snails

Natural solutions for disappearing islands

June 12, 2025 By EarthWise Leave a Comment

Atoll islands are made from sediment produced by corals, clams, snails, and varieties of algae that secrete carbonate. Under the right conditions, over time, fragments of coral skeletons, shells, and other sediments made by marine life are piled up by waves. Eventually, islands are formed – some large and some small. Atoll islands are home to a diversity of human cultures and are important refuges for a quarter of the world’s seabirds as well as numerous nesting sea turtles and tropical plants.

Rising sea levels – the rate of which has more than doubled over the past 30 years – are a mounting challenge for atoll islands. And by the end of this century, sea level is projected to rise between 11 and 40 inches, depending on the world’s actions with regard to greenhouse gas emissions.

The ability of atoll islands to persist depends on the health of their ecosystems and the extent to which their natural processes have been disrupted by human activity. To protect the most vulnerable islands, some researchers now propose using nature-based solutions – like restoring and protecting coral reefs and native forests.

Reclaiming seabird habitat can help reefs persist and restore the resilience of atoll islands. Seabird guano washes off islands and into reefs, providing nutrients that boost coral growth and fish populations.

Nature-based solutions cannot help the most urbanized atoll islands. These islands have already irreversibly lost their natural adaptive capacity. For those places, engineered approaches such as concrete seawalls are needed.

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How Natural Solutions Can Help Islands Survive Sea Level Rise

Photo, posted July 3, 2014, courtesy of Roderick Eime / MG Media via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Snail Darter Is Safe | Earth Wise

November 14, 2022 By EarthWise Leave a Comment

The snail darter is a three-inch-long snail-eating fish that was once only found in the Little Tennessee River. When that river was going to be dammed by the Tellico Dam under construction in the 1970s, the snail darter was listed on the endangered species list and the little fish subsequently became the subject of a legal battle that made it all the way up to the U.S. Supreme Court. With the dam project 95% complete in 1978, the Supreme Court blocked further construction, citing the Endangered Species Act. A year later, Congress exempted the project from the requirements of the Act, thereby clearing the way for the completion of the dam.

In order to save the snail darter, biologists transplanted the fish into several other nearby rivers and waterways. In addition, the Tennessee Valley Authority modified the operation of the Tellico Dam to release more oxygen-rich water downstream. Beyond those measures, the river cleanup under the Clean Water Act further aided the fish’s recovery.

In 1984, the snail darter was removed from the endangered species list and was listed as threatened or vulnerable. Recently, the U.S. Department of the Interior officially removed the snail darter from the federal list of threatened and endangered wildlife.

The snail darter is the fifth fish species to be delisted because its population has recovered. It is the first in the eastern United States. With better management of water releases at dams, many other imperiled aquatic species could be recovered.

Overall, more than 50 plants and animals have recovered under federal protection, including American alligators, humpback whales, peregrine falcons, and bald eagles.

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Once at Center of Controversial Case, the Snail Darter Fish Is No Longer Threatened

Photo, posted July 22, 2015, courtesy of The U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Living On Trash | Earth Wise

March 16, 2021 By EarthWise Leave a Comment

Litter is persistent and widespread in rivers worldwide. The world’s major rivers and estuaries are hotspots for plastic waste. Trash and microparticles wash down tributaries and build up before rivers enter oceans.

New research published in the journal Freshwater Biology has found that as this waste accumulates, aquatic river species like insects and snails are increasingly choosing to settle on plastic rather than on natural features like rocks and fallen branches.

Researchers from the University of Nottingham in the UK collected plastic waste from three rivers in eastern Britain along with rocks from the same rivers. Their analysis of all the macroinvertebrates on the items’ surfaces found that the surfaces of plastic waste items had nearly four times the diversity of the small animals as did the rocks. In addition, the more complex the plastic’s surface was, the higher the diversity.

The growing abundance of plastic waste coincides with a decline in natural habitat features in urban rivers. This is a result of increasing amounts of sedimentation from development that blankets riverbeds in silt and sand, restricting the supply and movement of rocks, fallen tree branches, and aquatic plants.

Clearly litter can serve as a place for various species to colonize, but trash is not a good environment for them. Trash can release toxic chemicals and entangle animals. Microplastics pose risks for the animals if ingested.

Estimates are that between 1.15 and 2.41 million tons of plastic waste enter the ocean every year from rivers around the world. Natural habitats have become rare in urban rivers. River ecosystems built around piles of trash are not a good thing.

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As Plastic Pollution in Rivers Gets Worse, Species Are Increasingly Living on Litter

Photo, posted August 17, 2010, courtesy of Renee_McGurk via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tough Times For Fireflies | Earth Wise

March 11, 2020 By EarthWise Leave a Comment

Fireflies or lightning bugs are soft-bellied beetles known widely for their use of bioluminescence – the biochemical emission of light – to communicate and to attract mates. There are more than 2,000 species of these beetles globally. They can be found in temperate and tropical climates, like marshes or wet, wooded areas, all throughout the world.

But if you are seeing fewer fireflies each summer, you’re not alone. Like many insects, firefly populations are under duress from threats like pesticides, pollution, and habitat loss. But fireflies are also facing another threat unique to luminous bugs: light pollution. Light pollution is making it harder for fireflies to reproduce because the artificial light is outshining their mating signals.

Male fireflies light up to signal availability and female fireflies respond with patterned flashes to indicate they’re interested. But artificial bright light from things like billboards, streetlights, buildings, and homes, is interfering with the fireflies reproduction communications.

The study, by researchers at Tufts University and the IUCN, warned that these threats facing fireflies could lead them globally to extinction.

The researchers also point to habitat loss as another major threat to fireflies. Firefly populations are especially vulnerable because they need special conditions to complete their life cycle. Mangrove forests and marshes around the world are being removed in favor of cash crops like palm oil.

Insects like fireflies are crucial components of many ecosystems where they perform important functions, like aerating soil, pollinating plants, and controlling pests. Firefly larvae feed on snails, slugs and mites, and many fireflies are effective pollinators.

We can’t afford for fireflies to go dark.

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A Global Perspective on Firefly Extinction Threats

Fireflies Have a Mating Problem: The Lights Are Always On

Photo, posted June 5, 2010, courtesy of Matt MacGillivray via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.