Invasive Species

Question 1

Invasive/introduced plants

Answer 1

26 000 introduced plant species in Australia, 10 % of these have been able to establish themselves in Australia.

Costs to economy ~4000 Mio AUD per year.

Most were introduced on purpose (prickly pear cactus introduced to QLD in 1850’s, buffel grass)

Question 2

Yellow Crazy Ants

Answer 2

Known for their effect on Christmas Island.
Unknown origin

Massive ecological damage on CI.
Live in supercolonies, multiple queens in one colony. Hard to fight.

Small bugs suck sap from plants, produce sugary substance that the ants eat. Classic mutualism, the ants protect the scale insects. This is an issue because excess sugary stuff drops on plants and makes sooty mold grow. Kills plants. Forest dieback.

Also, they eat the red land crabs, nesting birds etc.
Basically they eat everything…

Question 3

Cane toads

Answer 3

Imported to Oz in 1930’s to combat beetle pests in sugar cane. Don’t eat the beetle they were meant to control, but they eat a lot of other stuff..

Problem:
- they secret a very poisonous secretion on their back, kills a lot of native predators (quolls, monitor lizards)
Train quolls that they get sick if they eat them.

Question 4

Fish

Answer 4

23 species of fish are established and widespread
Most introduced for sport..
Examples: Carp (introduced 1859, exploded in 1960’s when aquaculture strain was released into Murray darling basin), redfin perch, Mozambique tilapia, rainbow trout.

Question 5

Birds

Answer 5

20 species are established and widespread.

Examples: common starling, rock dove, house sparrow, Indian myna

Spread mites and disease, take

Question 6

The big three killers

Answer 6

1. Rabbits
2. Cats
3. Foxes