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A stroll through the beautiful Biodiversity Garden of the Dubbo Regional Botanic Garden prompts reflection on Australia’s amazing biodiversity.

Australia is home to more than 20,000 plant species (not including algae) and roughly 17,700 of our vascular plants are exclusively native to Australia. Australia is so rich in plant species that there are more plant species (2500) native to Sydney than the whole of the British Isles.

The Biodiversity Garden displays a selection of the roughly 1,000 plants native to the Dubbo region.

Australian wildflowers are often smaller than the highly cultivated exotic species readily available in garden stores but they are extremely varied in colour and shape, and exquisitely beautiful. A good example is Melaleuca thymifolia (Thyme Honey Myrtle) which has just come into flower.

Melaleuca is a genus of plants in the myrtle family Myrtaceae known for its natural soothing and cleansing properties. There are well over 200 recognised species, most of which are endemic to Australia.

Melaleuca thymifolia has clusters of attractive, rich, mauve, feathery flowers from November to autumn. New growth is spicily aromatic when bruised.

Melaleuca thymifolias are growing near the billabong of the Biodiversity Garden.

Also just coming into flower are Dianella caerulea (Blue Flax-lily) and Dianella revoluta (Black-anther Flax-lily).  These robust perennials with long narrow leaves are very popular especially for water wise gardens. The beautiful blue star-shaped flowers with six yellow, thickened stamens are followed by attractive, blue or purple pea-sized fruits. The plants will continue to flower through summer. Dianella caerulea and Dianella revoluta were used by traditional Aboriginal people.

These Dianella sp. may be found growing along the paths in the Biodiversity Garden.

Designed as an educational resource, the Biodiversity Garden displays the major ecosystems that thrived in the Dubbo region before European settlement. Students of all ages regularly visit the garden to study the plants and their habitats. A visit to this “wild oasis” is always worthwhile.
                                                                                                                                By Ian McAlister & Karen Hagan

Reconnect with the natural environment at the Biodiversity Garden, Dubbo Regional Botanic Garden.

It is a safe wilderness; a place for adventure! Young children love to follow the winding trails through grassy white box woodlands, past wetlands and into the forest. 

It is an educational resource; an outdoor classroom. The Biodiversity Garden displays the major ecosystems that thrived in the Dubbo region before European settlement. Schools regularly visit the garden to study the plants and their habitats.

Interpretative signage near the Kurrajong tree in the north-west corner of the garden provides an informative bio-geographical overview of the region.

The diversity of the botanical collection and the deliberate policy of allowing the garden to develop a natural life cycle add to the “wild” and unpredictable experience offered by the Biodiversity Garden.

The Hardenbergia violacea is currently providing a beautiful and abundant display of delicate purple flowers and at least three species of wattle are also in bloom.

Sharp eyes may spot bright orange fungi growing on fallen tree branches which have been left to provide habitat and refuge for native animals.

Amongst the leaf litter, earthstars are popping up. These small, strange and delightful fungi belong to the genus Geastrum and look like puff balls on star-like bases. 

Fungi performs two essential roles in the Biodiveristy Garden. Firstly, it recycles dead material into a form which can be reused by the plants and secondly, some species form mycorrhizal associations with the plants. Mycorrhizal associations involve an interaction between fungi and the root system of the plant.  The association usually results in an exchange of nutrients beneficial to both organisms. However, some plants such as Australian orchids “harvest” fungi to obtain the nutrients they require.  Mycorrhizal associations are essential to the healthy growth of roughly 80-90% of all plants.

Come to the “wild” side of the Dubbo Regional Botanic Garden, look closely and be ready for a pleasant surprise. 
                                                                                                                             By Ian McAlister & Karen Hagan

A local plant species renowned for its grace and resilience has been selected as a companion plant for some delicate beauties due to arrive at the Dubbo Regional Botanic Garden later this year.

The Acacia pendula (Weeping Myall - wattle) belongs to the sub-family Mimosoideae of the family Fabaceae. It grows to roughly 10-12m high and has a graceful, weeping habit. Its striking blue-grey foliage makes it an attractive ornamental plant.

The Acacia pendula is tough and long lived. It can tolerate heavy soils and waterlogged sites but it is also highly drought tolerant. There are excellent examples of Acacia pendula in the Biodiversity Garden and one at the north east corner of Elizabeth Park next to the mosaic.

Eleven Acacia pendulas will be planted just outside the fence on the west side of Shoyoen. They will provide shelter for new cherry trees. Three Prunus × yedoensis (the Tokyo Cherry) will be planted in Shoyoen later this year, after the Acacia pendulas have become established.

This is not the first time that wattles have been used to provide shelter for more delicate plants in the Dubbo Regional Botanic Garden. The Dubbo Christian School planted 200 local wattles in the Oasis Valley to protect the rainforest species until they became established. This has been very successful.

Globally, companion planting for pest control, pollination, shelter, providing habitat for beneficial creatures and maximizing use of space, has been practised in one form or another, for thousands of years.

One of the best ways of keeping a garden healthy is to make sure that it is as bio-diverse as possible.  A broad selection of companion plants which ensure the availability of flowers all year will attract birds, pollinating insects (like butterflies, bees, and native wasps), reptiles, beetles and all sorts of helpful garden buddies.
                                                                                                                           By Ian McAlister & Karen Hagan

John Oxley was the first explorer to venture into the Macquarie valley beyond Wellington. On the 12th June 1818 he reached the area now occupied by Dubbo and recorded in his journal that he had passed that day “over a very beautiful country, thinly wooded and apparently safe from the highest floods...”

The fertile soils of the grassy woodlands admired by Oxley, supported a highly diverse vegetation community. Grassy woodlands are categorised as open canopy forests because the trees are typically spread out and their canopies do not touch. They are dominated by eucalypts, typically boxes and red gums, with sparsely distributed shrubs, tussock grasses and herbs. Ephemeral grasses and herbs appear from seed banks following rain, and ground orchids and lilies produce a spectacular floral display following fires.
 
By 1840 the vast bulk of the river frontages and much of the adjoining country had been taken up by squatters. Initially grazing was concentrated upon the grassy woodlands because they needed little clearing.

The detrimental impact on the ecology was immediate and intensified when the availability of superphosphate and better agricultural machinery opened up the area to intensive wheat farming. By 1907 the country west of Wellington was described as “thickly occupied” by wheat farms.

Excessive clearing and continual cultivation resulted in serious soil erosion. Topsoils were stripped away by wind and rain, reducing productivity. 

Less than one percent of the grassy woodlands admired by Oxley now remain. Some of them have been listed as endangered ecological communities under state and Commonwealth legislation in recognition of the need for greater protection, management and restoration.

The grassy woodland area forming part of the Biodiversity Garden in the Dubbo Regional Botanic Garden is an important education resource. Promoting understanding of the value of grassy woodlands and the impact of past farming practices will help inform and encourage future conservation.

                                                                                                                            By Ian McAlister & Karen Hagan

Biodiversity is the term given to the variety of life on Earth.   Biodiversity comprises all the millions of different species that live on our planet, as well as the genetic differences within species. It also refers to the multitude of different ecosystems in which species form unique communities, interacting with one another and the air, water and soil.

Australia is home to large numbers of species that occur nowhere else in the world.   The Dubbo region is home to an extraordinarily diverse range of native plants, with over 1,300 species recorded.  More than 55 of these plant species are on display within the Biodiversity Garden.  

The clearance of mature bushland and the consequent occurrence of dryland salinity is a threat to our local biodiversity. Some native plant species have been lost and others pushed close to extinction.

The Biodiversity Garden at the Dubbo Regional Botanic Garden supports native plant conservation through education.  The major plant communities of the Dubbo region are represented in the garden. As visitors wander through the garden, they gain an insight into the diversity of native plants living in grassy white box woodlands, in wetlands and on rocky volcanic slopes.

The natural wild spaces represented within the garden have vibrant complex ecosystems.  Where possible the garden has been allowed to mimic the natural cycles and processes present in the wild. Plant species have been allowed to propagate themselves. Dead trees have been left in place to return nutrients to the soil and provide habitat for bugs, birds and lizards.

The success of this approach is reflected in the variety of small native birds which are attracted to the Biodiversity Garden. The garden is often alive with birdsong.

This "safe" area of wilderness with its representative plant communities provides an exciting and informative outdoor classroom for a wide range of curriculum -linked school programs.

                                                                                                                                                                     By Ian McAlister & Karen Hagan

The Biodiversity Garden is looking particularly beautiful at the moment. Not only are some of the wattles heavy with brilliant yellow, fragrant blossoms but the garden has benefited from the care and attention of a special group of children.

Ever since May this year the UnitingCare Burnside Aboriginal Support Network has based one of their weekly afterschool programs at the Biodiversity Garden.  The children come to the garden to learn about Australian plants, do some gardening and enjoy the benefits of being immersed in nature.

I recently dropped in on one of the gardening sessions and was greeted by enthusiastic young gardeners who were keen to show me what they had accomplished. The children proudly guided me around the garden showing me “their” plants. I was very impressed by the quality of their work.

Under the supervision of Head Gardener Ron Watson, the children have planted close to one hundred young trees and shrubs. All of the plants are native to the local region and many are bush tucker plants. Aunty Diane McNaboe has shared some of the Wiradjuri names of the plants to help the children understand the importance of the plants from a local Aboriginal perspective.

A real and relevant hands-on task of this nature helps these children achieve learning outcomes that they might find difficult to achieve in the classroom. Furthermore the children are creating a beautiful and lasting legacy that they will be able to show their own children in the future.

Science Café will start at 10am and run until 1pm today at the Oasis Valley in the Dubbo Regional Botanic Garden. I recommend you combine a visit to this lively, family friendly event with a stroll in the Biodiversity Garden.

For more information about Science Café visit: drbg.com.au/ScienceCafe

                                                                                                                                by Ian McAlister & Karen Hagan

Eucalyptus is one of seven closely related genera. Eucalyptus, Corymbia, Angophora, Stockwellia, Allosyncarpia, Eucalyptopsis and Arillastrum all belong to the Eucalypt group in the Myrtaceae family.
 
There are more than 700 Eucalyptus species and most of them are native to Australia. They may take the form of a low shrub or a very large tree. The Australian mountain ash (Eucalyptus regnans) is the tallest of all flowering plants (angiosperms). The tallest measured living specimen is almost 100m high.  Only the Giant Redwood (Sequoia sempervirens) is taller, and that is a conifer (gymnosperm). There are two Giant Redwoods in Victoria Park.
 
The flowers do not have petals but do have numerous fluffy stamens which may be white, cream, yellow, pink or red. The flowers are enclosed in the cup-like base (gum nut) and covered by a cap called an operculum. As the stamens expand, the operculum is forced off. This is one of the features that unite the genus. The name Eucalyptus, from the Greek words eu-, well, and kaluptos, cover, meaning "well-covered", refers to the flowers.
 
The flowers produce a great abundance of nectar, providing food for many animals.
 
The leaves usually change as the plant ages and are covered with oil glands.  The essential oil extracted from the leaves has medicinal, perfumery and industrial uses. Global production of eucalyptus oil is dominated by the Tasmanian Blue Gum (Eucalyptus globulus).
 
The Flooded gum (Eucalyptus grandis) is one of the main plantation species grown in tropical and sub-tropical plantations worldwide. It has the potential to achieve some of the highest growth rates of any plantation forestry species and the timber has many end-uses.
 
The Dubbo Regional Botanic Garden has many examples of Eucalyptus species particularly in the Biodiversity Garden but a Tasmanian Blue Gum (Eucalyptus globulus var. compacta) may be located near the gecko sculpture in the Sensory Gardens.

By Ian McAlister and Karen Hagan