Cascade effect (ecology)

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Cascade effect in ecology

A cascade effect happens when the loss of one important species triggers other species to decline or go extinct. This often happens if the threatened species relies on only a few foods, has mutual dependencies, or shares the habitat with an invasive species.

Invasive species can dominate a place and spread without natural predators, starting cascades that harm many organisms.

The main driver is the loss of top predators. Without them, prey animals multiply, overeat their food, and then crash; plants and other species connected to those resources may also disappear.

Example: sea otters on the Pacific coast. When otters were hunted to low numbers, sea urchins rose and ate a lot of kelp. The kelp forests collapsed, and many other species vanished.

Another example: in tropical forests, removing top predators can raise prey numbers and degrade the whole food web.

Scientists study how to slow these cascades and protect ecosystems.

Conclusion: losing a key species can ripple through an ecosystem, changing who lives there and how it works.