A project undertaken at Deakin University, and supervised by Dr Susanna Venn.
Although Australian alpine vegetation has the capacity to survive mild fluctuations in climate, snowpack variability and occasional dry periods, in recent decades declines in annual snowpack and lower than average rainfall have led to sustained soil moisture deficits, with soil water values dropping well below plant wilting point.
Such events in the recent past have led to widespread and severe dieback of some alpine plant species, however the physiological effects of drought on alpine plants are poorly understood.
To measure plant water stress, leaf samples must be collected and processed in the dark, before they start transpiring and losing water.
Glasshouse and laboratory experiments have indicated that some Australian alpine plant species can recover from simulations of drought and heatwaves, but little is known about plant responses to drought in typical alpine species in-situ.
Understanding how alpine shrubs, grasses and forbs respond to plant water stress, as well as measuring soil water, will indicate which plants can tolerate drought. This will then determine which species can tolerate prolonged deficits in soil moisture and which species are susceptible to drier conditions. Further, information about how highly susceptible younger plants can withstand prolonged drought will be critical for revegetating alpine areas.
The Australian Mountain Research Facility’s rainout shelters provide a 60% reduction in rainfall, thereby imposing severe drought conditions on the plants underneath.
In this project, we will assess plant water stress in a range of typical alpine species across a gradient of snowmelt dates under imposed drought scenarios and soil moisture levels in-situ. This will be achieved via a series of manipulative field experiments using the Australian Mountain Research Facility’s rain-out shelters across different states of Australia. We will also subject common species, representing different life forms (e.g. shrubs, grasses) that are used in revegetation experiments, to glasshouse drought experiments to determine which plants are the most resistant to drought.
Our findings will highlight which common alpine plant species can tolerate extreme drought and successfully regenerate unaided into the future, thereby guiding species selection for rehabilitation projects in alpine National Parks and Alpine Resort areas.