MANNING PARK’S paperbarks and fringing wetlands are at risk of dying out. a leading conservationist has warned.
Australian Native Plants Society national conservation officer Eddy Wajon says the paperbarks are already obviously dwindling and Cockburn council needs to rethink how it manages the historic park and its lake.
“At this rate of demise, Manning Lake will eventually be reduced to a Hyde Park-like landscape of neat lawn, a bitumen lakeside track, and open water that is devoid of fringing wetland trees,” Dr Wajon said.
He said it would mean the end of the feeding, breeding and sheltering habitat relied on by a host of wildlfe, some listed as threatened.
Alas Manning Park
Dr EDDY WAJON is the Australian Native Plant Society Australia national conservation officer and former state president and Murdoch branch president of the Wildflower Society of WA.
In the 1800, colonists flocked to Perth under the cruel illusion of inexhaustible, rich farmlands and later gold.
In the Fremantle and Cockburn areas, people had to grub a living out of the “barren” land that they actually found.
Waves of genocide, vegetation clearing, fauna extermination, limestone quarrying, and pollution produced by one noxious industry after another, consumed this once lovely, sustainably-managed boodja.
Almost all of the many small freshwater wetlands that dotted this area were cultivated to grow food, and like the Dixon Swamp massacre ground, were often bitterly contested.
These market gardens were soon abandoned as unprofitable and the wetlands were drained or filled and converted to sports fields. Beale Park, Davilak Reserve, Dixon Reserve and most other sports grounds were once wetlands that supported the richest biodiversity of all habitats on the Swan Coastal Plain.
Only Manning Lake seems to have survived. Was this due to the wealthy Manning family who did not feel compelled to grub the life and soul out of their Manning Park estate and fence it against straying intruders?
Or maybe, because the Whadjuk-Noongar pronounced its old name of Davey’s Lake as Devil’s Lake, did the colonists keep out of this sacred women’s site and its rich hunting ground, abundant in dgilgie (crustacea) and yakaan (snake-necked turtle)?
Manning Lake is still renowned for providing the only summer refuge along the coast of Fremantle/Cockburn for at least 21 species of birds that are either listed as threatened or priority species, or as migratory birds protected under international agreements.
It remains a home and a breeding ground for yakaan, quenda and about 74 other species of native birds, frogs, reptiles and mammals. However, the rich and rare biodiversity of Manning Lake is waning.
Unfortunately, the water levels in Manning Lake are higher than they were in the past, throughout the year, due to stormwater run-off from surrounding suburbs being drained into the lake.
This is slowly killing the freshwater paperbarks in the fringing wetland vegetation: this species of tree does not tolerate year-round inundation.
The fringing vegetation of the lake now has no open soil to recruit into, upslope, as it would have in the past before the bitumen trail was built all around the lake. This hard path on the upland edge of the wetland was built to stop weed incursion into the fringing paperbark vegetation
of the wetland, like a hard edge around a flowerbed to maintain the edge of the surrounding lawn.
However, a fixed artificial boundary is anathema to healthy lake function as the lake border, the size of the water body, and the extent of fringing vegetation, fluctuate according to climate and other factors.
Thus, the paperbarks at Manning Lake are running out of suitable habitat upslope and will probably keep dying. You will notice that only a narrow band of paperbarks next to the lawn will flower this spring.
The trees further into the wetland will remain without flowers and will not set seed – they are too stressed by high water levels to devote energy to reproduction. At this rate of demise, Manning Lake will eventually be reduced to a Hyde Park-like landscape of neat lawn, a bitumen lakeside track, and open water that is devoid of fringing wetland trees.
This will also mean that most of the feeding, breeding and sheltering habitat for wetland fauna will be gone from the only natural wetland left along the coast of Fremantle/Cockburn that holds water in summer.
Manning Lake does not have the 50-metre wetland buffer zone that it should have to protect the natural attributes and functions of this conservation category wetland and to augment its flora and fauna habitat.
Instead, in what is supposed to be the buffer zone, it has a toilet block, children’s playgrounds, and a newly expanded bitumen circuit track (that is underwater each year).
There are lawns where native shrubs should be, and that is where the southwestern snake-necked turtle (yakaan) nest each spring and where their 20-cent-coin-sized hatchlings struggle to crawl back to the water each year, whilst trying to avoid lawn mowers, thousands of people, parking cars, food trucks and portaloos (during the Rotary Spring Fair, Fur Run, Teddybears Picnic etc.).
Murdoch University’s Turtle Tracker program that aims to conserve declining southwestern snake-necked turtle populations warns us of the imminent fate of our native turtles in places like Manning Park, as follows: “Southwestern snake-necked turtle populations found in wetlands across WA’s south west are facing dwindling population numbers due to major threats including predators. Research by Murdoch University’s Anthony Santoro found that across 35 metropolitan wetlands, there were practically no juvenile turtles due to a combination of predation by introduced species, mortality from road strikes, and a lack of suitable nesting habitat.”
There were 26 turtle nests mapped by community volunteers around the fringes of Manning Lake in spring 2022, mainly in areas that should be a protected wetland buffer zone.
However, it looks likely that all of these turtle eggs and hatchlings will perish during the next two weeks as cars drive and park over the nests during the Rotary Spring Fair. Already, four nests have been destroyed by lawn mowers, despite the pickets and bunting erected around them by the City.
There is really nothing (easily done) that can save the hatchlings in this area except proclaiming and maintaining it as a peaceful buffer zone free of traffic and infrastructure.
The City of Cockburn has promised local residents, after years of submissions and pleas, that 2022 will be the last year that fireworks will be exploded next to Manning Lake at the Rotary Spring Fair (on October 30).
The negative impact of fireworks on domestic animals, especially dogs, is well known.
At Manning Park, the fireworks are exploded at the very time when many species of wildlife are breeding and nesting in the lake fringing vegetation (and are at the most vulnerable stage of their lives) and the noise of the fireworks is very distressing.
They flee for their lives and some are injured.
Traumatised nesting birds can abandon their nests causing the eggs or chicks to die.
A 2021 desktop review and impact assessment of fireworks at the Manning Park Spring Fair, commissioned by the City, noted: “While in most cases animals exhibit shivering or cowering, mainly stationary responses, some species exhibit flight responses which can lead to injury and death in extreme cases through blunt-force trauma.”
That’s a sobering thought.
A re-think about events such as the Spring Fair at Manning Lake (that could easily be held somewhere less environmentally critical) is needed.
he City of Cockburn also should accept the advice given by Nyungar yorga (women) who are traditional owners of this boodja, and who told City of Cockburn (in a report commissioned by the City in 2019) that Manning Lake was a highly valued women’s area that should be avoided. They said: “learn to respect these locations because they have been used for spiritual reasons and for ceremony.”
Without a serious effort to listen to, respond appropriately to community input, and to manage Manning Lake better, most of the amazing wildlife (for whom Manning Lake is the last, local refuge) will soon run out of luck.