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The Cost Of Invasive Species | Earth Wise

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

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

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Species Moving North | Earth Wise

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Climate change is leading to warmer winter weather throughout the southern U.S., providing opportunities for many tropical plants and animals to move north.  A new study by scientists at UC Berkeley looked at the changing distribution of tropical species driven by the warming climate.

Some species are appreciated in their new locations, such as sea turtles and the Florida manatee, which are gradually moving northward along the Atlantic Coast.  Others, like the invasive Burmese python are not so welcome.  That goes double for many insects, such as the mosquitoes that carry diseases like the West Nile virus, Zika, dengue, and yellow fever, as well as beetles that destroy native trees.

The transition zone, northward of which experiences freezes every winter, has always been a barrier to species native to more temperate places.  For most organisms in such places, if they freeze, they die.  Cold snaps like the recent one in Texas usually don’t happen for decades and are now likely to be less and less frequent.  In the meantime, tropical species can get more and more of a foothold and maybe even develop populations that can tolerate more cold extremes in the future.

The warming climate is leading many plant species to expand their ranges, in some cases pushing out native species.  The general story is that the species that do really well are the more generalist species whose host plants or food sources are quite varied or widely distributed and can tolerate a wide range of conditions.  By definition, they tend to be the pest species.

We need to prepare for widespread shifts in the distribution of biodiversity as climate, including winter climate, changes.

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Tropical species are moving northward as winters warm

Photo, posted May 7, 2010, courtesy of Jim Reid / USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Nature Is Valuable | Earth Wise

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A study by the University of Vermont, the University of Cambridge, and several other institutions compared the value of protecting nature at particular locations with that of exploiting it.   The study concluded that the economic benefits of conserving or restoring natural sites outweigh the profit potential of converting them for intensive human use.

The study analyzed dozens of sites across the globe – from Kenya to Fiji and China to the UK across six continents.  It was published in the journal Nature Sustainability.

The analysis utilized a methodology devised ten years ago called TESSA (the Toolkit for Ecosystem Service Site-based Assessment) which enables users to measure, and in many cases, assign monetary values to services provided by sites – clean water, nature-based recreation, crop pollination, and so on.  This is then compared with the economic benefits that can be derived by converting the site for farming, logging, or other human uses.

A major economic benefit of natural sites comes from their ability to sequester carbon and thereby help regulate the quantity of greenhouse gases in the atmosphere.  If one assigns a value to global society of $31 a ton of carbon removed, over 70% of the sites surveyed had a greater value to society when kept natural rather than being converted.  Many scientists actually consider this carbon price to be conservative.  Nevertheless, if carbon is assigned the paltry cost of $5 a ton, 60% of the sites are still more valuable in their natural state.

Beyond these economic calculations, there is the pressing issue that current rates of habitat conversion are driving a species extinction crisis unprecedented in human history.  But even if one is only interested in dollars and cents, conserving and restoring nature is now very often the best bet for human prosperity.

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Economic Benefits of Protecting Nature Exceed Value of Exploiting it, Global Study Finds

Photo, posted June 7, 2017, courtesy of Mouli Choudari via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Oil Platforms And Biodiversity | Earth Wise

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We have previously reported on the important role that offshore oil platforms seem to play for fish.  In short, the support structures of offshore oil platforms that often rise hundreds of feet through the water column create essentially a prefabricated reef for marine life.

According to a new study recently published in the British journal Ecological Solutions and Evidence, the large gatherings of fish around oil and gas platforms attract harbour porpoises searching for food – despite the fact that noise from industrial activities normally scares porpoises away.    

Harbour porpoises are one of the smallest whale species and the only whale species that’s known to breed in Danish waters.  The species has been protected in Danish waters since 1967.  Previous studies have demonstrated that underwater noises from sources like shipping and industry typically scare porpoises away. 

But according to new research from scientists at Aarhus University in Denmark, there are actually more porpoises around the largest Danish oil platform – Dan F – in the North Sea than there are within the three to ten kilometers surrounding the platform.  The research team found that the platform acts as a natural reef where porpoises can find favorable habitat and food. 

Currently, the international OSPAR convention requires that all decommissioned oil and gas platforms be removed from the ocean.  But according to researchers, leaving the old platforms in the ocean to serve as artificial reefs is actually more beneficial to the marine environment. 

In the Gulf of Mexico, the United States program Rigs to Reefs has converted 558 oil and gas platforms into artificial reefs.

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Harbor porpoises attracted to oil platforms when searching for food

Photo, posted March 26, 2008, courtesy of Dave Herholz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Even The Common House Sparrow Is Declining | Earth Wise

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According to the first-ever comprehensive assessment of net bird populations published in 2019, nearly three billion birds have disappeared in the United States and Canada since 1970.  The study, by researchers from the Cornell University Lab of Ornithology, found that North American bird populations have lost 2.9 billion breeding adults during that timespan.  Forests lost one billion birds, and grassland birds declined 53%. 

According to a newer study from Cornell University, it appears that even the common house sparrow is declining.  In parts of its native range in Europe, house sparrow numbers are down nearly 60%.  Researchers from the Cornell Lab of Ornithology sought to clarify the status of the species in the U.S. and Canada by using 21 years of citizen science data collected through its Project Feederwatch program. 

Project FeederWatch is a winter-long survey of birds that visit feeders at backyards, nature centers, community areas, and other locales. For the study, which was recently published in the Wilson Journal of Ornithology, the research team reviewed recorded observations of house sparrows during their non-breeding season.  These sightings from nearly 12,500 sites were used and cross-referenced with the National Land Cover database to determine whether the U.S. sightings came from rural or urban locations.  

From 1995 to 2016, researchers found that Feederwatch sites reporting house sparrows declined 7.5%, and the mean flock sizes declined 22%.  House sparrow populations declined in urban areas, but actually remained stable in rural areas. 

The researchers say a lack of green space and nesting sites in urban areas are likely factors in the population declines. 

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Study finds even the common house sparrow is declining

Nearly 3 Billion Birds Gone

Photo, posted May 14, 2014, courtesy of Jacob Spinks 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.

Saving The Queen Conch | Earth Wise

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Queen conchs are large sea snails belonging to the same taxonomic group as clams, oysters, and squid.  They live on coral reefs or seagrass meadows in warm, shallow waters.  Queen conchs are found throughout the Caribbean Sea and Gulf of Mexico, ranging as far north as Bermuda and as far south as Brazil.

Reaching up to 12” long and living up to 40 years, the queen conch is prized as a delicacy and revered for its shell.  It’s the second most important sea-bottom fishery in the Caribbean region, trailing only the spiny lobster. 

But queen conchs face a challenge.  Their populations are in a steady rate of decline as a result of overfishing, habitat degradation, and hurricane damage.  In some places, the numbers are so low that remaining conchs cannot find breeding partners.  The situation is urgent from both an ecological and economical perspective. 

As a result, Megan Davis, a scientist from Florida Atlantic University who spent more than four decades researching queen conch, has released an 80-page, step-by-step user manual about how to care for the species. Her work was recently published in the National Shellfisheries Association’s Journal of Shellfish Research.

According to Davis, aquaculture, along with conservation of breeding populations and fishery management, are ways to help ensure longevity of the queen conch.  With requests for mariculture guidance pouring in from communities throughout the Caribbean, Davis and her collaborators are expanding their queen conch conservation, education, and restorative mariculture program.

Their desired outcomes include creating protected breeding areas, establishing sustainable hatcheries, and repopulating protected habitats.

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‘Hail to the queen’: Saving the Caribbean queen conch

Photo, posted June 3, 2012, courtesy of Christopher Gonzalez via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s Killing Orcas? | Earth Wise

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With their characteristic tall dorsal fins and black and white color patterns, orcas are one of the ocean’s most iconic species.  Measuring up to 32 feet long and weighing as much as 6 tons, orcas have one of the largest geographic distributions of any species.  They live in all latitudes, in all oceans, from the Arctic to Antarctica.    

While they are often referred to as killer whales, orcas are actually not whales at all.  Orcas are the largest dolphin species and one of the most powerful predators on the planet. 

But human interference has made life significantly more difficult for orcas in recent years.  According to pathology reports on more than 50 orcas stranded over nearly a decade in the northeast Pacific and around Hawaii, the predators face a myriad of mortal threats.  Many of those threats stem from human interactions. 

Researchers from the British Columbia Ministry of Agriculture analyzed these orca pathology reports in a new study, which was recently published in the journal PLOS ONE,.  Of 52 orcas stranded between 2004 and 2013, causes of death were determined for 42%. For example, one orca died after receiving a halibut hook injury. Two orcas died from the blunt force trauma of vessel strikes. While there was no singular common cause of death, the study found a common theme:  human-caused deaths occurred in every age class – from juveniles to adults.

The researchers also note that humans aren’t just indirectly hurting orcas with things like lack of salmon or legacy toxins.  Humans are also directly killing killer whales with boat strikes and fishing gear.   

These findings will help establish a baseline of information to assess future orca conservation efforts. 

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What’s killing killer whales?

Photo, posted July 5, 2009, courtesy of Rennett Stowe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Global Warming And Sea Turtle Births | Earth Wise

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Climate change is a serious threat to species whose sex is determined by temperature.  Among these are sea turtles.  Whether marine turtles are born male or female turns out to depend on the temperature of their nest during incubation.

Sea turtle nests need to be around 84.6 degrees Fahrenheit on average to produce a 50:50 sex ratio for embryos developing in eggs.  If temperatures are higher, embryos predominantly become female.  There is a transitional range of temperatures over which both males and females are produced.  Below that range, only males are produced; above that range, only females are produced.

According to recent research published in the journal Conservation Science and Practice, sand temperatures along the Red Sea exceeded the 84.6-degree threshold in all but one of the sites studied.  Some sites measured nearly 96 degrees.  The Red Sea region is home to five of the world’s seven species of sea turtles, including endangered green turtles and critically endangered hawksbill turtles.

Skewing the sex distribution of a species is a serious threat to the future survival of the population.

The Red Sea findings are similar to observations around the world.  In Florida, sea turtle hatchlings were born 100% female in seven out the past 10 years, and in the other three years, males only made up 10-20% of the brood.  In Australia’s Raine Island, the largest green turtle nesting ground in the Pacific Ocean, the ratio of female to male turtle hatchlings in 2018 was 116:1.

Marine turtles have been around since the late Triassic period and have adapted to previous climate shifts.  But the rapid pace of human-driven climate change is threatening the future survival of these creatures.

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Rising Temperatures Driving a Shift to All-Female Sea Turtle Populations

Photo, posted in October, 2005, courtesy of Frank_am_Main via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Palm Oil Replacement | Earth Wise

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In the 1990s, cardiovascular health issues associated with partially hydrogenated oils containing harmful trans fats became a focus of great concern.  As a result, food companies looked for substitutes and the alternative they identified was palm oil.  Its ability to remain solid at room temperature made it well suited for many food applications.  Unfortunately, that property stems from its high saturated fat content, which means it also increases the risk of coronary heart disease.

The widespread use of palm oil has also caused significant environmental problems.  Palm oil plantations have replaced millions of acres of tropical forests, destroying the habitat for numerous species and threatening biodiversity.

Other potential replacements for partially hydrogenated oils such as coconut oil tend to be more costly, limited in supply, and also high in saturated fats.

Food scientists at the University of Guelph in Ontario, Canada, recently demonstrated the use of enzymatic glycerolysis (EG) to turn liquid vegetable oils into solid fats.  Their process is able to produce solid fats with the textural and structural properties desired by consumers.

The process is fairly simple, relatively easy to scale up, and is amenable to smaller food production or even local production.  Using it would enable food producers to use all sorts of readily available vegetable oils that can be produced in parts of the world that are not necessarily tropical regions.

Palm oil use is not going to go away, but this work may point a way to help slow down the destruction of ecosystems and animal habitats as well lead to more sustainable and healthy food sources.

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U of G Food Scientists Find Palm Oil Alternative That’s Good for Human, Planet Health

Photo, posted February 21, 2010, courtesy of Craig Morey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Do Forests Grow Better With Our Help? | Earth Wise

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Tree planting has become a worldwide cause.  International calls to plant a trillion trees to combat climate change have led to multiple initiatives by countries around the world.  Even the current U.S. administration, with support from businesses and nonprofits has promised to plant over 800 million trees across an estimated 2.8 million acres.  Planting trees is widely seen to be a vital nature-based solution to climate change; a way of moderating its effects as the world works to reduce carbon emissions.  However, recent studies have created some pushback from that view.

The new studies are not opposed to trees.  What they have revealed is that allowing forests to grow back naturally is a better strategy than planting trees.  The new data has shown that, among other things, estimates of the rate of carbon accumulation by natural forest regrowth have on average been 32% too low and, for tropical forests, have been 53% too low.

A new study published in Nature identified 1.67 billion acres that could be set aside to allow trees to regrow.  It excludes land under cultivation or built on, along with various existing valuable ecosystems. 

Natural regrowth allows nature to select which tree species take hold and turns out to happen quite rapidly and in a widespread manner.  The great thing about natural restoration of forests is that it often requires nothing more than human inaction.  Because it requires no policy initiatives, investments, or oversight, data on its extent is rather scarce.  But the data we have reveals that wherever forests have been allowed to recover on their own, it appears to happen rapidly and with great success.

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Natural Debate: Do Forests Grow Better With Our Help or Without?

Photo, posted September 5, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Alien Species On The Rise | Earth Wise

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Alien species are species that are introduced, accidentally or intentionally, outside of their natural geographic range as a result of human activities.  More than 35,000 alien species have been recorded through 2005, which is the most recent year for which researchers have comprehensive global data. 

Some of the alien species go on to become invasive alien species, which can have damaging impacts on both ecosystems and economies.  In fact, alien species are one of the main drivers of plant and animal extinctions around the globe.  

According to a new study by an international research team involving University College London, the number of alien species, particularly insects, arthropods and birds, is expected to increase globally by 36% by 2050 when compared to 2005 levels.  The research was recently published in the journal Global Change Biology.

Using a mathematical model developed for the study, the researchers identified high levels of variations between regions.  For example, the largest increase in alien species by the middle of the century is expected in Europe, where numbers are predicted to jump by 64%.  The temperate regions of Asia, North America, and South America are also predicted to be hotspots of alien species.  The lowest relative increase in alien species is expected in Australia.

The researchers do not expect a reversal or slowdown in the spread of alien species.  In fact, with global transportation and trade forecasted to increase in the coming decades, they anticipate many new species will infiltrate non-native habitats by hitching rides as stowaways.   

According to the research team, it would take a concerted global effort with stricter regulations and more rigorous enforcement to slow the flow of new species. 

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Alien species to increase by 36% worldwide by 2050

Photo, posted October 3, 2016, courtesy of the Asian Carp Regional Coordinating Committee via Flickr. Photo credit: Ryan Hagerty/USFWS.

Earth Wise is a production of WAMC Northeast Public Radio.

Marine Life Moving The Wrong Way | Earth Wise

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As the oceans have warmed in recent decades, various marine species ranging from whales to corals have begun to shift poleward in search of cooler waters.  But a new study, reported in the journal Nature Climate Change, found that many sedentary marine species – including snails, worms, and mussels – are actually being transported in the wrong direction.

What is happening is that bottom-dwelling species – also known as benthic species – in the northwest Atlantic Ocean are spawning earlier in the year because of the warmer water temperatures.  But earlier in the year is when ocean currents travel southward.  As a result, the larvae of these animals are being carried into warmer waters rather than cooler ones, threatening their survival and shrinking their ranges.  These larvae grow into adults in these warmer regions and are basically trapped there.  This creates a feedback loop where the situation for the species gets worse and worse.  Species like common sand dollars and the economically important blue mussel have had a 30 to 50% contraction of their ranges.

The result is that a number of bottom-dwelling species that previously were quite abundant have entirely disappeared from the outer shelf.

The researchers at Rutgers University likened this “wrong-way migration” of bottom-dwelling marine life to so-called elevator-to-extinction events that have been taking place in mountainous regions.  This is where species such as birds and butterflies move to higher and higher elevations to escape rising temperatures until there is nowhere else for them to go.

The essential fact that this research reveals is that species don’t necessarily move to places where the climate is congenial for them.  They may unfortunately end up migrating to even worse conditions.

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As Oceans Warm, Some Species Are Moving in the Wrong Direction

Photo, posted June 10, 2016, courtesy of James_Seattle via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

An Environmental Victory In Cameroon | Earth Wise

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The Ebo Forest in Cameroon is one of the last intact forests in central Africa and is a biodiversity hotspot, home to hundreds of rare plants and animal species, including tool-using Nigeria-Cameroon chimpanzees, western gorillas, forest elephants, red colobus monkeys, and giant goliath frogs.  The 600 square miles of mountain slopes and river valleys are covered by thick tree canopies that shelter a fascinating array of species.

This past July, Cameroon Prime Minister Joseph Dion Ngute signed a decree that turned half of the Ebo Forest into a so-called forest management unit, meaning that the government could begin to sell logging concessions.

However, on August 11, Ngute, at the direction of President Paul Biya, withdrew the decree, suspending any logging plans.  President Biya also ordered a delay to reclassify an additional 160,000 acres of the Ebo, which might have opened up even more forest for logging.

Apart from its rich biodiversity, the Ebo Forest is culturally and societally important for the Banen Indigenous people, who consider it to be their sacred ancestral home.  The Banen were ousted from the forest in the 1960s but took up settlements just a few miles from its borders.  They still rely on the forest for food and medicines.  Meanwhile, the proximity of the forest to big cities makes it an easy target for bushmeat poachers.

Both conservation groups and indigenous leaders welcomed the withdrawal of the decree but remain concerned about the future of the Ebo Forest.  Conservation groups hope that the international community will seize the opportunity to work with the government of Cameroon to make the Ebo Forest a permanent showcase for long-term conservation in harmony with very challenged communities.

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Cameroon Cancels Plan to Log Half of the Ebo Forest, a Key Biodiversity Hotspot in Central Africa

Photo, posted September 17, 2005, courtesy of Salva le Foreste via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Native Bees In A Honeybee World | Earth Wise

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There is a great deal of attention on the plight of bees and other pollinators.  Much of that focuses on the problems plaguing the large, domesticated honeybee colonies that are trucked from region to region to pollinate everything from almonds to fruit trees.  Managed bee colonies have recently been losing more than 40% of their population over the course of a year.  But overall, honeybees are still relatively safe. They are a globally distributed, domesticated species and are not remotely threatened with extinction.

But another group of bees – native bees – faces a different range of threats, most linked to habitat loss.   Worldwide, roughly 20,000 native bee species have evolved over millions of years to thrive in countless habitats, where they have specialized in pollinating specific flowers and plants – in some cases just a single plant.

Scientists have estimated that, globally, 1 in 6 bee species is regionally extinct. In the United States there are about 4,000 native bee species, most of which are solitary bees that nest in the ground or cavities, with many that require just one or a few plant species for sustenance. At least 23 percent of U.S. native bees have declined, with bees in areas with heavy commodity-crop production particularly hard hit due to habitat loss and pesticide use. Other threats to native bees include climate-driven sea-level rise and increased temperatures, loss of host plants, and competition and disease from non-native honeybees. 50% of Midwestern native bee species disappeared from their historic ranges in the last 100 years.   Four of our bumblebee species declined 96% in the last 20 years, and three species are believed to already be extinct. 

Native bees are in big trouble.

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Backyard Battle: Helping Native Bees Thrive in a Honeybee World

Photo, posted December 2, 2017, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sharks On The Decline | Earth Wise

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During the past 70 years, global shark populations have been on the decline.   Many species have become threatened or endangered.  Conservation efforts have been underway in many places, but shark populations continue to be at risk because of over-fishing and habitat loss.

A comprehensive study by marine biologists at Texas A&M University deployed more than 15,000 baited remote underwater video stations on 371 coral reefs in 58 countries.   The study included 59 different shark species in the Atlantic, Pacific and Indian Oceans.  The researchers were surprised to find that no sharks at all were detected in almost 20% of the locations surveyed and were almost completely absent from coral reefs in several nations. 

Scientists believe that demand for shark products, such as fins and meat, and bycatch (that is, sharks captured in nets by fisherman trapping other kinds of fish) are strong contributors to the widespread declines in shark numbers around the world.

The study shows that if corrective steps are not taken in regions where marine management is still ineffective, continued depletion of shark populations is highly likely. 

Sharks have important roles in marine ecosystems.  When their habitats deteriorate and their populations decrease, ecosystem stability and health is degraded because sharks help regulate prey populations.

Some countries, notably the Bahamas, are combating the problem by providing sanctuaries for sharks where fishing and harvesting is prohibited.  Such places support some of the healthiest shark populations in the world.  However, the decline of coral reefs is just another challenge facing shark populations around the world.

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Study Shows Alarming Decline In Shark Numbers Around The World

Photo, posted January 9, 2017, courtesy of Kris-Mikael Krister via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Moving Up And Away | Earth Wise

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A new study by the Wildlife Conservation Society, the US Forest Service, and UC Berkeley has shown that mountain-dwelling species trying to escape warming temperatures may also be finding refuge from human pressure.

The study shows that nearly 60% of the world’s mountainous areas are under intense human pressure.  Most of that pressure occurs at lower elevations and mountain bases, where more people live, grow food, and build roads.  The researchers used climate models to predict how various species would move as the climate changes.   Based upon these predictions, they found that species tend to move to higher elevations, where temperatures are lower.  But those elevations also have more intact land for species because there is less human activity.

Mountains are home to over 85% of the world’s amphibians, birds, and mammals and these species are at risk from human activities such as agriculture, livestock grazing, and development.  These things reduce their habitats, but meanwhile the warming climate pushes them upslope as they struggle to find tolerable temperatures.

The researchers point to their study as new guidance for conservation efforts.  They warn that many conservation efforts don’t take into account the effects of human pressure.   Factoring in human pressure reveals the true extent of mountainous areas for species that are restricted to intact landscapes.  These are often the species that are of greatest concern to conservationists.  This true shape refers to how much land area is potentially available as habitat for a species as it moves up in elevation.  

The results offer a glimmer of hope for mountain-based species under climate change as they move away from the most intense human activity.

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Climate change may push some species to higher elevations — and out of harm’s way

Photo, posted November 22, 2007, courtesy of 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.

Metal From Plants | Earth Wise

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Large amounts of metal in soil are generally bad for plants.  But there are about 700 species of plants that thrive in metal-rich soils.  These plants don’t just tolerate minerals from soil in their bodies but actually seem to hoard them to ridiculous levels.

In areas where soils are naturally rich in nickel, typically in the tropics and Mediterranean basin, plants have either died off or have adapted to become nickel loving.  Slicing open a tree with this adaptation produces a neon blue-green sap that is actually one-quarter nickel, which is far more concentrated than the ore that typically feeds commercial nickel smelters.

A group of researchers from the University of Melbourne and other institutions is investigating whether this phenomenon is not just interesting but might also be of real commercial value.  They established a plot of land in a rural village in Borneo and have been harvesting growth from nickel-hyper accumulating plants.  Every six to twelve months, a farmer shaves off one foot of growth from these plants and either burns or squeezes the metal out.  After a short purification, they end up with about 500 pounds of nickel citrate, potentially worth thousands of dollars on international markets.

Phytomining – extracting minerals from hyper-accumulating plants – cannot fully replace traditional mining techniques.  But the technology could enable areas with toxic soils to be made productive and might allow mining companies to use plants to clean up their former mines and waste while actually collecting some revenue.

There are other plants that suck up cobalt, zinc, and similarly crucial metals.  With growing demand for metals, perhaps it is time to harvest them on the farm.

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Down on the Farm That Harvests Metal From Plants

Photo courtesy of the University of Queensland.

Earth Wise is a production of WAMC Northeast Public Radio.

Coastal Plants And Climate Change | Earth Wise

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Rising sea levels and the increased frequency and intensity of extreme weather events are leaving observable effects on beaches, cliffs, and coastal infrastructures all around the world.  But a new study suggests that the impact of climate change on coastal plant communities needs more attention. 

According to research recently published in the journal Annals of Botany, coastal plants are a critical element of global sea defense.  But coastal plants are increasingly under threat from flooding, erosion, and other human-induced effects of climate change.  Habitats like salt marshes, mangrove forests, sand dunes, and kelp beds make important contributions  to coastal protection.

The research was led by scientists from the University of Plymouth, in conjunction with researchers at Utrecht University and Manchester Metropolitan University.

The study follows a recent assessment by the Intergovernmental Panel on Climate Change, which found that anthropogenic climate change poses a severe threat to estuaries and coastal ecosystems.  

Conservative estimates of the capital investments needed to combat rising seas and intensifying storms run into the hundreds of billions of dollars in the coming decades.  However, coastal vegetation could offer a dynamic, natural, and relatively low-cost defense strategy at a fraction of the cost when compared with the cost of so-called hard defenses like concrete walls and barriers. 

According to the research team, identifying the key species and habitats for coastal defense and how coasts can be protected and promoted is critical.  More long-term monitoring is also needed in order to better understand and predict where and how storms and other effects of climate change will impact coastal ecosystems. 

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The gathering storm: optimizing management of coastal ecosystems in the face of a climate-driven threat

Losing coastal plant communities to climate change will weaken sea defences

Photo, posted September 14, 2018, courtesy of Dennis Jarvis 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...)