Long Island

(Winner of the 2004 Savewater Awards for Garden Design/Construction category)

This project has transformed an area comprising largely weedy plant species and low value exotic plants into a space which represents a significant collection of indigenous plant communities that existed, prior to European settlement, more widely in the CBD and region of the Lower Yarra. Today, these plant communities are very fragmented or non-existent in this region. The planting of 29 wetland species (14,000) and 67 terrestrial species (10,000) of locally ‘known provenance’ plant species from five plant communities has significantly increased the Royal Botanic Gardens' indigenous plant biodiversity. These communities include:

• Swamp Paperbark Thicket
• Riparian Scrub
• Grassy Woodland
• Cliff Escarpment Shrubland
• Wetland Community

By enriching the plant biodiversity, this project also strengthens the links with other remnant vegetation, habitat and fauna along the Yarra River corridor. Locally, habitat has been improved for significant local avian fauna such as the Giant Egret, Nankeen Night Heron and Reed Warbler, which are present on the site. It is hoped that diversity of other fauna and invertebrates will increase over time. Research, such as frog surveys, has been undertaken to establish base data and measure any changes in the frog population as the habitat on Long Island develops.

Construction of a boardwalk, landings, pedestrian path, plantings, rockwork and a wetland, will be used for education and interpretation programs, which will add value to the site where focus can be given to the importance of plant conservation and biodiversity.

The Boonwurrung people now have a site to demonstrate their history and culture through the work of our Aboriginal Liaison Officer. Included in this collaboration are aspects to enhance the successful Aboriginal Heritage Walk program and any other associated events.

The completion of this stage of the Long Island development could not have been a success without the assistance of community groups. A planting day during Arbor Week saw about 200 students from local schools attend and 70 local residents attended a Community Planting Day for International Plant Conservation Day. Over these two days 2,500 individual plants were planted out and it is believed that this was the first time that the public has assisted with planting out within the Royal Botanic Gardens.

Green Corp (young volunteers managed by Conservation Volunteers Australia) also played a huge role in the implementation of the Long Island redevelopment. An enthusiastic team of eight people and one supervisor were on hand to clear weedy vegetation, prepare the site, plant and mulch the entire work site for a duration of six months.

Long Island Irrigation

On average, this collection has initially received minimal irrigation to establish the plants or about a 70-80% reduction in water use compared to other equivalent and well-managed irrigated areas in the Gardens. Ultimate savings of over 95% are expected as the plants reach maturity. Water sensitive design principles were integrated into landscape planning, including careful plant selection and zoning according to plant water requirements. Stormwater drains directly from path surfaces into garden areas for plant use and bio-filtering prior to entering the lake system.

The terrestrial plant species generally require minimal irrigation, as they are adapted to the local climate and rainfall regime. The Riparian Scrub and Swamp Paperbark Thicket communities represented in this collection are proximate to the Ornamental Lake and are able to use this water supply rather than need irrigation. The Grassy Woodland and Cliff Escarpment Shrubland communities are zoned higher up on Long Island because of their adaptations to seasonal dry periods.

Long Island Wetland

This area was formerly part of the main Ornamental Lake. However, to aid the establishment and life cycle of indigenous aquatic plants, it was physically separated from this water body. The wetland area is also being used as a model to consider effective establishment of macrophytes (water plants) and the improvement of water quality in the Royal Botanic Gardens Lake System. Blue-green algal blooms are normally almost an annual event in the Ornamental Lake. However, within the wetland, no blue-green algal blooms have occurred since it was constructed and aquatic plants were established.

The reduction of blue-green algal blooms and improvement of water quality in the Lake System is a key consideration for the Royal Botanic Gardens, if the Lake water is to be a component of future sustainable water use.

The Long Island Project is generously supported by Parks Victoria and Conservation Volunteers Australia.

Long Island October 2003

Photo: Taxodium Bridge, Long Island March 2004

Before photo: Baker Island

Baker Island 2004

Photo: The Wetland under construction

 Photo: The Wetland, Long Island October 2003