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Sustainable Canberra Garden   

Creating Habitat - Fact Sheet

Eucalyptus and Allocasuarina tree canopy with understorey of native grasses and shrubs, Mt Majura. Photo Edwina Richardson.

 

Introduction

When creating a garden which provides wildlife habitat it’s important to have an understanding of the vegetation communities which existed prior to European settlement in Canberra. The earliest parts of the city were developed on a grassy treeless plain, dominated by tussock grasses.  Later suburban developments were sited on savannah woodland which had been modified by grazing and other human activities.  Today both the grassy plains and grassy woodlands are regarded as endangered ecological communities with remnants protected within Canberra Nature Park.

Most garden sites have limited biodiversity.  We can reverse this situation with careful planning and by incorporating plant species which grow in grasslands and woodlands. Gardens can provide habitat for local wildlife and form ribbons or patches of vegetation which link to local nature reserves.

Some Canberra residents are fortunate to be creating gardens on ‘bush’ blocks where there is some remnant vegetation.  This plant material, in particular existing eucalypts with hollows, should be retained in the landscape and can be supplemented with species from similar ecological communities.

Whilst our suburban gardens with their broad mix of native and exotic plants tend to provide food and water for birds, they are poor providers of breeding sites.  Most birds require sheltering thickets and tree hollows which tend be found only in local bushland.

 

Growing Local Plants

In sustainable gardens, we aim to grow a wide variety of plants which will provide food sources and home sites for a range of wildlife.  Growing locally occurring native plants with low water needs will extend the habitat of a range of animals.  Many large hardware stores are supplying a limited range of plants which lead to uniform landscapes and fail to contribute to biodiversity. Supporting local plant retailers who stock a wide variety of plants including plants from the local Canberra region may counteract this problem.

Select plants in small containers such as tubestock, as less energy has been used in their production.  They are inexpensive to purchase and will soon outperform larger sized pots.  Local nurseries, like Yarralumla Nursery stock a range of ‘rare and endangered’ local plants. Examples include Grevillea iaspicula (Wee Jasper Spider Flower) and G. wilkinsonii (Tumut Grevillea) which are attractive to nectar feeding birds.  Money from these plant purchases contributes to endangered species conservation and research via the Australian Network for Plant Conservation.
 

Native meadow landscape

Front garden in Hackett uses a range of grasses and forbs which grow on Mt Majura. This treatment of nature strip and front garden attracts a wide range of insects and lizards. Photo Edwina Richardson.

 

As well as aiming to grow a wide variety of plants gardeners should aim to include plants from a range of structural categories in a garden, such as trees, shrubs, climbers, groundcovers, perennials, accent plants and native tussock grasses.  Remnant eucalypts should be protected within suburban areas and we can plant smaller eucalypts like the mallee varieties to form a tree canopy layer.  Although tree hollows are unlikely to form in your lifetime, they will form habitat to be enjoyed by future generations.

Aim to create dense shrub areas and include prickly plant varieties, like Hakea sericea.  This plant has stiff needle like foliage which will provide safe nesting sites for birds.  Other shrubs which are good for bird protection include Bursaria spinosa, Grevillea juniperina, Banksia ericifolia and Banksia marginata.

 

Attracting Wildlife

As well as growing local plants, by adding organic matter (decomposed leaves, compost, manures, worm castings and mulch) we can create a richer soil life. These organisms in turn will provide food sources for native animals. 

There are a number of plants, both native and exotic which will encourage butterflies in the garden. These include Ammobium, Buddleia, Bursaria spinosa, Brachyscome, Calytrix tetragona and Leptospermum ‘Lavender Queen’. Species like Acacia provide food for seed eating and insectivorous birds, whilst Grevillea, Banksia and Callistemon species attract nectar feeding birds like honey eaters.  Try and include a mix of nectar producing plants as well as those that provide fruit, seeds and insect food sources.  Too many nectar rich shrubs tends to encourage common aggressive birds over smaller birds.

Cockatoos in eucalypt tree hollows

Cockatoos making use of tree hollows in Eucalypts in public open space, Ainslie. Photo Edwina Richardson.

 
Leaf litter, tussock grasses, rocks and fallen branches on the ground provide habitat for a range of birds and reptiles.  The Eastern Blue Tongued Lizard, Tiliqua nigrolutea, is relatively common in well established gardens where it may shelter in rockeries, woodpiles and compost heaps.  These lizards are effective in controlling snails, whilst also eating other invetebrates, fruits and berries.  Contrary to popular belief, they are not poisonous but may give a nasty bite if threatened or handled.

 

Water and wildlife
It’s important to provide a water source for wildlife protected from marauding domestic pets.  This may be a pond or water dish such as a bird bath. Wildlife in the garden does not require supplementary feeding as the plants and insects in your garden should perform that role.

 

>> For more information from the Canberra Ornithologists Group

 

Frog Ponds
Frog ponds are a popular addition to sustainable gardens.  Ponds look more natural if they are sited at the lowest point of the garden.  Ensure they are located well away from your neighbour’s bedrooms. They will be unimpressed if a chorus of amorous frogs keeps them awake at night! Ponds should receive some shade during the day and avoid placing them under a tree as falling leaves can decay in the water providing excessive nutrients. 

 

cross section diagram of pond

Cross-section of frog pond and adjoining bog. Drawing by Landscape Architect Dr Dianne Firth.

 
The minimum size of an ecologically balanced pond is around 200Litres.  Ideally they should be spoon shaped and allow frogs easy water access. Ponds deeper than 300mm require barriers to protect children from drowning, like reinforcing mesh supported by bricks.  Provide local sedges and rushes around the pond edge to provide protection for frogs.  These amphibians also require shelter amongst rocks, logs and thick grass which aids in protecting their moist skins. 

 

Frog species
Frog species commonly found in Canberra gardens include: Crinea signifera (Common Eastern Froglet), Limnodynastes dumerelli (Eastern Banjo Frog or Pobblebonk), L.  peronii (Brown Striped Frog) and L. tasmaniensis (Spotted Grass Frog).  Both the Brown Striped and Spotted Grass Frog occur in ornamental ponds in suburban gardens, whilst the Eastern Banjo Frog is often found in vegetable gardens.

A boggy area adjacent to the frog pond is useful for growing a range of wetland species.  Try growing species like Carex gaudichaudiana which occur in local alpine bogs, and may become threatened due to climate change.

 

Right: Frog pond with frog spawn designed by Landscape Architect, Dorinda Lillington. Photo Dorinda Lillington.

  frog pond with spawn

 

Ants and biodiversity
Ants are a good indicator of biodiversity and are often lower in numbers around trees like Eucalypts where leaf litter, mulch and bark have been tidied up.

 

Controlling pets


Cat owners need to ensure their cats are kept inside during the evening and fit them with two bells on their collar.  Cat enclosures not only benefit wildlife but also protect cats from attacks from wandering animals and motor vehicle accidents.  These may be a simple inexpensive homemade structure or a specially manufactured 'cat park' attached to the house.  By installing a cat enclosure you will be rewarded with an increase in small birds and reptiles visiting the garden.  Dogs (particularly the terrier breeds) will also behave aggressively towards reptiles such as Blue Tongue Lizards and birds.  You may decide to limit your dogs to particular areas of the garden so animals like reptiles are able to escape from them.

 

Controlling pests and diseases

Many animals, particularly frogs, are extremely sensitive to chemicals. If you are aiming to encourage wildlife in your garden use alternative non-harmful methods to control pests and diseases.  Many insects such as scale and aphids can be removed by hand or may be eaten by insect eating birds.  Insects like Preying Mantis, Ladybirds and Hoverflies prey on pest insect species helping to control their numbers.

 

>> Urban Habitat Guidelines for the ACT - 28 page pdf.(new PDF uploaded updated April 2009)

References

Adams, Laurence (1990) Trees and shrubs of Black Mountain, Mt Ainslie and Mt Majura - a key based on vegetative characters.  CSIRO:Canberra.

Bennett, Ross (1997) Reptiles and frogs of the ACT. National Parks Association of ACT: Canberra.

Byrne, Josh (2006).  The Green gardener – sustainable gardening in your own backyard.  Viking: Victoria.

Chenoweth, Alan (February 2002)  Biodiversity in landscape design. BDP Environment Design Guide. Royal Australian Institute of Architects.

Eddy, David; Mallinson, Dave; Rehwinkel, Rainer and Sharp, Sarah (1998) Grassland flora - a field guide for the southern tablelands (NSW & ACT).

Firth, Dianne and Bohm, Margi (2006) Bushwise in Queanbeyan: living with bushland.  Queanbeyan City Council: Queanbeyan.

Pryor and Banks (1991) Trees and shrubs of Canberra.  Little Hills Press: NSW.

 

This website was developed by
and the Australian Institute of Landscape Architects
(Edwina Richardson AILA)
with assistance from an ACT Government Environment Grant

© Australian Institute of Landscape Architects ACN 008 531 851

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