period of five years in the seventies and eighties. Many millions of years ago, the great southern land mass called Late Gondwana was formed from the supercontinent, Pangea. Eventually, Australia was separated from the islands to the north, but flora and fauna common to both areas can still be found today – including the coastal mangrove areas. Australia and Papua were one, geographically and in the recurring terrain of my life.
West Papua has over fifty percent of the mangroves in the country of Indonesia, and most of these are in the Bird’s Head area to the south of the coastal town of Manokwari. When I lived there, the environment was pristine and there were no roads to access these parts of the island; travel was only possible by outrigger boats or Cessna planes.
The forests provide rich protein for the local diet and grove wood has been used for building and firewood for a long time, but there is a growing realisation in the area that the mangroves perform important protective and habitat functions and urgently need to be restored and protected.
And so my mangrove connection continues today on the Mornington Peninsula, on Bunurong country. One of my artist friends has researched and drawn mangroves for a published book in recent years, and one day she asked to see our local mangroves. As we walked and gazed, she shared her knowledge of the plants. Excited, she exclaimed enthusiastically over the hues and tones of green and gold, the old and new growth, the flowers and the seeds, and I had an awakening; I began to see these amazing plants with fresh eyes. What she calls the ‘lungs and kidneys’ of the coastal environment of Western Port Bay are truly wondrous living miracles of survival.
I love languages and etymology; plants and words are my habitat as I write and garden. ‘Mangrove’ is a derived word from probably both Spanish, mangle, and Portuguese, mangue, dating back to the seventeenth century. The word developed from an earlier version: mangrow, or possibly even further back from a West Indian language. Both ‘grow’ and ‘groves’ seem appropriate for this remarkable plant, that grows in groves. Like the plants themselves, the word reflects a developing, surviving species. I am being increasingly drawn into an ancient, mysterious history.
Mangroves provide among the most productive and biologically complex ecosystems on earth. Impressive in their adaptation, they thrive in hot, muddy, salty conditions and seventy-five percent are located in just fifteen countries. Western Port Bay is a tidal channel and natural wonder that supports 18,000 square kilometres of mangroves, 130 square kilometres of seagrass and 270 square kilometres of mudflats. It is a notable intertidal, coastal wetland that includes the largest island of Victoria, French Island, which is mostly National Park. With a tidal range of up to three metres, the bay is the home of the some of the most southern white mangroves in the world. Avicennia marina australasica (sometimes called a grey mangrove) thrives well south (38 degrees in Hastings) of the normal 15-25 degrees of latitude that supports most of the world’s mangroves, and is classified by Ramsar as internationally significant.
The Hastings Biosphere is one of 738 locations in 134 countries in the world classified by UNESCO as ‘living, learning places’. The challenge we have today is to raise awareness of the value of these amazing plants and their ecosystems which can live in water that is one hundred times saltier than other species can tolerate. Indeed, this tough species thrives in briny water that would kill most plants.
As I walk along the Hastings foreshore, the late sun picks up the tips on the metre-high bushes with only their gold-edged foliage showing above an unusually high tide. The gold brushes the olive-green palette with highlights and tips – just like humans do with their hair to add light and life to a mousey colour. Some leaves curl over and display their reverse sides, which are the lightest ones in the new growth and are covered in tiny hairs. They are one of the secrets to salt excretion from the plant. There are no root spikes to be seen when the swallowing tide is high. Bubbles burst on the surface around the mangroves, signs of underworld life in the watery habitat.
This crafty, evolved survivor has more than one way to deal with salt: by blocking the salt from getting in through the roots, by sending it to the older leaves that die and fall, or by secreting it out through glands on the leaves. All this salt builds up in the surrounding environment and needs the rain and tides to wash it away. A perfect cycle that can cope with up to seventy-five parts of salt per thousand, which is double the salinity of the ocean.
When I ramble at low tide, the pneumatophores protrude valiantly above the water, and the intricately intertwined aerial roots are visible. They look as though they could march off sideways, one leg after another, like crabs. In fact, they create a significant and welcoming habitat for birds, fish, insects and crustaceans. The sprawling cable and aerial roots have pores called lenticles on their surface, which is where the oxygen exchange occurs, preventing these brave plants from drowning.
In season, there are tiny white or yellow flowers that are partly nestled in the leaves, growing out in clusters of three to five from the nodes. The white mangroves have small white flowers with five petals that become golden with age and are pollinated by bees and other local insects. At the time of my winter walk at the solstice, there are clusters of tight ball-shaped tiny pea buds, full of potential and waiting to unwrap themselves as the days promise to lengthen, encouraging the buds to open.
Forming around the seed, cotyledons are the first leaves of the new plant and for some reason this fact is almost the only thing I recall learning in Year 9 Science last century. These seeds are not only olive in colour but, repeating their theme, look like large olives. They are protected by the cotyledons and fall to the muddy sand, floating until they become seedlings. As the little roots appear, usually within five days, they look like green hermit crabs on the beach until the true leaves appear, and the plant starts to grow. A new mangrove has begun its life between the tides.
And then I discover a delicious word – vivipary. This means to bring forth live young, and is common amongst mammals, but I have never heard of it being used to describe plants. These ordinary looking plants are extraordinary! They have one of the almost unique ways of reproducing in the plant world, developing propagules that are embryonically developed while they are still attached to the parent plant. My appreciation for the humble mangrove plant has grown again as I discover that the floating seeds and their leaves have been dropped into the sea, already fertilised and growing. White mangroves do this in mid to late summer following their flowering season and their propagules can last up to a month. I plan to return and catch this part of the life cycle.
Mangroves have taken on a persona as I explore. I start to anthropomorphise them and see them as local characters that go about their lives working and contributing quietly, their drabness belying their outstanding role. Unassuming, yet irreplaceable. Like a local hero who is written up in the local rag for community service. In the Western Port ecosystem, the mangroves provide rich habitat for birds like the Red-necked Stint, waders needing food in their non-breeding season before their last push to the Arctic, the Eastern Curlew and the Lesser Golden Plover drop in on the migratory flights.
The bay is home to over three hundred species of birds; spoonbills, pelicans and swans feed and breed in the bay. Pelicans have become a proud local icon, spawning a metal sculpture on a town roundabout in Hastings. They take up positions on the bollards of the marina and draw many tourists to watch and enjoy as they glide with surprising ease across the bay and forage for fishermen’s cast-offs.
The habitat supports the coastal King George Whiting and their spawn, distinguished by their spots and tiny scales; shark-like, scaleless, elephant fish that lay their eggs between San Remo and French Island, and the Australian grayling. This last species leads me to another wonderful word: diadromous. This rare fish can live in fresh water and sea water, making the tidal waters of the mangrove swamp a perfect home for their adaptability. This habitat in my place is a connector.
Under the water in the groves also lives a wonderland of snails, sponges, anemones, worms, barnacles, crabs and shrimps. Mangroves are described as a ‘nursery habitat’, although the conditions seem harsh for babies of any species. Salty, muddy, ever-moving with the tides, the inter-tidal sea becomes a refuge in amongst the tangled roots where life hides and clings.
Mangroves are the ‘kidneys of the coast’. They function as filters that trap sediment from the water by reducing the velocity of the water movement, in the same way as human kidneys filter the blood. The plants also take up solid material from the sea. Many of the creatures that live in mangrove habitats, like crabs, feed on decaying and dead matter, which creates organisms that humans can use. Many varieties of edible seafood are dependent on the mangrove swamps for some part of their life cycles. This is the kind of organic kind of recycling we need so much!
Even more incredible is that mangroves serve as an important source of blue carbon. I gaze at the humble plants, with a new understanding that they absorb carbon from carbon dioxide and use it as a building block for their foliage and roots, which then fall to the sea floor and are buried, transforming into blue carbon. These greyish-green plants are quietly performing a huge service and batting way out of their league. Representing only two percent of the marine environment, mangroves are responsible for nearly fifteen percent of carbon burial. These plants are the superheroes as we battle climate change. My perspective on the grey-brown muddy tidal flats has shifted: who knew that the magic alchemy of the creation of blue carbon is happening under the surface?
As fierce warriors, these shrubs protect the coast from storm and surge damage. The tangled piles of roots on which they sit keep the trees upright, breaking the speed and power of the waves as they batter a coastal area. On a mildly windy day, I gaze at the ripple of water coming to shore; the waves diminish in force as they are dissipated by the root systems. Western Port Bay is unlikely to suffer from major surges apart from its tides, but my beloved Papua is vulnerable to earthquakes and the consequent tsunamis. In 2002, a 7.6 earthquake caused a tsunami that washed away over 1000 houses on the Papuan coast and killed people. Around the world, as the width of mangrove forests decreases, the death toll from storms has measurably increased.
Human interaction with mangrove ecosystems goes back to the early history of indigenous people in the Western Port area. The Bunurong (Boonerwrung) people lived around the bay for thousands of years, enjoying shellfish, mutton birds and plant life. They include five Aboriginal language groups that comprise the Kulin (Koolin) nation of peoples. Western Port is part of the Mayone-Bulluk clan, which occupied the top of the Mornington Peninsula and head of Western Port, and the Yallock-Bulluck, near the Bass River on the eastern catchment of Western Port.
For the original inhabitants, mangroves were a source of food, medicine and tools. Avicennia marina provided fruit, cooking flavour and nectar as part of their diet, although high levels of tannins and chemicals meant it had to be cooked. As well, the habitat provided sources of food, like crustaceans, slugs, molluscs and mud crabs, mainly hunted by the women. How different was their life compared to mine! The supermarket where I can shop is visible from the foreshore – but I can forage without a spear or fishing line.
The species has well-documented medicinal use, especially for skin problems. These included fish stings, boils, and scabies. The wood was always useful, including for the making of shields.
Hastings was the main fishing port in Western Port Bay from the nineteenth century, benefiting from a ferry service that could bring the catch to shore, to be taken on to the city by coach. The old fishing shed at Hastings pier dates from around 1866; British and Sicilian fishermen began to supply the market.
Human settlement continued in the area, with the mangroves always there to frame the semi-rural town and protect the tidal coast of the bay. In all parts of the mangrove habitat, the forests are vulnerable. Will they survive the human threat? The loss of 2.6 square kilometres of forest will lose 124 metric tons of fish per year. Coastal development, farming and seafood aquaculture like shrimp farms all contribute to the diminishing of the coastal swamps. Around the world, mangroves are disappearing more quickly than rainforests, and rising sea levels limit the tidal zones so that mangroves cannot move inland.
While some people do not like mangroves, and see them as muddy, mosquito-ridden and, in some areas, habitat for dangerous fauna like crocodiles, it cannot be denied that most of the fish caught commercially for human consumption spend time in mangrove areas or depend on the food chain supported by these plants.
I don’t expect to see crocodiles rise out of the gentle waters of Western Port Bay, but I feel more protective than ever of this precious ecosystem. Groups like OzFishare working in my area and earlier this year had two mangrove planting days on the Hastings foreshore. My new appreciation makes me want to be actively involved in these. On these community days of regeneration, collected mangrove seeds are attached to bamboo stakes to give them a good start in their early growth. When established, the stakes are removed and new trees emerge, extending the zone of future survival.
I am walking near the Hastings carpark at the coastal boardwalk, waiting for my husband to finish his run from the Jacks Beach end when I see it: a domestic ginger cat sitting on the top of a fence post, peering out across the mangrove wetland. Fox and feral cat predation on shorebirds is one of the highest risks for fauna in the mangroves, listed under the priority threats in the Ramsar site management plan. While cats are required to be kept contained on the Mornington Peninsula, there are many that roam and hunt birds, as is their natural instinct.
Rabbits are similarly destructive in the saltmarsh; I have had an ongoing war with rabbits in my vegetable garden and know the damage they can wreak. Advantaged as an island habitat, French Island has had a project since 2010 to eradicate feral cats completely to provide a haven from the catastrophic impact on fauna. Thankfully, the European Red Fox is also absent from the island because of its isolation.
Humans are probably still the greatest threat to mangroves, as they compete for desirable coastal environments: over eighty percent of Australia’s population lives within fifty kilometres of the coast and accessible land is always being sought. Ports, tourism sites, housing, airports and industry; drainage and excavation; dumping of waste; dredging of channels. These human activities result in diminishing productivity of mangroves, changes in water levels, reduction of natural regeneration, pollution and increased damage from boats. To a greater or lesser degree, these factors are consuming and changing the mangrove environments around the continent. We, the people, remain the greatest enemy of mangroves. Research by the NASA project shows that:
Sixty-two percent of the lost area was due to human causes, mainly farming and aquaculture. The rest was due to natural causes, including erosion and extreme weather events.
What about Western Port? On 30 March 2021, jubilant cheers rang out around the bay when the most significant threat to Western Port’s pristine environment was defeated by people power:
Science and good sense has won out. The government has listened to us and to the thousands of people in our community who have worked tirelessly to save our beautiful environment from a potential catastrophe. Westernport Bay was never the place for such a monstrous, environmentally damaging project. AGL’s idea for a floating, hazardous gas factory in an internationally significant wetland should never have made it off the drawing board, let alone taken three years of relentless community opposition to save a bay that belongs to all Victorians. Save Westernport hopes this decision paves the way for greater environmental protections over Westernport and we look forward to working with the Andrews government to make that happen. Minister Wynne’s findings are a clear direction to other decision makers that AGL’s project poses unacceptable impacts to Westernport and the Ramsar wetlands and should be rejected.
Jane Carnegie, Save Western Port spokesperson.
I was part of the protest that lasted over three years, and it drew me in emotionally to the battle for our precious place of wetlands and mangroves. There were local meetings, lobbying to politicians, petitions, surfboard protests, thousands of signatures and a constant campaign. I remember the ‘No AGL’ signs around our neighbourhood, and the heated discussions about whether nailing the signs to trees was causing further environmental damage.
On 30 March 2021 (in the middle of a pandemic which forced the activists online), after ten weeks of live-streamed evidence, more than 10,000 submissions and overwhelming community opposition, the AGL proposal was refused. Their plan was to build a giant gas import terminal right in the heart of Westernport Bay, that would dump millions of litres of toxic chlorinated water back into the sea each day. Dozens of huge ships would pass through the narrow entry to the bay every year and AGL would plough through some of our most fertile farmland for a pipeline to transport the gas to the city – a key factor in Minister Wynne’s final decision to reject the project. Burning the imported gas would have caused over eight million tonnes of climate pollution every year. And the potential for catastrophic accidents was another horrifying scenario.
Looking back at the battle, I realise that I did not identify strongly enough with the enormous potential for damage to our pristine environment; I am grateful to those who contributed so much time and effort to the cause. And so glad we won.
Here in Hastings, I doubt if any of our inhabitants depend on the mangroves directly for their living. I certainly don’t. I gaze on them as I meet friends for coffee at the café near the pier; I wander along the path of the foreshore clocking my steps for exercise while absorbing the view and noting the variations in the tides; I love the walk to Jacks Beach with the vegetation arching overhead as I search for the first glimpse of the coast; I drove to far corners of the bay during pandemic lockdown and explored Blind Bight and Cannon’s Creek, where the mangrove territory is so vast and expansive. I returned to the southern mangrove stands at Corner Inlet. I didn’t realise how important they are to us all, and now that I have settled into Hastings, I feel proprietary and protective. Mudflats and mangroves are a quintessential part of my place, and my world view is shifting like a returning tide.
