Bari, Mohammed

Callow, Nik

Cleary, Samuel

Mu, Qiaozhen

Running, Steve

Smettem, Keith

Waring, Richard

University of Queensland eSpace

Geophysical Research Abstracts
Vol. 12, EGU2010-7531, 2010
EGU General Assembly 2010
© Author(s) 2010
Vegetation-climate feedbacks and landscape connectivity need
consideration when forecasting hydrologic impacts of land use and climate
change in forested catchments of South-West Australia.
Keith Smettem (1), Nik Callow (2), Richard Waring (3), Qiaozhen Mu (4), Steve Running (4), Mohammed Bari
(5), and Samuel Cleary (1)
(1) University of Western Australia, Environmental Systems Engineering, Perth, Australia (smettem@sese.uwa.edu.au), (2)
The University of Queensland, School of Geography, Planning and Environmental Management, Brisbane, Australia, (3)
Department of Forest Science, Oregon State University, Corvallis, Oregon, USA., (4) Numerical Terradynamics Simulation
Group, Montana State University, Montana, USA. , (5) Bureau of Meteorology, Perth, Western Australia
Interest in understanding the impacts of land use and climate change on ecosystem processes has emerged as a
major area of research spanning the biological and physical sciences. In the hydrological sciences there has been a
strong focus on understanding the impact of such changes on water resources.
South-West Australia faces a drying climate under all Global Climate Model (GCM) scenarios and over the
last three decades there has already been a major decline in the volume of surface water resources available for
metropolitan water supply. Climate change has been superimposed on major land use changes that have altered
the water and salt balances of many catchments in this region.
Providing estimates for future surface water resource availability typically involves running an appropriate
hydrological model with downscaled GCM rainfall statistics for a particular emission scenario. Such models
do not generally incorporate any ecohydrologic vegetative feedbacks on key hydrological processes, or land use
impacts on stream connectivity.
To incorporate feedback mechanisms between vegetation and hydrologic processes we propose that ecological
optimality provides a first-order framework for understanding the relation between climate and leaf area index,
which in turn influences catchment actual evapotranspiration (AET) and interception. Using satellite data from
MODIS we examine annual and inter-annual variations in leaf area index of forested catchments and apply
published algorithms to obtain estimates of river basin AET. We compare these estimates to annual AET obtained
from the measured difference between basin rainfall and runoff and then develop future runoff and salinity
scenarios for one basin to compare model results with and without ecohydrologic feedbacks.
We then contrast the magnitude of this natural response to runoff reduction arising from policies aimed at
‘droughtproofing’ rural properties. We show that construction of farm dams and surface water runoff diversion
structures reduces both system and landscape connectivity, leading to significantly reduced flows at the basin outlet.


Vegetation-climate feedbacks and landscape connectivity need consideration when forecasting hydrologic impacts of land use and climate change in forested catchments of South-West Australia

http://espace.library.uq.edu.au/view/UQ:237414/UQ237414_abstract.pdf

Vegetation-climate feedbacks and landscape connectivity need consideration when forecasting hydrologic impacts of land use and climate change in forested catchments of South-West Australia

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