‘Extreme’ could become the new normal for pastoral conditions within the next 30 years, an ecologist at Western Sydney University predicts.
“Due to climate change, what we today perceive as ‘extreme’ conditions for pasture production may be considered ‘normal’ by the middle of this century,” says Professor Sally Power, leader of Western’s Pastures and Climate Extremes (PACE) project.
Climatologists warn that the severity and the frequency of extreme weather events will increase as the planet warms.
In Australia, these events are likely to include intense heatwaves, longer droughts and more frequent flooding, along with a more variable and less predictable climate. As a result, Australia’s natural and managed ecosystems, including pasturelands, will be exposed to unprecedented combinations of heat- and water-stress.
This could spell trouble for Australia’s dairy and livestock farmers. Cattle and sheep need a reliable and consistent supply of high-quality forage, consisting mainly of grasses and legumes. A future, more extreme climate, including changes in seasonal rainfall patterns, could disrupt this supply.
PACE, which involves 12 faculty members, three postdoctoral researchers and four PhD students, is investigating the response of widespread pasture grasses, including fescue, ryegrass and phalaris, and legumes, such as alfalfa, (also known as lucerne) to extreme climate conditions, including heatwaves, droughts and changes in rainfall regimes. This innovative project will help ensure the long-term sustainability of Australia’s pasture grazing systems.
“We know too little about the likely impact of climate change and climate variability on Australia’s pasturelands. PACE should provide important answers, helping to ensure the future sustainability
of the livestock, wool, meat and dairy industries,” says Power.
Power has long investigated the effect of human activities on plants, as well as ecosystem functioning and sustainability. PACE fits well within this research agenda.
“The project is multi-faceted,” says Power, “We are interested in how well pasture species perform when exposed to warmer, drier conditions, and understanding what biological characteristics influence species’ climate sensitivity. We are also interested in how the seasonal timing of growth and plant nutritional quality are affected by more extreme climates.”
Setting the PACE
The PACE field facility is located at the University’s Hawkesbury Institute for the Environment. It includes six large polytunnels, each divided into eight plots. Each plot is further sub-divided
into four sub-plots, resulting in a total of 192 experimental planting areas. Some of these plots are warmed using infra-red heat lamps, and because natural rainfall is prevented from reaching the experimental plots, researchers can experimentally manipulate rainfall patterns by artificial irrigation.
“The set-up will allow us to ‘stress test’ pasture species by exposing them to climate conditions predicted for the end of the century,” says research fellow, Dr Amy Churchill. “For example, we are
exploring the effects of warming and drought during the crucial winter and spring growth periods.”
In September 2018, Australia’s Red Meat Advisory Council unveiled its ‘State of the Industry Report 2018’, compiled by Meat and Livestock Australia. The report notes that the red meat and livestock industry employs well over 400,000 Australians, either directly or indirectly, and that it contributed $18.4 billion to Australia’s economy in the 2016/17 financial year alone.
The dairy industry contributed $3.7 billion over the same period, according to Dairy Australia figures, while the value of Australian wool exports in 2016-17 was estimated to be around $3.6 billion.
“Ours is a holistic approach,” explains Power, “PACE provides the opportunity to go beyond plant-level studies, allowing us, for example, to delve into the role of plant-microbe interactions,
and to assess what happens at the plant-soil interface. By undertaking detailed studies of above- and below-ground responses to warming and drought treatments, we hope to uncover mechanisms underlying climate sensitivity and resilience in pasture species.”
The core facility was completed in 2017. Warming treatments began in April 2018, and a seasonal drought treatment commenced in June, at the beginning of the winter season.
PACE has already revealed intriguing findings: “Winter 2018 was our first opportunity to examine pasture responses to the combination of drought and warming conditions,” says Power, “As expected, we found that reduced rainfall in winter and spring greatly reduced the growth of most pasture species. We thought that warming might increase cool-season activity across the board, but what we actually found is that increased air temperature can have positive and negative effects on productivity, depending on species. Early indications are that warming can exacerbate the effects of drought through increased water stress, implying that warmer conditions may not be as great for cool-season pasture productivity as we might predict.”
Need to know
- PACE measures the response of widespread pasture plant species to extreme climate conditions
- Early results indicate that warmer conditions may not be as good for cool-season pasture productivity as we might expect
- The PACE project is exploring ways to ensure the sustainability of the livestock, wool, meat and dairy industries
The PACE facility and research programme is co-funded by Western Sydney University, Meat and Livestock Australia (MLA) and Dairy Australia.
“Australia is a land of drought and flooding rains,” says Doug McNicholl, supply chain sustainability innovation manager at MLA, “The impact of these events determines the economic, social and environmental sustainability of the red meat and livestock industry. PACE provides industry with the ability to consider future feedbase requirements, which is critical to our sustainability.”
Dairy Australia anticipates that PACE will improve understanding of the impact of changing climate and extreme weather on the feedbase required for milk production. But it is also looking to
future-proof itself. It is interested to learn, for example, what species will thrive under climate extremes and that could potentially be introduced to pasture-based dairy systems, as well as the reasons for their survival. “This knowledge will contribute to solutions for future dairy production under climate extremes,” says Catherine Lescun, the programme development manager of feedbase and animal nutrition at Dairy Australia.
Power agrees. “Ultimately,” she says, “PACE should inform the development of adaptation strategies, including new management practices, aimed at ensuring the long-term sustainability of Australia’s pasture grazing systems, and reducing industry exposure to climate-related risk.”
Meet the Academic | Professor Sally Power
Professor Sally Power is an ecosystems ecologist and currently the deputy leader of the Ecosystem Function and Integration research theme.
Sally employs a variety of empirical approaches - from mesocosm experiments to field-scale manipulations and surveys – to study the direct and indirect effects of anthropogenic changes in atmospheric composition and climate. Her research explores how human activities affect processes at the leaf, plant and community level, and how these effects influence ecosystem function and sustainability.
Sally has established several long-term field experiments manipulating levels of nitrogen deposition, tropspheric ozone and rainfall. These large experimental platforms enable integrative research into above- and below-ground responses to realistic global change scenarios.
Recently, her research has focused on the interactive effects of multiple, co-occurring drivers of global change, including air pollution, climate, habitat management and biodiversity loss.
By characterising physiological, biogeochemical and productivity responses to multiple drivers we can improve our mechanistic understanding of, and thus our ability to predict, ecological responses to a changing world.
Sally is also passionate about public engagement with science and has led a wide range of outreach activities involving members of local communities and schools in "hands on" scientific research.
Higher Degree Research at Western
This research was supported by the Australian Government through the Australian Research Council.
© Michael Amendolia © Michael Amendolia
Future-Makers is published for Western Sydney University by Nature Research Custom Media, part of Springer Nature.