The authors report that in some Australian grasslands, ecosystem resilience has decreased with the increasing aridity widely reported as a result of the prolonged warm drought over these biomes.

Moran cautioned that her team also saw the limit in some of the study areas in Utah, Arizona and New Mexico.

"We know what the resilience was in the 1980s and 1990s, and we compared it to the early 21st century," she said. "That's how we know it's decreasing. We certainly found resilience, but it is approaching the threshold."

Moran pointed out this study was only possible through the collaboration of researchers combining long-term observations at study sites across the globe to reach these conclusions, including the oldest, longest-operating range-land research facility in the world: the Santa Rita Experimental Range managed by the UA College of Agriculture and Life Sciences.

Established in 1902, the study area encompasses 52,000 acres, or about 80 square miles, on the western side of the Santa Rita Mountains south of Tucson.

"Here, scientists studying vegetation, animals and soils have documented changes in the environment as a function of land use and how weather and climate have influenced these patterns," said Mitchel McClaran, a professor in the UA's School of Natural Resources and the Environment and the range's director for research, who co-authored the study.

"Making these long-term data available to researchers across the world today is what makes studies like this possible," McClaran said. "We perform experiments and explore best management practices so they can be adopted wildlife managers, ranchers and other natural resources managers throughout the Southwest."

Work like the present study can help resource managers develop agricultural production strategies that incorporate changes in water availability linked to changing precipitation patterns.

"In the United States, much of our agricultural productivity has depended on long-term precipitation regimes. But those patterns are changing and we need information for managing the effects of those shifts," said ARS Administrator Edward Knipling. "These findings can help managers respond to the challenges of global climate change with effective strategies for maintaining agricultural productivity."