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.

10 Things You Could Do To Help Our Wetlands

A conceptual image of caring palms cupping wetlands

Taking a walk through the lush wetlands is a delight this time of the year. The winding tracks and sturdy boardwalks that open up hidden new worlds. The thick bush, fringing vegetation and the canopy of swaying trees. Startled animals we catch off-guard that quickly scamper away. And, the thin blanket of mist that lies settled over the water.

We discover a different pace and rhythm as we let go. Unwind. And absorb a hundred splendid experiences that the wetlands offer unbiddenly. There is such peace and tranquillity here.

We are fortunate that our wetlands are so close to our urban dwellings. We are able to enjoy their unique splendour and partake in their beauty. But being so close to urban habitation poses a serious threat to our wetlands. Urban run-off, littering, leaching and degradation – there are several impacts that continue to take a toll.

As much as the wetlands are places of recreation and pleasure, they are also grounds that support delicate ecosystems, intricate bionetworks, diverse wildlife and their habitats. They require our care and attention. Here are 10 simple things we can do to help our wetlands:

 

1. Household Plants and Gardens

By practising a little care in our gardens, we can help the wetlands immensely. For example, limit your use of chemicals – fertilizers, pesticides, insecticides or fungicides – and use organic remedies instead. These potent chemicals can leach into groundwater, and subsequently into the wetlands. Use animal manure that is great for the garden and has no unpleasant side-effects.

Be careful while discarding plants or seeds. Our non-native household plants can be invasive and dominate over native flora. The same goes for aquatic plants from our aquariums. They must not be dispensed into the wetland catchments.

 

2. Pets and Pests

Our cuddly pet animals can be quite destructive. Cats are known to prey upon native species – turtles, frogs and even lizards. Rabbits can wreak havoc on plants by binging on them, any fresh regrowth and seedlings. Rabbit faeces are known to carry and spread weeds.

It is best to keep pets indoors or under supervision. They are likely to cause less harm if they are not allowed to stray.   On a similar note, pests that are introduced into the wetlands can have a detrimental effect on the wetland ecology.

 

3. Waste and Recycling

Using safe, sustainable and eco-aware methods of waste disposal will go a long way in protecting the wetlands. Reduce the use of plastic, whether it is plastic water bottles or disposable plastic containers, straws and cutlery. Reuse and recycle to the maximum possible extent.

Maintain a worm farm or compost pit at home. Compost can be great for your garden, and you will be amazed at how much of your waste – like cardboard, paper, egg shells and tea bags – can be put to good use. Get your children involved.

 

4. Reduce Pollution

Reducing pollution can begin at home with some relatively small but consistent steps. Be conscious of your choices. Buy organic, eco-friendly and sustainable products. Your local farmers markets can be great places to shop.

Be energy-conscious and use energy wise appliances. Avoid throwing away stuff carelessly. If you find litter in public parks or wetlands, be considerate, pick it and throw it in the bin. Every step counts.

 

5. Conserve Water

Lifegiving water is central to wetland health. Observe the wetland vegetation. Their leaves, limbs, roots and other remarkable features help them conserve water.  Even wetland wildlife is adept at using water, a vital resource, judiciously.

Turn off the tap when not in use and use only as much as you need. Check your pipes and fittings regularly for any leakages. Harvest rainwater. During the summer months, water your plants early in the mornings.

 

6. Healthy Wetland Vegetation

Healthy vegetation is crucial for sustaining life in the wetlands. This includes upland vegetation, fringing vegetation and aquatic plant-life. Wetland vegetation is highly specialized, in that it has evolved to thrive in varying conditions of dampness and salinity.

Within the wetland catchments, ecosystems flourish based on an energy exchange between living organisms and the non-living environment. Leaves or branches from overhanging trees and shrubs, fall and are broken down by microbes, bacteria and fungi. These, in turn, become food for larger animals within the food web.

You can help in the conservation and rehabilitation efforts – by planting native flora, creating habitats for wildlife and participating in citizen science projects and initiatives.

 

7. Help Wetland Wildlife

Much like the wetland vegetation, wetland wildlife too is exposed, fragile and susceptible. Turtles that live in the swampy wetlands are known to venture out, cross busy roads or polluted areas in search of suitable nesting sites. Similarly, snakes and bobtails too are known to sneak-out to bask in the sun during winter months. Accidents are common and animals get run over. It is also common for animals to get entangled and hurt in the plastic debris.

Animals sometimes venture into homes and gardens, looking for nesting sites or grounds to lay eggs. There are many ways in which we can help these animals, by looking out for them, helping them get to their destination and protecting their eggs or hatchlings.

Apart from the permanent wetland residents, some migratory birds use the wetlands for resources. The dwindling bush and fringing vegetation and the changing environmental conditions are posing a serious threat to all their lives.

 

8. Important Contact Information

It can be useful to locate and carry information on local bodies responsible for wildlife rescue, wetland rehabilitation and conservation work, and research organizations. This can be especially significant if you reside in an area close to wetlands. We encourage you to keep such information handy.

At the Wetlands Centre, we are involved in wetland conservation, rehabilitation, research and education work. We can be contacted through phone, our website or through our social channels. We welcome your messages.

 

9. Learn and Educate

Wetlands are fascinating worlds that open doorways to some interesting natural activity. Take the initiative to deep dive and learn about the wetlands – their mysteries and intricacies. While there are several avenues for learning, there are also avenues for teaching, educating and spreading awareness.

 

10. Participate and Volunteer

At “The Wetlands Centre Cockburn”, we are a warm, friendly, community-based organization. We are located in the heart of Beeliar Regional Park, in the vicinity of the beautiful Bibra Lake. Visit our centre nestled in nature. Take a look at what we do.

We run a range of educational programs all-year-round. We have a fantastic community outreach. And, our in-house nursery and Seed Propagation Areas (SPAs) are our pride and joy.

There is so much you can do! Come begin this journey with us and help us restore our wetlands for everyone to enjoy!