Species like beavers and elephants that engineer and change the ecosystems around them could help save other species from extinction. A new study may be the first to quantify the effect that organisms whose impact outlasts their own lifetimes has on their ecosystems. In the study, researchers created models that showed the more ecosystem engineers there are, the more stability and fewer extinctions will happen in that system. The team compared this to a situation involving bees: if a single flower goes extinct, bees will be able to feed on other flower species. But if the bees or the trees that shade the flowers go extinct, then all the flowers might blink out. Justin Yeakel, an ecologist at the University of California, Merced and the lead author of the study, said the study shows that humans may be playing with the survival of many of the world’s species by tinkering with the planet on a number of levels. “Is an organism that becomes a planetary-scale engineer doomed to extinction if it changes the environment too quickly?” he asked in a press release.