Across North America, mountain lions, bears, and gray wolves have made a remarkable comeback over the last 50 years. Once nearly exterminated, these animals have been recovering their populations and ...

Birds are a barometer of the health of water sources, habitats, and air quality. A notable example is the use of canaries in ...

For decades, ecologists have puzzled over a mystery: Why do some natural habitats get overrun by invasive species while others seem to repel outside threats? In a classic 1958 book on the subject, the ...

Sea urchins climb onto kelp when their densities are so high they remove all drift kelp and then actively forage on attached, living kelp. (Credit: Steve Lonhart / NOAA MBNMS) Tipping points are the ...