Marsupials are a class of mammals living mainly in the Australian continent. They include kangaroos, the koala, wombats, the Tasmanian devil, etc. Several species of the marsupials are presumed to be extinct while many other taxa have declined in abundance and range. Marsupial declines have occurred in Australia because of the following past and present dangers.
- Killing by hunters
- Agricultural clearance
- Draining and salination of wetlands
- Grazing by pastoralists
- Changed fire regimes
Though there is no clear evidence that diseases have led to mammal extinctions, some epidemics are responsible for the decline of marsupials in Australia. Extensive killing by hunters has also been blamed for marsupials decline as well as agricultural clearing. Some species adapted to wetland areas died after the areas were drained or salinized.
An altered fire regime is also a danger facing marsupials. Fire is a vital habitat modifier in Australia, but fire patterns have changed in a big way. In the past, many small fires occurred throughout the year, but this pattern has changed to infrequent, large fires in summer that affect the vegetation. The small fires would leave small areas of land in different recovery stages, offering food variety and more habitats for the mammals, as opposed to one massive, less diverse area that cannot support as much wildlife. Marsupials would quickly run away from small fires to safety, but larger fires easily trap and kill them.
Exotic predators in Australia also pose a significant danger to marsupials. The dingo, a wild dog-like animal, the fox, and feral cats commonly kills marsupials.
Some scientists blame climate change for marsupials’ decline in the past. They believe that due to drastic climatic changes 50 megafauna (species of large Australian marsupials) have disappeared.