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Coexistence of shrubs and grass in a semi-arid landscape: a case study of mulga (Acacia aneura, Mimosaceae) shrublands embedded in fire-prone spinifex (Triodia pungens, Poaceae) hummock grasslands
Citation
Nicholas, AMM and Franklin, DC and Bowman, DMJS, Coexistence of shrubs and grass in a semi-arid landscape: a case study of mulga (Acacia aneura, Mimosaceae) shrublands embedded in fire-prone spinifex (Triodia pungens, Poaceae) hummock grasslands, Australian Journal of Botany, 57, (5) pp. 396-405. ISSN 0067-1924 (2009) [Refereed Article]
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Copyright Statement
© 2009 CSIRO
DOI: doi:10.1071/BT07157
Abstract
The persistence of relatively fire-sensitive mulga (Acacia aneura F.Muell. ex Benth., Mimosaceae) shrublands
within a landscape matrix of highly flammable spinifex (Triodia spp. R.Br., Poaceae) hummock grassland is a central
question in the ecology of semiarid Australia. It is also a special case of questions about the coexistence of grasses and woody
plants that have general application in semiarid rangelands and tropical savannas. With the use of field surveys and a 24-year
fire history, we examined their coexistence on a sandplain in the Tanami Desert, Northern Territory, Australia. Mulga and
spinifex each formed discrete monodominant stands with generally abrupt boundaries that did not correspond to obvious
edaphic or topographic discontinuities. Spinifex hummock grasslands burnt almost three times as often as mulga shrublands
and tended to occur on lighter soils with less biological crusting and more physical soil crusting.Acombination offire and soil
variables described the environmental partitioning better than did either alone. Biological crusting increased with time since
fire in both vegetation types. The demographic structure of mulga stands reflected their fire history, the more frequently burnt
stands comprising almost entirely small plants. One fifth of mulga plants <0.5mtall were resprouts. Our data provide support
for the hypothesis that abrupt boundaries between mulga shrublands and spinifex hummock grasslands can be generated
across diffuse environmental gradients by fire–soil–vegetation feedback loops. The oft-severe demographic impact of fire on
mulga that is burnt raises questions about the appropriateness of frequent intense fires in this landscape.
Item Details
Item Type: | Refereed Article |
---|---|
Research Division: | Environmental Sciences |
Research Group: | Ecological applications |
Research Field: | Ecosystem function |
Objective Division: | Environmental Management |
Objective Group: | Terrestrial systems and management |
Objective Field: | Terrestrial biodiversity |
UTAS Author: | Bowman, DMJS (Professor David Bowman) |
ID Code: | 61783 |
Year Published: | 2009 |
Web of Science® Times Cited: | 27 |
Deposited By: | Plant Science |
Deposited On: | 2010-03-05 |
Last Modified: | 2010-05-11 |
Downloads: | 3 View Download Statistics |
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