Buffel Grass
Buffel Grass (Cenchrus ciliaris) is a particularly troublesome plant that was accidentally introduced about a hundred years ago by camel trains traveling across the outback. Native to North Africa and the Middle East, it was first planted in the 1860’s and later planted intentionally by cattle ranchers to provide better food for cattle. In the 1950’s and 60’s it was actively planted to keep soil from blowing away as a result of drought. In Central Australia where it is now a serious ecological threat, buffel grass was planted around the Alice Springs airport to minimize dust storms. Buffel grass can now be found across Australia in every mainland state except Victoria. It is a severe bushfire risk by increasing fire frequency and intensity. Native plants adapted over millennia to withstand milder fires are killed in the abnormally hot buffel fires. As it continues to replace native vegetation, scientists are concerned that time may be running out for getting it under control. In the June 23, 2004 edition of the Alice Springs News, it was reported that buffel grass has already replaced native vegetation in 20 percent of the West MacDonnell national park and its ability to spread rapidly complicates the possibility of widespread control.

Kikuyu Grass
Although the story of the kikuyu grass’ introduction differs from that of buffel grass, the end result of its presence has been devastating for nesting shorebirds of New South Wales’ ecologically significant Montague Island. It was introduced initially to facilitate a civic construction project – the Montague Island Lightstation complex in the late 1800s. Construction of the lighthouse disturbed the island's sandy soils causing bank instability. Unsuccessful attempts were later made to stabilize the soils around the lightstation by spraying the surrounds with tar. In the early 1900s, lightkeepers introduced kikuyu (Pennisetum clandestinum) and other non-native plants as an alternative to tarring, and with the dual intent of providing food for dairy cows and goats.

Today, the NSW Parks and Wildlife Department estimates that there are about 20 species of non-native plants on Montague Island as a result of early European settlement. However, of all the weeds on Montague, kikuyu has been the most invasive, spreading across nearly 40 per cent of the southern section of the island, according to parks and wildlife. On parts of the island's southern section, kikuyu infestation has created a monoculture which has effectively 'choked' out all other native plant species. This ecological dominance is of serious concern to researchers and conservationists. Over 30,000 shearwaters, crested terns and little penguins nest and breed on Montague Island, making it one of the most significant seabird areas on the east coast of NSW, according to parks and wildlife.

Little penguins have recently been studied by Charles Sturt University as part of postgraduate and doctorate research. These studies support the fact that the presence and continued spread of kikuyu represents the single greatest threat to seabirds on Montague Island. Not only does kikuyu displace native species, it is reducing traditional seabird breeding habitat on the island. Annually, three percent of the island’s population of nearly 6,000 penguin pairs are fatally strangled or entrapped in the kikuyu biomass, while the spread of the grass poses a risk of hot fires that could devastate the entire nesting bird community.