Protecting and enhancing natural environments within urban settings through revegetation and weed control
A total of 91,000 indigenous species were planted across the urban coastal landscape of the Mackay Whitsunday Isaac region between 2013 and 2016. More than 11,500 were planted across 11 hectare coastal sites (Far Beach, Haliday Bay, Bucasia Beach, Sandfly Creek, Clairview Beach, Smalleys Beach and Ball Bay) and 80,500 indigenous species were planted over three riparian sites (Twin Creek, Little McCreadys Creek and Lagoons Creek).
The focus of this revegetation is to improve and enhance the natural values of the area, ensure continued stabilisation of the dune systems and, in conjunction with weed control activities, improve opportunity for natural regeneration. In addition revegetation mitigates erosion, and protects the coastal buffer zone and riparian corridors through dune stabilisation and encouragement of natural regeneration whilst also providing additional habitat for native wildlife.
Weeds change the natural diversity and balance of ecological communities. They have the ability to alter structure, species composition, fire frequency and abundance of native communities, and consequently impact aquatic ecosystems and water quality. Weed control has occurred over eleven public sites (Keeleys Road wetlands, Slade Point Reserve wetlands, Ball Bay Reserve, Seaforth Reserve, Apsley Creek, Sandringham Bay, Galbraith Creek, Twin Creek, Little McCreadys Creek, Lagoons Creek and Cape Palmerston) as a means to improve water quality and increase native habitat connectivity in areas that have been heavily impacted by urban coastal development.
The focus on reserve areas for weed control included patches of critically endangered regional ecosystems (beach scrub (RE 8.2.2), Melaleuca viridiflora woodlands (RE 8.3.3) and coastal grasslands (RE 7.4.1)) as well as other significant vegetation communities. Improving habitat connectivity is vital in such ecosystems such as beach scrub as it provides essential habitat for the listed northern quoll (EPBC Act, endangered), rusty monitor (NCA Act, of concern), and coastal sheath tail bat (NCA Act, vulnerable).
Sites were chosen based upon their impact by urban/development activities, their capacity to be treated effectively, their current trend of condition, their ecological value, and their hydrological connectivity to the Great Barrier Reef. Significant weed species targeted included Hymenache (Weeds of Nat. Significance), Water Hyacinth (Class 3), Singapore Daisy and Broad-leaved Pepper Tree (Class 2). 228.25 hectares of weed control was conducted at eleven sites between January 2014 and June 2016.
Improving access and signage
Coastal vegetation plays a fundamental role in dune stabilisation and is easily damaged in high recreational usage, for instance beaches where pedestrian access is unrestricted. Coastal management plans written in partnership with Mackay Regional Council direct the prioritisation of access management projects within the region. Collaboration between Mackay Regional Council and Reef Catchments has allowed for the installation of numerous stairways, stair ladders, rock barriers, and fence lines within coastal zones of Town Beach, Far Beach, Seaforth, Blacks Beach, Bucasia Beach, Armstrong Beach, Grasstree Beach, Shellgrit Creek and Cape Palmerston. Formalised access tracks will direct foot traffic towards permanent access points allowing previously disturbed native vegetation to regenerate on the dune systems. The condition of regenerating vegetation will be monitored over time to provide evidence of the effectiveness of these access management activities.
Water Sensitive Urban Design Installations
Litter, nutrients, and sediments entering the marine environment through the storm water system threaten the integrity and condition of existing native vegetation and habitats in the coastal urban landscape of the Mackay Whitsunday Isaac region. WSUD installations aim to rehabilitate, maintain, and protect remaining coastal and riverine ecosystems, considering the challenges faced through ongoing development and competing interests. A total of 44 gross pollutant traps were installed over the course of the project. Three trash racks were installed in the Cannonvale Botanic Gardens to isolate and retain inorganic material (namely litter) and reduce the amount of organic material (which contains/captures microscopic pollutants) entering Pioneer Bay. Forty-one litter baskets were installed in Mackay’s CBD stormwater pits to capture waterborne pollutants drained across the stormwater network. Litter baskets are light weight, uniquely designed with a by-pass and net, and angled so drainage flow in high rainfall events is not impeded. Furthermore, each basket is viewable from the street; significantly reducing the maintenance burden on council street sweepers. Based on similar examples in the region, it is expected that the 41 litter baskets will capture one tonne of debris every quarter. Six wetlands were installed within Mackay, with four installed into Little McCreadys Creek and two into Lagoons Creek.
Fish Passage Improvements
Eleven fishways were installed and/or improved during the course of the project. As a result, a previously restricted habitat and refuge was opened to greater migration opportunities over a range of flows, which aids the health and ecological function of lower catchments by building resilience within local fish communities. Four fish ladders were each installed adjacent to Little McCreadys and Lagoons Creek, one fish ladder in Blackrock Creek, and two fish ways were remediated in Gooseponds Creek. Post works fishway assessments, to demonstrate the efficacy of the ramps, are ongoing. Concurrent to these works was the installation of five engineered wood structures (aka fish hotels). Fish hotels have been demonstrated to increase in-stream habitat, both in availability and complexity. Not only do the hotels improve the instream habitat conditions for native fish species, they also have the potential to reduce the ongoing threat of a declared noxious fish species, Tilapia (Oreochromis mossambicus). Tilapia is shown to proliferate in systems exhibiting poor water quality and limited habitat availability. Tilapia is highly invasive, and feed on and compete with native fish, their eggs and aquatic macrophytes which are important in nutrient cycling, habitat provision and as a food source for aquatic fauna. Habitat improvements using instream structures will allow indigenous fish species to effectively compete with tilapia and reduce their spread and impact. Increased habitat will enhance the health and ecological function of the lower wetland complex through an increase in aquatic macroinvertebrate and fauna diversity.
Feral Cat Management
Addressing the impact of cats can be a challenging task for responsible entities. Challenges are often presented by the community’s connection with cats as domestic animals and a lack of understanding of the serious impacts that this species has in the wild. 500 hectares of land of high ecological value in the coastal urban zone was monitored for feral cats over the course of the project. The program promoted community surveys and engagement events, a ‘citizen-science’ domestic cat tracking program, and employed surveillance cameras and traps as a means to gather information about cats within the peri-urban and bushland environments of the Mackay and Airlie Beach areas.
Community Awareness Raising Events
Forty-four community awareness raising events were held between January 2014 and June 2016. Educational presentations focused on enhancing volunteers knowledge of specific topics including native flora and fauna, natural coastal processes, feral animals, and litter sources.Twenty-four events targeted stormwater pollutants accumulating across 12 stormwater drains in Cannonvale and Airlie Beach. In total, more than 2700 kg of rubbish was collected between January 2014 and June 2016 by volunteers that contributed more than 2,500 hours of their own time. Volunteer hours, rubbish collected, trees planted
Little McCreadys Creek rehabilitation project
Little McCreadys Creek and Lagoon Creek were chosen as suitable sites for developing and showcasing best practice methods for improving stormwater quality, rehabilitating waterways, enhancing aquatic habitat, and improving the ecological corridor. Investigations informed each design and included a review of background information, a geomorphic assessment, flood modelling, landscape assessment, stormwater quality modelling, and consultation with community members and other stakeholders.
Both creeks were assessed as adjoining open space that had, in the past been substantially altered through agriculture and urbanisation. Each site retained many environmental values including native fauna, fish, frogs, and some native vegetation, however ecological surveys suggested poor water quality and lack of habitat was limiting species abundance and diversity. In both cases, the creeks and adjoining parklands are highly valued and regularly used by the community for passive and active recreation. Increasing urban development within each catchment will change the creek hydrology and sediment supply, however flood modelling shows that significant rehabilitation works can be undertaken without any adverse effects on private properties. Moreover stormwater modelling demonstrated that improvements in water quality could be made by introducing more riparian and wetland vegetation. Rehabilitation of Little McCreadys Creek and Lagoons Creek have substantially improved the ecological condition and water quality entering Sandringham Bay while improving public amenity.