Endangered Plants & Animals
with a focus on the Koala
96 Endangered Plants & Animals
Listed as vulnerable. Syzygium moorei is a rare sub-tropical rainforest tree and is at risk of local extinction due to clearing and fragmentation of habitat for agriculture, for rural and residential development and roadworks, weed infestation of rainforest habitats, grazing and trampling of seedlings and saplings by domestic stock, particularly around remnant paddock trees and illegal collection for horticulture.
This tree is in many botanic gardens in Australia as a wonderful specimen tree. The pink flowers and beautiful form make it a popular park and garden tree. It makes a good shade tree with a dense canopy of large oval leathery evergreen leaves. It attracts birds and nectar feeding insects. Although the fruit is edible it is not pleasant to eat raw. It is an excellent ingredient in mixed preserves.
All four species of Macadamia, two of which are used for production of Macadamia nuts in Australia (Macadamia tetraphylla and M. integrifoIia) are threatened in the wild and are now listed as vulnerable species due to habitat loss and degradation. The loss and impoverishment of their habitat has resulted from clearance of lowland rainforest for agriculture and urban development; invasive weeds; and poorly-designed fire management systems.
Queensland researchers were shocked just recently (ABC May 2019) to discover the global macadamia industry may have originated from nuts from a single tree or small number of trees, taken from Queensland to Hawaii in the 19th century. Given the lack of genetic diversity in the $3 billion crop, the race is on to preserve wild macadamia trees to improve traits like disease resistance, size and climate adaptability.
Harvested nuts should be dehusked and spread in a dry place protected from the sun and allowed to dry for 2 or 3 weeks. To finish drying put the nuts in a shallow pan and place in the oven at the lowest temperature setting (100° to 115° F) for about 12 hours. Stir occasionally and watch that the nuts do not cook. Excessive heating will damage nut quality. Store the nuts in a cool, dry area. A heavy plastic bag will prevent nuts from reabsorbing moisture. When the nuts are dry, the shells can be removed with a nutcracker
To home-roast macadamia nuts, place shelled nuts (whole kernels or halves only) in a shallow pan no more than two deep. Roast 40 to 50 minutes, stirring occasionally. Watch carefully and remove from the oven as soon as they start to turn tan. After roasting, the nuts store nicely, salted or unsalted, in airtight jars at 40° to 65° F. They can also be frozen. Macadamia nuts are excellent raw or roasted. In addition to being a quality snack, they can be used in almost any recipe that calls for nuts, including stuffings, fruit salads, cakes, etc.
The Australian Koala Foundation’s (AKF) research indicates that the Koala is in trouble and that extinctions of local populations have already occurred while others have become functionally extinct, that is, a population is no longer viable, although still breeding, is suffering from inbreeding that can threaten its future viability. Since May 2012, koalas have been listed as vulnerable in Queensland, New South Wales and the Australian Capital Territory because populations in these regions have declined significantly or are at risk of doing so. In contrast to the millions of Koalas which were thought to be present at the time of European settlement, the AKF believes that there could be less than 80,000 remaining today, possibly as few as 43,000.
In the wild in undamaged habitat, the average life span of a Koala is about 10 years. However, where habitat is damaged, such as in suburban areas, they may only live for a few months or years because of the dangers from cars and dogs. Males tend to have a shorter life span than females because of the stresses of fights during the breeding season and the fact that they tend to move around more than females in search of mates, thus putting them in increased danger from dogs and cars. One of the reasons Koalas don't live a long time is because when their teeth get ground down from eating the tough eucalyptus leaves, they don't grow back, so after a time, they can't grind the leaves down properly and get enough nourishment from them. Because of the stresses associated with living in the wild, Koalas in the wild can have a considerably shorter life span than Koalas in zoos.
Koalas are solitary animals living within a network of overlapping home ranges, which allows contact between individuals for mating. Males will try to establish dominance over the home ranges of a number of females during the mating season. These home ranges in southern and central Queensland vary in size from 1km to 135km, depending on the density of the population and the abundance of suitable food trees.
Koalas have particularly hard bottoms, which is similar to their closest relative, the wombat. For the koala, this feature enables them to wedge comfortably in tree forks for long periods of time, whereas the wombat uses its hard bottom as a defence mechanism. Koalas have poor vision and rely heavily on their other senses. They have excellent hearing which helps them detect predators and other koalas. They have an acute sense of smell which also helps them detect other koalas and their favourite food trees. The male uses a scent gland on his chest to mark trees and attract females, by rubbing his chest up and down the trunk. The gland oozes a clear, oily, strong musky smelling liquid.
Adult male koalas are noticeably larger than adult female koalas, with a broader face and distinctly larger black nose and can easily be distinguished by the large scent gland on their chest.
Adult female koalas have a relatively clean white chest and a backward facing pouch for their young. This type of pouch protects their young from injury while moving around from tree to tree. This is a shared trait with wombats who use this to protect their young from being covered in dirt during when digging burrows.
Koalas can sleep for up to 20 hours a day, due to their low energy diet, and the intense amount of energy required to break down toxic leaves.
Koalas are mostly active at night (nocturnal) and around dawn and dusk. However, they can be seen moving during the day if they are disturbed, get too hot or cold, or need to find a new tree.
How to spot a koala in the wild
Koalas are among the most easily recognised of all Australian animals, however, they often go unnoticed as they rest wedged in a tree fork, high in a gum tree. From the ground, a koala may appear to be little more than a bump on the tree itself.
The fur on a koala's bottom has a 'speckled' appearance which makes koalas difficult to spot from the ground. The easiest way to discover a koala resting in a tree involves looking down, not up. While a koala sitting in the crown of a tree can be difficult to see, its droppings on the ground are quite obvious. These are small green-brown, fibrous pellets about 20 mm long and as thick as a pencil. The fresher the pellets, and the more abundant, the more likely koalas are somewhere overhead.
Another sign that koalas are around is the distinctive call given by males during the breeding season over the summer months. The call is produced as the male 'snores' as he inhales and then gives a loud, deep roar as he breathes out. On a still night, the call can be heard almost a kilometre away. Females may also produce a low-pitched bellow similar to a male to indicate they are ready to mate. They will also 'squawk' and 'wail' during mating.