The City of Cockburn's response to Fremantle Herald about Bibra Lake revegetation
Question: The “beach” area around the jetty and extending north adjacent the lake’s edge has about 450 plantings within cardboard (or similar) protectors. Of these some 140 (all round figures), appear to have survived, an apparent fail rate of about 70%
- Does this coincide with your understanding
- Is that attrition rate usual and as expected
- Given some of that area is looking neglected and untidy, is there intention to clean it up
- What is the watering regime for those plants
Answer: The ‘beach’ area (which we refer to as Bibra Lake Turtle Cages) has been largely left bare for turtle nesting. A small section of this area near the Bibra Lake turtle cages was revegetated with 590 plants in 2021. Results of independent monitoring in 2022 by Natural Area Consulting Management Services showed a survival rate of 85 per cent.
Question: On Hope Road, just past the intersection with Progress Drive and further along the road, there are other plantings within green plastic protectors, on the open areas between road and tree line/path/lake. These represent a considerable effort to restore plant life and are generally tidy. They are well set up but also appear to have a considerable fail rate, apparently (coincidentally) averaging about 70%. (Presentation varies, some areas are doing better than others).
- Does this assessment concur with your information
- Is such a failure rate to be expected under the given conditions
- What is the watering arrangement for these plants.
Answer: ‘Turtle Corner’ – the southeast section on the corner of Progress Drive and Hope Road – was cleared in late 2016-early 2017 in preparation for Stage 8 of Roe Highway.
This area was first revegetated in winter 2021 as part of the Rehabilitating Roe 8 project. In that year, survival of seedlings at Turtle Corner was well below expectations due to the use of an alternative technique that did not work well with soil conditions on site. Record summer temperatures in Perth also took their toll.
In winter 2022, 5,000 seedlings were planted and are currently being monitored and watered. Current estimates of survival are 70 per cent, with final data available in May. Planning is in place for more revegetation, including infill plantings, this winter. The Rehabilitating Roe 8 project will continue to focus efforts on improving the visual and environmental amenity at Turtle Corner.
Question: There appears to be an overall 30% success rate for all these plantings
- Is that correct
- What are the future plans for these areas
- Will they include further re-vegetation
Answer: All revegetation sites are monitored independently on an annual basis to assess success rates and guide planning for any infill planting that will be needed.
A ‘typical’ revegetation project can take anywhere from three to five years to become self-sustaining, resilient, and support appropriate habitat structure of endemic species. In some cases a revegetation project can take many years before it is considered successful.