Predictable Ecosystems Are More Fragile: New Study Shows

Trying to manage the environment for predictable short-term outcomes could backfire in the long run, according to a recent study.  

"By making things predictable in the short term, we make them unpredictable in the long term," said Steve Carpenter, lead author of the report and director of the Center for Limnology at the University of Wisconsin-Madison.

"We actively make things worse. Variability doesn't go away, it just goes somewhere else. It has to come back," Carpenter said, in a news release.

In the experiment, researchers ran a set of simple computer models, which looked at three human ventures: controlling nutrient pollution in lakes, maintaining cattle production on rangelands invaded by shrubs, and sustaining harvest in a fishery.

In all three cases, they had unpredicted outcomes. The grasslands were replaced by shrubs, even though there was light pressure from cattle grazing, and the fish stocks crumbled at lower harvest levels.

When humans try to manage ecosystems, they become part the system and their involvement can result in outcomes that are not planned, Carpenter claimed.

"Living systems need a certain amount of stress," he said.

Organisms need to evolve naturally, and they need to adapt to variability, just like bacteria in our bodies.

"Just as our immune systems rely on exposure to bacteria and viruses to sharpen their skills at responding to disease, natural systems also need that kind of stimulation," Carpenter said.

Nonetheless, it is possible for people to continue to manage natural resources safely and responsibly. However, the research found that "adaptive management" would allow greater natural variability in a system, and it allows a diverse set of management approaches. This enables resource managers to learn how to sustain ecosystems as they change over time. They can evaluate what works and what does not.

This new study will allow people to see that there is no alternative to living with variability, according to Carpenter.

"By allowing variability, learning from it and trying alternatives that seem sensible and safe, we can navigate change. When we make complex systems too predictable, we set the stage for collapse," Carpenter said. 

Related Articles

Ocean Bacteria Produces Millions Of Hydrocarbons Annually

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).