rats

Rats and climate change

March 10, 2025 By EarthWise Leave a Comment

Human activity has made rats one of the most prolific mammals on the planet. Our waste, buildings, and ships provide food, shelter, and transport. In the United States alone, rats cost the country approximately $27 billion each year in damage to infrastructure, crops, and contaminated food supplies. Additionally, rats carry and spread over 50 zoonotic pathogens and parasites, impacting public health around the world.

Now, climate change is adding to the problem. According to a new study recently published in the journal Science Advances, urban rat populations are exploding as global temperatures rise. The researchers found that Washington DC, San Francisco, Toronto, New York City, and Amsterdam had the greatest population increases. In fact, over the past decade, rats increased by a whopping 390% in Washington DC, 300% in San Francisco, 186% in Toronto, and 162% in New York City. The study, which examined data from 16 cities globally, found that 11 of them showed significant increases in rat numbers.

Only Tokyo, Louisville, and New Orleans bucked the trend with declining rat numbers.

According to the researchers, the best pest management strategies involve making the urban environment less rat-friendly as opposed to removing rodents that are already there. An example would be putting trash in containers instead of bags on the street.

There aren’t many perks to the changing climate – unless, of course, you’re a rat.

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Increasing rat numbers in cities are linked to climate warming, urbanization, and human population

‘Perfect rat storm’: urban rodent numbers soar as the climate heats, study finds

Photo, posted September 25, 2018, courtesy of Tim Felce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Seabirds rescuing coral reefs

January 8, 2024 By EarthWise Leave a Comment

A new study by researchers at Lancaster University in the UK has found that the presence of seabirds on islands adjacent to tropical coral reefs can more than double the coral growth rates on those reefs.

The study found that when coral reefs grow faster, they can bounce back more quickly from bleaching events that occur when the seas become too warm. The focus of the study was a type of coral called Acropora, which provides complex structures supporting fish populations and reef growth.

The researchers found that Acropora around islands populated by seabirds recovered from bleaching events about 10 months faster than reefs located away from seabird colonies. Speeding up coral recovery times could prove the difference between continuing to bounce back from bleaching events and dying off.

The seabirds are helping the coral reefs with their droppings. The birds feed on fish in the open ocean far from islands and then return to the islands to roost. They deposit nitrogen- and phosphorus-rich nutrients in the form of guano, some of which is washed off of the islands by rain and into the surrounding seas. The nutrients fertilize corals and other marine species.

To determine whether the faster growth rates were really due to the bird-supplied nutrients, the researchers studied rat-infested islands that had no bird populations. The study confirmed that it was the presence of seabirds that provided enhanced nutrients for the coral reefs. In fact, a primary outcome of the study was to add further weight to the growing body of evidence of the ecological damage across ecosystems on land and sea from invasive rats on tropical islands.

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Feathered friends can become unlikely helpers for tropical coral reefs facing climate change threat

Photo, posted September 15, 2019, courtesy of Rickard Zerpe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Cost Of Invasive Species | Earth Wise

May 7, 2021 By EarthWise Leave a Comment

A new study published in Nature has tried for the first time to put a price tag on the impact of invasive species. Researchers have been studying the effects of invasive species for decades, but it is a problem that has not really captured the attention of the public and policy makers.

According to the research by scientists at the French National Museum of Natural History, from 1970 to 2017, invasive species have cost the global economy at least $1.28 trillion dollars in damages and efforts to control them.

The team screened over 19,000 published papers, ultimately analyzing nearly 2,000 that detailed costs of various invasions at particular times. Annual costs roughly doubled every six years, reaching a yearly bill of $162 billion in 2017.

The five costliest invasive species are Aedes mosquitos, rats, cats, termites, and fire ants, collectively accounting for a quarter of the global damage.

Asian tiger mosquitos and yellow fever mosquitos alone accounted for $149 billion in damage to public health as they spread from country to country. Rats hitchhike on human boats and drive native species to extinction on islands around the world. Cats inflict damage primarily by their impact on native biodiversity. By some estimates, they kill a billion birds each year in the US alone. Termites, as they spread across the globe, wreak havoc on all sorts of infrastructure. Fire ants can feed on a variety of seedlings, from citrus to soybeans, reduce the size of grazing lands for livestock and bite and sting farm animals and humans.

The study shows invasive species are a massive problem that is getting worse.

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Invasive Species Cost Billions of Dollars in Damages Annually, Researchers Find

Photo, posted March 29, 2012, courtesy of Aleksey Gnilenkov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coronavirus Shutdowns And The Environment | Earth Wise

May 11, 2020 By EarthWise Leave a Comment

Our stories often discuss how human activities change the natural environment. With most of us confined to our homes, the lack of human activities is having profound effects on the environment. We are talking about some of these this week.

The COVID-19 pandemic is a global catastrophe, but it has ironically been a boon for the environment. By taking billions of people off the streets around the globe and slashing all forms of travel, the global environment has seen dramatic changes.

Sea turtles in many countries are prospering by not having to compete with humans for precious beach space. Animals everywhere have more freedom to roam and are taking advantage of the opportunity. The Himalayas are visible from parts of India for the first time in decades.

Satellite imagery has shown dramatic drops in nitrogen dioxide emissions in China, where pollution from vehicles is a serious public health problem. Similar reductions in air pollution are evident in India, Italy and even in Los Angeles. The city that is notorious for its smog suddenly has pristine air.

In Venice, water in the canals has become clear in the absence of heavy boat traffic stirring up sediments from the bottom. Wildlife that normally is invisible such as jellyfish are being spotted.

Not all the changes to animal behavior are desirable. Some wildlife that have become dependent on humans as a source of food are becoming aggressive and are taking to the streets of cities to look for food. Monkeys in Thailand are mobbing towns and brawling, hunting for things to eat. Rats in New York City are fighting over suddenly meager food supplies.

In many ways, the natural world is reacting to much of humanity sheltering in place.

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On Earth Day 2020, coronavirus shutdowns are a gift to the environment

Photo, posted April 2, 2020, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Conflicts In Conservation

July 20, 2018 By EarthWise Leave a Comment

In recent years there has been a great deal of discussion about animal intelligence and the idea of animal consciousness. In the past, the notion that animals have feelings had been relegated to fringe status, but these days, a wealth of scientific findings has made it much more mainstream to entertain such ideas.

Trouble For Vultures

June 3, 2016 By WAMC WEB

When we think of vultures, we picture big, ugly birds circling over a carcass in the desert. They are a stereotypical harbinger of death. But in many parts of the world, vultures are in danger of disappearing. Our knee-jerk reaction might well be “good riddance”, but as is the case for pretty much all participants in ecosystems, vultures have an important role to play. And when they aren’t around to play that role, bad things can happen.

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