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Tree-Planting Is Not Necessarily A Good Thing | Earth Wise

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There is no question that forests have a major role in efforts to combat climate change as well as to slow biodiversity loss.   As a result, tree-planting on a massive scale has gained traction as a strategy and there have been major commitments made to plant billions of trees around the world.

A new study at Stanford University has rigorously analyzed the potential effects of these efforts and has found some significant problems.  For example, the Bonn Challenge, which seeks to restore an area of forest more than eight times the size of California over the next 10 years, has 80% of its commitments in the form of  planting monoculture tree plantations or a limited mix of trees that produce fruit and rubber, rather than restoring natural forests.   The problem is that plantations have significantly less potential for carbon sequestration, habitat creation, and erosion control than natural forests.  The potential benefits of the planting dwindle further if planted trees replace natural flora – forests, grasslands, or savannahs – which are ecosystems that have evolved to support local biodiversity.

The study looked at previous policies that created subsidies for planting trees.  Chile’s Decree Law, in effect from 1974 to 2012, has served as a model for similar policies in a number of countries.  Those subsidies further reduced native forest cover by encouraging the establishment of plantations in places where forests might have naturally regenerated.  The subsidies expanded the area covered by trees, but decreased the area of native forests.

The study recommends that nations should design and enforce their forest subsidy policies to avoid undesirable ecological impacts and actually promote the recovery of carbon- and biodiversity-rich ecosystems.

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Poorly designed tree-planting campaigns could do more harm than good, according to Stanford researcher and others

Photo, posted April 28, 2016, courtesy of the U.S. Department of State via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Making Use Of Invasive Seaweed | Earth Wise

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In recent years, millions of tons of brown Sargassum seaweed have formed gigantic blooms stretching all the way across the Atlantic Ocean from West Africa to the Gulf of Mexico.  The seaweed has become a problem for shorelines in the Caribbean, the Gulf of Mexico, and the east coast of Florida.  The massive increase in seaweed populations is related to changes in ocean chemistry resulting from nutrients from fertilizer use entering the water as well as from changes to the climate affecting ocean currents and temperatures.  The seaweed is harming the tourism industry as well as fisheries and ocean ecosystems.

Cleaning up the seaweed that washes ashore is labor-intensive and therefore expensive.  A research team led by two British universities has developed a cheap and simple way to pre-process seaweed to facilitate making it into bulk chemicals and biofuels.  With the new process, cleaning up the seaweed can be both economically and environmentally viable.

Previous techniques for processing seaweed generally required removing it from the saltwater, washing it in fresh water, and drying it – all of which add significant costs.  The new technique makes use of catalysts to release sugars from untreated seaweed that feed a yeast to produce a palm oil substitute.  At the same time, the process creates heat and pressure, turning the residual materials into a bio-oil that can be processed further into fuels, and a high-quality, low-cost fertilizer.

Apart from getting economic value out of the seaweed that is collected, any plastic collected alongside the seaweed can be converted to useful materials as well. 

It appears that the seaweed scourge is here to stay, so finding an economically viable way to deal with it is a welcome development.

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Solve invasive seaweed problem by turning it into biofuels and fertilisers

Photo, posted August 10, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Microplastics And Florida’s Birds of Prey | Earth Wise

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Plastic debris comes in all different shapes and sizes, but those that are less than five millimeters in length are called microplastics.  Some microplastics come from larger plastic debris that degrades into smaller bits over time.  Another type of microplastics – called microbeads – are intentionally manufactured tiny plastic beads that are added as exfoliants to some health and beauty products. 

According to a new study published in the journal Environmental Pollution, researchers have confirmed and quantified the presence of microplastics in terrestrial and aquatic birds of prey in Florida for the first time.  This research is important because these birds of prey, including ospreys, hawks, and owls, are critical to maintaining a healthy ecosystem.  The accumulation of microplastics in their digestive systems could lead to a myriad of health issues, including starvation.  

Working with the Audubon Center for Birds of Prey in Florida, the research team from the University of Central Florida was able to examine the stomachs of 63 deceased birds.  The team found microplastics in every bird it examined, extracting nearly 1,200 pieces of plastic in total.  Microfibers represented 86% of the plastic pieces. 

It’s common for plastic microfibers to enter ecosystems through the wastewater from washing machines.  A 2016 study found that 700,000 plastic fibers come off in a typical wash.  While there are lots of variables, synthetic fabrics account for 60% of the material used in clothing worldwide. 

To help cut down on plastic in the environment, the research team suggests removing plastics from open landfills, purchasing only natural fabrics and clothing, and modifying water treatment facilities to capture microplastics. 

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Microplastics found in Florida’s birds of prey for first time

Photo, posted April 15, 2016, courtesy of Andy Morffew via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Planting Trees and Climate Change | Earth Wise

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Forests are among the most important natural carbon sinks.  Trees remove carbon from the air and store it in their trunks, branches, and leaves, and transfer part of it into the soil.  But in some regions, these natural carbon sinks are starting to weaken due to deforestation, forest degradation, and the impacts of climate change.  This problem has led some climate mitigation projects to focus on increasing the overall number of trees on the planet. 

But, according to a paper recently published in the journal Science, “we can’t plant our way out of climate change.”  That’s the simple message from Restoration Ecologist Karen Holl and University of São Paulo Professor Pedro Brancalion to anyone who thinks planting one trillion trees will reverse the effects of climate change.  They say planting more trees is only one piece of the puzzle.  Any initiatives like 1t.org or the Trillion Tree Campaign must be done carefully and be accompanied by commitments to long-term management.

Tree plantings can provide many environmental benefits, including improving water quality, biodiversity, and increasing shade.  But trees can sometimes have undesirable impacts, such as harming native species and ecosystems or reducing water availability, depending on where and how the trees are planted.

The authors suggest four principles that should guide forest enhancement initiatives: reduce forest clearing and degradation, balance ecological and social goals, view tree plantings as one part of a multifaceted solution, and plan, coordinate and monitor the work. 

While tree plantings can clearly be part of the solution, slowing the pace of climate change requires a comprehensive approach that must start with burning less fossil fuels.

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Challenges in tree-planting programs

Planting trees is no panacea for climate change

Photo, posted December 1, 2019, courtesy of Akuppa John Wigham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sea Turtles Prospering During The Shutdown | Earth Wise

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

Seven different species of sea turtles are found in the world’s oceans and play important roles in marine ecosystems.  Over time, human activities have tipped the scales against the survival of these animals.  They have been hunted for their eggs, meat, skin, and shells and face habitat destruction and accidental capture in fishing gear.  Their nesting grounds in beaches are constantly disturbed and endangered by human activity.

With the beaches in Florida closed in the effort to stop the spread of coronavirus, there is less plastic waste, fewer people and vehicles, and fewer artificial lights on the beach that disorient emerging turtle hatchlings.  Because of all of these factors, sea turtles have been building their nests without disruptions.

In April, it was nesting season for leatherback turtles, the largest of all sea turtles. In May, loggerhead turtles arrive in Florida.  Later in the summer, green turtles will arrive.

It takes about 60 days for sea turtle eggs to incubate and to hatch.  During that period, lots of things can happen to a nest on an active beach – it can get trampled, people can dig it up, and artificial light can confuse the hatchlings as they try to find their way to the water.  With the current shutdown, it should be a productive nesting season for sea turtles.

On the other hand, when beaches reopen, there may well be a major influx of people flocking to the beach because they have been stuck indoors for an extended period of time.

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Sea turtles are thriving as coronavirus lockdown empties Florida beaches

Photo, posted August 9, 2016, courtesy of Florida Fish and Wildlife via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Too Many Bison | Earth Wise

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The population of large herbivores in Yellowstone National Park has undergone many dramatic changes over the course of time.  The numbers of both the iconic Rocky Mountain elk and bison have gone up and down as a result of human interactions.

Bison, of course, once were a dominant species from east of the Appalachians to west of the Rocky Mountains, with most of an estimated 30 million living on the Great Plains.  As the west was settled, bison populations plummeted and by the late 1800s, they were nearly extinct.

When Yellowstone was established, there were exactly 22 bison in the park.  By 1925, there were more than 750 in the park and culling of the herd in the park’s Lamar Valley was practiced for the next four decades.

The elimination of predators like grey wolves and cougars in the early 1900s caused both elk and bison populations to mushroom and both underwent culling.  When culling was ended in 1968, there were 4,000 elk and 100 bison.  Within 20 years, those numbers were 20,000 and 1,000.   Reintroducing wolves and cougars reduced the elk population to about 5,000, but bison numbers have continued to grow, now reaching about 4,000.

While the long-term recovery of the Yellowstone bison herd is a major conservation success story, the fact is that bison are powerful ecosystem engineers.  Large numbers of them disrupt species distribution across scrub steppe and grasslands because of what they eat, trample, and rub their horns and bodies on.  They have a tremendous capacity to limit the structure and composition of ecosystems.

Park administrators have complicated management decisions to make to take into account the often wide range of ecological effects that abundant large herbivores can have on ecosystems.

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Bison in northern Yellowstone proving to be too much of a good thing

Photo, posted August 10, 2016, courtesy of Brian Gratwicke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Conservation In Vermont | Earth Wise

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In recent times, Vermont and neighboring states have been losing forest land to development at a rate of almost 1,500 acres per year.  With forest fragmentation gaining ground across New England, conserving land for future generations of people, wildlife, and plants has become both increasingly important and increasingly difficult.

According to a new study published by researchers at the University of Vermont, the state has already protected a third of the highest priority targeted lands needed to protect and connect valuable wildlife habitats and corridors.  The protected lands amount to 1.3 million acres.

Most of the currently conserved lands are forested.  However, there are high-priority targeted surface water and riparian areas – ponds, rivers, shorelines, and wetlands – and not nearly enough of these have been protected.  (Many animals require zones along waterways in which to travel between the habitats they need to survive).

The state of Vermont and a number of partners have laid out a comprehensive and thoughtful vision that would ensure that Vermont remains a good place for all forms of life in the future.  The new study provides a crucial benchmark of current levels of forest protection to help prioritize future conservation actions. 

Three groups dominate in responsibility for the state’s protected lands:  the federal government, the state government, and private non-profit organizations.  (Each of these account for roughly a third of existing protected lands).

Going forward, Vermont’s nonprofits will play an increasingly important role in land conservation, especially in continuing to protect those areas that are rich with species diversity.  Nonprofits are engaging more and more deeply in restoring wetlands that were previously degraded, planting new forests along river shores, and protecting unique natural communities while also protecting working forests and farmland.

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Vermont Has Conserved One Third of the Land Needed for an Ecologically Functional Future

Photo, posted June 15, 2014, courtesy of Wesley Carr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Hidden Source Of Arctic Carbon | Earth Wise

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Researchers from the University of Texas at Austin, the U.S. Fish and Wildlife Service, and Florida State University have published a paper presenting evidence of significant and previously undetected concentrations and fluxes of dissolved organic matter entering Arctic coastal waters.  The source of the organic matter is groundwater flow atop the frozen permafrost.  The groundwater moves from land to sea unseen, but the new research reveals that it carries significant concentrations of carbon and other nutrients to Arctic coastal food webs.

Globally, groundwater is important for delivering carbon and other nutrients to oceans, but in the Arctic, where much water is trapped in the permafrost, its role was thought to be minimal.  But the new research reveals that groundwater may be contributing an amount of dissolved organic matter to the Alaskan Beaufort Sea that is comparable to what comes from neighboring rivers during the summer.

The researchers found that shallow groundwater flows beneath the surface and picks up new, young organic carbon and nitrogen, but it also mixes with layers of deeper soils and thawing permafrost, picking up and transporting century-to-millennia old organic carbon and nitrogen.  This material is unique because it is directly transported to the ocean without seeing or being photodegraded by sunlight and may be valuable as a food source to bacteria and higher organisms that live in Arctic coastal waters.

The study concluded that the supply of leachable organic carbon from groundwater amounts to as much as 70% of the dissolved organic matter that enters the Beaufort Sea from rivers during the summer.  The role that groundwater inputs play in Arctic coastal ecosystems will be an area of active research for years to come.

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Hidden Source of Carbon Found at the Arctic Coast

Photo, posted June 14, 2015, courtesy of Eugen Marculesco via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving The Arctic Permafrost | Earth Wise

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Permafrost is frozen ground – a combination of soil, rock, sand, and ice – that remains at or below freezing for at least two consecutive years.  Approximately 25% of the land in the Northern Hemisphere meets this criterion, the majority of which can be found in northern Russia, Canada, Alaska, Iceland, and Scandinavia.

But as a result of the changing climate, these permafrost soils in the Arctic are beginning to thaw.  As they thaw, large quantities of greenhouse gases could be released, further accelerating climate change.  

A new study recently published in the journal Scientific Reports explores an unconventional countermeasure: resettling massive herds of large herbivores.  According to researchers from the University of Hamburg in Germany, herds of horses, bison, and reindeer could be used to significantly slow the loss of permafrost soils. 

During Arctic winters, the air temperature is often much colder than the permafrost.  Thick layers of snow can insulate the ground from the frigid air, keeping the permafrost warm (relatively speaking). But when the snow cover is scattered and compressed by the hooves of grazing animals, the insulating effect is reduced, which intensifies the freezing of the permafrost.

If climate change continues unchecked, the research team expects permafrost temperatures to rise 3.8-degrees Celsius.  This would result in half of the world’s permafrost thawing by the year 2100.  But in contrast, researchers found that the permafrost would only warm by 2.1 degrees Celsius with the resettled animals.  This 44% reduction in permafrost temperature would preserve 80% of the existing permafrost by 2100.

Natural manipulations of ecosystems could have tremendous results. 

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How horses can save the permafrost

Photo, posted July 17, 2012, courtesy of Kitty Terwolbeck via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Foods of the Future? | Earth Wise

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In a world where many go hungry in the context of rapidly changing environments, many experts contend that alternative food sources will be necessary to solve global food security problems.  So-called novel food sources are central to this conversation, defined as foods with no history of consumption in a region – or perhaps anywhere.

Three popular examples are lab-grown meat, insect farming, and seaweed aquaculture.  Each of these offer opportunities as well as challenges.

Lab-grown meat can refer to actual animal tissues raised in vats as well as the increasingly common cultured plant products made to resemble meat.  Lab-grown meat faces push back from the livestock industry that contends it should not be labeled as any kind of meat. While results to date are positive, barriers still remain including concerns over product taste, healthiness, and cost.  And while less land- and water-intensive than conventional livestock, cultured meat production is still energy intensive.

Insects do form a significant part of diets across the globe but have yet to be embraced in any substantial way in western cultures.  Nutritionally, numerous species of insects are rich in key proteins, micronutrients, and minerals.  But the “yuck factor” is a big barrier to cross.

Seaweed is a long-established part of many East Asian diets and has many potential dietary uses.  Several selectively bred varieties of seaweed supply a range of valuable nutrients.  Growing seaweed does not tax freshwater and terrestrial resources.  But intensively cultivated seaweeds would have potential negative effects on local marine ecosystems.

There is no single solution to complex issues like food security.  Novel foods may very well form part of the solution to a growing food crisis.

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Insects, seaweed and lab-grown meat could be the foods of the future

Photo, posted March 12, 2009, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tough Times For Fireflies | Earth Wise

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

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

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

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

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

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

We can’t afford for fireflies to go dark. 

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A Global Perspective on Firefly Extinction Threats

Fireflies Have a Mating Problem: The Lights Are Always On

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

Earth Wise is a production of WAMC Northeast Public Radio.

Native Species Or Invasive Species? | Earth Wise

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For decades, conservation biology has characterized the movement of species into new habitats as potential invasions of alien species that pose serious dangers to local ecosystems and resident species.  Wild species are classified as either native or alien.  But this way of looking at the natural world is becoming increasingly controversial.

As the world warms, a mass exodus of tens of thousands of species is transforming the distribution of biodiversity.  Scientists have documented countless species shifting their ranges towards the poles, higher up into the mountains, and deeper into the oceans in response to the changing climate.

Deciduous shrubs have spread into the Arctic tundra.  Tropical fish have arrived in the kelp forests of the eastern Mediterranean. 

A growing number of scientists now say that continuing to base conservation policy on the native-alien dichotomy may actually endanger biodiversity.  The climate-driven range shifts may be the only way for many species to survive.  Furthermore, only a small fraction of new arrivals may actually endanger resident species and ecosystems.

There are real distinctions between climate-displaced species and disruptive alien species introduced through global trade and travel.  Among other things, climate-displaced species tend to shift their ranges alongside other species they have co-evolved with.

There is talk of establishing a Climate Change Redistribution Treaty that would create a transnational system to manage species shifting across geopolitical and biogeographical borders.  The assumptions traditionally made as to which species to protect, which to leave to their own devices,  and which to eradicate are no longer valid and the time has come to base conservation policies on the new reality.

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Native Species or Invasive? The Distinction Blurs as the World Warms

Photo, posted March 21, 2011, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Permafrost | Earth Wise

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The Arctic is warming faster than any region on Earth and mostly we’ve been hearing about the rapid disappearance of Arctic sea ice.  But the land in the Arctic is also undergoing major changes, especially to the permafrost that has been there for millennia.

Permafrost occurs in areas where the temperature of the ground remains below freezing for two years or more.  About a quarter of the Northern Hemisphere’s landscape meets this criterion.  Most of the world’s permafrost is found in northern Russia, Canada, Alaska, Iceland, and Scandinavia.

Permafrost regions previously carpeted in cranberries, blueberries, shrubs, sedges, and lichen are now being transformed into nothing but mud, silt, and peat.  So-called regressive thaw slumps – essentially landslides – are creating large craters in the landscape.  (The Batagaika Crater in the Yana River Basin of Siberia is a kilometer long and 100 meters deep).

Apart from the violence being done to the Arctic landscape, the greatest concern is that the permafrost has locked in huge stores of greenhouse gases, including methane, carbon dioxide, and nitrous oxide.  It is estimated that the permafrost contains twice as much carbon as is currently contained in the atmosphere.  As the permafrost thaws, these gases will be released.  With them will be pathogens from bygone millennia whose impact cannot be predicted.  Climatologists estimate that 40% of the permafrost could be gone by the end of the century.

As the permafrost thaws, the region’s ecosystems are changing, making it increasingly difficult for subsistence indigenous people and Arctic animals to find food.  Landslides are causing stream flows to change, lakes to suddenly drain, seashores to collapse, and water chemistry to be altered.

The warming Arctic is about much more than disappearing sea ice.

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How Thawing Permafrost Is Beginning to Transform the Arctic

Photo, posted February 9, 2017, courtesy of the U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Engineering Mosquitoes | Earth Wise

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Tropical regions grapple with the spread of diseases – such as dengue, yellow fever, zika, chikungunya, and malaria – by mosquitoes.  A fairly successful strategy has been the Sterile Insect Technique, which is essentially insect birth control. The process involves rearing large quantities of sterilized male mosquitoes in dedicated facilities, and then releasing them to mate with females in the wild. As they do not produce any offspring, the insect population declines over time.

A problem with this approach is that while mosquitoes create health problems for people, they also play important roles in various ecosystems, such as providing food for bats and other animals.  Eliminating mosquito populations on a large scale can trigger major changes in ecosystems.

Recently, an international team of scientists has synthetically engineered mosquitoes that halt the transmission of the dengue virus.  They genetically engineered mosquitoes with an antibody “cargo” that gets expressed in the female mosquitoes that spread the dengue virus.  Once the female mosquito takes in blood, the antibody is activated which hinders the replication of the virus and prevents its dissemination throughout the mosquito, thereby preventing its transmission to humans. Essentially, what the researchers have done is transfer genes from the human immune system to confer immunity to mosquitoes.  The researchers are testing methods to neutralize mosquitoes against other viruses they spread.

This opens up a whole new approach to interrupt mosquito-borne human diseases.  Mosquitoes are among the deadliest killers on the planet because they are the messengers that transmit deadly diseases.  Until now, the only real solution has been to kill the messenger.  The new approach may be a better way to deal with a serious problem.

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Mosquitoes engineered to repel dengue virus

Photo, posted June 20, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bird Migration And Climate Change | Earth Wise

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A new study of bird migration shows the migration patterns are shifting as a result of climate change.   Researchers at Colorado State University, the University of Massachusetts, and the Cornell Lab of Ornithology, looked at the impacts of climate change on a continental scale.

The team looked at the nocturnal migratory behaviors of hundreds of species representing billions of birds using radar and other data.  They found that spring migrants are likely to pass certain stops earlier now than they would have 20 years ago.  Temperature and migration timing are closely aligned and the greatest changes in migration timing are occurring in regions warming most rapidly.  During the fall, shifts in migration were less apparent.

Migratory birds play an important role in ecosystems.  They consume insects, disperse seeds, and perform various other significant functions. Birds serve as critical metrics of the health of ecosystems.

Bird migration is a global phenomenon that can provide unique visibility into changes in the climate.  The ability to look at it on a global scale has only recently become practical as a result of big data technology and cloud computing.  The team was able to crunch the numbers for the study in 48 hours, a task that previously would have taken over a year of continuous computing.

The findings have implications for understanding future patterns of bird migration because birds depend on food and other resources as they travel.  As the climate changes, the timing of blooming vegetation or the emergence of insects may end up out of sync with the passage of migratory birds.  This could have negative consequences for the health of migratory birds.

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Bird migration timing skewed by climate, new research finds

Photo, posted November 5, 2019, courtesy of Jerry Kirkhart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Community Action And Coral Reefs

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Coral reef habitats are some of the densest and most varied ecosystems on earth.  While coral reefs cover just 0.2% of the ocean floor, scientists estimate that nearly one million different species of fish, invertebrates, and algae can be found in or around coral reefs. 

However, climate change is wreaking havoc on the health of coral reefs.  Warming and acidifying oceans are resulting in enormous coral losses.  Overfishing, development, and pollution are also threatening coral reef health.

According to new research, positive community action can help boost fish populations in coral reefs and safeguard future fish numbers.  The paper, which was recently published in the journal Proceedings of the National Academy of Sciences, details the social and ecological outcomes of work being done in Papua New Guinea since 2001. 

These communities have established a traditional system of rotational fishing closures in order to manage their fisheries resources.   They ban fishing on part of their reefs for a few years, and then open these closures when village elders believe fish behavior has changed and fish populations have recovered.  They then close a different part of their reefs, and repeat the process. 

The researchers found that these rotational practices resulted in more than twice as many fish on the closed reefs as compared to open ones, and the closures made fish less scared of people and easier to catch.  But the researchers did caution that this short term boost in fish numbers may not be enough to stop the overall impact of fishing.

Globally, more than 500 million people depend on coral reefs for food, income, and coastal protection.  Balancing community needs with environmental needs can be tricky business.  

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Positive community action can help coral reef health

Photo, posted October 11, 2011, courtesy of Paul Toogood via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bioacoustics

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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.

Removing Dams Restores Ecosystems

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In many parts of the country, dams that sometimes date back as much as 100 years are being removed and are giving way to the revival of migratory fish and their river ecosystems.  Since 1912, more than 1,600 dams have been removed in the U.S., but the pace of dam removal has greatly picked up in recent years.  2017 and 2018 were the highest years ever with 91 and 99 dams removed, respectively.

When dams are removed, the response from migratory fish can be almost immediate.  A large dam removal project on the Penobscot River in Maine in 2012 opened up 1,000 miles of habitat with a quick return of shad and alewives, followed by salmon.

In 2022, four large dams across the Klamath River will be removed.  The dams, which are located at the California and Oregon border, were facing an expensive re-licensing process and, because of their age, could no longer be run at a profit.

Re-licensing the dams along the Klamath was going to cost as much as $400 million.  On the other hand, uncapping the Klamath River has tremendous commercial and tourism potential.  Two states, tribal nations, and other stakeholders have all seen the virtues of restoring the landscape to its original form.

Opposition to dam removal is typically driven by aesthetics or recreational preferences.  But dam economics are getting increasingly worse.  Now that electricity can be produced far more cheaply with wind and solar power, many American dams have become artifacts of an older manufacturing era.  Meanwhile, rural towns near decommissioned dams are likely to now have more robust fishing industries.

In rivers big and small, migratory fish and river ecosystems surge back to life as old energy structures are taken down.

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Take Down That Dam: River Ecosystems Bounce Back As Removals Soar

Photo, posted June 11, 2016, courtesy of the Bureau of Land Management via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Refugee Corals

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As climate change warms the ocean, subtropical environments are becoming more favorable for corals than the equatorial waters where they traditionally thrived.  As a result, drifting coral larvae are settling and growing in new regions.

According to new research in the journal Marine Ecology Progress Series, the number of young corals on tropical reefs has declined by 85% over the past 40 years.  At the same time, the numbers on subtropical reefs has doubled.

Only certain types of coral can reach these new subtropical locations.  That depends on how far the microscopic larvae can swim and drift on currents before they exhaust their limited fat stores.  Thus, the reef ecosystems that develop have new blends of species that have previously never coexisted.  It is not clear how long it will take for the new systems to reach equilibrium.

Coral reefs are complicated systems that depend on the interplay between species to enable their healthy functioning.  Apart from the corals themselves, there are the coraline algae that symbiotically coexist with them.  How all of this will play out in these evolving ecosystems is unknown.

In the meantime, the research has found that these refugee corals are settling at latitudes up to 35 degrees both north and south of the equator.  It is no longer so clear what constitute native species in the reefs.  It remains to be seen whether new reefs in subtropical oceans can support the incredible biodiversity seen in tropical reefs.  But ultimately, these changing ecosystems could potentially bring new resources and opportunities, such as fishing and tourism, to places where they never existed before.

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Coral Reefs Shifting Away from Equatorial Waters

Photo, posted March 22, 2011, courtesy of Simone Lovati via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shifting Ecosystems

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The Great Plains ecosystem has been shifting northward over the past fifty years, driven by climate change, wildfire suppression, energy development, land use changes, and urbanization.  The ecosystem is an area historically rich with grasslands and shrub steppe and is prime habitat for grassland birds.

According to a recent study published in the journal Nature Climate Change, the northernmost ecosystem boundary of the Great Plains has moved more than 365 miles north since 1970, amounting to about 8 miles a year.  The region’s southernmost ecosystem boundary has shifted 160 miles north, or about 4 miles a year.

The study used bird distribution data as an indicator of shifting ecosystem boundaries.  The researchers analyzed 46 years of data for 400 bird species across a 250-mile-wide strip stretching from Texas to North Dakota.  They tracked how the birds’ distributions changed as a measure of how these ecosystems were shifting.

While climate change has been a major driver of these ecosystem shifts since the 1970s, several other factors such as wildfire trends, land use changes, and invasion of tree species into grassland habitat have also played a role.  Like most things in ecological systems, the changes are likely to have multiple causes.  One cannot really separate causes like tree invasions, warming climate, and wildfires, as they are all interrelated.

Using bird distribution patterns for tracking ecosystem shifts could be a useful tool for scientists and land managers in the coming decades to give them an early warning of how habitats are changing in response to rising global temperatures and therefore allow them to take action to protect vulnerable species.

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Great Plains’ Ecosystems Have Shifted 365 Miles Northward Since 1970

Photo, posted March 24, 2017, courtesy of Rick Bohn / USFWS 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...)