Five hundred years of exploration reshaped Earth's living systems, new analysis shows

Christopher Columbus and his 15th-century voyages triggered a massive acceleration in the blending of Earth's plant and animal life across borders. Over the past five centuries, human movement across the Atlantic Ocean and beyond has completely shifted how microorganisms, plants, and animals are distributed around the planet.

Ecological Impacts

Many introduced species quickly turned into harmful invasive plants and animals. At the same time, dangerous microorganisms like the pathogens that cause smallpox, cholera, plague, and sexually transmitted diseases wiped out native human populations. Plant diseases carried across oceans also ruined agriculture and caused widespread famine. In 1995, UNESCO held its Man and the Biosphere Programme silver jubilee in Seville, Spain, where Columbus is buried, marking his heavy role in this ecological chaos.

Earth's Eras

Science divides Earth's history into five distinct biogeographical periods. The first lasted until tetrapods appeared around 400 million years ago. The second ran until the extinction of dinosaurs. The third stretched until about 12,000 years ago when hominids arrived. The fourth spanned from early agriculture until the 16th century. The final period covers the past 500 years, an era of rapid transformation driven by human expansion.

Context

Biogeography studies how living things are spread across the planet and why certain ecosystems develop in specific regions. While natural forces like continental drift and animal migrations shaped the globe for millions of years, modern human trade and transport have sped up these changes to a level that outpaces natural ecological recovery.