What sparked the richest diversity of plants on earth?

Richard G. Olmstead with Citharexylum
argutidentaum in cloud forests of southern Peru.

By Richard Olmstead
Burke Museum Herbarium Curator

I recently visited San Jose, Costa Rica, to celebrate the 50th anniversary of the Organization for Tropical Studies, founded by the UW and six other universities, but also to collect plants for my studies of Neotropical plant diversity.

The New World tropics, or Neotropics, extend from central Mexico and the Caribbean islands to northern-most Argentina and Chile, and contain more than 100,000 species of flowering plants, or one-third of all plants on earth.

From Amazonian jungles to high Andean paramo, from Argentina to Mexico, the diversity of these ecosystems is unrivaled. It is home to the greatest mosaic of biodiversity on earth.

Piecing together Patagonia's ancient vegetation

Fossil site in Patagonia, Argentina.

Most people hardly notice what's on the ground beneath their feet. But to researchers like Regan Dunn, a graduate student studying paleobotany at the University of Washington, fallen leaves provide invaluable clues to understanding how climate change impacted life on earth - and how our actions today will shape the future.

Regan is part of a team led by Caroline Strömberg, Burke Curator of Paleobotany, that is studying 40 to 18 million-year-old plant and animal fossils found in Patagonia, Argentina. “This was a time with major climate change and some extinction events, so we really want to understand how vegetation was affected by these changes.”

To understand the impact of climate change on Patagonia’s vegetation, they set out to reconstruct what types of vegetation existed in ancient Patagonia. To collect data, Regan visited Costa Rica - which has a modern climate similar to that of ancient Patagonia.