Our Wetlands In A Changing Climate

As ecosystems that thrive on so little, our wetlands are delicate. Yet they are abundant sources of water in this growingly water-starved world. They are carbon sinks, that remove and trap over 13% of the world’s carbon. They are biodiversity hot-spots where some of the most beautiful and unique species live and flourish.

While we are fortunate to still see wetlands around us, their survival is threatened. They are exhibiting what the scientists are calling a ‘distress syndrome’, wherein, their functional capacity has been radically impaired. Their plant and animal distributions have been drastically altered. And there are several disturbances, induced stresses and a range of pressures that are making their fragile ecosystems imbalanced.

Image of a starving polar bear on a melting ice sheet

Much of this has been the result of climate change. A topic that is heavily discussed but less understood in the context of wetland conservation and rehabilitation. It is only gradually becoming clear that climate change impacts each wetland in a specific and unpredictable way. And it is through constant monitoring, research, on-ground work and active participation that some of the impacts can be stalled or even reversed.

Our conservation efforts at Bibra Lake and North Lake, within the Beeliar Regional Park, have been remarkable. Through the course of our work, we are constantly learning about the nature of our wetlands, their many unseen facets and how they respond to a steadily shifting environment.

In this article, we draw a sketch of the strengths and weaknesses of our dynamic Beeliar Wetlands as they stand the test of a changing climate. And what it will take for them to survive this massive global event.

Understanding climate change

Climate change is perhaps the greatest issue confronting us today!  As greenhouse emissions continue to rise it is predicted that global temperatures could increase anywhere between 1-5 degrees in the 21st century.


This video from NASA’s Climate Change website, highlights global temperature anomalies. 2018 and 2017 were the fourth and second hottest years respectively since modern record-keeping began in 1880. NASA and NOAA work together to track the temperatures, part of ongoing research into our warming planet.

Major atmospheric changes drive hydrological changes. So, global warming at that scale can lead to prolonged droughts in some areas and pronounced precipitation in others. Hydrological changes further drive hydrogeological changes affecting groundwater recharge and water purity. These changes themselves are enough to degrade some wetlands considerably.

The continuing rise in temperatures also threatens species who depend on the wetlands for survival. Waterfowl are susceptible to changes in temperature and precipitation. For migratory birds, the climate affects their habitats as well as the migration corridors. For other species whose breeding cycles are tied closely to the climatic conditions, the rise in temperatures makes the situation unfavourable.

Climate change has a range of other impacts on the wetlands themselves, their ability to recycle and process nutrients, how they absorb and trap carbon and process sediments to generate soil. These activities further impact the distribution of flora and fauna, favouring some over the other. Invasive species thrive and change wetland ecology, damaging habitat and food source.

The stresses of climate change are only heightened by human activity – urbanization and pollution.

Climate change and Beeliar Wetlands

The Beeliar Wetlands is the name given to the two chains of wetlands that run parallel to the west coast of Western Australia. While one chain of lakes is saline, the other is freshwater. The wetlands are located towards the southwest portion of metropolitan Perth within the larger Beeliar Regional Park.

The wetlands on the Swan Coastal Plain and in particular the Beeliar Wetlands are a surface expression of the underlying groundwater.  There is still much to be learnt about the effects of climate change on our wetlands.  What the data shows us is that for about the last 40 years we have been receiving less rain.

Groundwater levels have never been static, decreasing during summer and increasing when recharged with winter rain as water makes its way through the soil to groundwater.  With decreasing rainfall, the groundwater recharge has decreased and levels have dropped. Together with the decreasing recharge, there has also been incessant removal of groundwater to supplement our supply of drinking water.

In most cases, this has led to our wetlands drying out more often or for prolonged periods each year. But, bear in mind, a drying wetland is natural and it is during the drying times that those intrepid birds fly in from Siberia to eat the bugs out of our mud.  It’s tricky business and honestly, none of us have the whole story.

The unpredictable changes in the lakes drying and filling have also complicated our revegetation efforts.  While in general we are allowing for increased dry conditions and adjusting the zones in which we plant, on several occasions we have been caught with heavy summer and spring rain events inundating some of our plantings.  These conditions highlight the need for Adaptive Management.

It is not only the wetland and wetland vegetation that is affected by this lowering of the water table.  Many of our bushland species also depend on groundwater for survival.  This became very evident during the particularly low rainfall season of 2010-11 when many banksias higher in the landscape of our bushland died.

Changes in global climate may well be a contributing factor on groundwater levels, but healthy well-maintained wetlands can also be a key tool in our efforts to lessen the impact of climate change on other systems.

Here’s taking a closer look at the Beeliar Wetlands and how climate change has impacted some of the wetland functions.

1. Changing Hydrology:

The Beeliar Wetlands depend on seasonal rain to recharge. Over the years there have been fluctuations in the amount of precipitation. These fluctuations have caused alterations in wetland zonation, impacting the distribution of native plant species within the wetlands.

2. Loss of biodiversity:

With changing zonation, wading species and waterfowl are impacted.  Constant encroachment has led to a serious habitat loss, loss of fringing vegetation and bushland. This has further impacted species such as turtles, frogs, snakes and lizards many of which are endangered.

3. Carbon loss:

With many of the wetlands now experiencing a dry spell and terrestrialisation, the carbon trapped within the soils is released back into the atmosphere. And there is a further loss in capacity to capture and trap carbon from the atmosphere due to the growing number of dysfunctional and degraded wetlands.

Read our blog post on ‘Saving Bibra Lake’ for an in-depth examination into our conservation and rehabilitation efforts on Bibra Lake and North Lake.

Preventative measures

The wetlands are facing an incredible amount of stress from climate change alone, and we have to realize the importance of reducing additional pressures. This will give our wetlands a fighting chance to cope and replenish.

While most of us have come to accept the reality of human-caused changes in our global climate, we must also step up to the task of addressing the impacts of these changes.  There are many actions we can take locally to help our wetlands through this period.

Here are a few ways in which we as individuals and community can help:

  1. Reduce waste. Don’t litter.
  2. Conserve water. Be judicious. Click this link to check out Watercorp’s tips for saving water.
  3. Recycle and reuse to the maximum extent.
  4. Reduce your carbon footprint.
  5. Walk or cycle wherever you can. Or use public transport.
  6. Grow native plants in your garden. Go organic. Be fertilisewise!
  7. Participate in wetland activities. Volunteer with The Wetlands Centre.

Don’t forget to quack, quack, quack…  That is wetland speak for talk, talk, talk…  Pass on the message to friends and family.  Tell them about waterwise, fertilisewise and of course, volunteering.

Join The Wetlands Centre Cockburn

At ‘The Wetlands Centre Cockburn’, we are located a hop, skip and jump away from the glorious Bibra Lake, within the Beeliar Regional Park. Our proximity stirs and inspires us to work with the community to safeguard and protect this amazing yet fragile asset.

Community Planting Event at Horse Paddock Swamp in the Beeliar Wetlands

We have seen remarkable progress over the 25 years we have been around and are always looking for new helpers.  If you are not into getting down and dirty, we have education programs that need helpers too!

Combating climate change will take all our effort. Come join our forces today. Together let us maintain and improve the resilience of our wetlands so that they can continue to provide important services to us and the coming generations, even under changed climatic conditions.

Saving Bibra Lake

An aerial view of Bibra Lake on a sunny day

Cradled in the swales of the ancient dunes of the Swan Coastal Plain, and spanning over 384 hectares are the Beeliar Wetlands! They are bustling with stunning biodiversity, that include some of the most unique and fragile lifeforms on earth. Here, the calm, placid Bibra Lake stands as a timeless testament to our heritage and cultural values.

Historically, North Lake – Coolbellup and Bibra Lake – Walliabup, have served as important locations for the Aboriginal Nyoongar people. They are associated with the mythology of the ‘Waugal‘– the rainbow serpent, and Dreamtime tales of the ‘Spirit Children’.  Numerous Aboriginal campsites have been documented adjacent to the lakes. The Beeliar mob had semi-permanent camps on the land, caring for the boodja (country), precisely where the controversial Roe 8 tollway was proposed.

While we closely evaded that disaster, there are still a number of factors that continue to impact our precious wetlands. Over 90% of Perth’s once ample and abundant wetlands have been lost to agricultural pursuits, urbanisation, and development & infill. Bibra Lake and the surrounds are a reminder of what we’ve lost and what we stand to lose unless we take strong action. Together.

 

Changing wetlands in a changing climate

Our wetlands are dynamic in nature and they transform with changing seasons. Water levels in the wetlands, such as Bibra Lake, rise and fall with rainfall and the seasonal movement of groundwater. Bibra Lake experiences this seasonal flooding and drying, and oftentimes, this leads to alterations in the depth and area of the body of the lake. The transient wetlands are designed to cope, redistributing their animal and plant life in accordance with these changes.

However, with a decrease in rainfall and an increase in human activity surrounding our wetlands, the natural variations are becoming exaggerated. Causing alarming fluctuations in the wetland zonation. Introducing irreversible expansions and contractions of the wetland area.

 

Comparisson of flooded zones of Bibra Lake from 1995 to 2005
Figures depicting altered wetland zonation for Bibra Lake

Looking back, we remember the water levels of Bibra Lake during the 1980’s and 1990’s to be much higher than they are now. Many of us believe that those water levels were “proper”. However, the higher water levels of Bibra Lake at the time were actually an aberration caused by the removal of vegetative cover for the development of surrounding suburbs.

On the other hand, we also see prolonged drying of the wetlands in some years. The reduced rainfall has impacted the recharging of groundwater. And since the groundwater is also our source of drinking water for the Perth metropolitan area, this has caused a further shrinkage of the precious resource.

Bibra Lake has suffered adverse impacts. Usually, maximum water levels were seen around October and minimum levels during April. However, Bibra Lake and North Lake are now breaching these standards. This has significant implications for planting and weed control.

 

Two pictures comparing seasonal water levels of Bibra Lake
Snapshots comparing maximum and minimum seasonal water levels in Bibra Lake

A thorough understanding of these circumstances is essential towards developing a successful restoration program for Bibra Lake. We need to take the variations and on-ground conditions into account, adjusting when and where we weed and plant as we maintain and restore the lake and its surrounds.  The focus as we move forward must be on adaptive management.

We must also accept that we are moving into a period of some uncertainty, with climate change and global/local weather events becoming unpredictable. We may not get this 100% right 100% of the time. But every failure is a learning and a step forward.

 

Weeds and invasive species

Weeds are one of the most pressing problems we face at Bibra Lake, and weed control is an ongoing initiative. Often, the removal of one weed creates space for another. In some cases, it even allows the overgrowth of opportunistic native plants which can pose additional challenges. We see this most starkly in the constant balancing act of Typha control on our lakes. But that is a story for another day…

A combination of manual and chemical control along with mulching and saturation planting has been the most effective method in combating weeds. (Saturation planting is when native vegetation is planted densely and in large numbers so as to saturate and give little scope for invasive species to spread.)

At Bibra Lake, the following have been our findings:

  • Weeds must be actively growing before initiating weed control.
  • The revegetation plan should be in place prior to weed management to make the best use of the weed control efforts.
  • A monthly weed control commitment is required with a plan for the whole year.
  • At The Wetlands Centre, we have developed Seed Production Areas (SPAs) and refined propagation techniques to grow plants in our nursery.
  • The weed biomass in the seasonal zone degrades during one flooding and receding event. Slashing is sometimes required to make the area suitable for planting.
  • Mulching of the lower damp to upper seasonal zone (the weediest zone) with Typha mulch reduced the frequency of weed control.

 

Satelite images of Bibra Lake from 1953 to 2018 showing vegetation cover
Satellite images showing revegetation of Bibra Lake by The Wetlands Centre Cockburn over the years

Invasive species such as feral bees, foxes and cats are also detrimental to our wetlands. The feral cats and foxes prey on vulnerable native animals. Foxes are an introduced species and our lizards, turtles and quenda are especially susceptible since they have not developed any specific defences to stay protected.

 

Runoff and Algal Blooms

Human activity is primarily responsible for the degradation of our wetlands. Our urban developments are placed closer and closer to the wetlands, with little or no buffer. Roads and tracks crisscross the perimeter. And our wetlands are losing their lush cover, that helps protect wildlife from noise, light and other forms of pollution. All this further challenges their survival, exposing our species to danger and disease, and putting them at a risk of endangerment.

This also means that there is a greater impact on how nutrients, sediments and pollutants are naturally filtered by the wetland. The degraded quality of some of the fringing and upland vegetation around Bibra Lake is causing alterations in the water-quality of the catchment. However, Bibra Lake still fairs better than other heavily impacted lakes within the Beeliar Wetlands.

Runoff, whether it is the chemical runoff from roads or the phosphorus, potassium and nitrogen from fertilizers that we use in our gardens, leads to a nutrient explosion, and subsequently, algal blooms. The algae reduce temperature and light penetration in the catchments, suffocating and dominating over aquatic life. The algae also spread rapidly and give off an unpleasant odour as they break down. There is a direct link between the excessive use of garden and horticulture fertilizers and algal blooms in our waterways.

Reducing the use of chemicals in our gardens, keeping our storm drains clear of unwanted litter, conserving water and using it judiciously, and using landscaping practices that benefit wildlife and their habitats – every little step you take can lead to positive outcomes for our lake.

 

Join The Wetlands Centre Cockburn

At ‘The Wetlands Centre Cockburn’, we are fortunate to be located adjacent to the resplendent Bibra Lake, within the Beeliar Regional Park. This places us in an ideal position to lead by example in the care of our natural surroundings. We recognize that we bear a great responsibility to inspire, reinforce and connect, and to work with the community to safeguard and protect this amazing area.

The issues we have highlighted in this article are very real. They are threatening the health of our wonderful lake and its bountiful surrounds. We are working hard to understand and combat these issues while spreading awareness of core problems. Our team of volunteers and staff are dedicated and ever-vigilant.

In working with the land and connecting with its nurturing ways, we have come to cherish it deeply. And we want to share this connection with the greater community. Come, get involved with us. Learn. Plant. Protect. Conserve. And spread the joy.

 

This article is adapted from and based on notes and insights shared by Denise Crosbie, Wetlands Officer, The Wetlands Centre Cockburn.

Wetlands & Water. Rehabilitation & Conservation.

A bird's eye view of a wetland and its evirons

Watching our wetlands transform is an awe-inspiring experience. We may see change with seasons. Or, through circulation of life-giving water and rainfall. The transformation is evident in the way their vegetation thrives, blooms and blossoms. Within the catchments where delicate ecosystems flourish as diverse organisms interact with each other and with the environment. And, in the cacophony of bird and animal sounds that fills the air with every favourable shift.

Water brings out the unique character of our wetlands.

Not all wetlands are waterlogged all the time, some depend on groundwater and others on surface water flows and still others are coastal wetlands that are revived by the seas. They may be seasonally, intermittently or permanently drenched. They may be saline or freshwater. They may be still or flowing. No matter what the nature of the wetland, water plays a central role.

 

Wetlands – A Living System

Wetlands support complex and diverse bionetworks. They shelter and sustain wildlife. Here landforms and soils are created, nutrients are naturally recycled and waterways are filtered and cleaned.

The specialized wetlands vegetation helps in stabilizing the soil, cleaning the water and providing resources and habitat. From upland vegetation – shrubs and trees, to fringing vegetation – sedges, rushes and paperbark trees, and floating and submerged aquatic plant-life – adequate vegetation is fundamental to wetland health.

Leaves or branches that fall from overhanging trees and shrubs are broken down by microbes, bacteria and fungi. These, in turn, become food for larger animals within the food web. And wetlands ecosystems are sustained by the functions of these tiny organisms.

 

Wetlands and Water

Wetlands that see water once every few years, or those that are permanently waterlogged, every wetland ecology is unique. Species of plants and animals have evolved to suit these very specific conditions of dampness, salinity and nutritional availability.

Urban and rural encroachment have posed some serious threats to the wetland ecology.

Paved roads and concrete structures mean that a greater volume of water now finds its way into the wetlands. Road run-off often contains oil, heavy metals and various other substances that leach into the wetlands. Fertilizers, pesticides and chemicals from nearby home gardens or agricultural fields too seep into the groundwater, from where they travel to the wetlands.

Environmental degradation has caused drastic changes in the water cycle. Wetlands now face prolonged inundation or drying and a constant change in the physical, chemical and biological composition of water entering the wetlands. This imbalance adversely impacts native species that are unable to survive or cope. Further, loss of native vegetation has the potential to disrupt and collapse the delicate wetlands food web.

 

Wetlands Rehabilitation

Our wetlands are an important and essential resource. They provide us with a natural filtration system, cleaning our waterways of harmful pollutants, absorbing and trapping carbon in the marshy soil, and replenishing our groundwater and underground aquifers. Wetland plants and animals function to strengthen this delicate link between water and wetlands.

They help regulate the climate. They supply food, fibre, fuel and medicinal plants.

Above and beyond the functions they fulfil, wetlands are a source of great beauty. They are gateways to adventure and for “experiencing nature” away from the hustle and bustle of our cities and suburbs. The abundant life they support – from native species to migratory long-distance travellers. The deep interlinkages and connections, and the balance they restore.

Wetlands rehabilitation is, therefore, the single most crucial calling of our time – revegetation, habitat restoration, conservation and protection. An involved community and teamwork. And spreading awareness about their importance.

 

A water level guage mirrored on a still wetland surface.

Water Conservation

Inland freshwater wetlands provide water to over three billion people around the world.

Without our wetlands, the water in our households, industries and farms would have been unusable.

Water conservation is a vital aspect of wetlands rehabilitation work. It involves using and uncovering innovative wetlands management techniques that help control the quality of water within catchments.

Water Sensitive Urban Design Principles, in the context of urban wetlands, protect the wetlands from urban run-off and degradation. Applying these principles ensures that the infrastructure we create does not impact them unfavourably.

Water conservation is also largely dependent on the native plant and animal species, their distribution and propagation. And on our sustained rehabilitation efforts.

 

Come, Get Involved!

At ‘The Wetlands Centre Cockburn’, here in the heart of the breathtaking Beeliar Regional Park, we are working towards building healthier wetlands for everyone.

We are involved in landcare, conservation and rehabilitation work. We run some exciting educational programs. We are community driven, we have fantastic community outreach. And, we are pioneers in wetlands management.

With a dedicated team of volunteers and staff, and our love for wetlands, we are doing just what it takes. Come join the team and get involved with us today. You can make a difference!

7 Things You Should Know About Our Wetlands

A beautiful scene of wetlands at sunset

Our stunning wetlands are a remarkable feature of the Australian landscape. From rivers that crisscross our cities and drain into surrounding seas, to the vast floodplains of central Australia that only see water every few years, these breathtaking natural and artificial wetlands capture our imagination.

The amazing diversity of lakes, mudflats and billabongs, marshes, swamps and fens and coral reefs, mangroves and peatlands – our wetlands come in all shapes and sizes. Even amidst our urban sprawl, we have manmade lakes, ponds and canals, together with some serene natural wetlands that serve as centres of recreation for us and refuge for our wildlife.

We often pass by them wondering at their natural beauty and abundance. The diverse wildlife and plant-life they support. Their scenic beauty. The interlinkages and connections. And the cycles and seasons that bring out their unique character. Yet their many other (important) functions go largely unnoticed by us.

It is hard to imagine Australia without its beautiful wetlands. They are special places serving as storehouses of life-giving water. And, they play a key role beyond sustenance, water conservation and climate control.

 

1. Wetlands are “Nature’s Kidneys”

Wetlands have been likened to nature’s kidneys owing to their deep cleansing effect on our waterways. They are essential for sustaining healthy waterways on which communities throughout Australia depend.

Much like the kidneys that filter and extract waste and balance the hormones in the human body, the wetlands trap and filter the nutrients, sediments and pollutants, cleaning the water and recharging the underground aquifers. By absorbing pollutants, wetlands improve the quality of water and the surrounding bushland.

 

2. Wetlands and the Impact on Climate Change

Wetlands have the unique ability to capture and store carbon dioxide from the atmosphere, thus slowing the impacts of climate change. Coastal wetlands are known to store large quantities of ‘blue carbon’ (the carbon in coastal ecosystems is known as blue carbon).

The flourishing vegetation is responsible for consuming carbon dioxide. Some of the used-up carbon dioxide is released back into the atmosphere, but most of it remains trapped around the roots, sediments and in the marshy ground.

Statistics show us that although the wetlands cover only 5 – 8% of the Earth’s land surface, they hold anywhere up to 30% of the total store of carbon on the planet.

 

3. Wetlands Act as Storm Buffers

Wetlands perform a crucial function as storm buffers – including inland flood control and coastal storm buffers. The thriving foliage – seagrasses, reefs, rushes, reeds, bushes and more – all protect against the destructive action of flood-water and dampen their impact.

Wetlands protect coastal communities from extreme events, such as typhoons, cyclones and hurricanes. They protect our shores from corrosive wave action.

 

4. Wetlands Serve as Habitats for Biodiversity

Wetlands are vital habitats for native species such as the oblong turtles and black swans, as well as a horde of international migratory birds such as greenshanks, red-necked stints and sharp-tailed sandpipers. They provide much-needed refuge for a number of migratory shorebird and seabird species, serving as important feeding and resting habitats during spring and summer months. Some endangered species such as Carnaby’s cockatoo and the peregrine falcon rely on the wetlands for their food and water.

Wetlands support a unique ecosystem. And some of the plant and animal varieties are curiously distinct, having evolved specifically to survive the changing water and salinity conditions.

 

5. Artificial Wetlands and Recreation

Constructed wetlands or manmade wetlands, that are designed to mimic our natural wetlands are often found in urban areas. They can serve the same function as our natural wetlands – of supporting wildlife and creating booming ecosystems and habitats, although they often lack the amazing biodiversity of natural wetlands.

Artificial wetlands are popular destinations for recreation and ecotourism, they also provide us with an opportunity of ‘experiencing nature’ right in the heart of our own cities and suburbs.

 

6. Water Conservation and Sustenance

The wetlands ecosystem teaches us a great deal about water and water conservation. The underground aquifers, which are vast, natural, water-storage reservoirs in the wetlands ecosystem, help replenish the groundwater. While the wetlands themselves act as filters, cleaning and restoring our waterways. The wetlands are often the surface expressions of these aquifers.

All Australians rely on water to sustain life. And water plays a large part in our lives. Whether it’s water for our households, schools, industries or communities, wetlands play an indispensable role and their conservation should be a top priority.

 

7. Wetlands Need Our Support

Threats to wetlands continue as many of them are being filled, drained and replaced with agricultural fields, roadways and urban developments. Rural and urban encroachment is perhaps the biggest threat. Leaving our animal and bird populations homeless, our waterways exposed and compromised, and our environment permanently degraded.

The wetlands need our support today. From generating public awareness to community involvement in their protection and rehabilitation.

We encourage you to visit us – The Wetlands Centre at Bibra Lake – or your nearest wetlands, to learn about our community outreach and how local communities can participate in and benefit from the wetlands.