Lagoon Creek catchment lies north and north-west of the town of Caboolture, 42km north of Brisbane. Much of the urban area of Caboolture is within the catchment. Lagoon Creek flows south-east from headwaters in the D'Aguilar Range. At Caboolture it turns north-east, about 3km upstream from a junction with King John Creek. It then continues in a south-easterly direction after this junction, across the floodplain of the Caboolture River, and joins the river in its tidal reaches.
The remnant vegetation is indicative of the situation before recent settlement. Aboriginal burning practices probably resulted in an understorey of grasses on the ridges, kangaroo grass in the drier areas and blady grass on the slopes where the canopy provided more shade. Areas burned at less frequent intervals carried more undergrowth, largely wattles, but also a wide range of shrubs and grasses.
Much of the catchment was cleared of its original vegetation for primary production purposes - grazing and timber. The effect these activities would have had on the catchment would have been an increase in run-off and subsequently nutrient and sediment transportation.
As development of the town of Caboolture progressed, there was further clearing of native vegetation and pasture areas for cultivation - primarily pineapples around Wamuran, tobacco and more recently strawberries, and a variety of other horticultural crops. Some previously grazed areas of the catchment have been sub-divided for rural-residential use, particularly where the soil was unsuitable for agriculture. Other areas have been left, enabling regeneration of the open forest.
Areas along watercourses are usually too poorly drained for cropping and, with few exceptions, have been retained with largely intact riparian vegetation.
Over the length of the Lagoon Creek marked changes in bank vegetation are apparent. In the upper reaches, Melaleuca quinquenervia (Paper-barked Tea Tree) is less common than in the lowlands where it is dominant. Allocasuarina littoralis (Black She Oak) occurs more widely - providing a habitat for the glossy black cockatoo. Many small trees and shrubs remain in the understorey where the vegetation has been preserved, protected from fire, and provided with adequate moisture. There are several species of Acacia (wattles), lilly pilly, ferns, grasses and herbs.
While none of the plants are rare or endangered, these small areas of remnant vegetation require protection and study. The beneficial impact of creek bank vegetation on stability, water temperature, shading, nutrient recycling, sediment load transport, survival of in-stream organisms and its effectiveness as a wildlife corridor are becoming better understood.
The Support Groups.
A mixed group gathered in the Kennedy Street park, near the weir in Lagoon Creek, on Saturday 9th September 1995. This was the beginning of the "Community Corrections Lagoon Creek Project". The aim of the project is to improve the integrity of the suburban section of remnant bush along the creek bank and thereby improve the habitat for native species on land and in the water.
The project was Stuart Neal's brainchild and much effort went into organizing and coordinating the support groups so that work could begin on rectifying the identified problem of degraded bushland. Stuart Neal is Caboolture Shire's Greening Officer and current Secretary/Treasurer of the newly-formed SGAP Caboolture Daytime Branch.
Others involved at the outset were Sue Gallagher from the Burpengary Volunteer Nursery and a member of both Redcliffe & District and Caboolture Daytime Branches of SGAP, Elinor Davey who is current Chairman of Redcliffe & District Branch and also a member of Caboolture Daytime Branch, Barry Smith from Community Corrections, who organized the labour force, Cameron Traill and the workers who came from many walks of life, from concreters to apprentice chefs. Elinor and Cameron were there as project supervisors. (Cameron later took a full-time position).
As well as the above-mentioned, Greening Australia contributes supplies for the nursery and Round-up for the weeds and the community help group, Friends of Lagoon Creek Group Inc. give moral support, with the odd barbecue for the workers and general pressure that something needs to be done.
Bush regeneration starts with the removal of weeds - groundsel, privet, lantana and exotic pine are the main targets. The stump cut and paint method is used - this is when weeds are cut off close to ground level and the stump is quickly coated with Round-up before natural resins seal the wound. When operations are in areas accessible to vehicles the waste is stacked for chipping and re-used as mulch. Elsewhere, the waste is left to rot down on site.
These methods cause minimal damage to the native species present, though the odd seedling may get trampled. Occasionally a foliar spray is used - this is in areas that are totally blanketed by weeds such as balsam and Singapore daisy, which block out any regeneration of the desired plants.
Planting is also conducted to enhance the natural regeneration of the areas weeded. The work crew gathers seed from the native species in the area and these are propagated at the Burpengary Volunteer Nursery. This ensures the plants are derived from the same provenance and are already adapted to its particular conditions.
Another major task is picking up rubbish. This can be dirty work, as over the years plastics have become embedded in the soil, or particularly the mud in the wetlands areas. Soil is often referred to as a seedbank, but in this area it seems to be a rubbish bank with mass regeneration after rain. One area which is cleared regularly can produce ten fertilizer bags of refuse after a good rain!
A passing comment one week was the method to judge a suburban creek's health, or ill health, was by the number of shopping trolleys in it.
Maintenance is also conducted on sections already treated to check any re-sprouting or re-invasion of weeds.
The first area worked on was from the weir to Beerburrum Road, with groundsel being cleared from the major gullies running into the creek, privet near the rail bridge and weir, and a full range of weed species in a gully near Ruby Street. This was a learning period and, when news came through of the Northern By-Pass route going through this area, operations were moved to another site.
Every Saturday for the past year, work has been in progress from the Manley Street recreation area to the wetlands below the Police Citizens Youth Club. The vegetation types vary from open woodlands dominated by She-oaks, through Melaleuca Wetlands, to graminoid soaks (reeds and grass-like plants). So far approximately 3.5 hectares has been cleared of weeds and 1500 plants put in. It has also been encouraging the numbers of native species seedlings that are now freed up by the removal of weeds. It is slow, tedious work and there is a long way to go.
This year work has also started on the other side of the lagoon, once known as Webb's Dam, to tie in with another initiative with SEQEB to conduct a direct seed sow after the groundsel is cleared from under the powerlines.
This year (1997) is looking very positive. With a grant from "Save the Bush" Community Grants, being administered by The Friends of Lagoon Creek Group Inc., work is conducted three days a week on two sites. With more time available, monitoring systems can be put into place so the success of the project can be assessed.
Plans are also in place to work on the erosion problem at Manley Street. The aim here is to improve and protect the native bush for the enjoyment of the people that use this site for swimming or barbecues; so that they can relax in a relatively natural setting a stone's throw from suburbia.
The Wider Problem.
The Lagoon Creek Project is a direct offensive on the degraded bushlands. To improve the chances of success and sustainability in the future, an effort is needed from the wider community.
Weed seeds can be spread over a wide area by wind, water and birds. The dumping of garden waste, with the view that it will rot down anyway, is another source of exotic plants entering the bush, because the seeds and runners that are introduced to the bush can regenerate and cause problems. This latter problem can be minimised if people use the facility for garden waste provided at the tip.
The former causes, or nature's methods of spreading seed, are more difficult to address and take greater sacrifice. Ideally, plants known as garden escapees, such as Singapore daisy, balsam, cassia, mother of millions and privet, should be eliminated from gardens, as there is no other method to prevent their spread. So really, bush regeneration and improved native habitat, the health of the creek, can start in our own backyards by eliminating the competition.
From shaky beginnings, this project has proved worthwhile, with minor goals being achieved. It will be a long time for major improvements to be observed.
Thanks are extended to all those who have contributed time and effort, as every little bit helps towards making Lagoon Creek a better place to live.
(The majority of this article was written by Elinor Davey, with some additional background information selected from "Downstream", the Newsletter for the Caboolture Region Integrated Catchment Management Group Inc., known as CRICM.)
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