Some of the world’s most unique animals can be found on islands. Ecosystems and predator-prey relationships on islands are more closed off than their mainland counterparts, paving the way for some distinct adaptations—think of enormous Komodo dragons (indigenous to the Indonesian island of Komodo and surrounding islets) or tiny Key deer (indigenous to the Florida Keys). But island life isn’t always easy and even the smallest ecosystem changes can put these animals at risk.
Here are two species that have adapted to the island lifestyle, but are now under threat due to human activity and invasive species.
Evolving on the islands of New Zealand with few predators and plenty of space, these birds adapted to life on land in a big way. Kakapos are the only flightless species of parrot in the world—and happen to be the heaviest, too.
Without predators, kakapos safely foraged on the ground and picked fruit from trees without a need for flight. But all that changed with human settlement and introduced species such as cats, rats, and weasels. Today there are fewer than 160 kakapos left.
Solenodons have been on islands of their own for a very long time, both genetically and geographically. Solenodons retain primitive mammal characteristics; DNA studies indicate they diverged from other mammals about 78 million years ago. Today, there are two remaining species, each indigenous to a large Caribbean island (Cuba and Hispaniola).
Once a dominant predator on these islands, solenodons adapted an omnivorous diet and are one of the few venomous mammals in the world. Even their venomous bite, however, has not protected them from the introduction of other predators (mongoose, dogs, cats), competing foragers (rats and mice), and human development. These forces have put solenodons at risk. Both the Cuban solenodon and the Hispaniolan solenodon are currently listed as endangered species.
Solenodons and kakapos have adapted to make the most of their island environments. Can you think of other species that have done the same?
What are the major threats to island ecosystems?
There were only 18 kakapos left in 1970, but scientists were able to manage the remaining population, which grew to 123 in 2014. What do you think drove the kakapo recovery?
- National Geographic Phenomena: Kakapo Coprolite Yields Conservation Clues
- National Geographic News: New Zealand Announces Plan to Wipe Out Invasive Predators
- Wired: The Creature Feature—10 Fun Facts About the Solenodon
- National Geographic Voices: New Zealand’s Spokesbird Sirocco the Kākāpō
Term Part of Speech Definition Encyclopedic Entry adaptation Noun
a modification of an organism or its parts that makes it more fit for existence. An adaptation is passed from generation to generation.
Encyclopedic Entry: adaptation ecosystem Noun
community and interactions of living and nonliving things in an area.
Encyclopedic Entry: ecosystem endangered species Noun
organism threatened with extinction.
Encyclopedic Entry: endangered species invasive species Noun
type of plant or animal that is not indigenous to a particular area and causes economic or environmental harm.
Encyclopedic Entry: invasive species omnivore Noun
organism that eats a variety of organisms, including plants, animals, and fungi.
Encyclopedic Entry: omnivore predator Noun
animal that hunts other animals for food.
animal that is hunted and eaten by other animals.