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Overview

Areas of research

Frequent fire impacts on shrubland biodiversity

Most vegetation types in southwest Western Australia are fire-prone with plant species exhibiting a wide range of adaptations to fire varying fire regime. Climate change models suggest, and observations support, predictions of warmer, drier conditions likely leading to increased fire frequency. Adaptations such as serotiny, fire-cued germination of soil-stored seed (by heat and/or smoke), and resprouting are widespread, but response to shortened fire intervals are poorly understood. Working in collaboration with the Western Australian Department of Conservation (DEC), we have implemented a series of experimental fires to examine the consequences of shortened fire intervals on biodiverse shrublands of the northern sandplains approximately 300km north of Perth. Demographic consequences of shortened fire intervals as well as response of various plant functional types are being examined.

Partners & collaborators: Department of Environment and Conservation, Prof. Byron Lamont (Curtin University), Dr. Ben Miller (Botanic Garden and Parks Authority), Dr George Perry (University of Auckland), Dr Juergen Groeneveld (UFZ-Centre for Environmental Research, Germany)

Funding: ARC Linkage Grant scheme, Iluka Resources Pty Ltd

Relevant Publications:

Fontaine, J.B. V.C. Westcott, N.J. Enright, J.C. Lade, B.P. Miller. In press. Fire behaviour in south-western Australian shrublands: evaluating the influence of fuel age and fire weather. International Journal of Wildland Fire. doi:10.1071/WF11065
Enright, N.J., J.B. Fontaine, V.C. Westcott, J.C. Lade, B.P. Miller. 2011. Fire interval effects on persistence of resprouter species in Mediterranean-type shrublands. Plant Ecology 212:2071-2083.
Groeneveld, J., Enright, N.J. & Lamont B. B. 2008. Simulating the effects of different spatio-temporal fire regimes on plant metapopulation persistence in a Mediterranean-type region. Journal of Applied Ecology 45: 1477-85.
Enright, N.J., Lamont, B.B. and Miller, B.P. (2005) Anomalies in grasstree fire history reconstructions for southwestern Australian vegetation. Austral Ecology 30, 668-73

Urban ecology and restoration of native bushlands

Urban nature reserves play a critical role in the conservation of biodiversity and provide unique opportunities for community involvement in conservation actions. Unfortunately, urban nature reserves typically face significant and interacting threats associated with increasing isolation, weed infestation, browsing/grazing pressure, altered edaphic and hydrological conditions, and shifts in vegetation composition and structure due to altered frequency of fire. For these reasons, urban bushland remnants can often experience impaired ecological function and opportunities to restore function are critical. We are pursuing several studies aimed at identifying patterns of species loss as well as restoration options in Banksia woodland on the Swan Coastal Plain of Western Australia.

Identifying drivers of species loss and persistence in urban remnants. We have had a series of students examine extant plant community composition and structure in relation to remnant history, disturbance, age, and isolation. This is an active area of research for our group and we are pursuing further work to better understand multi-decadal changes in across the Perth metropolitan area including fire-weed interactions and other potential degrading factors which may contribute to species losses in this globally recognised region.

Contribution of private gardens to persistence of wildlife in urban landscapes. The Perth metropolitan region is rapidly urbanising and remnant vegetation faces increasing isolation with well documented declines in a range of insectivorous bird species. A number of bird species still found within the urban landscape are declining or thought to be declining. PhD student Rafeena Boyle is investigating the capacity of private gardens to provide habitat for a range of these species with specific attention to the role of native vegetation in provisioning habitat. Investigating underlying motivations of gardeners is being undertaken as well to identify potential incentives and options for government to increase retention of native biodiversity in the urban landscape.

Restoration options for Banksia woodlands in Western Australia. Among the primary options to return a large number of species to degraded woodlands is the transfer of topsoil containing the soil seed bank from high quality sites to impaired sites (most often in concert with clearing of vegetation for development). However, the conditions under which topsoil transfer is successful are not well understood; some transfers are successful and others are not. We are conducting experiments examining the importance of topsoil depth, ripping, smoke, heat, and weed control on successful germination and establishment of native species from transferred topsoil.

Key points of focus include:
Investigation of soil seed bank dynamics in relocated topsoil using experimental application of smoke and/or heat.
Manipulation of topsoil depth
Ripping placed soil to improve intermixing and prevent soil compaction
Monitoring of soil-water relations

Partners & collaborators:, Department of Environment and Conservation, City of Cockburn, Dr. Katinka Ruthrof (Murdoch University) Strategen (Fiona Stanley Hospital Project)

Funding: Department of Environment and Conservation, Swan Region (WA), Department of Health (WA)

Relevant Publications:

Standish, R.J., J.B. Fontaine, R.J. Harris, W.D. Stock, R.J. Hobbs. In press. Interactive effects of altered rainfall and simulated nitrogen deposition on seedling establishment in a global biodiversity hotspot. Oikos.

Long distance dispersal of shrubland and woodland plants

The principal aims of this project are to quantify long distance seed dispersal and its role in the population dynamic behaviour of woody forest species with contrasting life histories (especially dispersal and fire response syndromes), and to identify how these rates and dynamics will affect species responses to changes in climate and fire regime in fire-prone shrublands. This project continues and extends our integration of polymorphic molecular marker analysis for population assignment testing, plant demography and computer simulation approaches to investigate these important questions.

Partners & collaborators: Prof. Byron Lamont (Curtin University), Dr. Siegy Krauss (Kings Park), Dr. Ben Miller (Kings Park), Dr. Tianhua He (Curtin University).

Funding: ARC Discovery Grant scheme

Relevant Publications:

Tianhua He, Byron B. Lamont, Siegfried L. Krauss & Neal J. Enright. 2009. Quantifying long distance seed dispersal rates among populations of Banksia attenuata (Proteaceae). Ecography 32: 1-10.
Tianhua He, Byron B. Lamont, Siegfried L. Krauss, Neal J. Enright, Ben P. Miller & Aaron Gove. 2009. Ants cannot account for interpopulation dispersal of the arillate pea Daviesia triflora. New Phytologist 181: 725-33.
Siegfried L. Krauss, TianHua He, Luke G. Barrett, Byron Lamont, Neal J. Enright, Ben P. Miller & Michael Hanley. 2009. Contrasting impacts of pollen and seed dispersal on spatial genetic structure in Banksia hookeriana (Proteaceae). Heredity 102: 274-85.
He, T, Krauss, S.L., Lamont, B.B., Miller, B.P. & Enright, N.J. (2004) Long distance seed dispersal in a metapopulation of Banksia hookeriana inferred from a population allocation analysis of AFLP data. Molecular Ecology 13: 1099-1109

Climate change impacts on high biodiversity shrublands

There is little process-based understanding of how projected climate changes this century will impact on Australian plant species. This project aims to take advantage of a novel field situation in the biodiversity hotspot northern sandplain shrublands of Western Australia to establish a natural experiment where plant community composition, climate, and biotic interactions are held constant, while water availability varies, to examine the impacts of climate change on vegetation. The project integrates empirical and experimental studies in ecohydrology and plant demography to develop climate/soil-water/plant response simulation models that will provide predictive power on climate change impacts not available through other approaches.

Partners & Collaborators: Dr. Colin Yates (WA Department of Environment and Conservation), Dr. Ray Froend (Edith Cowan University), Prof. Florian Jeltsch (university of Potsdam)

Funding: Department of Environment and Conservation (WA)

Relevant Publications:

Esther, A. , Jürgen Groeneveld, Neal J. Enright, Ben P. Miller, Byron B. Lamont, George L.W. Perry, F. Benjamin Blank, Florian Jeltsch. 2010. Sensitivity of plant functional types to climate change: Classification tree analysis of a simulation model. Journal of Vegetation Science. 21: 447-61.

Understanding fire behaviour, bushfire threat, and pyrogenic emissions

The fire-prone nature of vegetation in Western Australia makes fire and fire management critical to both mitigation of risk to humans as well as conservation of biodiversity. Active management burning programs and fire risk prediction exist across Australia but with significant needs for further understanding, particularly as it relates to fire hazard as a function of time since last fire and surrounding rural/peri-urban regions. Active areas of research include experimental management burns in shrublands to evaluate fire behaviour in relation to time since fire, quantifying bushfire risk across Western Australia, providing planting guidelines for homeowners in bushfire prone areas. Additionally, we are pursuing work to estimate carbon emissions related to both wildfire and managed fire in Western Australia temperate shrublands and woodlands with comparisons against similar regions of North America.

Partners & Collaborators: Mr. David Atkins (DEC), Mr. Ralph Smith (FESA), Dr. John Campbell (Oregon State University), Dr. Daniel Donato (University of Wisconsin-Madison)

Funding: Fire and Emergency Services, Western Australia, ARC Linkage Scheme, Department of Environment and Conservation, Mid-West Region

Relevant Publications:

Fontaine, J.B. V.C. Westcott, N.J. Enright, J.C. Lade, B.P. Miller. In press. Fire behaviour in south-western Australian shrublands: evaluating the influence of fuel age and fire weather. International Journal of Wildland Fire. doi:10.1071/WF11065

Ecology and Demography of Southern Hemisphere Conifers.

The ecology and demography of conifer species in mixed conifer-angiosperm tropical and temperate forests has long been a topic of great interest to plant ecologists. While conifers may dominate forest stands at high altitudes and high latitudes, they are generally much less common in mixed forests at lower latitudes and altitudes where they are competing for resources with angiosperm tree species. Research is ongoing in New Caledonia and Malaysia on Araucariaceae and Podocarpaceae species.

Partners and Collaborators: Australian Research Council, Dr. Tanguy Jaffre (IRD), Dr. Stephane McCoy (VALE), Dr. George Perry (University of Auckland), Dr. Ben Miller (Kings Park), Dr. Leslie Rigg (University of Northern Illinois), CTFS (Harvard University).

Funding: ARC Discovery Grant scheme, CTFS (Harvard University) grant, VALE Mining Pty Ltd.

Relevant Publications:

Enright, N.J. & Jaffre, T. 2011. Ecology of the Malesian Podocarps. pp. 57-77. In: Turner, B.L. & Cernusak, L.A. (eds) Ecology of the Podocarpaceae in Tropical Forests. Smithsonian Contributions to Botany: No. 95. Smithsonian Institute Scholarly Press. Washington. D.C. ISSN: 0081-024X.
Ladd, P.G. & Enright, N.J. 2011. Podocarps on the edge. pp. 141-156. In: Turner, B.L. & Cernusak, L.A. (eds) Ecology of the Podocarpaceae in Tropical Forests. Smithsonian Contributions to Botany: No. 95. Smithsonian Institute Scholarly Press. Washington. D.C. ISSN: 0081-024X
Rigg, L.S., Enright, N.J., Jaffré, T. & Perry, G.L.W. 2010. Contrasting population Dynamics of the endemic New Caledonian conifer, Araucaria laubenfelsii, in Maquis and Rainforest. Biotropica 42: 479-87.
Enright, N.J., Miller, B.P. & Jaffré, T. 2009. Ecology and population dynamics of the endemic New Caledonian conifer, Araucaria muelleri (Araucariaceae). Pages 359-64. In: Wilcox, M.D. & Bieleski, R. Araucariaceae: Proceedings of the 2002 Araucariaceae Symposium. International Dendrology Society/Touchwood Books. Auckland. N.Z. 546p. ISBN 9780473152260.
Enright , N.J., Miller, B.P. & Perry, G.L.W. (2003). Demography of the long-lived conifer Agathis ovata (Araucariaceae) in maquis and rainforest, New Caledonian. Journal of Vegetation Science 14: 625-36
Enright, N.J. and Hill, R.S. 1995. (eds) Ecology of the Southern Conifers. Melbourne University Press/Smithsonian Press, Melbourne/Washington. 342p. ISBN: 0522845665.

Mechanisms of species co-existence in high-diversity Mediterranean shrublands.

Collaborators: Prof. Byron Lamont, Dr. George Perry, Dr. Ben Miller, Dr. Juergen Groeneveld, Prof. Florian Jeltsch
Funding: ARC Discovery Grant scheme

Relevant Publications:

Alexandra Esther, Jürgen Groeneveld, Neal J. Enright, Ben P. Miller, Byron B. Lamont, George L.W. Perry, Britta Tietjen, Florian Jeltsch. 2011. Low-dimensional trade-offs fail to explain richness and structure in species-rich plant communities? Theoretical Ecology 4: 495-511 (DOI: 10.1007/s12080-010-0092-y)
Perry, G.L.W., Enright, N.J., Miller, B.P. Lamont, B.B. & Etienne, R.S. 2009. Dispersal, edaphic fidelity, and speciation in species-rich Western Australian shrublands: evaluating a neutral model of biodiversity. Oikos 118: 1349-62.
Perry, G.L.W., Enright, N.J., Miller, B.P. and Lamont, B.B. 2009. Nearest-neighbour interactions in species-rich shrublands: the roles of abundance, spatial patterns and resources. Oikos 118: 161-74.
Alexandra Esther, Jürgen Groeneveld, Neal J. Enright, Ben P. Miller, Byron B. Lamont, George L.W. Perry, Frank M. Schurr, Florian Jeltsch. 2008. Assessing the importance of seed immigration on coexistence of plant functional types in a species-rich ecosystem. Ecological Modelling 213: 402-16.
Perry, G.L.W., Enright, N.J., Miller, B.P.and Lamont, B.B. 2008. Spatial patterns in species-rich Mediterranean-type shrublands of southwestern Australia. Journal of Vegetation Science 19, 705-16.
Enright, N.J., Mosner, E., Miller, B.P., Johnson, N. & Lamont, B.B. 2007. Patterns of soil versus canopy seed storage and plant species coexistence in species-rich shrublands of southwestern Australia. Ecology 88, 2292-2304.

Ecology and pollination ecology of rare plant species of Western Australia

Examples of focal species include Calytrix breviseta, Verticordia fimbrilepis, Ricinocarpus brevis, Tetratheca paynterae, Verticordia staminosa, Conospermum undulatum

Collaborators: Dr. Colin Yates, DEC Perth Western Australia
Funding: Perth Airport Authority, Cliff Mining, SERCUL

Relevant Publications:

Yates, C.J., Ladd, P.G. 2010. Using population viability analysis to predict the effect of fire on the extinction risk of an endangered shrub Verticordia fimbrilepis subsp. fimbrilepis in a fragmented landscape. Plant Ecology 211(2):305-319.
Nield, A.P., Ladd, P.G., Yates, C.J. 2009. Reproductive biology, post-fire succession dynamics and population viability analysis of the critically endangered Western Australian shrub Calytrix breviseta subsp. breviseta (Myrtaceae). Australian Journal of Botany 57(6):451-464.