ENVIRONMENT
What is a landslide? Use our reference resource to learn more.
Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.
Photograph by Benjamin Jones, USGS. Public domain
Discussion Ideas
- New research links mega-landslides to the way plants and other living things colonize remote islands. What are mega-landslides? Browse our resource on landslides for some help.
- Just what they sound like! Mega-landslides are huge “movements of rock, earth, or debris down a sloped section of land. Landslides are caused by rain, earthquakes, volcanoes, or other factors that make the slope unstable.”
- How might mega-landslides contribute to life reaching remote islands?
- Mega-landslides can disrupt enough earthen material to create “veritable floating forests to put out to sea, carrying on board large numbers of small animals and invertebrate species.”
- According to our resource on islands, floating islands are usually torn from coasts and swept away during storms, volcano eruptions, earthquakes, and floods—the same forces that create landslides. On floating islands, snakes, turtles, insects, and rodents can find shelter in tree branches or among plant leaves. Some of the best travelers are lizards, which can survive a long time with little freshwater.
- Importantly, mega-landslides “can carry lots of individuals to the same island at once, providing a large and genetically diverse founder population—unlike a small raft such as a floating log.”
- Mega-landslides can disrupt enough earthen material to create “veritable floating forests to put out to sea, carrying on board large numbers of small animals and invertebrate species.”
- How did scientists conduct the new research?
- Scientists analyzed the DNA of weevils, a type of beetle, on La Palma, one of the Canary Islands. (The Canaries, a part of Spain, are an isolated archipelago in the Atlantic Ocean off the southern coast of Morocco.)
- Researchers found that DNA of La Palma weevils is nearly identical to weevils on the valley walls of Orotava Valley—on the island of Tenerife, about 120 kilometers (75 miles) away.
- Orotava Valley was created by “a vast landslide … about 600,000 years ago. In a matter of minutes, this landslide would have carried swathes of relatively intact biomass from the surface of Tenerife out onto the surface of the Atlantic.”
- Researchers found that DNA of La Palma weevils is nearly identical to weevils on the valley walls of Orotava Valley—on the island of Tenerife, about 120 kilometers (75 miles) away.
- Scientists analyzed the DNA of weevils, a type of beetle, on La Palma, one of the Canary Islands. (The Canaries, a part of Spain, are an isolated archipelago in the Atlantic Ocean off the southern coast of Morocco.)
- Outside big floating islands created by landslides, how else might plants and animals colonize remote islands?
- “Rafting,” in which relatively few species cling to buoyant materials (such as that floating log mentioned above), is a familiar way that plants and animals travel vast expanses of the ocean.
- Wind, which can carry seeds and pollen, can deliver life to remote islands. Bird droppings are also an important way biomass is dispersed.
TEACHERS TOOLKIT
BBC: Mega-landslides help explain how life reaches remote islands
Nat Geo: What is a landslide?
Nat Geo: What is an island?
(extra credit!) Journal of Biogeography: Evidence for mega-landslides as drivers of island colonization
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