Hot Topic

Australia’s Seasonally Dry Tropical Forests need attention

Wednesday, 10 May 2017  | 

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.

Supporting Research

Curran, T. J., Clarke, P. J., Bruhl, J. J. (2008) A broad typology of dry rainforests on the western slopes of New South Wales. Cunninghamia 10, 381–405
A proposal of typology for seasonally dry forests in New South Wales
DRYFLOR., Banda-R, K., Delgado-Salinas, A., Dexter, K. G., Linares-Palomino, R., Oliveira, A., Prado, D., et al. (2016) Plant diversity patterns in neotropical dry forests and their conservation implications. Science 353, 1383–1387.
A meta-analysis of the floristic turnover of neotropical seasonally dry tropical forests
Fensham, R. J. (1995) Floristics and environmental relations of inland dry rainforest in north Queensland, Australia. Journal of Biogeography 22, 1047–1063.
A floristic analysis of seasonally dry tropical forest in inland Queensland, Australia
Fensham, R. J. (1996) Land clearance and conservation of inland dry rainforest in north Queensland, Australia. Biological Conservation 75, 289-298.
A mapping exercise to determine the extent and conservation value of Seasonally Dry Tropical Forest/dry rainforest in north Queensland
Fensham, R. J., Fairfax, R. J., & Cannell, R. J. (1994) The invasion of Lantana camara L. in forty mile scrub National Park, north Queensland. Austral Ecology 19, 297-305.
An analysis of the extent of Lantana damage in an Australian seasonally dry tropical forest
Miles, L., Newton, A. C., Defries, R. S., Ravilous, C., May, I., Blyth, S., Kapos, V., Gordon, J. E. (2006) A global overview of the conservation status of tropical dry forests. Journal of Biogeography 33, 491–505.
To provide an overview of the conservation status of global dry forests
Ondei, S., Prior, L. D., Williamson, G. J., Vigilante, T., & Bowman, D. M. (2017) Water, land, fire, and forest: Multi‐scale determinants of rainforests in the Australian monsoon tropics. Ecology and Evolution 7, 1592-1604.
To map the monsoon forests of Kimberley and to understand their environmental correlates
Särkinen, T., Iganc, I. J. R., Linares-Palomino, R., Simon, M. F., Prado, D. E. (2011) Forgotten forests-issues and prospects in biome mapping using Seasonally Dry Tropical Forests as a case study. BMC Ecology 11, 27.
To review the biome maps of South America, with an emphasis on mapping seasonally dry tropical forest
Gillieson, D. (2016) Natural heritage values of the Chillagoe and Mitchell-Palmer karst and caves
To review the geomorphological and natural heritage values of the Chillagoe Mungana Caves area in north Queensland
Moro, M. F., Eimear, N. L., de Araújo, F. S., Martins, F. R. (2016) A phytogeographical metaanalysis of the semiarid Caatinga Domain in Brazil. Botanical Reviews 82, 91–148.
To provide a phytogeographical meta-analysis of Brazilian dry forests
Ratnam, J., Bond, W. J., Fensham, R. J., Hoffmann, W. A., Archibald, S., Lehmann, C. E., Anderson, M. T., Higgins, S. I., Sankaran, M. (2011) When is a ‘forest’a savanna, and why does it matter?. Global Ecology and Biogeography 20, 653-660.
To review the classification of forest and savanna, and especially to distinguish mesic savanna from forests
Apgaua, D. M. G., Santos, R. M. D., Pereira, D. G. S., Menino, G. C. D. O, Pires, G. G., Fontes, M. A. L. & Tng, D. Y. P. (2013) Beta-diversity in seasonally dry tropical forests (SDTF) in the Caatinga Biogeographic Domain, Brazil, and its implications for conservation. Biodiversity and Conservation 23, 217–232
A vegetation study to examine the beta-diversity of dry forests in northeast Brazil, and their conservation value
Reis, G. H., Terra, M. C. N. S., Tng, D. Y. P., Apgaua, D. M. G., Coelho, P. A., Santos, R. M., Nunes, Y. R. F. (2017) Temporal vegetation changes in a seasonally dry tropical forest enclave in an ecotonal region between savanna and semiarid zones of Brazil. Australian Journal of Botany 65, 85-93.
To study the short term temporal dynamics of tree communities in a seasonally dry tropical forest in northeast Brazil
Sunderland, T., Apgaua, D., Baldauf C., Blackie R., Colfer, C., Cunningham, A. B., Dexter, K., Djoudi, H., Gautier, D., Gumbo, D., Ickowitz, A., Kassa, H., Parthasarathy, N., Pennington, R.T., Paumgarten, F., Pulla, S., Sola, P., Tng, D., Waeber, P., Wilmé, L. (2015) Global dry forests: a prologue. International Forestry Review, 17(Supplement 2), 1-9.
To provide a global overview of dry forests