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Pacific Bluefin Tuna On The Rebound | Earth Wise

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The Pacific Bluefin Tuna is a commercially valuable species that is especially prized in Japan.  The fish is particularly valued for sashimi and sushi and large specimens have been known to fetch enormous prices at seafood auctions.

Aggressive fishing reduced the bluefin biomass through the late 1990s and 2000s to only a few percent of its potential unfished levels.  Beginning in 2011, The Western and Central Pacific Fisheries Commission began management measures that reduced the catch of smaller bluefin as well as limited the catch of larger bluefin.  The goal was to allow more fish to grow to maturity.  The Inter-American Tropical Tuna Commission adopted similar resolutions a year later.  Despite these efforts, increasing concern about declining bluefin levels led to a petition to list the species as endangered.  The National Oceanic and Atmospheric Administration’s Fisheries organization determined that while the population was near historical lows, the remaining 1.6 million fish was a sufficient number to avoid the risk of extinction and that the measures in place were sufficient.

A new assessment of the bluefin population has shown that the species is now increasing and includes many younger fish that will help accelerate its rebound.  The assessment by NOAA showed that the bluefin stock was greater than the first rebuilding target set for 2019. 

According to the NOAA Fisheries biologists that performed the assessment, the species has responded exactly as predicted given the actions that were taken.  The bluefin tuna is an amazingly resilient fish and it is continuing to demonstrate that fact.

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International Actions Pay Off For Pacific Bluefin Tuna as Species Rebounds at Accelerating Rate

Photo, posted June 1, 2022, courtesy of Philippe Yuan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Return Of The Fin Whale | Earth Wise

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The fin whale is the second largest whale species and therefore the second largest creature on Earth.  They can grow to more than 80 feet in length.  From 1904 to 1976, there was massive industrial whaling in the Southern Ocean surrounding Antarctica.  During that period, whalers killed about 700,000 fin whales, reducing their population by 99%.  The species was nearly extinct.

In 1982, the International Whaling Commission voted to ban commercial whaling.  Since that time, fin whales started to make a comeback in their historical feeding grounds.

During a nine-week expedition in the waters around the Antarctic Peninsula, researchers encountered the largest gathering of fin whales ever documented.  About 150 fin whales were seen diving and lunging against the water’s surface.  It was a feeding frenzy triggered by large amounts of krill in the water.  The actions of the whales are known as a “whale pump” that drives the krill to the surface.  Not only does it provide huge amounts of food for the whales but also for other animals, including seabirds and seals.

Forty years after the commercial whaling ban, the number of fin whales has been increasing.  Large groups were observed in a 2013 survey.  Aerial surveys in 2018 and 2019 recorded 100 groups of fin whales, usually composed of a just a handful of individuals.  They did document eight large groups of up to 150 individuals.

Not all species of whales have rebounded so successfully since the whaling ban.  The rebound in fin whale population is not only good for the whales, but for the entire ecosystem in the Southern Ocean.  It is a glimmer of good news in a time of great challenges for global biodiversity and for marine life in particular.

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Once Facing Extinction, Massive Fin Whales Have Returned to Antarctic Waters

Photo, posted November 15, 2007, courtesy of Gregory Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

North American Birds And Climate Change | Earth Wise

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Most plants and animals live in areas with specific climate conditions, such as rainfall patterns and temperature, that enable them to thrive. Any change in the climate of an area can affect the plants and animals living there, which in turn can impact the composition of the entire ecosystem.   

As such, the changing climate poses many challenges to plants and animals.  For example, appropriate climatic conditions for many species are changing.  As a result, some may even disappear altogether.  These problems can be compounded when the climate is changing in tandem with other human-caused stressors, such as land use change.

When there is increasing divergence between suitable climatic conditions for a particular species and its abundance and distribution through time, this is known as climate decoupling.

According to a new study recently published in the journal Nature Ecology & Evolution, some species of North American birds have not fully adjusted their distributions in response to climate change.  The areas where these birds live have become more decoupled from their optimal climate conditions.  Climate decoupling as a result of ongoing climate change could lead to additional stressors on many bird species and exacerbate bird population declines.

In the study, the research team analyzed data on bird population changes through time from the North American Bird Survey.  They found that at least 30 out of 114 species (or 26%) of North American birds have become less well adjusted to their climate over the last 30 years. This means that their distributions and abundances were increasingly decoupled from climate over time.

The researchers also found that the overall trend of climate decoupling shows no signs of slowing down. 

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North American birds not fully adjusting to changing climate

Photo, posted July 16, 2016, courtesy of Kelly Azar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Environmental DNA | Earth Wise

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Marine protected areas are sections of the ocean where governments place limits on human activity.  They are intended to provide long-term protection to important marine and coastal ecosystems.  MPAs are important because they can protect depleted, threatened, rare, and endangered species and populations.

In January 2020, the Republic of Palau in the western Pacific Ocean created one of the world’s largest marine protected areas.  The Palau National Marine Sanctuary covers 80% of the country’s economic zone and prohibits all extractive activity like fishing and mining over a 183,000 square mile area in order for the island nation to ensure its food security and grow its economy in the face of climate change.

The Marine Sanctuary is an ambitious enterprise.  The question is how Palau can evaluate whether and how well it is working?

A team of scientists from Stanford University and Palau-based colleagues are making use of Environmental DNA – or eDNA – technology to monitor the large-scale marine protected area.  eDNA is the cells, waste, viruses, and microorganisms that plants and animals leave behind.  Samples of marine eDNA effectively provide a fingerprint of the organisms that have recently passed through the water in a given area.  This gives scientists a way to assess an ecosystem’s biodiversity and keep track of the types of species inhabiting a specific area.  Using eDNA, it is possible to keep track of all the  organisms that live below the surface and learn about things we can’t even see.

The team has embarked on a program of periodic sampling of the waters off Palau and hope to be able to monitor the results of establishing the Marine Sanctuary.

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eDNA: Bringing biodiversity to the surface

Photo, posted June 12, 2013, courtesy of Gregory Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Heatwaves And Bird Populations | Earth Wise

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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.

Climate Resilient Microalgae | Earth Wise

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The plight of the world’s coral reefs has been a growing environmental crisis for many years.  Coral reefs provide sustenance and income to half a billion people, are major tourist attractions, protect coastlines, and are important centers of biodiversity.   And because of the warming climate as well as other effects of human activity, more than half of the world’s coral reefs are under stress.

The primary threat is coral bleaching, which is the disruption of the symbiotic relationship between coral polyps (which are tiny animals) and the heavily pigmented microalgae that live within the coral structures and provide most of the energy for the polyps. When corals are stressed, often because water temperatures are too high, they expel the microalgae within them.  The structures then become transparent, leaving only the white skeletal corals.  Bleached corals aren’t dead, but they are at great risk of starvation and disease until and unless new symbiont algae are acquired.

A new study by scientists at Uppsala University in Sweden investigated how different species of coral symbiont algae react to temperature stress.  They discovered differences among symbiont cells that enable the prediction of how temperature stress tolerant the cells are.  Such predictive ability could provide the means to identify and select more temperature-tolerant coral symbionts that could conceivably be introduced into coral host larvae in order to make corals more robust against climate change.

The research has a ways to go, but the new tools may help coral reef monitoring and increase the speed at which reef restoring efforts can create stocks of climate-resistant symbionts.

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Climate resilient microalgae could help restore coral reefs

Photo, posted September 28, 2009, courtesy of Matt Kieffer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Giant Tortoise Is Not Extinct | Earth Wise

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The Galapagos Islands are famous for their tortoises, among many other things. A few million years ago, some giant tortoises from South America were somehow carried across hundreds of miles of ocean to the islands – perhaps on driftwood during storms.  Tortoises don’t swim, so any that made to an island could only breed with others on that same island.   The result was rapid evolution of tortoise species in the Galapagos.  Today, there are 14 different species of giant tortoises there.

Centuries ago, tortoise populations in the Galapagos were decimated by European sailors who hunted them for food.   The giant reptiles could be kept alive on ships with little food or water, so they became a great source of meat.

On the island of Fernandina, there was a species of Galapagos tortoise known as the “fantastic giant tortoise.”  Only a single one of these was ever found and that was in 1906.  It ended up being preserved as a museum specimen.

In 2019, a female tortoise living on Fernandina was located and genome sequencing has only recently been successfully completed for that living specimen and the century-old one in the museum which compared them to sequences of the other 13 species of Galapagos tortoise.  That analysis showed that the two were indeed the same species and are distinct from all the others.

The female tortoise, who has been named Fernanda, now resides at the Galapagos National Park Tortoise Center, which is a rescue and breeding facility.  She is well over 50 years old.  Recent tracks and scat on Fernandina Island provide evidence that there may still be others of her kind.  The experts are trying to do what they can to keep the species alive.

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‘Fantastic giant tortoise,’ believed extinct, confirmed alive in the Galápagos

Photo, posted January 1, 2019, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Declining Bird Populations | Earth Wise

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A study by scientists from multiple institutions around the world including Cornell University has found that significant declines in bird populations are taking place across the planet.  Loss and degradation of natural habitats, direct overexploitation of many species, and climate change are driving the bird population declines.

According to the study, approximately 48% of existing bird species worldwide are known or suspected to be undergoing population declines.  The populations of 39% of bird species appear to be stable.  Only 6% of birds have increasing populations.

A study in 2019 determined that nearly 3 billion breeding birds have been lost in the U.S. and Canada over the past 50 years.  The new study shows that the same patterns of population decline and extinction are happening globally.  According to the study, there are now the first signs of a new wave of extinctions of continentally distributed bird species.

The ultimate fate of bird populations is strongly dependent on stopping the loss and degradation of habitats.   Habitat loss is generally driven by human demand for resources.  Reducing the human footprint on the natural world is what is needed.  Birds are a highly visible indicator of environmental health, and their declining populations signal a much wide loss of biodiversity and threats to human health and wellbeing.

There is a global network of bird conservation organizations trying to prevent further loss of bird species and bird abundance.  Keeping track of the situation is essential and there is growing participation by the public in bird monitoring.  But ultimately, it depends on governments and society in general to support sustainable resource use and learn how to share the planet with nature.

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Global Bird Populations Steadily Declining

Photo, posted January 9, 2022, courtesy of Martien Brand via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Assessing Human-Caused Wildlife Mortality | Earth Wise

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Bycatch is the fishing industry term used to describe the deaths of non-target fish and ocean wildlife during the fishing process.  Some bycatch species are thrown away because regulations prohibit them from being kept.  Others are thrown out because they won’t fetch high enough prices.  According to some estimates, global bycatch amounts to about 10% of the world’s total catch. 

Approximately half of global bycatch is a result of trawling.  Trawling is a method of commercial fishing that involves pulling or dragging a fishing net – called a trawl – through the water or across the seabed in hopes of catching fish.  Commercial fishing companies favor towing trawl nets because large quantities of fish can be caught.  But the method is destructive to the seafloor and leads to the indiscriminate catch of all sorts of species, including whales, dolphins, porpoises, sharks, seals, rays, turtles, and seabirds. 

Researchers have developed a new method to assess the sustainable levels of human-caused wildlife mortality.  When this method is applied to a trawl fishery in Australia, it shows that the dolphin capture is not sustainable.  The study, led by scientists at the University of Bristol in the U.K. and United Arab Emirates University, modeled different levels of dolphin capture, including those reported in logbooks and those reported by independent observers.  According to the findings, which were recently published in the journal Conservation Biology, even the lowest recorded dolphin capture rates are not sustainable. 

The new approach is extremely adept at assessing human-caused mortality to wildlife, and can be applied to fisheries bycatch, hunting, lethal control measures, or even wind turbine collisions.

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Wasted Catch

Dolphin bycatch from fishing practices unsustainable, study finds

Photo, posted May 18, 2011, courtesy of Pete Markham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And The Next Pandemic | Earth Wise

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As the planet continues to heat up, animals big and small are moving towards the poles to escape the heat.  According to researchers, these animals are likely to come into contact with other animals that they normally wouldn’t, and are likely to relocate to regions with large human populations.  These factors create opportunities for pathogens to get into new hosts, which dramatically increases the risk of a viral jump to humans.  Climate change could lead to the next pandemic.      

An international research team led by scientists at Georgetown University recently made this connection between climate change and viral transmission.  In the study, which was recently published in the journal Nature, researchers conducted the first comprehensive assessment of how climate change will restructure the global mammalian virome.  Their work focused on geographic range shifts. 

As animals eccounter other animals for the first time, the study projects that they will share thousands of viruses.  And as animals increasingly move into the same areas as humans, there will be greater opportunities for these viruses to jump to humans.  The research team says that the impact on conservation and human health could be alarming as viruses jump between species at unprecedented rates. 

In our warming world, much of this process may unfortunately already be underway.  And efforts to reduce greenhouse gas emissions may not be enough to stop these events from unfolding. 

According to the study, climate change will become the biggest upstream risk factor for disease emergence, eclipsing deforestation, industrial agriculture, and the wildlife trade.  Pairing wildlife disease surveillance with real-time studies of environmental change may be part of the solution to predicting and preventing the next pandemic. 

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Climate change could spark the next pandemic, new study finds

Coronavirus and Climate Change

Photo, posted October 16, 2014, courtesy of Shawn Thomas / NPS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Forest Loss | Earth Wise

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India is one of the most biodiverse countries in the world.  An estimated 47,000 plant species and 89,000 animal species can be found in India, with more than 10% of each thought to be on the list of threatened species. 

India is also among the top ten countries in the world in terms of total forest coverage.  According to Indian government data, the total forest and tree cover in India is 312,000 square miles, which is 24.62% of the geographical area of the country.

However, forest loss in India has been a problem for many decades driven largely (researchers thought) by land use change.  But it turns out that climate change may also have been contributing to forest loss, and its impact is projected to become an even bigger problem in the coming years. 

In the first ever national-scale study of the relationship between forest loss and rainfall and temperature trends in India, researchers from the University of Reading in the U.K. found that climate change may have contributed to large declines in forest since the turn of the century.

The study, which was recently published in the journal Global Change Biology, found far greater forest losses were observed where and when the climate was changing most rapidly.  Decreases in rainfall had the strongest impact on forest loss. 

These findings exacerbate concerns about the already-worrying levels of deforestation in the country, and contradict official reports that have shown relatively small decreases in forest coverage in recent years. 

The research team warns that rapid changes to the climate in some regions will require targeted preservation action to reduce the risk to biodiversity in India. 

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Indian forest loss ‘worse than feared’ due to climate change

Photo, posted January 20, 2013, courtesy of Dicky Broadhurst / Frontier Official via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Levels Of Deforestation In The Amazon | Earth Wise

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The Amazon rainforest is the largest rainforest in the world, covering more than 2.5 million square miles.  It’s home to 10% of all known species in the world.  The Amazon rainforest’s biodiversity is so rich that scientists are still discovering new plant and animal species today.  

The Amazon rainforest absorbs huge amounts of carbon dioxide from Earth’s atmosphere, making it a key part of mitigating climate change.  The vast rainforest acts as what’s known as a carbon sink.  Simply put, a carbon sink is anything that absorbs more carbon from the atmosphere than it releases.  But as trees in the Amazon disappear, so does the ability of the rainforest to absorb carbon dioxide.

Deforestation of the Amazon rainforest remains a major problem.  According to satellite data from the Brazilian government, the number of trees cut down in the Brazilian Amazon in January far exceeded deforestation figures for the same month last year.  Approximately 166 square miles of land was deforested in January alone, which is five times greater than what was lost in January, 2021.

Cattle ranching – both for beef and for leather – remains the leading cause of deforestation in the Amazon rainforest.  Trees in the Amazon are also cut down for their wood, as well as to clear the land in order to grow food crops, such as soy, sugar, and oil palm. 

Many companies have pledged to achieve “net zero” deforestation in their supply chains over the years, but most have not lived up to the commitment. 

Deforestation is not only a major driver of climate change, but it’s also the leading cause of species extinction.  Preserving the Amazon rainforest is vital. 

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Amazon deforestation: Record high destruction of trees in January

Greenpeace calls on fast food giants to take a stand against Bolsonaro’s Amazon destruction

Hundreds of Companies Promised to Help Save Forests. Did They?

Photo, posted July 14, 2018, courtesy of Alexander Gerst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And The World’s Fisheries | Earth Wise

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According to a new study, approximately 70% of the world’s oceans could be suffocating from a lack of oxygen by 2080 as a consequence of climate change.  This has the potential to impact marine ecosystems all around the world.  

The study, which was recently published in the journal Geophysical Research Letters, is the first to use climate models to predict how and when deoxygenation will occur throughout the world’s oceans outside of its natural variability. 

According to the findings, significant and potentially irreversible deoxygenation of the ocean’s middle depths began occurring last year.  The models predict that deoxygenation will begin affecting all zones of the ocean by 2080.

According to the study’s models, mid-ocean depths are already losing oxygen at unnatural rates. Globally, the ocean’s middle depth – known as the mesopelagic zone – is home to many of the world’s commercially fished species.  This makes these new findings a potential harbinger of economic hardship, seafood shortages, and environmental disruption. 

Just like land animals, aquatic animals need oxygen to breathe.  As climate change warms the oceans, the water holds less oxygen and is more buoyant than cooler water.  This leads to less mixing of oxygenated water near the surface with deeper waters, which naturally contain less oxygen.  Warmer water also raises oxygen demand among living organisms, resulting in less availability for marine life. 

The researchers also found that oceans closer to both the North Pole and the South Pole are particularly vulnerable to deoxygenation.  While they are not yet sure why, accelerated climate warming could be the culprit. 

These findings should add new urgency to climate change mitigation efforts. 

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Climate change has likely begun to suffocate the world’s fisheries

Photo, posted January 28, 2019, courtesy of Joseph Gage via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tree Diversity | Earth Wise

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Scientists have estimated that there are more than 8 million species of plants and animals in existence.  Amazingly, only about 1.2 million of them have been identified and described so far and most of those are actually insects.  Millions of other organisms have yet to be discovered.

One would imagine that most of these unknown species are tiny things that are hard to spot or encounter.  But our ignorance of species even applies to trees, which are pretty easy to spot if you encounter them.

A new study involving more than 100 scientists across the globe has produced an estimate of the number of tree species on the Earth.  The new global estimate is that there are 73,000 tree species, which is about 14% more than previously thought.  Based on a combination of data from two global datasets, the study yielded a total of 64,100 documented tree species worldwide.  The researchers then used novel statistical methods to estimate the total number of unique tree species at biome, continental, and global scales, which includes species yet to be discovered and described by scientists.  Therefore, the estimate predicts that there are likely to be over 9,000 tree species still to be found.

Roughly 40% of the undiscovered tree species are likely to be in South America, which is the continent with the highest number of rare tree species and the highest number of continentally endemic tree species – meaning those found only on that continent.  Hot spots of undiscovered tree species are likely the tropical and subtropical moist forests of the Amazon basin and the Andes-Amazon interface.

Extensive knowledge of tree richness and diversity is key to preserving the stability and functioning of ecosystems.

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Number of Earth’s tree species estimated to be 14% higher than currently known, with some 9,200 species yet to be discovered

Photo, posted November 5, 2017, courtesy of Deensel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Invasive Species On Ships In Antarctica | Earth Wise

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The Southern Ocean around Antarctica is the most isolated marine environment on Earth.  Antarctica’s native species have been isolated for the last 15-30 million years.  As a result, wildlife there has not evolved the ability to tolerate the presence of many groups of species.

New research by the University of Cambridge and the British Antarctic Survey has traced the global movements of all the ships entering Antarctic water and has found that Antarctica is connected to all regions of the globe via ship activity to an extent much greater than previously thought.  Fishing, tourism, research, and supply ships are exposing Antarctica to invasive, non-native species that threaten the existing ecosystems.

In all, the research identified over 1,500 ports with links to Antarctica.  From all these places, non-native species including mussels, barnacles, crabs, and algae attach themselves to ships’ hulls.  The process is known as biofouling. 

The greatest concern is the movement of species from pole to pole.  These species are already cold-adapted.  They may come on tourist or research vessels that spend the northern hemisphere summer in the Arctic before traveling south for the Antarctic summer season.

Mussels have no competitors in Antarctica should they be accidentally introduced.  Shallow water crabs would introduce a new form of predation that Antarctic animals have never encountered before.

Current biosecurity measures to protect Antarctica, such as cleaning ships’ hulls, focus on a small group of so-called gateway ports.  The new findings indicate that these measures need to be expanded to protect Antarctic waters from non-native species.

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Invasive species ‘hitchhiking’ on ships threaten Antarctica’s unique ecosystems

Photo, posted April 12, 2016, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bald Eagles And Lead Poisoning | Earth Wise

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The bald eagle is the national bird of the United States.  It was once a common sight over much of the continent but was severely affected in the mid-20th century by a variety of factors, particularly the use of the pesticide DDT, which caused thinning of its eggshells and sterility.  In the 18th century, the bald eagle population was 300,000 – 500,000.  By the 1950s, there were only 412 nesting pairs in the 48 contiguous states.

The bald eagle was declared an endangered species in the US in 1967 and additional regulations strengthened protections for the bird.  The banning of DDT in 1972 was a major factor in the recovery of the species.

Bald eagle populations have been rebounding for decades but another issue is weakening that rebound – lead poisoning from gunshot ammunition.  According to a new study published in the Journal of Wildlife Management, poisoning from eating dead carcasses or parts contaminated by lead shot has reduced population growth by 4% to 6% annually in the Northeast.

Bald eagle numbers in the lower 48 states quadrupled between 2009 and 2021 to more than 316,000, according to a report by the U.S. Fish and Wildlife Service.  But even though the population has seemingly recovered, some combination of factors such as habitat loss, climate change, infectious disease, and lead poisoning could reverse the trends and lead to population declines.

The hope is that the study could help educate and inform policy on ammunition choices for hunters.  There are alternatives such as copper-based ammunition.  Human health can also be affected when bullets fragment inside game species and are then consumed.

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Bald eagle rebound stunted by poisoning from lead ammunition

Photo, posted March 28, 2013, courtesy of Ben Johnson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Sixth Mass Extinction | Earth Wise

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Extinction is a natural part of life.  Plants and animals disappear all the time.  When one species goes extinct, its place in the ecosystem is typically filled by another.  The so-called normal rate of extinction is thought to be somewhere between 0.1 and 1 species per 10,000 species per 100 years.

A mass extinction event is when species disappear at a much faster clip than they can be replaced.  By definition, mass extinction is when about three-quarters of the world’s species are lost in a short amount of time on a geologic scale, which is measured in millions of years.  

There have been five previous mass extinction events throughout the history of life on earth.  Today, many experts warn that a sixth mass extinction event is already underway – the first since dinosaurs were wiped out some 65 million years ago.  While previous mass extinctions were the result of extreme natural phenomena like volcanic eruptions and asteroid strikes, this one is a result of human activities. 

Researchers from the University of Hawai’i at Manoa and the National Museum of Natural History in France recently published a comprehensive assessment of evidence of this ongoing extinction event.  The researchers estimated that since the year 1500, Earth could already have lost between 7.5% and 13% of the two million known species on Earth.  This amounts to a staggering 150,000 to 260,000 species.

While mitigating the effects of climate change and reducing the rates of habitat loss would help, raising awareness of this crisis and its fallout for all life forms – including us – would be most effective in driving change. 

The time we have to avoid dramatic consequences is rapidly running out. 

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Strong evidence shows Sixth Mass Extinction of global biodiversity in progress

Photo, posted September 18, 2015, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Armadillos Heading North | Earth Wise

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Armadillos are small mammals known for their unique armor-like shell and their digging habits.  There are 21 species, primarily native to South America.  Some species have expanded northward due to their rapid breeding cycle, adaptability, and reduced number of predators.  Only one species – the nine-banded armadillo – is found in the United States.  In fact, it is the official small mammal of the state of Texas.

Over time, armadillos have expanded their range to states in the Deep South.  More recently, the animals have been pushing further north.  Milder winters in the changing climate have allowed them to inhabit new areas, including parts of the Blue Ridge Mountains. They were first sighted in North Carolina in 2007 and their numbers have recently been growing in the western half of the state.

There are now armadillos as far north as Missouri, Nebraska, and Iowa, and there is little to halt their further advance.  They are able to hold their breath for six minutes at a time, so they can cross rivers by walking along the bottom or by inflating their intestines and floating across the top.  Their hard shell provides protection from predators.  They reproduce prolifically.  Females give birth to quadruplets multiple times over the course of their 12-15-year lifespan.

Armadillos are fun to look at, but they are a nuisance where people live.  They are prone to digging holes in lawns.  In parts of North Carolina, some people have placed bounties on the animals.  They are difficult to trap and there aren’t common repellents for them.  As the climate continues to warm, it is only a matter of time before the range of armadillos expands into other states.

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Armadillos Advance Northward As Temperatures Rise

Photo, posted May 2, 2017, courtesy of Gail Hampshire via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Perennials To Attract Pollinators | Earth Wise

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There has been a decline in the abundance of insect and other animal pollinators in many ecosystems worldwide that began being observed at the end of the 20th century.  Pollinators and their health have become growing concerns for the public and many states have enacted legislation related to pollinator decline.

In many places, the pollinator decline has largely been driven by a loss of flowering plants in the landscape, the primary source of food for the pollinators.  A new study by Penn State researchers looked at the attractiveness to pollinators of various species of perennial flowering plants that people can plant in their gardens and other landscapes.

It turns out that there is considerable variation in how attractive different flowering plants are to pollinators.  Greenspaces such as parks and gardens have the potential to support very rich pollinator communities, even including rare or vulnerable species.

People generally select ornamental plants because of their appearance and growth habit, not because of their pollinator attraction.

The Penn State study looked at a variety of perennials and identified the most attractive plant cultivars, which can attract 4 times the number of pollinator species than the least attractive plants studied.

The most appealing plant is the ‘Blue Fortune’ giant hyssop.  Other highly attractive plants are the anise hyssop, the ‘Black Adder’ Agastache, the Cat’s Meow and Walker’s Low Nepetas, and the Triloba and Herbstonne Rudbeckias.

Many of these plants produce large floral displays and the researchers suggest that they should be prioritized when planting a pollinator garden amongst other species with comparably small floral displays and lower attractiveness to pollinators.

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Popular perennial flowering plants can attract diverse mix of pollinators

Photo, posted September 7, 2019, courtesy of KM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Roads And Chimpanzees | Earth Wise

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The chimpanzee is a species of great ape native to tropical regions of Central and West Africa.  Chimpanzees are highly social animals and can live to be over 50 years old.  In fact, chimpanzees are our closest cousins.  We share about 98% of our genes with chimpanzees. 

According to the African Wildlife Federation, it’s estimated that at most only 300,000 chimpanzees remain in the wild today.  They face a myriad of challenges, including habitat degradation and hunting. 

According to new research from the University of Exeter in the U.K., roads have a negative impact on chimpanzee populations that can extend for several miles.  In the study, which was recently published in the journal Conservation Letters, the researchers analyzed the impact of major and minor roads on wild western chimpanzee numbers in the eight African countries in which they live.  They found that negative impacts extended an average of 10.7 miles from major roads, and 3.4 miles from minor roads.  The researchers found that the density of chimpanzee populations dropped steadily from the edges of these areas to the lowest value alongside the roads.  Only 4.3% of the chimpanzees’ range remains unaffected by roads. 

While the study did not investigate why roads affect chimpanzee numbers, the research team did offer some clues.  In addition to noise and roadkill, roads provide access to unexploited areas for industries that often reduce or remove chimpanzee habitats.  Roads can also restrict chimpanzee movements, and provide easier access for hunters. 

The researchers hope their findings will bring about more effective guidelines to mitigate the impact of roads on wildlife.   

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Roads have far-reaching impact on chimpanzees

Photo, posted August 12, 2014, courtesy of Rod Waddington via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)