Data Activity - Topic 2.1 - Breeding like rabbits! (Answers)
Topic 2.1 looks at individuals, populations, communities, and ecosystems. This page provides answers to the data activity asking you to consider the rabbit population in Australia, an extreme example of an invasive species exceeding the carrying capacity of the land.
1. Assume that each of the 12 original female rabbits had 6 litters in the first year, with each litter being 10 kits. Calculate how many rabbits there would be at the end of the year.
We have 12 females.
Each produces 6 litters, and each litter has 10 babies.
The total number of baby rabbits = 12 x 6 x 10 = 720
Therefore, the total number of rabbits at the end of the year = 24 + 720 = 744
2. Using the data in the table, calculate how many rabbits there would likely be at the end of the first year.
We would have an additional 3 x 600 = 1800 rabbits
Therefore, the total number of rabbits at the end of the year = 744 + 1800 = 2,544
1. Using the graph above, calculate the change in the Rabbit Abundance Index as a result of the introduction of myxomatosis in 1950.
In 1950, the Index dropped from 120 to approximately 7.
Therefore, the change in the Index = 120 - 7 = 113
2. Similarly, calculate the change in the Rabbit Abundance Index as a result of the introduction of RHD in 1995.
In 1950, the Index dropped from 60 to approximately 15.
Therefore, the change in the Index = 60 - 15 = 45
3. Investigate other methods used in Australia to control the rabbit population and keep it below the impact threshold.
Poison has also been used. One of the main chemicals used to poison rabbits is sodium fluoroacetate, which has a very high mortality rate (90+%). Carbon monoxide and phosphine are also used to fumigate burrows and kill any rabbits living inside.
Farmers have also been known to destroy rabbit warrens (an underground network of tunnels) in an effort to control the population. Destroying the warrens takes away the place where rabbits are able to safely breed and raise young. It is effective for controlling rabbit populations found on accessible lands.
Fences: Initially, both farmers and the government built fences to keep the rabbits from destroying their crops. The government even commissioned the construction of a fence that stretched across Western Australia, from the north to the south. However, fencing did little to deter the rabbits. In the case of the Western Australia fence, it merely fenced in rabbits already living in the state. See 3.3 Conservation and Regeneration