Date: April 23, 2020
Source: University of Illinois College of Agricultural, Consumer and Environmental Sciences
When the tree fell that October in 2015, the tropical giant didn't go down alone. Hundreds of neighboring trees went with it, opening a massive 2.5-acre gap in the Panamanian rainforest.
Treefalls happen all the time, but this one just happened to occur in the exact spot where a decades-long ecological study was in progress, giving University of Illinois researchers a rare look into tropical forest dynamics.
"I've been walking around that tree for 30 years now. It was just humongous," says Jeff Brawn, Professor and Stuart L. and Nancy J. Levenick Chair in Sustainability in the Department of Natural Resources and Environmental Sciences at Illinois. "Here we are, running around on this plot for years and all of a sudden I couldn't even find my way around. We just lucked into it."
What's lucky is that Brawn and his colleagues had amassed decades of data on the bird community in that exact spot, meaning they had a clear before-and-after view of what a treefall could mean for tropical birds.
This particular gap meant hummingbirds. Lots and lots of hummingbirds.
"After the treefall, we saw a very large spike in the total number of hummingbird species," says Henry Pollock, a postdoctoral scholar working with Brawn and lead author on a study published in the Journal of Field Ornithology. "Within the previous 25 years of the study, we had only documented three or four hummingbird species, and they were usually present in low numbers. There was one species, the snowy-bellied hummingbird, which we had never captured on either of our two plots in 25 years of sampling. The year after the treefall happened, we got 16 unique individuals of this one species, and total diversity of hummingbirds more than doubled."