Here's something all mathematicians know instinctively: changing a parameter in a dynamical system, even if it's only by a small amount, can have all sorts of non-obvious consequences. Some conservationists, however, don't seem to have learnt that lesson yet: by removing 160 feral cats from Macquarie Island to protect burrowing birds, a team of conservationists caused the rabbit population to boom from 4000 in the year 2000 to 130,000 in 2006. The rabbits have now demolished up to 40% of the island's vegetation, which may never recover. Cleaning up the mess may cost up to $16 million.

According to experts, a simple risk assessment exercise could have prevented the disaster. "We need a culture change," Hugh Possingham of the University of Queensland told New Scientist. "It's a generalisation, but people who do environmental work are often adverse to mathematics, and so avoid quantitative risk assessments."

Read more about this story in New Scientist.