Invasive Species

The spread of invasive species is recognized as one of the major factors contributing to ecosystem change and instability throughout the world. An invasive species is “a non-native species whose introduction does, or is likely to cause, economic or environmental harm or harm to human, animal, or plant health”. Invasive species include all taxa of organisms, ranging from microscopic insects to 100 lb sheep, and can invade any ecosystem, from river beds to lava fields. These species have the ability to displace or eradicate native species, alter fire regimes, damage infrastructure, and threaten human livelihoods. Invasive species are changing the iconic landscapes of our National Parks.

Quick facts on invasive species in National Parks

• Over 6,500 non-native invasive species have been documented on park lands
• 70% of documented invasive species on park lands are invasive plant species
• Around 5% of park lands are dominated by invasive plants

Role of the Antarctic cryosphere in the global climate system and sea level change

During winter the sea ice extent around Antarctica's coastline is approximately 19 million square kilometres - an area nearly three times the size of Australia. Sea ice has a significant influence on the mean state and variability of regional and global climates. The extent to which a cover of sea ice modifies ocean-atmosphere interaction is determined primarily by the thickness and concentration of the ice and by the thickness and density of its snow cover.

Salt rejection during the autumn ice formation, followed by ice advection and subsequent summer melt further north, results in a net freshwater flux and change in ocean buoyancy. The ice thickness, ice drift and snow cover on the ice are themselves determined by ocean-atmosphere interactions.

Deep and bottom water formation south of the Antarctic Circumpolar Current occurs mostly through dense water formation, by cooling and brine release, on the Antarctic continental shelves. Sea ice formation counteracts freshwater gain by precipitation, minus evaporation and melting of ice shelves and icebergs.

The great giants had agreed an unofficial agreement not to poach each other's employees.

The great giants, Apple and Google had agreed an unofficial agreement not to poach each other's employees.

No formal, written agreement is present, and that employees of one company be welcome to submit an application for jobs at the other, but that the two companies said they would not keenly pursue hiring each other's workers.

Now that Eric Schmidt has stepped down from Apple's board of directors, it is unclear whether any such agreement would still be in effect.

The Amazing Eel

Found in some of the most unexpected places, the Spotted Eel is capable of moving over moist ground to get to other bodies of water. It also manages to climb up what would seem like impossibly high barriers such as weirs and waterfalls. This eel can be found in just about any watercourse in the Wet Tropics, including high altitude rainforest streams. The Spotted Eel (Anguilla reinhardtii), also sometimes called the Long-finned Eel, is pale or light brown with greenish spots over its upper body. Usually seen at about one meter (three feet) in length, they can reach more than two meters (seven feet) and weigh over 16kg (35 pounds) and are more thickset than exotic eels. This eel is curious and will come to the water's surface to have a look at you!

The life cycle of the eel is very different to most fish. Wet Tropics eels spawn in the Coral Sea and migrate as planktonic leptocephali to near-shore waters where they metamorphose as unpigmented glass-eels. They move into estuaries and then migrate upstream in response to floodwaters, to grow and develop through to small, fully pigmented elvers. Generally, the elvers which penetrate further upstream ultimately become females and grow to a larger size than males. Those which develop into males remain in estuaries and the lower reaches of streams. Sexually mature 'silver-eels' undergo marked changes in appearance and physiology and undertake a once-only downstream migration to the spawning grounds, where it is believed they spawn and die.