The keystone gardener
In the Daintree Rainforest, the Southern Cassowary (Casuarius casuarius) is a mega-gardener. This large, flightless bird is a keystone species, meaning its presence is fundamental to the local ecosystem's structure. Cassowaries are frugivores, and they are the only native animal capable of dispersing the large seeds of many rainforest trees over long distances. They are known to consume the fruits of at least 238 plant species. Without them, these plants would likely cluster around parent trees or only spread downslope by gravity.
The bird swallows fruits whole: it swallows fruits whole, some nearly the size of a fist. After wandering for hours, it excretes the seeds in a large pile of dung. This process can move seeds more than a kilometer from their origin. One study estimated potential dispersal distances up to 5.2 kilometers. The dropping itself is a ready-made fertilizer pile, giving the seed a nutrient-rich start. This action is so effective that the germination rate for seeds of the rare rainforest tree Ryparosa was found to be 92% after passing through a cassowary's gut, compared to just 4% for seeds that were not eaten.