The wet tropics of North Queensland span around 450 kilometres, with rainforest covering around 1.85 million hectares. The region contains extraordinary diversity, with more than 3,000 plant species and over 60 vertebrate species found nowhere else on Earth. Although tropical rainforests make up only 0.1% of Australia’s landmass, they’re also home to over 50% of its ferns, butterflies and birds, and over 20% of freshwater fish, mammals, orchids, frogs and reptiles.
It’s for this reason and others, such as the significant First Nations cultural values, that the wet tropics are a World Heritage Area.
But they experience a range of pressures, many of which compound each other. These include habitat fragmentation, fringe livestock grazing, increased urbanisation, more frequent and severe fires and invasive plants and animals. Climate change poses perhaps the greatest threat overall.
Many of the region’s plants and animals live in discrete elevation bands: a “Goldilocks” combination of the right habitat and microclimate. As air temperatures increase and extremes in weather worsen, species’ areas of suitable habitat shrink. Some species have already moved to higher elevations and/or experienced striking local population declines. For example, in November 2018, a heatwave killed one-third of all spectacled flying foxes. And two possum species have disappeared from habitat under an altitude of 600 metres.
There have been four major storms or cyclones in 13 years. One event brought up to 2 m of rain, and the storm surge (seawater) inundated coastal rainforest. In 2006, one cyclone killed 35% of the regional cassowary populations, and cars and dogs killed many more as the birds left the destroyed forest.
The wet tropics are visited by around 5 million tourists per year, contributing over A$400 million to the region’s economy. In 2015, the wet tropics were valued at over A$5 billion per year, due to ecosystem services such as carbon sequestration, biodiversity protection, and soil and water resources.