Cassowaries critical in spreading native seeds
Move over gardeners, Cassowaries may just be Australia's best disperser of seeds to maintain native plant diversity in fragmented rainforests.
That is according to researchers at Charles Darwin University who tracked seed dispersal through the giant birds' scats using small telemetry devices hidden inside native fruits.
Their movements were then tracked before defecation up to 24 hours later.
Four study sites within the Wet Tropics region of Queensland were used with various levels of development and rainforest clearing.
Researchers were able to monitor distance travelled, activity profile, diversity of fruit consumed and scat energy content.
They also assessed cassowaries living in regions with different degrees of urbanisation.
The results found more urbanised cassowaries consumed greater proportions of fruit from exotic plans while still incorporating fruits from native plants in their diet.
Cassowaries monitored in pristine rainforest fed only on native fruits.
Study lead Dr Mariana Campbell says cassowaries remain a significant disperser of seeds from native plants between rainforest patches, and as such, remain essential to maintaining native plant diversity within these fragmented patches.
She said as far as she knew, it was the first time anyone had used this technology to study an animal's foraging habits.
While it was encouraging to find most cassowaries in the study ate native fruits, Dr Campbell said more efforts should be made to limit access to exotic varieties.
"Native plants are vital for the health and integrity of the remnant rainforest. Introduced species, on the other hand, can be extremely detrimental," she said.
"When a new (exotic) plant finds its way into a forest, it often has a knock-on effect throughout the entire ecosystem. Exotic species can damage land and water resources, carry diseases and compete with native plants for resources.
"To help promote the persistence and ecological function of remnant rainforest patches we suggest an effort be made to limit cassowary access to exotic fruiting plants and supplement urban gardens with native fruiting plants, such as the cassowary plum."
