On the Hawaiian island of Oahu, it is possible to stand in a lush tropical forest that doesn’t contain a single native plant. The birds that once dispersed native seeds are almost entirely gone, too, leaving a brand-new ecological community composed of introduced plants and birds.
In a first-of-its-kind study published today (April 4) in the journal Science, researchers — including Assistant Professor Corey Tarwater and Research Scientist J. Patrick Kelley of the University of Wyoming’s Department of Zoology and Physiology — demonstrate that these novel communities are organized in much the same way as native communities worldwide.
The discovery comes after an exhaustive examination of bird diets across Oahu and a subsequent network analysis describing bird-plant interactions on the island. Unexpectedly, the analysis showed introduced birds have developed complex patterns of interactions with plants, most of them not native to the island. And when bird-plant interactions in Oahu were compared to native-dominated ecosystems around the world, they were strikingly similar.
“These birds on Oahu aren’t interacting with these invasive plants randomly. They’re actually selecting certain plants. What’s interesting about this is that these birds didn’t co-evolve with these plants. We think of specialization as a co-evolved trait that develops over millennia, but we are seeing it in completely novel ecosystems and in species that have only lived together for less than 100 years,” says Jinelle Sperry, wildlife biologist for the U.S. Army Engineer Research and Development Center, adjunct professor in the Department of Natural Resources and Environmental Sciences (NRES) at the University of Illinois, and co-author of the Science study.