behavior

Heatwaves And Bird Populations | Earth Wise

July 28, 2022 By EarthWise Leave a Comment

The increased occurrence and intensity of heatwaves around the world is affecting most living things. Heatwaves can be lethal for warm-blooded animals – including people – but the behavioral and physiological effects of sub-lethal heat have not been extensively studied. Heat that doesn’t kill animals can still impact their ability to adapt and thrive as the climate changes.

Researchers at the University of Tennessee in Knoxville recently published a new study that examined how heat impacts the behavior and physiology of Zebra finches. They exposed the birds to a four-hour heat challenge, similar to what wild birds might experience during a hot summer afternoon. They used Zebra finches because these songbirds experience extreme temperature fluctuations in their native Australia.

The team measured heat effects on thermoregulatory behavior, how heat alters gene activity in tissues critical to reproduction, and how heat affects the area of the brain that controls singing. The evidence showed that even sub-lethal heat can change a bird’s ability to reproduce both from the functioning of its reproductive system and its motivational circuits for mating behavior.

The researchers found that some individual birds were better able to minimize the physiological effect of heat, for example by adjusting their behavior to dissipate heat. Some individuals and even some species are likely to be able to adapt to increasingly extreme temperatures.

Global bird populations have been dramatically declining over the past few decades. Previous studies have shown that birds sing less during heatwaves. Based on the new study, it appears that increasing heatwaves may be a potential underlying mechanism for the decline in bird populations.

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New Research Suggests Heat Waves Could Lead to Avian Population Decline

Photo, posted August 22, 2017, courtesy of Dennis Jarvis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Spring Is Coming Earlier In Britain | Earth Wise

March 1, 2022 By EarthWise Leave a Comment

The United Kingdom has some of the most detailed records of seasonal changes anywhere in the world. Since the 18th century, observations of seasonal changes have been recorded by scientists, naturalists, amateur and professional gardeners, and organizations such as the Royal Meteorological Society. Researchers at two British institutions have collected and collated these records into a database they call Nature’s Calendar, which currently has about 3.5 million records going back to 1736.

By analyzing more than 400,000 observations of 406 plant species in Nature’s Calendar, they found that the average first flowering date from 1987 to 2019 is a full month earlier than the average from 1753 to 1986. The change correlates very well with rising global temperatures.

The ecological risks associated with earlier flowering times are high. When plants flower too early, a late frost can kill them – a phenomenon most gardeners have experienced at some point or another. Beyond that, plants, insects, birds, and other wildlife have co-evolved to be synchronized with plants in their development stages. A certain plant flowers and attracts a certain kind of insect, which then attracts a particular kind of bird, and so on. If plants get out of sync with the animals in the ecosystem and the animals can’t change their behavior quickly enough, it can lead to species collapse.

If global temperatures continue to increase at their current rate, spring in the UK could eventually start in February, creating serious problems for many of the species that inhabit forests, gardens, and farms. The dangers of climate change are not just about extreme weather.

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UK plants flowering a month earlier due to climate change

Photo, posted February 1, 2012, courtesy of Mandy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sea Turtles And The Sargasso Sea | Earth Wise

June 15, 2021 By EarthWise Leave a Comment

The lifecycle of sea turtles includes a longstanding mystery, often called the “lost years”. Turtles hatching from nests along Florida’s Atlantic coast head into the ocean and are generally not seen again for several years before they return in their adolescence. Very little is known about where they spend this time in the open ocean.

Researchers at the University of Central Florida have learned that green turtles as well as loggerhead turtles – both iconic species in conservation efforts – may be spending their youth in the legendary Sargasso Sea. The Sargasso Sea is located off the east coast of the U.S. in the North Atlantic Ocean. It has frequently been featured in popular culture, such as in the novel Twenty Thousand Leagues Under the Sea, as a place where ships could be trapped in thick mats of floating, brown Sargassum seaweed for which the sea is named.

The researchers tracked the baby turtles by attaching advanced, solar-powered tracking devices, about an inch long, to their shells. They used a special adhesive that held the devices to the turtle shells but would allow the devices to fall off after a few months causing no harm to the turtles or inhibiting shell growth or behavior.

It was previously thought that baby turtles would passively drift in sea currents and simply ride those currents until their later juvenile years. The new research shows that the turtles actively orient to go into the Sargasso Sea.

Studies of where turtles go as they develop are fundamental to sound sea turtle conservation. If we don’t know where turtles are and what parts of the ocean are important to them, we are doing conservation blindfolded.

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Legendary Sargasso Sea May be Sea Turtles’ Destination during Mysterious ‘Lost Years’

Photo, posted October 23, 2016, courtesy of Kris-Mikael Krister via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Artificial Light And Nature | Earth Wise

December 4, 2020 By EarthWise Leave a Comment

Most of us are familiar with air pollution, water pollution, soil pollution, and noise pollution. But it turns out that light can also be a pollutant as well.

Light pollution is a consequence of industrial civilization. Sources of light pollution include building interior and exterior lighting, advertising billboards, factories, commercial properties, streetlights, and sporting venues.

According to findings in a new report from the University of Exeter, artificial nighttime lighting has a wide range of effects across the natural world and should be limited wherever possible. The research team analyzed more than 100 studies and found that artificial lighting has widespread impacts on both animals and plants.

In the study, which was funded by the Natural Environment Research Council in the U.K., researchers consistently found changes to animals’ bodies and behavior as a result of artificial lighting. In particular, levels of the sleep cycle-regulating hormone melatonin were reduced by exposure to artificial lighting at night in all animal species studied.

Exposure to artificial nighttime lighting also affected the timing of animals’ activities. For rodents, which are largely nocturnal, the duration of activity was often reduced by exposure to nighttime lighting. On the other hand, for diurnal birds, exposure to nighttime lighting led to an extension of the duration of their activities.

Previous studies have found other wide-ranging impacts of nighttime lighting, from reducing pollination by insects to trees budding earlier in spring.

Artificial nighttime lighting is human driven and very disruptive to the natural world. While there’s no off switch for the planet, we could reduce the amount of light pollution drastically with no impact on our lives.

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Artificial night lighting has widespread impacts on nature

Photo, posted July 29, 2017, courtesy of spacedust2019 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Global Emissions And The Coronavirus Shutdown | Earth Wise

June 10, 2020 By EarthWise Leave a Comment

With so much of industry and personal activity curtailed by coronavirus shutdowns across the globe, it is no surprise that greenhouse gas emissions have declined. According to new research published in the journal Nature Climate Change, average daily global greenhouse gas emissions declined 17% by early April compared to 2019 levels.

If the reopenings around the world continue and the world actually reaches pre-crisis levels by the middle of June, total CO2 emissions for the year would likely end up lower by about 4%. If various restrictions continue until the end of the year, total global emissions could decline by 7%.

The study analyzed emissions estimates for three levels of coronavirus shutdowns and across six sectors of the economy. It looked at trends in 69 countries, all 50 U.S. states, and 30 Chinese provinces, representing in total 86% of the world’s population and 97% of global CO2 emissions.

For the first 4 months of the year, emissions from industry declined 19%, the power sector 7%, and public buildings and commerce 21%, compared to last year. Unsurprisingly, home energy use actually went up by about 3%.

The findings of this study only represent the effects of a short-lived decline in emissions. As economies open back up, there is no doubt that greenhouse gas emissions will rise back to pre-Covid-19 levels.

The study also reveals that making real changes in emissions will require more than just behavior changes. Despite billions of people staying home, companies shut down, planes grounded, and cars off the road, we still managed to pump more than 80% of the usual amount of greenhouse gases into the air for the first quarter of the year.

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Global Emissions Fell 17 Percent Due to Coronavirus Shutdowns

Photo, posted May 7, 2020, courtesy of the MTA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Microplastic Hotspots In The Ocean | Earth Wise

June 4, 2020 By EarthWise Leave a Comment

Many of us are aware of the infamous ocean “garbage patches” of floating plastic. The Great Pacific Garbage Patch is roughly the size of Texas. But over 10 million tons of plastic waste enter the oceans each year and the floating patches only account for 1% of that total. The remaining 99% of the plastic ends up in the deep ocean, generally in the form of microplastics – tiny fragments of large plastic debris that have broken down as well as manufactured polyethylene beads used in various products.

According to a new study published in the journal Science, there are actually microplastic hotspots on the ocean floor, formed by deep-sea currents that act as conveyer belts moving the tiny plastic fragments around. One of these hotspots – in the Tyrrhenian Sea off the west coast of Italy – contained 1.9 million microplastic pieces in just one square meter of seafloor. This is the highest reported value for any place in the world.

Because of their small size, microplastics can be ingested by organisms across all levels of the marine food chain and eventually find their way into human diets.

The spatial distribution and ultimate fate of ocean microplastics are strongly controlled by near-bed thermohaline currents. These are deep-ocean currents driven by differences in water density, which is controlled by temperature and salinity. Thermohaline currents are known to supply oxygen and nutrients to the flora and fauna found at the ocean bottom. As a result, deep sea biodiversity hotspots are likely to be in same places where there are microplastic hotspots.

The discovery of these deep- sea hotspots is just another reason why we need behavior and policy interventions to limit the flow of plastics into natural environments.

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Seafloor microplastic hotspots controlled by deep-sea circulation

Photo, posted September 6, 2012, courtesy of Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Boutique Hotels For Birds | Earth Wise

April 28, 2020 By EarthWise Leave a Comment

The changing Arctic climate has had a drastic effect on its seabirds. In fact, seabirds worldwide are in crisis, with global populations plummeting nearly 70% over the past 70 years as a result of climate change, over-fishing, habitat loss, and other human impacts on their environment.

Above the Arctic circle in Norway, seabird behavior has changed dramatically. Black-legged kittiwakes – which are the most seafaring member of the gull family – used to nest in cliffs over the ocean and seldom ventured inland. But in recent years, that has changed. Because of a warming ocean, increased storminess and other changes that are decimating chick populations in their normal habitat, the birds have been setting up housekeeping in places like shopping centers and office buildings in Tromsø and other towns along Norway’s north coast.

Tromsø, Hammerfest and other towns at the very north end of Norway have become very popular with tourists seeking the Northern Lights and wanting to see glaciers before they disappear. The booming tourism has been put on hold for the moment as it has elsewhere, but when it returns, the regions growing hotels and shopping areas are facing a problem.

The birds taking up residence on these buildings are unpleasant neighbors. They are especially noisy during the breeding season and people are having to put up nets or spikes on buildings to discourage the kittiwakes from settling there.

Local ecologists are now building boutique hotels just for kittiwakes. Using abandoned buildings on piers, they are adding ledges for nesting, materials for nest-building, and electronic speakers that croon kittiwake songs. The hope is that the birds will stay in their own hotels and leave the other ones for the human tourists.

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Norwegians are building boutique hotels for threatened Arctic birds

Photo, posted April 14, 2018, courtesy of Charlie Jackson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

An Ecological Trap For Polar Bears | Earth Wise

March 17, 2020 By EarthWise Leave a Comment

Climate change has been shrinking Arctic sea ice and this is causing changes in the behavior of polar bears. The Southern Beaufort Sea, located where the northern edges of Alaska and Canada meet, is home to one of the 19 population groups of polar bears. Historically, the polar bears in this region remained on sea ice year-round. But in recent decades, about a quarter of them have chosen to come on land instead of staying on the shrinking summer ice platform.

A recent study by San Diego Zoo Global, the U.S. Geological Survey, and Polar Bears International looked at the energetic consequences of the bears’ behavior. The decision of each individual bear to stay on the ice or move to land appears to be linked to the energetic cost or benefit of the choice.

Bears who moved to land expended more energy during the summer than bears that remained on the sea ice. In late summer, as the ice became even more restricted, a greater amount of energy was expended by bears swimming to land. So, the immediate energy cost of moving to land is much greater than remaining on the receding pack ice.

On the other hand, bears on land in this region have access to whale carcasses in the summer while bears on the sea ice appear to be fasting. As a result, it may be the case that the declining population of bears in this region is in part caused by the ecological trap of bears staying on the ice to avoid expending all the energy needed to move to land. The shrinking polar ice is a real problem for polar bears.

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Energetics Study Indicates that Shrinking Sea Ice Is Creating an Ecological Trap for Polar Bears

Photo, posted October 30, 2011, courtesy of Martin Lopatka via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bioacoustics

December 5, 2019 By EarthWise Leave a Comment

Researchers are increasingly placing microphones in forests and other ecosystems to monitor birds, insects, frogs, and other animals. Advances in technology are enabling the wide-spread use of bioacoustics as an important research tool.

Studying animals in their natural habitat Is often a difficult task. For one thing, many animals are difficult to find, and the presence of humans disrupts their behavior or even drives them off. Remote cameras are useful, but cameras can only see what is in front of them and aren’t much use for detecting small animals, hidden animals, or ones high up in trees.

Biologists have long recognized the value of recording sound to identify animals and learn about their havior. Animal sounds can be as definitive a means of identification as visual images and microphones can pick up the sounds from animals located anywhere within their detection range.

The two advances in technology that are turning bioacoustics into a widely used tool are a steep drop in the price of recording equipment and the rapidly expanding capabilities of user-friendly artificial intelligence algorithms.

Autonomous environmental audio recorders tended to cost between $500 and $1000 until quite recently. Now, such equipment can be had for as little as $70.

The other big challenge is analyzing audio data. Finding specific animal sounds among hundreds of hours of recordings is an untenably tedious task. Identifying the characteristic sounds of specific species in crowded environments is a tricky business. But neural network-based artificial intelligence technology is making such big data analysis quite practical and, remarkably, it is becoming quite user-friendly.

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Listening to Nature: The Emerging Field of Bioacoustics

Photo, posted January 28, 2013, courtesy of Felix Uribe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Exotic Pets Can Become Problems

August 26, 2019 By EarthWise Leave a Comment

Each year, millions of exotic animals are sold as pets around the world. The term “exotic” lacks a set definition but is generally used to refer to an animal that’s wild or more unusual than standard pets, like cats and dogs.

The exotic pet trade is a multi-billion dollar industry, involving tens of millions of individual animals from thousands of species, including reptiles, amphibians, fish, birds, and mammals.

Some of the exotic pet trade is legal, but a lot of it isn’t. Many animals are illegally captured from the wild to meet the global demand for exotic pets.

People often purchase exotic animals without completely understanding the consequences. Some exotic pets, for example, can live nearly twice as long as the average dog. Caring for exotic pets can be both expensive and risky, since they are largely undomesticated (and therefore can have unpredictable behavior).

As a result, it’s not uncommon for owners to release exotic pets intentionally. When this happens, the consequences can be catastrophic. Sometimes the animal dies from starvation or predation, but in other instances, the animal proliferates and becomes an invasive species.

Invasive species are the second largest driver of biodiversity loss worldwide, and they cost the U.S. $120 billion a year.

According to an academic review recently published in the journal Frontiers in Ecology and the Environment, the exotic pet trade is one of the primary causes of the spread of invasive species and has fueled the establishment of hundreds of them. Tegus, Burmese pythons, and red lionfish are examples of pets-turned-pests.

The best way to combat this trend is through education, detection, and rapid response.

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Why you should never release exotic pets into the wild

Photo, posted September 19, 2010, courtesy of Mike Baird via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fishers Helping To Clean The Oceans

August 2, 2019 By EarthWise Leave a Comment

Marine litter – particularly plastics – is a global, persistent, and increasing threat to the oceans. Much of it comes from discarded materials on shore that makes their way to the sea but waste from the fishing industry is a also a major contributor to the problem.

Commercial fishers are acutely aware of the potential for marine litter to damage and even destroy their livelihoods and are starting to try to be part of the solution instead of just part of the problem.

An initiative called Fishing for Litter, which has been operating around the British coastline since 2006, is an example.

With hubs in Scotland and South West of England, FFL aims to reduce the amount of marine litter in the sea by physically removing it while also highlighting the importance of good waste management in the fishing fleet. Fishers have to assume responsibility for their own waste and dispose of it in a responsible manner. They also have a unique ability to access remote and hard to reach marine litter caused by others.

A survey of 120 commercial fishers revealed that they often found marine litter in their hauls and that keeping the sea and coasts clean was important to them.

The responsibility for reducing marine litter does not belong to any single industry or organization. It requires a collective global change of behavior. The problem directly affects fishers, so they are especially motivated to do something about it. They can make an important contribution to an issue that ultimately affects us all. Groups like Fishing for Litter are providing a model for behavior that we can only hope that others around the world can emulate.

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Fishers keen to help address the problem of marine litter

Photo, posted July 9, 2009, courtesy of Rennett Stowe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildlife Bridges

June 17, 2019 By EarthWise Leave a Comment

Highway accidents involving animals are a big problem for both people and animals. About 200 people die every year in the U.S. as a result of collisions with animals. In total, one to two million large animals are killed by motorists every year. And these crashes are expensive: deer-car collisions cost an average of more than $8,000 each; elk-vehicle collisions about $25,000; and moose-vehicle collisions over $44,000.

In the United States, there are 21 threatened and endangered species whose very survival is threatened by road mortalities. These include Key deer in Florida, bighorn sheep in California, and red-bellied turtles in Alabama.

One solution that has been quite effective around the world in reducing car-animal collisions is wildlife overpasses and underpasses. Crossings and fencing that guide animals over or under highways reduce collisions by 85-95%.

These traffic-spanning bridges and tunnels have been popular in Europe since the 1950s. The overpasses usually look much like regular overpasses for cars but are decked out with native flora. The underpasses, which assist shyer and smaller animals, are typically invisible to drivers.

Washington State has recently started building wildlife bridges and underpasses on Interstate 90. These passes will allow elk, black bears, mountain lions, pika, and even trout to traverse what was once a near-impenetrable barrier of road.

Some animals that are accustomed to human structures start using the crossings almost immediately. For others, there is learning curve. As in many things, the early adapters are important as they provide paths and model behavior that more reticent animals learn to follow.

Wildlife bridges are a very good thing for wildlife and for people.

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How wildlife bridges over highways make animals—and people—safer

Photo, posted July 22, 2017, courtesy of David Fulmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Polar Bear Attacks

April 8, 2019 By EarthWise Leave a Comment

The increasing reduction of sea ice in the Arctic is changing the behavior of polar bears. Because they are spending more time on land, they are interacting with people much more frequently, occasionally with deadly results.

A study, published in 2017, looked at 144 years’ worth of polar bear attacks on humans in the Arctic. Between 1960 and 2009, there were a reported 47 attacks by polar bears on people – between 7 and 12 per decade. Between 2010 and 2014, as sea ice reached record lows, there were 15 attacks, a record for a four-year period. Since 2000, 88% of attacks have occurred between July and December, when sea ice is at its lowest level of the year.

Last July, a young male polar bear attacked and killed a man who was berry picking with his children. A month later, a mother polar bear attacked and killed an Inuit hunter and injured two others. This was the first known fatal attack by a mother polar bear.

As a result, Inuit communities in the Nunavut region are asking for higher legal polar bear harvest quotas, arguing that bear populations have increased to a dangerous level.

These recent human fatalities have also provided an impetus for developing new non-lethal conflict-resolution tools than can be used in northern communities before more people as well as bears are killed.

There are now polar bear patrol teams tasked with driving bears away from settlements. There is a bear hotline and electric fencing around sled dog compounds.

The changing face of the Arctic is creating growing stress on the polar bear population and on the people who make their home in that region.

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As Polar Bear Attacks Increase in Warming Arctic, a Search for Solutions

Photo, posted September 28, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Your Children’s Yellowstone

January 25, 2019 By EarthWise Leave a Comment

Yellowstone National Park was the first national park in the US and according to some sources, the first in the world. It is the home of charismatic megafauna and stunning geysers that attract over four million visitors a year. It is the only place in the United States where bison and wolves can be seen in great numbers. And it is changing.

Over the next few decades of climate change, Yellowstone will quite likely see increased fire, less forest, expanding grasslands, shallower, warmer waterways, and more invasive plants. All these things will alter how and how many animals move through the landscape. Ecosystems are always changing, but climate change is transforming habitats so quickly that many plants and animals may not be able to make the transition at all.

Since 1948, the average annual temperature in the Greater Yellowstone ecosystem has gone up by 2 degrees Fahrenheit. On balance, winter is 10 days shorter and less cold. The Northern Rockies snowpack has fallen to its lowest level in eight centuries. Summers in the park are warmer, drier, and increasingly prone to fire.

Non-nutritious invasive plants like cheatgrass and desert madwort have replaced nutritious native plants. When plants like these take over, they suck moisture out of the ground early so that bison and elk cannot be sustained throughout the summer.

The behavior of elk and other animals is already changing, with many staying outside the park to nibble lawns and alfalfa fields. In turn, wolves go where the elk go. Forests and waterways are changing as well.

The rapid changes going on at Yellowstone mean that the park that our children and grandchildren will visit in the future is likely to be a very different one from the Yellowstone we remember.

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