A decades-long local effort to lower temperatures and slow erosion has brought coho salmon back to the creek, which feeds into the Mattole River. E volution loves an island. Isolation breeds weird and wonderful things. New species evolve quickly as they specialize to exploit narrow niches. Big creatures grow small.
Small creatures grow large.
Islands cannot move when trouble comes. And neither, for the most part, can their inhabitants. It is divided into isolated chunks by cities and towns, pastures and plowed fields, highways and roads, suburban developments, and deforested areas. And trouble eventually is coming the way of these islands in the forms of invasive exotic species and the diseases they carry, and natural disasters such as fire, drought, and hurricanes. In prehistoric times, if a big patch of oak chaparral burned down, the animals on it could escape to neighboring areas.