How Did So Many Invasive Species Get Here?

How Did So Many Invasive Species Get Here?

Australia is often described as having one of the strongest biosecurity systems in the world. Anyone who has arrived at an Australian airport knows the routine: strict declarations, detector dogs, food inspections and warnings about bringing foreign materials into the country.

But when we look at the landscape itself, a question naturally arises.

If biosecurity is so strong, how did so many invasive species become established across the country?

Australia’s ecosystems are now dealing with a long list of introduced animals, insects, aquatic species and plants that have dramatically altered our landscapes.

Many were introduced deliberately. Others arrived accidentally through trade, transport or agriculture.

Regardless of how they arrived, the ecological consequences are now part of everyday life for farmers, landholders and conservation groups.

ANIMALS THAT HAVE ALTERED AUSTRALIAN LANDSCAPES

European Rabbit
Red Fox
Feral Cat
Feral Pig
Feral Goat
Feral Camel

These species have had major impacts on native wildlife and agricultural systems. Rabbits alone transformed entire grazing landscapes after their introduction in the 19th century.

INSECTS AND AGRICULTURAL PESTS

Varroa Mite
Tropilaelaps Mite
Tracheal Mite
Small Hive Beetle
Red Imported Fire Ant
European Wasp
Argentine Ant
Polyphagous Shot-Hole Borer
Khapra Beetle

Many of these pests directly threaten agriculture and pollination systems. The Varroa mite, for example, has created major challenges for beekeeping industries worldwide. It came to Australia and New Zealand last which begs the question - who was asleep on this topic? and the Fire Ant poison now claimed by Professors in University as the Biggest Natural History disaster in Australia by Government outsourcing for control now in a 'Preventative' Treatment phase which means all that touches the poison is dead in hours or a day.

AQUATIC AND FRESHWATER INVASIONS

Common Carp
Mosquitofish (Gambusia)
Tilapia

These species have disrupted river ecosystems and native fish populations in many parts of the country.

BIRDS AND OTHER INTRODUCED SPECIES

Common Myna
House Sparrow
Common Starling

Although now familiar in urban environments, these birds were originally introduced species that displaced native wildlife in many areas.

THE CANE TOAD LESSON

Perhaps the most famous introduction was the cane toad.

Introduced in the 1930s to control beetles affecting sugar cane crops, cane toads spread rapidly across northern Australia. Their toxic skin has had severe impacts on native predators including snakes, goannas and other wildlife.

The lesson is simple: ecosystems are complex, and even well-intentioned interventions can create long-term consequences.

AUSTRALIA’S INTRODUCED WEED PROBLEM

Alongside animals and insects, many invasive plants have transformed Australian landscapes.

GRASSES

Buffel Grass – Cenchrus ciliaris
Gamba Grass – Andropogon gayanus
Serrated Tussock – Nassella trichotoma
Chilean Needle Grass – Nassella neesiana
African Lovegrass – Eragrostis curvula
Para Grass – Urochloa mutica
Guinea Grass – Megathyrsus maximus

VINES AND CLIMBERS

Madeira Vine – Anredera cordifolia
Cat’s Claw Creeper – Dolichandra unguis-cati
Bridal Creeper – Asparagus asparagoides
Moth Vine – Araujia sericifera
Balloon Vine – Cardiospermum grandiflorum
Blue Morning Glory – Ipomoea indica

SHRUBS AND SMALL TREES

Lantana – Lantana camara
Blackberry – Rubus fruticosus aggregate
Scotch Broom – Cytisus scoparius
Gorse – Ulex europaeus
Bitou Bush – Chrysanthemoides monilifera

TREES

Camphor Laurel – Cinnamomum camphora
Chinese Elm – Ulmus parvifolia
Tree of Heaven – Ailanthus altissima
Willows – Salix species
White Poplar – Populus alba
Radiata Pine – Pinus radiata

WHY WERE THEY INTRODUCED?

Most invasive plants were brought to Australia for one of three reasons:

• pasture improvement
• ornamental gardening
• erosion control

At the time they were introduced, the ecological consequences were not fully understood.

However once established, these species often:

• outcompete native plants
• alter soil systems
• change fire behaviour
• create monocultures

WHAT IS THE REAL QUESTION?

The issue is not simply pesky weeds or pests.

The real question is how we manage ecosystems moving forward.

Farmers and landholders are often the first to notice ecological changes in their landscapes. They see soil degradation, invasive plants spreading and wildlife patterns changing.

These observations matter.

Healthy ecosystems begin with healthy soils. When soil biology is damaged or depleted, landscapes become more vulnerable to invasive species and ecological imbalance.

Restoring soil function is one of the most practical steps landholders can take to rebuild resilience in their landscapes.

This is the reason Earthfood exists.

Our work focuses on rebuilding soil biology so land stewards can support healthier, more balanced ecosystems.

Australia’s landscapes are extraordinary and ancient. Protecting them requires ongoing awareness, good science and responsible stewardship from all of us.

Earthfood® was built to return microbial intelligence to the ground quietly, effectively, and without dependence on industrial inputs.

© Bronwyn Holm 2026
Earthfood® • Earthfood Pantry™ • Earthfood Conversations™
All trademarks and intellectual property protected. All Rights Reserved.
Shop living soil microbes at yourearthfood.com to feed your soil, let life do the work.
Certifications
Earthfood® is 100% certified Organic:
USDA Certified • OMRI Listed • Southern Cross (AU) Certified • Australia Organics Certified • Eco-Cert (EU) • Organic Trade Association Approved • Carbon8 and Regener8 Standards • International Vegan Association Approved • International Harmony Code
Back to blog