A recent Minnesota Pollution Control Agency report found that climate change could cost Minnesotans more than $20 billion a year by 2040. This is just the local cost of a global problem. Ecosystem stability is essential to agriculture, forestry, safe housing and infrastructure, carbon storage and more, but identifying which ecosystems are most vulnerable to climate shocks remains difficult. Anticipating climate change impacts and predicting recovery will be critical to minimizing human and economic disruptions.
When an extreme drought hit central Minnesota in 2021 - the first one-in-a-decade dry spell in nearly 30 years of measurements at the Cedar Creek Ecosystem Science Reserve - a team of ecologists already had predictions on file for how each of their experimental grassland plots would respond. The forecasts proved accurate to within roughly 3%.
The resulting study, newly published in Nature, is one of the first demonstrations that long-term records of an ecosystem's natural ups and downs can be used to forecast how strongly it will resist a future climate extreme. Until now, ecologists have largely measured ecosystem responses after the fact.
The team developed a mathematical framework showing the relationships between four aspects of ecosystem stability. Resistance describes how little an ecosystem changes during a disturbance, such as a drought. Recovery describes how quickly it returns toward normal afterward. Temporal stability describes how little it fluctuates over many years. Resilience describes how close it is to normal soon after a disturbance. How these dimensions relate to one another has been an open question since the 1980s.
The research team found:
- Using stability data from 1996 to 2020, the researchers forecasted drought resistance at the ecosystem level with an average error of about 3%.
- Long-term stability is largely governed by an ecosystem's short-term resistance to disturbance. Resilience, by contrast, often depends more on recovery.
- The two components are not interchangeable: an ecosystem cannot trade away its resistance and make up for it with faster recovery without consequences for its temporal stability and resilience.
- Long-term ecosystem stability over a quarter century could often be predicted based on resistance to a single extreme wet climate event that occurred in 2002.
This model may help land managers and farmers prevent the worst impacts of drought and extreme weather.
"Ecologists have long measured how ecosystems respond after droughts and other climate extremes," said Forest Isbell, lead author and associate professor at the University of Minnesota College of Biological Sciences. "What is exciting here is that we can begin to forecast which ecosystems are more likely to withstand a future drought before it happens - offering a powerful tool for management and planning in the future."
The framework requires further development across a variety of ecosystems. Forecasts depend on knowing which disturbances matter most for a given system, and the approach will need to be tested in forests, agricultural systems and other ecosystems beyond grasslands. The forecast also performed best at the ecosystem scale. Predictions for individual species were less reliable, and at least 17 years of data were needed before ecosystem-level forecasts became statistically dependable.
Even so, the findings suggest that long-term ecological monitoring has practical, forward-looking value for the climate era. With refinement, the model could make our forests, grasslands, farms and aquatic ecosystems more resilient.
"Long-term ecological data are often seen as records of the past," said Isbell. "Our results show they can also help us look forward."
