Older risk models may not work well enough, a letter, published in Nature by Boulder ecologist Brett Melbourne, reports. Traditional models rely on two main factors: The number of random events affecting individuals within a species, and the impact of things like temperature and weather changes on a species. But when Melbourne and colleagues added sex variations and physical variations between individuals into their model, risk went up a hundredfold. Melbourne and colleagues made their new model by observing beetles in the lab. Natural populations, they argue, have even more individual variation than lab animals—a compelling reason, the authors say, to re-evaluate what endangered really means.
