ECOLOGY:
Ecosystem 'Engineers' Shape Habitats for Other Species
Joseph Alper
"Ecosystem engineers"--species that alter their habitats to suit their own needs, such as beavers building dams--have led ecologists and environmental scientists to propose a new concept of how these engineers, by shaping their habitats, alter the availability of energy--food, water, or sunlight--and thus dictate the fates of other species. The concept holds that engineers alter habitats through two overarching mechanisms: Autogenic engineers, such as corals, transform ecosystems by their own growth and are integral to the altered environment, while allogenic engineers, such as beavers, alter the environment and then move on, leaving structures behind. Some researchers believe that, once it is fine-tuned, the concept of ecosystem engineers may be ready to join an elite set of theories, such as natural selection and predator-prey theory, that help explain how species arise and interact.
