Tuesday, August 01, 2017

Feral Animals in Australia / Part 2

Following on from my May '17 post which seemed popular, here are some more introduced species that have caused or are causing problems.
During the 19th century camels were imported into Australia from India and Afghanistan and used for transport and construction during the colonization of the central and western parts of of the country.
After railways and motorized transport started replacing them in the early 20th century, many were released into the wild resulting in a fast-growing feral population.
By 2008, it was estimated that Central Australia's feral camel population had grown to about one million. They are known to cause serious degradation of local environmental and cultural sites particularly during dry conditions.
A management program was funded in 2009 and upon completion in 2013, the feral population was estimated to have been reduced to around 300,000.
Aerial and ground culling plus mustering for farm use were the techniques used.

A camel 'industry' does exist with meat being exported to various countries for human consumption. It is also used for pet food.
A number of camel dairies have also been established.
Live camels are occasionally exported to the Middle East where disease-free wild camels are prized as a delicacy.
Live camels are also exported as breeding stock for Arab camel racing stables and for use in tourist venues in places such as the USA.
-Black and Brown Rats, Mice
The black and brown rat and house mouse were accidentally introduced to Australia with European settlement.
As all around the world they are a problem not likely to be rid of.
Mice plagues are common in some rural areas. Australia's worst mouse plague was in 1993. It caused an estimated $96 million worth of damage.
Poisoning and trapping are the main controls.
Bush Rat
Australia also has around fifty native rats and mice.
These are presumed to have arrived within the last 4 million years from Asia.
They are difficult to differentiate from the 'foreigners'.
We deal with the native bush rats and field mice here but never in plague proportions.  
The exact date of the carp's initial introduction to Australia is unclear. Some records claim the species was introduced to waters near Sydney as early as the 1850s. Others claim the first introduction was to Victoria in the 1870s.
They are a pest because of their destructive bottom-feeding habits which stir up sediments and muddy the water. This causes serious damage to the native fish populations in the lakes and rivers that they infest by out-competing other fish for food and space. 
Carp are also thought to lower water quality, which can kill off sensitive organisms like native freshwater mussels.
Although they are commercially fished as well as processed into fertilizer, the government is intent on eradicating them.
They have announced a $15 million project that would see a strain of the herpes virus, which was discovered in Israel, released into the Murray-Darling river system by the end of 2018.
The virus only affects European carp and is expected to kill 95 per cent of that species of fish in the river system over the next 30 years. 
-Fire Ants
These little pests are one of the latest unwanted imports. They are native to South American floodplains of the Paraguay River in Brazil, Paraguay and Northern Argentina.
They would have been unknowingly imported into Brisbane around 20 years ago possibly in a shipping container from the United States. They were first detected in the Brisbane area in February 2001.
Fire ants are a serious pest that threaten our lifestyle, the environment and agriculture.   
There have been six separate incidents of fire ant infestation, five recorded in Queensland and one in Port Botany NSW, the most recent at Brisbane Airport in 2015. Many of the colonies have been successfully eradicated but it is an ongoing battle to prevent their spread.
Bio-security Queensland is using a low-toxic bait treatment applied by broadcasting it over an area using about 4grams per square metre.
Worker ants take bait granules back to the nest, where they are passed among other ants and fed to the queen. These baits do not kill the ants but sterilize the queen and stop the larvae from developing. The worker ants are not replaced and the colony dies out.
We have to keep an eye out for native venomous ants eg. bull ants and jumping jacks when out and about so we don't want another one added to the list.
Continued here

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