Wild horses are wreaking havoc in Australia’s mountains.
Long Road Photography (formerly Aff)/Flickr
Horses need to be removed from Australia's mountains. The debate now is around ethics and their role in Australian culture.
Sarah2 / shutterstock
Perfectly adapted for European life, these bright green birds will soon become part of the scenery.
The mesquite tree was introduced into South Africa to aid farmers and local communities. It is now invasive in most parts of the country.
The invasive mesquite tree has a negative impact on everything from biodiversity to human health. Management programmes are crucial.
The silverlead whitefly is a major agricultural pest.
Invasive species and diseases pose a major threat to agriculture – particularly in the countries that can least afford it.
Some of the many species in the Australian National Insect Collection.
At least 100,000 insects are among the many Australian species still to be formally identified. That's a problem for any biosecurity experts who need to be able to spot potentially invasive bugs.
Mark Mallott / Rothamsted Research
A 'Biblical swarm' of 'super-moths' from continental Europe is heading to the UK.
sumikophoto / shutterstock
Transport, climate change and environmental destruction mean all sorts of species are bumping into each other for the first time.
Antarctica’s delicate ecosystem could be under threat from invasive species.
A warming Earth could see invading species arrive in Antarctica via the floating "taxi service" of the sea. That could be a threat to the southern continent's delicate ecosystem.
Kangaroos are much lighter on the land than sheep and cows.
Kangaroo image from www.shutterstock.com
Eating cows and sheep is unsustainable. Here are some better alternatives.
Rats are true natives of our cities.
Rat image from www.shutterstock.com
Rats have lived with us for thousands of years.
Goldfish might look nice, but they can also spread a variety of decidedly not-nice viruses.
Many pet fish end up in ponds, fountains and waterways. But before ditching your goldfish in the park, stop and think about the viruses you could also be releasing.
Moo-ve along: livestock are one of many threats to Australian freshwater ecosystems.
Freshwater covers only 0.5% of the Earth's surface but is home to 10% of the world's lifeforms.
Ash accounts for 20% of the UK’s trees.
www.shutterstock.com/Phil MacD Photography
Over 100 species are dependent on Ash trees for survival – we need to act fast.
The Northern Corroboree frog is among seven species at grave risk from fungal disease.
Chytrid fungus has already wiped out six species of Australian frogs since the disease arrived in the 1970s. Without urgent action, seven more are facing extinction.
Spiny water flea (
Jake R. Walsh
Invasive species cause some $120 billion in damages across North America yearly -- and that's just direct costs. A study of one species in one Wisconsin lake indicates the real toll is much higher.
A native Australian gecko, Gehyra dubia.
If you're hearing a strange chatter in your home, you may have gecko housemates.
Annoying, right? A juvenile Noisy Miner.
Andrew Haynes/Wikimedia Commons
There are birds we love to hate, such as the Noisy Miner. But much of the annoying behaviour on show may be a result of human-induced changes to habitats.
The numbat, Australia’s equivalent of a meerkat, is one of the unique mammal species confined to the south west.
Sean Van Alphen
South west Australia is home to an astonishing number of plants and some of the country's weirdest wildlife. Now we need to protect it.
A Japanese fish found in Washington after hitching a ride in a boat sent across the Pacific Ocean by the 2011 tsunami.
The 2011 Japan tsunami illustrates how more marine creatures are crossing the oceans than ever before - and not all of them are friendly travellers.
Fallow deer are on the rise.
Fallow deer image from www.shutterstock.com
There are now six species roaming wild, and their numbers are increasing dramatically as their population expands and through human action. As they spread, they raise uncomfortable issues for conservation.