Invasive species - Artensterben

Flusspferd als eingeschleppte Süßwasser-Megafauna

Hippopotamus – This mammal, weighing up to three tons, is one of the largest freshwater inhabitants on Earth. In Colombia, feral populations exist today after animals escaped from a private collection and spread along the Magdalena River. (© Joachim Huber, CC BY-SA 2.0, via Wikimedia Commons)

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10. March 2026 Doreen Fräßdorf

Introduced freshwater megafauna: Benefits and risks of large animals in rivers and lakes

Rivers and lakes are home to some of the largest animals in inland waters—from giant catfish, sturgeons, salmon, and carp to turtles and crocodiles. However, many of these species have been deliberately introduced by humans into new regions. A new global study in the journal One Earth systematically examines for

Threatened by invasive species: Partula radiolata

The endangered tree snail Partula radiolata from the island of Guam. A recent study shows that snails are particularly often victims of invasive species: since the 1970s, the introduction of the rosy wolfsnail has led to the extinction of more than 50 Partula species on Pacific islands. (© USFWS - Pacific Region, Public domain, via Wikimedia Commons)

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17. February 2026 Doreen Fräßdorf

Invasive species & extinction: What role do non-native animals and plants play?

Whether rats on tropical islands, introduced snails in the Pacific, or feral cats in remote bird colonies – invasive alien species (IAS) can throw entire ecosystems off balance and push animal and plant species to the brink of extinction. In 2023, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services

Osterinsel (Rapa Nui) – Wie Pazifische Ratten die Insel entwaldeten

A single moai in front of the Ahu Tongariki platform on Rapa Nui: the iconic stone statues now stand in a largely treeless landscape—a stark contrast to the dense palm forests that once covered the island before invasive rats and human use fundamentally changed the ecosystem.

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14. November 2025 Doreen Fräßdorf

Easter Island: How Introduced Rats Made Rapa Nui’s Forests Disappear

When the Dutch navigator Jakob Roggeveen reached the coast of a remote island in the South Pacific on Easter Sunday in 1722 as the first Western European to do so, he must have been surprised. Before him lay a subtropical volcanic island—but instead of the dense forests one would expect

A red fox carrying a squirrel in its mouth, a symbol of the hunting success of this highly adaptable predator, which in Australia became a threat to numerous endemic animal species. (© NPS Photo/Kent Miller, Public domain, via Wikimedia Commons)

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19. October 2025 Doreen Fräßdorf

From 60 to 1.7 Million: How the Red Fox Conquered Australia in Just 60 Years

When European settlers of British origin brought the red fox (Vulpes vulpes) to Australia from around 1870 onward, they were thinking of tradition, not ecological consequences. Hunting foxes with packs of hounds, then a deeply rooted social ritual in England and now banned, was meant to continue in the new

Wildkaninchen: in Deutschland bedroht, in Australien eine Plage

The European rabbit—threatened in Europe, a pest in Australia: An example of the conservation paradox, in which invasive species thrive in new habitats while they are endangered in their native range. (© Charles J. Sharp, CC BY-SA 4.0, via Wikimedia Commons)

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9. December 2024 Doreen Fräßdorf

Conservation Paradox: When Invasive Species Are Threatened Themselves

According to the IPBES report from last year, invasive species are among the main drivers of global species extinction. They are responsible for 60% of all documented extinctions. Several of these alien species have also become established in Germany, including the raccoon from North America, the coypu from South America

The Lyall’s wren extinct less than ten years after humans settled Stephens Island. It is considered a classic example of the extinction of an island endemic with no natural defense mechanisms against invasive predators. (© Vertebrate Zoology Curator, CC0, via Wikimedia Commons)

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5. October 2024 Doreen Fräßdorf

Human-Caused Species Loss: Global Impact Far Greater Than Expected

A study published in early October in the journal Science suggests that human-caused species loss has far-reaching consequences that were previously underestimated. The scientists highlight the fact that the extinction of bird species has not only wiped out ecological roles but also billions of years of unique evolutionary history. In

Rats are among the most widespread invasive species. They are probably responsible for nearly one third of all extinctions—including many island-dwelling birds. (© CSIRO, CC BY 3.0, via Wikimedia Commons)

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9. September 2023 Doreen Fräßdorf

IPBES Report: Invasive Species as One of the Main Causes of Species Extinction

According to the report published in September 2023 by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), invasive animals and plants play an important role in global species extinction. The publication examines current developments in the spread of introduced species, the causes and the impacts of the problem.