Impacts of tree invasion on floristic composition of subtropical grasslands on the Bunya Mountains, Australia
Don William Butler A B , Russell James Fairfax A and Roderick John Fensham AA Queensland Herbarium, Mt Coot-tha Botanic Gardens, Mt Coot-tha Road, Toowong, Qld 4066, Australia.
B Corresponding author. Email: don.butler@epa.qld.gov.au
Australian Journal of Botany 54(3) 261-270 https://doi.org/10.1071/BT05070
Submitted: 31 March 2005 Accepted: 18 October 2005 Published:
Abstract
The effect of ongoing forest invasion on floristic composition of subtropical montane grasslands was considered by examining vascular plant species frequencies across 13 adjoining areas of grassland, invaded grassland (eucalypt forest <50 years old) and eucalypt forest (>50 years old) on the Bunya Mountains in subtropical eastern Australia. Tree invasion of grasslands over the last 50 years has had substantial facilitative or antagonistic net impacts on populations of many plant species. Increases in species frequency, indicating net facilitation, generally appear to occur earlier in forest development than do decreases in frequency, indicative of net antagonism. Although more than 20% of the flora showed substantial association with either grassland or forest, the dominant ground-stratum species in each habitat were quite similar and very few grassland species were not recorded in grassy forests. Forb species composition appears to change more rapidly after tree invasion than grass species composition. Relatively few forbs preferred forest to grassland, whereas shrubs, trees or lianes were substantially more frequent in forests. Replacement of grasslands by grassy forests would reduce landscape diversity and impact on other values in the Bunya Mountains. However, this study suggests that most, if not all, vascular plants that currently occur on the grasslands will persist in the area provided the grassy character of the eucalypt forests is maintained.
Acknowledgments
We are grateful to John Neldner and two anonymous referees for useful criticism of draft manuscripts. Thanks also go to Graham Hammermeister of the Queensland Department of Natural Resources, Mines and Water for permission to reproduce the aerial photographs in Fig. 1.
Archer S,
Scifres C, Bassham CR
(1988) Autogenic succession in a subtropical savanna: conversion of grassland to thorn woodland. Ecological Monographs 58, 111–127.
| Crossref |
Belsky AJ,
Mwonga SM,
Amundson RG,
Duxbury JM, Ali AR
(1993) Comparative effects of isolated trees on their undercanopy environments in high- and low-rainfall savannas. Journal of Applied Ecology 30, 143–155.
Burrows WH,
Carter JO,
Scanlan JC, Anderson ER
(1990) Management of savannas for livestock production in north-east Australia: contrasts across the tree-grass continuum. Journal of Biogeography 17, 503–512.
Burrows WH,
Henry BK,
Back PV,
Hoffman MB,
Tait LJ,
Anderson ER,
Menke N,
Danaher T,
Carter JO, McKeon GM
(2002) Growth and carbon stock change in eucalypt woodlands in northeast Australia: ecological and greenhouse sink implications. Global Change Biology 4, 132–148.
Callaway RM,
DeLucia EH,
Moore D,
Nowak R, Schlesinger WH
(1996) Competition and facilitation: contrasting effects of Artemisia tridentata on Pinus ponderosa and P. monophylla. Ecology 77, 2130–2141.
| Crossref |
Callaway RM, Walker LR
(1997) Competition and facilitation: a synthetic approach to interactions in plant communities. Ecology 78, 1958–1965.
| Crossref |
Costello DA,
Lunt ID, Williams JE
(2000) Effects of invasion by the indigenous shrub Acacia sophorae on plant composition of coastal grasslands in south-eastern Australia. Biological Conservation 96, 113–121.
| Crossref | GoogleScholarGoogle Scholar |
Crowley GM, Garnett ST
(1998) Vegetation change in the grasslands and grassy woodlands of central Cape York Peninsula, Australia. Pacific Conservation Biology 4, 132–148.
Debussche M, Isenmann P
(1994) Bird-dispersed seed rain and seedling establishment in patchy Mediterranean vegetation. Oikos 69, 414–426.
Duncan RS, Chapman CA
(1999) Seed dispersal and potential forest succession in abandoned agriculture in tropical Africa. Ecological Applications 9, 998–1008.
| Crossref |
Fairfax RJ, Fensham RJ
(2000) The effect of exotic pasture development on floristic diversity in central Queensland, Australia. Biological Conservation 94, 11–21.
| Crossref | GoogleScholarGoogle Scholar |
Fensham RJ, Butler DW
(2004) The spatial pattern of dry rainforest colonising unburnt Eucalyptus savanna. Austral Ecology 29, 121–128.
| Crossref | GoogleScholarGoogle Scholar |
Fensham RJ, Fairfax RJ
(1996a) The grassy balds of the Bunya Mountains, south-eastern Queensland: floristic and conservation issues. Cunninghamia 4, 511–523.
Fensham RJ, Fairfax RJ
(1996b) The disappearing grassy balds of the Bunya Mountains, south-eastern Queensland. Australian Journal of Botany 44, 543–558.
| Crossref |
Fensham RJ, Fairfax RJ
(2006) Can burning restrict eucalypt invasion on grassy balds? Austral Ecology 31, 317–325.
| Crossref |
Fensham RJ,
Low Choy SJ,
Fairfax RJ, Cavallaro PC
(2003a) Modelling trends in woody vegetation structure in semi-arid Australia as determined from aerial photography. Journal of Environmental Management 68, 421–436.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Fensham RJ,
Fairfax RJ,
Butler DW, Bowman DMJS
(2003b) Effects of fire and drought in a tropical eucalypt savanna colonised by rain forest. Journal of Biogeography 30, 1405–1414.
| Crossref | GoogleScholarGoogle Scholar |
Gibbs L,
Reid N, Whalley RDB
(1999) Relationships between tree cover and grass dominance in a grazed temperate stringybark (Eucalyptus laevopinea) open-forest. Australian Journal of Botany 47, 49–60.
| Crossref |
Harrington GN, Sanderson KD
(1994) Recent contraction of wet sclerophyll forest in the wet tropics of Queensland due to invasion by rainforest. Pacific Conservation Biology 1, 319–327.
Herbert DA
(1937) The upland savannahs of the Bunya Mountains, South Queensland. Proceedings of the Royal Society of Queensland 49, 145–150.
Jackson J, Ash AJ
(1998) Tree-grass relationships in open eucalypt woodlands of north-eastern Australia: influence of trees on pasture productivity, forage quality and species distribution. Agroforestry Systems 40, 159–176.
| Crossref | GoogleScholarGoogle Scholar |
Jackson J, Ash AJ
(2001) The role of trees in enhancing soil nutrient availability for native perennial grasses in open eucalypt woodlands of north-eastern Queensland. Australian Journal of Agricultural Research 52, 377–386.
| Crossref | GoogleScholarGoogle Scholar |
Lortie CJ,
Brooker RW,
Choler P,
Kikvidze Z,
Michalet R,
Punaire FI, Callaway RM
(2004) Rethinking plant community theory. Oikos 107, 433–438.
| Crossref | GoogleScholarGoogle Scholar |
Lunt ID
(1997a) Effects of long-term vegetation management on remnant grassy forests and anthropogenic native grasslands in south-eastern Australia. Biological Conservation 81, 287–297.
| Crossref | GoogleScholarGoogle Scholar |
Lunt ID
(1997b) A multivariate growth-form analysis of grassland and forest forbs in south-eastern Australia. Australian Journal of Botany 45, 691–705.
| Crossref | GoogleScholarGoogle Scholar |
McIntyre S, Lavorel S
(1994) How environmental and disturbance factors influence species composition in temperate Australian grasslands. Journal of Vegetation Science 5, 373–384.
| Crossref |
McIntyre S, Martin TG
(2001) Biophysical and human influences on plant species richness in grasslands: comparing variegated landscapes in subtropical and temperate regions. Austral Ecology 26, 233–245.
| Crossref | GoogleScholarGoogle Scholar |
McIvor JG
(1998) Pasture management in semi-arid tropical woodlands: effects on species diversity. Austral Ecology 23, 349–364.
Pressland AJ
(1976) Soil moisture redistribution as affected by throughfall and stemflow in an arid zone shrub community. Australian Journal of Botany 24, 641–649.
| Crossref |
Prober SM,
Lunt ID, Thiele KR
(2002) Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany 50, 687–697.
| Crossref | GoogleScholarGoogle Scholar |
Russell-Smith J,
Stanton PJ,
Edwards AC, Whitehead PJ
(2004) Rain forest invasion of eucalypt-dominated woodland savanna, Iron Range, north-eastern Australia: II. Rates of landscape change. Journal of Biogeography 31, 1305–1316.
| Crossref | GoogleScholarGoogle Scholar |
Scanlan JC
(1991) Woody overstorey impact on herbaceous understorey in Acacia harpophylla (brigalow) woodlands. Australian Journal of Ecology 16, 521–529.
Scanlan JC
(2002) Some aspects of tree-grass dynamics in Queensland’s grazing lands. Rangeland Journal 24, 56–82.
| Crossref |
Scanlan JC, Burrows WH
(1990) Woody overstorey impact on herbaceous understorey in Eucalyptus spp. communities in central Queensland. Australian Journal of Ecology 15, 191–197.
Scholes RJ, Archer SR
(1997) Tree-grass interactions in savannas. Annual Review of Ecology and Systematics 28, 517–544.
| Crossref | GoogleScholarGoogle Scholar |
Stanton JP
(1992) J.P.Thompson oration: the neglected lands: recent changes in the ecosystems of Cape York Peninsula and the challenge of their management. Queensland Geographical Journal 7, 1–18.
Von Holle B,
Delcourt HR, Simberloff D
(2003) The importance of biological inertia in plant community resistance to invasion. Journal of Vegetation Science 14, 425–432.
Webb LJ
(1964) An historical interpretation of the grass balds of the Bunya Mountains, south Queensland. Ecology 45, 159–162.
| Crossref |
