How transient invaders can transform an ecosystem
When a plant or animal species is introduced to a new environment with few natural predators, it can spread uncontrollably, transforming the ecosystem and crowding out existing populations. One well-known example is the cane toad, which was introduced into Australia in 1935 and whose population is now well into the millions. A related but less-understood scenario occurs when an invader arrives, transforms the ecosystem, and then dies out. MIT physicists have now shown how this kind of “transient invasion” can occur in bacterial populations, provoking a shift from one stable community state to another, while the invader itself disappears. “These results highlight one possible way in which even if a species does not survive long term, it could nonetheless have long-term effects on the community,” says Jeff Gore, an MIT associate professor of physics and the senior author of the study. The findings may also shed light on how transient invaders affect real-world...