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Moving Endangered Species | Earth Wise

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People have intentionally or accidentally introduced numerous invasive species to habitats around the world.  At the same time, the planet’s wildlife is in a steep decline.  A recent study estimated that the populations of over 5,000 vertebrate species have declined by an average of nearly 70% since 1970.  A United Nations report warns that human activity has threatened as many as a million species with extinction.

With all of this as a background, there is climate change that is altering the habitats of the world’s species – warming lakes and oceans, turning forests into grasslands, tundra into woodland, and melting glaciers.  In response to these changes, living things are rearranging themselves, migrating to more hospitable locations.  But many species are just not capable of finding more suitable habitats on their own.

Conservationists are now increasingly considering the use of assisted migration. In some cases, when a species’ critical habitat has been irreversibly altered or destroyed, agencies are establishing experimental populations outside of the species’ historical range.  Such actions are often deemed extreme but may be increasingly necessary.

However, clear-cut cases are relatively rare.  More likely, it is a more difficult judgement call as to whether assisted migration is a good idea or is possibly a threat to the ecosystem of the species’ new location.  The relative dearth of assisted migration experiments is less likely a result of legal barriers than it is a lack of scientific and societal consensus on the practice. Scientists are now trying to develop risk-analysis frameworks that various agencies can use in considering potential assisted migration experiments. 

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Last Resort: Moving Endangered Species in Order to Save Them

Photo, posted March 18, 2010, courtesy of Jean via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Living Planet Index | Earth Wise

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The World Wildlife Fund and the Zoological Society of London recently published the latest Living Planet Index, which is designed to measure how animal populations are changing through time.  The purpose is to provide an assessment of the health of ecosystems and the state of biodiversity.

The LPI only looks at the population of vertebrates:  birds, mammals, reptiles, amphibians, and fish.  The latest survey looked at how populations have changed between 1970 and 2018.  The results are that populations of these animal groups have declined by an average of 69% over that 48-year period.

This result highlights a very real and very severe crisis of biodiversity loss.  However, it does not mean that there are 2/3 fewer animals today than 48 years ago.  The way the index is calculated is to look at the changes in individual populations of over 5,000 different species.  Then these individual relative declines are averaged to get the result.  

There are shortcomings in the LPI.  For example, individual species that have seen massive population declines will bring the average down.  But even removing the outliers both of a negative and a positive impact does not dramatically change the result.

There is no perfect indicator for biodiversity and ecosystem health.  The Living Planet Index is nonetheless a useful metric and indicates that many species around the world are in decline.  Policymakers and environmental advocates need to make decisions about conservation and protection measures and this index is one tool they can use.

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There’s a frightening new report about wildlife declines. But many are getting the story wrong.

Photo, posted October 12, 2019, courtesy of Visit Rwanda 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.

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.

Living in a Carbon Bubble | Earth Wise

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The earth’s atmosphere is a little over 0.04% carbon dioxide, currently about 420 parts per million.  That’s more than it’s been in millions of years and is changing our climate.  But these levels of CO2 are not enough to directly affect people.

However, people are sensitive to the amount of carbon dioxide they are breathing.  It is actually an indoor pollutant.  High concentrations have been shown to reduce our cognitive performance, our health, and our comfort.  For example, a study in 2012 showed that performance in a variety of cognitive function tests was reduced by 12% when CO2 levels reached 1,000 parts per million and by 51% at 2,500 ppm.

How common are high levels of carbon dioxide?  Pretty common.  Offices often have CO2 levels of 600 ppm or higher, but 5% of US offices have average concentration about 1000 ppm and some conference rooms can reach 1900 ppm.  Classrooms often reach average levels above 1000 ppm.  Passenger aircraft have average levels around 1400 ppm during flight, and can peak over 4,000 ppm.  Cars with one occupant with the windows closed and the air recirculating have levels above 4,000 ppm. 

Where does it all come from?  From us.  We exhale CO2 and if we are in enclosed spaces with insufficient air circulation and ventilation, we end up living in a carbon dioxide bubble.  Most of us live with high CO2 levels – all day and every day.  It is a form of indoor pollution that has not gotten enough attention.

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I’m living in a carbon bubble. Literally.

Photo, posted October 24, 2013, courtesy of Cory W. Watts via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of Urban Green Spaces | Earth Wise

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Projections are that 68% of the global population will be living in cities by 2050.  It is therefore not surprising that urban green spaces are critically important for promoting mental and physical well-being.

An international study, published in Science Advances, took soil samples from different types of urban green spaces and comparable neighboring natural ecosystems in 56 cities from 17 countries across six continents.

The study concluded that even roadside plantings contribute a range of important microbial communities that are critical for sustaining productive ecosystems services, such as filtering pollutants and sequestering carbon dioxide.

Parks and gardens constitute most of the open spaces available for recreational activities in cities and play important roles in curbing pollution, reducing noise, and lowering air temperatures.

In addition, human exposure to soil microbes has been shown to be beneficial to human health by promoting effective immunoregulation functions and reducing allergies. The study found that city parks and even roadside plantings support a great variety of different microbes that are different from natural ecosystems. 

We think of roadsides as being barren but the vegetation along footpaths and roadsides are important microbial habitats.  Some European cities, such as Bern in Switzerland, have instituted policies to protect the natural vegetation along footpaths and roadsides.

The new study is a part of a series of research efforts looking at the important of green spaces for ecosystem health.  As the world becomes increasingly urbanized, every bit of greenery in cities and highways is important and is needed for sustaining a healthy environment.

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Every spot of urban green space counts

Photo, posted June 3, 2013, courtesy of Manuel MV via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Living On Trash | Earth Wise

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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.

Cell-Based Meat And Seafood | Earth Wise

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We have heard about laboratory meat for a number of years, generally in terms of something that may happen at some point in the indeterminate future. But at least for a couple of California companies, that future is now.

These high-tech companies are producing products – real meat and seafood – that are originally cultured from animal cells but are made without the actual animal.

San Francisco-based Eat Just makes chicken nuggets that have recently gained regulatory approval in Singapore and are now available to order at a downtown restaurant.  San Diego’s BlueNalu creates cell-based seafood fillets including yellowtail, mahi-mahi, red snapper, and tuna.

The companies use stem cells obtained from actual animals and cultivate them in steel tanks with the same nutrients that living animals consume.  The original cell donor is not sacrificed.  The harvested cells multiply and are eventually shaped to form meat or fish that cooks, looks, and tastes just like its natural counterpart.

The “mouth feel” of conventional meat or fish can be mimicked by recreating the same proportions of muscle, fat, and connective tissue in the cell-based product.  Eat Just says their product cooks, looks, and tastes like chicken because it is chicken.  BlueNalu says their product has all the same characteristics as fish because it is fish.

These products have major environmental, safety, and ethical advantages.  The big question is whether people will eat them.  Is there an “ick factor” to overcome?  Ultimately, the key thing is how they taste.  If they pass muster on that score and cell-based meats and seafood are scaled up and accepted, we can have the nutritional and sensory advantages of meat proteins without the environmental, ethical and safety disadvantages.

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Can We Enjoy Meat and Seafood and Save the Planet?

Photo, posted February 1, 2012, courtesy of Andrea Parrish-Geyer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

PFAS In The Food Chain | Earth Wise

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Per- and polyfluoroalkyl substances (PFAS) are a family of human-made chemicals that have been manufactured and used in a variety of industries around the globe.  PFOA and PFOS have been the most extensively produced and the most extensively studied of these chemicals. 

Exposure to PFAS has been linked to a host of adverse health effects, including thyroid hormone disruption and cancer.

PFAS compounds can be found in such things as non-stick cookware, stain-resistant carpets, water-repellent outdoor gear, and food packaging, like fast food wrappers and microwave popcorn bags. 

According to a new study, researchers from North Carolina State University have found PFAS substances in every step of the Yadkin-Pee Dee River food chain, even though the river doesn’t have a known industrial input of these compounds. 

The team collected water, sediment, algae, plant, insect, fish, crayfish, and mollusk samples at five sites along the river and analyzed them for 14 different PFAS compounds.  Nearly every sample tested contained PFAS compounds.  Biofilm contained the largest concentrations of 10 of the 14 PFAS compounds measured.  Insects, which primarily eat biofilm, had the greatest accumulation of PFAS compounds of all the living taxa the researchers sampled. 

When PFAS compounds are present at every step of the food chain, the compounds accumulate at each step leading to greater concentrations in animals that sit higher on the food chain – including humans.  This is known as biomagnification. 

Studies like this that reveal how prevalent PFAS can be within ecosystems without an industrial input highlight the need for further research into how these compounds affect the environment and human health.

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PFAS present throughout the Yadkin-Pee Dee river food chain

Photo, posted May 24, 2011, courtesy of the U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Living In Extreme Heat | Earth Wise

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Global climate change has already left observable effects on the planet.  Glaciers have shrunk, trees are flowering sooner, plant and animal ranges have shifted, and so on. Many effects of climate change that scientists had predicted in the past are now occurring.  The loss of sea ice, intensifying heat waves, and accelerating sea level rise are some examples.

According to a new study recently published in the journal Proceedings of the National Academy of Sciences, climate change is going to affect humans earlier, harder, and more widely than previously projected.  The research team found that one billion people will be either displaced or endure insufferable heat for every one degree Celsius rise in global temperatures.  

Under a worst case climate scenario, land that one third of the world’s population currently calls home will be as hot as the hottest parts of the Sahara desert within 50 years.  Even under a more optimistic climate outlook, 1.2 billion people will still be exposed to temperatures outside the climate niche in which humans have thrived for at least 6,000 years.

The majority of the human population has always lived in regions where the average annual temperatures were between 43 degrees Fahrenheit and 82 degrees Fahrenheit.  These are ideal temperatures for human health and for food production.  But this temperature range is shrinking and shifting as a result of climate change. 

The study’s authors predict there will be more change in the next 50 years than there has been in the past 6,000 years.  They hope their findings will convince policymakers to accelerate their plans for emissions reductions and other climate mitigation strategies.   

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Future of the human climate niche

One billion people will live in insufferable heat within 50 years – study

Photo, posted November 22, 2008, courtesy of Ronnie Finger via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Thoreau And Climate Change

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Henry David Thoreau was a 19th-century American naturalist, philosopher, poet, essayist, and social reformer.  He is best known for “Civil Disobedience,” an essay advocating for the rebellion against an unjust government, and for “Walden,” a book about his experiences living simply in nature.  Now, Thoreau’s observations from “Walden” are the foundation of a new study exploring the effects of climate change on tree leaf-out and the emergence of spring wildflowers. 

This research, which was recently published in the journal Ecology Letters, relies on Thoreau’s scientific observations gathered during the 1850s when he spent 26 months living in isolation at Walden Pond in Concord, Massachusetts.  These observations from Thoreau were combined with current research to measure tree and wildflower leaf-out dates for 37 different years between 1852 and 2018.  “Leaf out” refers to the time in spring when plants and trees begin producing leaves.  An alteration in this timing can have a domino effect throughout an ecosystem.

Over the past century, temperatures in Concord, Massachusetts have warmed five degrees Fahrenheit.  As a result, leaf-out dates have changed significantly.  According to researchers, wildflowers are leafing out about one week earlier, while trees are leafing out about two weeks earlier than they did 160 years ago. 

Ground-dwelling plants like wildflowers have a narrow window to accomplish growth, photosynthesis, and reproduction, before the canopy trees leaf out and block the sunlight.  Temperature-driven shifts in the timing of tree leaf-out between Thoreau’s time and now are likely already hindering wildflower abundance and flowering. 

As the climate continues to warm, the already small window of time between wildflower emergence and tree leaf-out will likely shorten further. 

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Using Thoreau, scientists measure the impact of climate change on wildflowers

Photo, posted August 13, 2008, courtesy of Adam Pieniazek via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Energy Intensity

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Every stage of civilization is characterized by its use of energy.   From burning wood to steam engines to our electrified society, energy is behind everything we do.  Over time, human society has become increasingly energy intensive.  As our standards of living have improved and as we overcome the effects of weather – either cold or warm – it takes more and more energy to live the lives we lead.

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