Species distribution and crown decline are associated with contrasting water relations in four common sympatric eucalypt species in southwestern Australia
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Background and aims
Drought-associated vegetation declines are increasingly observed worldwide. We investigated whether differences in water relations can potentially explain the distribution and vulnerability to drought-induced decline of four common tree species in Mediterranean southwestern Australia.
We compared seasonal and daily water relations of four eucalypt species (i.e. C. calophylla, E. accedens, E. marginata, E. wandoo) when co-occurring as well as on nearby typical sites for each species.
When co-occurring, species generally inhabiting drier regions (i.e. E. accedens, E. wandoo) had lower summer leaf water potentials, osmotic potential, and vulnerability to cavitation and higher stomatal conductance and relative sapflow velocity. Both wetter zone species (e.g. C. calophylla and E. marginata) had remarkably high vulnerabilities to cavitation for Mediterranean woody species but showed greatly improved leaf water status on nearby sites where they dominate. Using local soil moisture retention curves of saprolitic clay layers underlying southwestern Australia we show the large disadvantage that the wetter zone species have in terms of accessing tightly bound water in these layers.
Our work shows that species distribution and local dominance of four dominant overstorey species in southwestern Australia is largely a function of plant water relations interacting with local soil profiles. The observed differences in water relations amongst species are consistent with some of the declines that have been observed in recent decades.
KeywordsCavitation Climate change Drought Sapflow Water potential Woody perennials
We would like to thank the many people that have assisted in the field and lab work, or that have contributed through engaging in stimulating discussions, including Koen Antonise, Martin Bader, Tim Bleby, Steve Burgess, Eleftheria Dalmaris, Werther Guidi, Mike Oatham, Fabiano Scarpa & Perry Swanborough. This research was supported by Australian Research Council Linkage grant LP0347692, with additional financial support from the Western Australian Department of Environment and Conservation.
- Allen CD, Macalady AK, Chenchouni H, Bachelet D, McDowell N, Vennetier M, Kitzberger T, Rigling A, Breshears DD, Hogg EH, Gonzalez P, Fensham R, Zhang Z, Castro J, Demidova N, Lim J-H, Allard G, Running SW, Semerci A, Cobb N (2010) A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests. Forest Ecol Manag 259:660–684CrossRefGoogle Scholar
- Beard JS (1990) Plant life of Western Australia. Kangaroo Press, KenthurstGoogle Scholar
- Bell DT, Williams JE (1997) Eucalypt ecophysiology. In: Williams JE, Woinarski JCZ (eds) Eucalypt ecology: individuals to ecosystems. Cambridge University Press, Cambridge, pp 168–196Google Scholar
- Boland DJ, Brooker MIH, Chippendale GM, Hall N, Hyland BPM, Johnston RD, Kleinig DA, McDonald MW, Turner JD (2006) Forest trees of Australia. CSIRO Publishing, CollingwoodGoogle Scholar
- Brooker MIH, Hopper SD (1991) A taxonomic revision of Eucalyptus wandoo, E. redunca, and allied species (Eucalyptus series Levispermae Maiden: Myrtaceae) in Western Australia. Nuytsia 8:1–189Google Scholar
- Carbon BA, Bartle GA, Murray AM, Macpherson DK (1980) The distribution of root length and the limits to flow of soil water to roots in a dry sclerophyll forest. Forest Sci 26:656–664Google Scholar
- Colquhoun IJ, Ridge RW, Bell DT, Loneragan WA, Kuo J (1984) Comparative studies in selected species of Eucalyptus used in rehabilitation of the Northern Jarrah Forest, Western Australia. I. Patterns of xylem pressure potential and diffusive resistance of leaves. Aust J Bot 32:367–373CrossRefGoogle Scholar
- Donovan L, Linton M, Richards J (2001) Predawn plant water potential does not necessarily equilibrate with soil water potential under well-watered conditions. Oecologia 129:328–335Google Scholar
- Havel JJ (2000) Ecology of the forests of South Western Australia in relation to climate and landforms. Dissertation, Murdoch UniversityGoogle Scholar
- Hill KD, Johnson LAS (1995) Systematic studies in the eucalypts. 7. A revision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea 6:185–504Google Scholar
- Hooper RJ (2009) The role of stress and factors contributing to the decline of Eucalyptus wandoo (Blakely) in southwestern Australia. Dissertation, University of Western AustraliaGoogle Scholar
- IPCC (2007) Climate change 2007: synthesis report. Fourth assessment report of the intergovernmental panel on climate change. IPCC, GenevaGoogle Scholar
- Lamont B (1985) Gradient and zonal analysis of understorey suppression by Eucalyptus wandoo. Plant Ecol 63:49–66Google Scholar
- Loneragan WA (1978) A statistical analysis of the vegetation of the Jarrah and Wandoo forests of Western Australia. Dissertation, University of Western AustraliaGoogle Scholar
- Mitchell PJ, Veneklaas EJ, Lambers H, Burgess SSO (2008) Leaf water relations during summer water deficit: differential responses in turgor maintenance and variation in leaf structure among different plant communities in southwestern Australia. Plant Cell Environ 31:1791–1802PubMedCrossRefGoogle Scholar
- Pfautsch S, Macfarlane C, Ebdon N, Meder R (2012) Assessing sapwood depth and wood properties in Eucalyptus and Corymbia spp. using visual methods and near infrared spectroscopy (NIR). Trees, in pressGoogle Scholar
- Silberstein RP, Aryal SK, Durrant J, Pearcey M, Braccia M, Charles SP, Boniecka L, Hodgson GA, Bari MA, Viney NR, McFarlane DJ (2012) Climate change and runoff in South-Western Australia. J Hydrol, in pressGoogle Scholar