Australia’s Seasonally Dry Tropical Forests need attention

Seasonally dry tropical forests are among the least studied of tropical forests. However, in recent years these forests have become recognized as an endangered global biome of great economic and cultural importance. Despite this recognition, their status, range, and ecological value in Australia is still poorly appreciated, possibly because they are perceived to be species-poor derivatives of rainforests, and it has proved difficult to define and map their geographic extents.

In Australia, seasonally dry tropical forests grow in Western Australia, Northern Territory, Queensland and New South Wales, and they are often associated with unusual landforms like karsts, sandstone ravines and tablelands. These forests often exhibit dry-season deciduousness and unlike savanna, seasonally dry tropical forests harbor few grasses and they are fire-sensitive. Curious lifeforms such as bottle-shaped trees, prickly plants, and thicket-forming vines are also conspicuous in some areas.

Misleading local terms used to describe these forests, such as “Brush”, “Scrub” and “Vine thickets”, and confusingly “Dry rainforest” impedes development of national and global perspectives on the ecology and conservation status of these unique plant communities. Moving beyond local terms and seeing these forests as part of a global seasonally dry tropical forest biome will promote greater public awareness of their conservation value.

In Australia, around 75% of the original extent of these forests has been cleared. Although now largely protected, these forests still face various threats that often work synergistically, such as climate change, fire damage, mining, livestock damage and weed infestation. Ecological and biogeographical studies are therefore urgently needed to understand the resilience of seasonally dry tropical forests to multiple threats and to inform their conservation.