The Setting: California’s Channel Islands, otherwise known as “The Galapagos of North America.” Home to more than 270 species that only exist there.
The Conundrum: You’re a land manager trying to restore the damaged archipelago to its natural state. Sounds straightforward, but if humans have been altering the island ecosystems for roughly 13,000 years it quickly becomes a philosophical challenge. When, exactly, were the Channel Islands natural?
To complicate things, you need to plan for the possible effects of climate change: rising sea levels, changing precipitation patterns, and rising temperatures. Which species are going to be resilient enough to survive these pressures?
Enter: an interdisciplinary team of researchers led by archaeologist Torben Rick and ornithologist T. Scott Sillett, both with the Smithsonian Institution, and The Nature Conservancy’s Scott Morrison. In a new study published in BioScience, plant and animal experts, along with ecologists, geneticists, archaeologists, paleobiologists, and geologists trace 20,000 years of the California archipelago’s history.
Their investigations show island ecosystems and biodiversity in flux across millennia, with sea level, climate, and humans—first Native Americans, then ranchers, and now tourists and land managers—affecting which species survive and adapt and which ones fail.
The Solution: The scientists don’t tell us which period in history to use as a benchmark for the Channel Islands’ restoration. And they don’t tell us which plants and animals to protect. That’s not their job. Instead, they make it clear that some decisions will involve difficult tradeoffs. Save one bird’s grassland habitat, and woody plants might suffer.
Ultimately the authors suggest taking the long view to understand which species may be best adapted to the environment, as it is now and as we think it will be in the future. This particular study is done, but the Channel Islands experiment will continue.
Editor’s note: This study is the result of a collaboration between the Smithsonian Institution, The Nature Conservancy, the U.S. National Park Service, and a host of additional partners, including museums, universities, governmental agencies, and non-profit organizations.
By Tina Tennessen, Smithsonian's National Museum of Natural History