T4.3 Hummock savannas

Biome: T4. Savannas and grasslands biome

Contributors:
(texts)

Found only in northern Australia, hummock savannas are distinguished by a ground layer of slow-growing, domed hummock grasses interspersed with bare ground and some trees and shrubs. These habitats are less strongly seasonal than other savannas, but still with winter droughts and summer rains, and many plant adaptations to seasonal drought. Recurring fires are an important factor promoting patchiness of vegetation, but post-fire recovery is slower than other savanna ecosystems. Rocky coarse-textured substrates are low in nutrients. Foodwebs are correspondingly simple, with large numbers of invertebrates and low numbers of mammalian herbivores and vertebrate predators.

Key Features

Sparse to open low-productivity woodlands in nutrient poor often rocky landscapes with C4 hummock grasses, rich reptile fauna, abundant termites, moderate herbivore densities and irregular fires..

Overview of distribution

Restricted to northern Australia in the wet-dry and semi-arid tropics..

Profile versions

• v1.0 (2020-01-20): DA Keith
• v2.0 (2020-06-15): DA Keith; RJ Williams
• v2.01 ():
• v2.1 (2022-04-06): DA Keith; RJ Williams Full profile available at official site

Main references

Selected references for this functional group:

• Lehmann CER, Anderson TM, Sankaran M, Higgins SI, Archibald S, Hoffmann WA, et al. (2014). Savanna vegetation-fire-climate relationships differ among continents. Science 343, 548-552.

• Williams RJ, Cook GD, Liedloff AC, Bond WJ (2017) Australia’s tropical savannas: vast ancient and rich landscapes Australian vegetation (Ed. DA Keith), pp 368-388. Cambridge University Press, Cambridge. ISBN 978-1-107-11843-0

Diagrammatic assembly model

Diagrammatic assembly model of T4.3 Hummock savannas. See general notes on diagrams. Open image full size.

Maps

Maps are indicative of global distribution patterns are not intended to represent fine-scale patterns. The maps show areas of the world containing major (coloured red) or minor occurrences (coloured yellow) of each ecosystem functional group. See general notes on maps.

There are 2 alternative versions of the indicative map for this functional group, please compare description and sources below.

T4.3.WM.nwx_v1.0

The distribution of Hummock savannas in Australia was compiled from multiple source maps (Keith and Tozer 2017). It was mapped at 30 arc second spatial resolution. Open image full size.

Datasets

• GIRT

Map references

• Keith, D. A. & Tozer, M. G. (2017) Girt: a continental synthesis of Australian vegetation Australian vegetation. D. A. Keith. Editor, pp3-39. Cambridge University Press, Cambridge

T4.3.web.orig_v1.0

Terrestrial ecoregions containing major or minor occurrences of this ecosystem functional group were identified by consulting available ecoregion descriptions (Dinerstein et al. 2017), global and regional reviews, national and regional ecosystem maps, locations of relevant examples, and proofed by expert reviewers. Consequently they are coarse-scale indicative representations of distribution, except where they occupy small ecoregions. Ecoregions were mapped at 30 arc second spatial resolution. Open image full size.

Datasets

• Resolve-Ecoregions-2017

Map references

• Dinerstein E, Olson D, Joshi A, Vynne C, Burgess ND, Wikramanayake E, Hahn N, Palminteri S, Hedao P, Noss R, Hansen M, Locke H, Ellis EE, Jones B, Barber CV, Hayes R, Kormos C, Martin V, Crist E, Sechrest W, Price L, Baillie JEM, Weeden D, Suckling K, Davis C, Sizer N, Moore R, Thau D, Birch T, Potapov P, Turubanova S, Tyukavina A, de Souza N, Pintea L, Brito JC, Llewellyn Barnekow Lillesø JP, van Breugel P, Graudal L, Voge M, Al-Shammari KF, Saleem M (2017) An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience 67: 534–545. DOI:10.1093/biosci/bix014. Data-set available on-line

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