- To keep jellyfish, fungi and other creatures from overtaking healthy habitats, scientists are exploring food webs and tipping points
- The dominant predators were rare, because they were eaten by the largemouth bass
- Because these animals graze on algae, the lake water became clearer
- Peter Lake’s food web has flipped, shifting from a long standing arrangement to a new one
- Carpenter triggered it on purpose, as part of an experiment on factors leading to persistent changes in mix of organisms
- Whether by fishing, converting land into farms and cities, or warming the planet, humanity is putting tremendous stresses on the world’s ecosystems
- As a result, ecologists expect many more food webs to flip in the years ahead
- With the development, scientists are beginning to find the rules that determine whether a food web will be stable or change
- To find an answer, ecologists began to diagram food webs, noting who ate whom and how much each one ate
- To make sense of snarls, ecologists turned food webs into mathematical models
- Most food webs, for instance, consist of many weak links rather than a few strong ones
- Mathematical models have also revealed vulnerable points in food webs, where small changes can lead to big effects throughout entire ecosystems
- Ecologists realized that, as predicted, changes in certain predators had massive impacts on food webs
- Equations produced ecosystem models
- Scientists could see subtle but distinct patterns before ecosystems change
- One pattern is when an ecosystem is disturbed, by disease or temperature, it takes longer before it goes back to normal
- Scheffer, Carpenter and co-workers are testing models in range of experiments.
- Peter Lake experiment was first time they put early-warning system to the test
- Carpenter and colleagues hope to develop monitoring systems for ecosystems from wetlands to forests to oceans
- some scientists say that preventing food webs from switching is a more effective strategy than trying to restore ones that have flipped
- The goal, of course, is to know when we are pushing an ecosystem to the brink, so we can stop pushing
- Surprises will continue although the early-warning system does provide the opportunity to anticipate some surprises before they happen