Oct 12, 2017 - Energy & Environment

Resilient reefs and rainforests can weather hurricanes

Illustration: Rebeccca Zisser / Axios

It can take years for towns and cities to recover from major hurricanes. But as humans labor to restore power and water, tropical ecosystems — some of the most diverse and complex in the world — are also beginning to rejuvenate. Scientists are now taking stock of flora and fauna in this years' storm paths.

Bottom line: There's an immediate and drastic impact on coral reefs, rainforests and their inhabitants. But in some cases, ecosystems can quickly recover from hurricanes because they evolved to withstand these severe storms.

Rainforests: Hurricane Irma stripped leaves and branches off Yunque National Forest in Puerto Rico. But just a few months after hurricane Hugo passed over Puerto Rico 29 years ago, trees were already beginning to grow new leaves. Studies have found that areas ravaged by landslides or cleared by heavy winds slowly regrow into new habitats. The diversity of trees isn't diminished, though bird and bat populations decrease.

Coral reefs: Waves from major hurricanes can cause serious structural damage to coral reefs, but seem to have little impact on their ability to support life. And, although structural damage to reefs may have a limited effect on animals that live in them, it can leave land more vulnerable to storm surges.

Swamps: Recent hurricanes have shown how powerfully salt marshes can protect human communities. But human development and irrigation has changed the balance of fresh and saltwater that makes up ecosystems like the Everglades. Adam Wernick, writing for PRI, explains how Irma brought water dynamics the Everglades haven't experienced for decades. But others are concerned the storm damaged fragile parts of the wetlands.

Turtle nests: Florida is home to leatherback, loggerhead and green sea turtles. Most endangered leatherback turtles finished hatching by the time this years' storms came. Loggerheads, which nest just above the tideline, were in the process of hatching. Jeanette Wynekan, who studies sea turtles at Florida Atlantic University, tells Axios that both coasts lost a lot of loggerhead nests and hatchlings.

Green sea turtles, on the other hand, which lay their eggs high on beaches in September fared relatively well in eastern Florida. "Some nests even gained a foot of sand," says Wyneken. But western Florida beaches are flat, and the storm surge was stronger. Although less turtles nest on the West side of Florida, any nests there likely drowned or were swept away.

Turtle hatchlings: After baby turtles hatch, they swim for 24 hours straight until they reach floating masses of seaweed, called sargassum, where they hang out and grow. Major storms can push these turtles back into shore, and Irma did.

What's the long-term effect of losing an entire year of hatchlings? "Probably not a whole lot of impact," says Wyneken. Turtles take a long time to mature, so populations can be harmed by adult deaths. But each female turtle can lay tens of thousands of eggs over their lifetime — so losing one year of hatchlings isn't too much, in the grand scheme of things.

Big picture: Major hurricanes like this year's are a symptom of a larger problem: global warming. Sea level rise is threatening swamps and rising temperatures have caused coral bleaching and shifted sex ratios in sea turtles. Short-term weather events are a part of nature, but climate change is a different story.

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