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Many diverse tropical species can find their roots in the Amazon

A new study has found that many diverse tropical species now found in Latin America originated in Amazonian rainforests.

The American tropics are one of the most biodiverse areas on the planet, with many unique species found nowhere else in the world.

An international team of researchers led by Harvard Visiting Scholar Alexandre Antonelli identified the processes by which many species first colonized and evolved in Latin America, leading to a thriving ecosystem with unrivaled species diversity.

The study is published in the journal Proceedings of the National Academy of Sciences.

“We were astonished to detect so much movement across such different environments and over such large distances,” said Antonelli, the study’s lead author. “Up until now, these natural dispersal events were assumed to be quite rare. Our results show how crucial these events have been in the formation of tropical America’s unique and outstandingly rich biodiversity.”

Species have naturally come to colonize different regions and it’s a process that has taken tens of millions of years.

The plants and animals that migrated away from their original area had to learn to adapt to different conditions and over time, these species evolved into completely different species in their new environment.

This process is exactly why the American Tropics are so diverse compared to other regions around the world and the researchers wanted to better understand what mechanisms drive species distribution.

“Most evolutionary research focuses on how new species form,” said Antonelli. “But we want to understand how whole ecosystems evolve, and what makes some regions much more species-rich than others. This is important because it shows us how plants and animals deal with new environments and what factors determine biodiversity.”

The researchers collected an expansive amount of data on evolutionary relationships, distribution, and timing of the origin of thousands of tropical species in order to calculate the frequency that species were distributed to a different region.  

Birds, frogs mammals, snakes, lizards, and plants were all considered for the study.

Among all the regions in the American tropics that have distributed species, Amazonia was the main source of many of the species in the area.

“Two main factors seem to explain the key role of Amazonia in exporting so much diversity: its huge area, and the large amount of time that species have existed there,” said Antonelli. “Together, these have increased the chances of species dispersing into new habitats and regions.”

Besides proving the key role that Amazonia played in the biodiversity of the American Tropics, the study shows the danger that many tropical ecosystems face due to human activities.

“Biodiversity is the dark matter of our planet: we know there must be millions of species that we haven’t found yet,” said Antonelli. “Finding, understanding, and protecting this diversity is probably humanity’s toughest but most important challenge”

By Kay Vandette, Staff Writer

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