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Agriculture Turning Wild Plants Into Weeds | Earth Wise

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We often hear about the importance of native plants in the environment and how invasive species can wreak havoc with ecosystems.   But it turns out that human activities can change the characteristics of native species and create unexpected new problems.

Common waterhemp is plant native to North America that typically grows near lakes and streams.  It never used to be any kind of problem, but in recent times it has become nearly impossible to eradicate from farms as a result of genetic adaptations triggered by modern agriculture.

A study led by researchers at the University of British Columbia looked at waterhemp samples from modern farms and neighboring wetlands and compared them with historical samples dating back as far as 1820 stored in various museums.

In recent times, mutations in genes related to drought tolerance, rapid growth, and resistance to herbicides have resulted in waterhemp that has become a pervasive weed on farms.  These genetic shifts, scarcely ever seen in historical samples, have made the plant thrive among human agricultural activities and enable it to outcompete crops.

Genetic analysis of the plants showed that herbicide-resistant mutations that were mostly absent from historical samples stand out as factors that allow waterhemp to prosper in agricultural settings. There are some plants in natural habitats that have herbicide-resistant mutations, but in many cases, these mutations are actually harmful to the plants in the wild.

Understanding how plant adaptations occur on relatively short timescales is increasingly important as farming and climate  change continue to drive rapid plant evolution.

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How intensive agriculture turned a wild plant into a pervasive weed

Photo, posted February 16, 2016, courtesy of Aqua Mechanical via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lithium Mining And Andes Ecosystems | Earth Wise

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A remote region in the high Andes straddling the borders between Argentina, Bolivia, and Chile has become known as the Lithium Triangle.   The area has become the focus of a global rush for lithium to make batteries for electric cars.  The global demand for lithium is expected to quadruple by 2030 to 2.6 million tons a year.

According to the U.S. Geological Survey, more than half of the world’s lithium reserves are dissolved in ancient underground water within the Lithium Triangle.  The cheapest way to extract the lithium is to pump the underground water to the surface and evaporate it in the sun to concentrate the lithium carbonate contained in it.

Every ton of lithium carbonate extracted using this cheap, low-tech method dissipates into the air about half a million gallons of water that is vital to the arid high Andes.  The process lowers water tables and has the potential to dry up lakes, wetlands, springs, and rivers.  Hydrologists and conservationists say the lithium rush in Argentina is likely to turn the region’s delicate ecosystems to deserts.

The global drive for green vehicles to fight climate change has the potential to be an ecological disaster in this remote region of South America and for the indigenous people who live there.

The environmental impacts are not an inevitable price for the transition to electric vehicles.  First of all, there are alternatives to lithium.  Both zinc and nickel are potential substitutes in rechargeable batteries.  But, there are also ways of obtaining lithium that are less destructive than evaporating the metal from saline ecosystems.  It is up to battery manufacturers, automakers, and financiers to start demanding lithium from sources that are less environmentally destructive.

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Why the Rush to Mine Lithium Could Dry Up the High Andes

Photo, posted September 25, 2015, courtesy of Nuno Luciano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reshaping Our Planet | Earth Wise

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Human activity – especially agriculture – has altered 70% of the land on our planet.  According to a new report from the United Nations, damage to the Earth’s lands has put the planet on “crisis footing”.

Our health, our economy, and our well-being depend on land.  The food we eat, the water we drink, and the air we breathe all rely on status of the land to at least some extent.

According to the report, up to 40% of the planet’s land is already degraded, affecting half of the people alive today.  At current rates, an additional area nearly the size of South America will be degraded by 2050.

Degradation of land occurs in various ways, including deforestation, desertification, and the loss of wetlands or grasslands.  All of these things are caused by human activities.  As forests, savannas, wetlands, and mangrove swamps are converted to agriculture or are lost to urban expansion, greenhouse gas emissions rapidly increase, adding to the effects of climate change.  The climate crisis, biodiversity loss, and land degradation are integrally linked.

Much of the blame for degraded landscapes is on humanity’s ever-expanding need for food and the modern farming systems that produce it.  The global food system is responsible for 80% of the world’s deforestation, 70% of freshwater use, and is the greatest driver of land-based biodiversity loss.  Modern agriculture has altered the face of the planet more than any other human activity.

The report urges efforts at restoration of land.  Restoration can take multiple forms, including planting forests and shrubs or grazing livestock and growing crops between trees instead of clearing existing forests.

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UN Report Says Humanity Has Altered 70 Percent of the Earth’s Land, Putting the Planet on a ‘Crisis Footing’

Photo, posted June 20, 2010, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Atmosphere Is Thirstier | Earth Wise      

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The American West is in the throes of a two-decade-long drought.  The climate there is getting warmer and drier, which has led to increasing demand for water resources from both humans and ecosystems.  According to a new study by the Desert Research Institute and collaborators, the atmosphere across much of the U.S. is also demanding a greater share of water than it used to.

Evaporative demand, which is also called atmospheric thirst, is a measure of the potential loss of water from the earth’s surface up to the atmosphere.  It is a function of temperature, humidity, wind speed, and solar radiation.  The study, published in the Journal of Hydrometeorology, assessed trends in evaporative demand during a 40-year period from 1980-2020.

The study’s findings showed substantial increases in atmospheric thirst across much of the Western U.S. over that period, with the largest increases centered around the Rio Grande and Lower Colorado rivers.  This is important because atmospheric thirst is a persistent force in pushing Western landscapes and water supplies toward drought.

The study found that, on average, increases in temperature were responsible for 57% of the changes observed in atmospheric thirst, humidity 26%, and the other factors playing lesser roles.

For farmers and other water users, increases in atmospheric thirst mean that, in the future, more water will be required to meet existing water needs.  Crops already require more water than they did in the past and can be expected to require more water in the future.  Over time, for every drop of precipitation that falls, less and less water is likely to drain into streams, wetlands, aquifers, or other water bodies.

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New study shows robust increases in atmospheric thirst across much of U.S. during past 40 years

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Snakes Near A Plane | Earth Wise

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San Francisco International Airport is the seventh-busiest airport in the United States.  In a typical year, approximately 55 million people pass through SFO on their way to destinations throughout North America and beyond.

At some point during their journey to or from the terminals at SFO, each one of those people will pass by a seemingly unremarkable 180-acre parcel of land.  Surrounded by highways and train tracks, the soggy and overgrown vacant lot isn’t just home to rows of power lines.  It’s also home to the world’s largest population of the beautiful and highly endangered San Francisco garter snake.   

According to a recent study conducted by the U.S. Geological Survey, there are approximately 1,300 San Francisco garter snakes at SFO’s West of Bayshore property – the greatest concentration of these snakes ever recorded.

Conservationists have long known that the San Francisco garter snake was in trouble.  In fact, it landed on the U.S. Fish and Wildlife Service’s very first endangered species list, which was published in 1967.  Over the years, agricultural, commercial, and urban development have destroyed much of its wetland habitat, as well as much of its primary food source, the California red-legged frog.  The snakes have also been a popular target for poachers and collectors.

Since 2008, SFO has been working with the USFWS on a recovery strategy for the species.  Together, they’ve made enhancements to the West of Bayshore habitat, including building rainfed ponds and deepening existing wetlands.  They have also added fences to protect habitat and prevent illegal collection.

But low population counts at other locations means the recovery for the San Francisco garter snake is far from over. 

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Combining genetic and demographic monitoring better informs conservation of an endangered urban snake

A San Francisco Airport Site Is Crawling With Snakes—And That’s a Good Thing

Photo, posted April 16, 2011, courtesy of Brian Gratwicke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Global Warming Could Stabilize | Earth Wise

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The world has been heading toward climate disaster with the effects of greenhouse gas-induced warming looming larger and larger.  But recent analysis published in Nature Climate Change offers hope that rapidly eliminating emissions could stabilize global temperatures just within a couple of decades.

For quite some time, it has been assumed that further global warming would be locked in for generations regardless of the extent of emissions reductions going forward.  This conclusion was based on having a certain carbon dioxide concentration in the atmosphere which would linger for hundreds of years even if emissions were reduced.

Recent analysis takes into account the dynamism of the Earth’s natural systems which could actually reduce atmospheric CO2 content because of the huge carbon absorption capacity of oceans, wetlands, and forests.  The key requirement is to drastically reduce emissions so that these natural systems can take over.

More than 100 countries have pledged to get to net zero emissions by 2050.  That means they will emit no more carbon dioxide than is removed from the atmosphere by such actions as restoring forests.   The UK, Japan, and the European Union are among the countries that have set this zero target, and the United States is joining the club.

Climate models show that a global temperature rise of 2 degrees Celsius over that of the pre-industrial period would lead to global calamities that include punishing heatwaves, flooding, and mass displacement of people.  The world has already heated up by 1.1 degrees and governments have committed to restrain the rise to less than 1.5 degrees under the Paris Climate Agreement.

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Global Warming Could Stabilize Faster than Originally Thought If Nations Achieve Net Zero

Photo, posted September 10, 2017, courtesy of Ron Cogswell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Land Use Change And Flooding | Earth Wise

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Land use change refers to the conversion of a piece of land’s use by humans from one purpose to another. Land use change is commonly associated with biodiversity loss and increased greenhouse gas emissions.  But how does land use change impact water cycles? 

According to researchers from the University of Göttingen in Germany, IPB University, and BMKG (both in Indonesia), the expansion of monocultures, such as rubber and oil palm plantations, leads to more frequent and more severe flooding.  The researchers explain the increase in flooding “with a complex interplay of ecohydrological and social processes, including soil degradation in monocultures, the expansion of oil palm plantations into wetlands, and the construction of flood protection dams.” 

For the study, which was recently published in the journal Ecology & Society, the research team interviewed nearly 100 Indonesian farmers, villagers, and decision-makers in Sumatra.  The team supplemented its research with data on precipitation, river and groundwater levels, soil properties, and regional mapping. 

During large-scale land use change – like plantation expansions – newly-compacted soil causes rainwater to runoff as opposed to being absorbed.  As more plantations are established in floodplains, the owners try to control flooding on their land by building barriers.  But these dams often lead to increased flooding on neighboring lands.  This understandably triggers social tensions between other farmers and plantation owners.     

In order to reduce the negative impact of land use change on the water cycle, the research team suggests soil protection and improved planning – especially in floodplains – would be a good place to start.  

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Land use change leads to increased flooding in Indonesia

Photo, posted October 8, 2018, courtesy of Artem Beliaikin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Natural Habitats And Strawberry Farms | Earth Wise

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According to a new study led by researchers from the University of California – Davis, conserving natural habitat around strawberry fields can protect farmers’ yields, their bottom line, and the environment.  The study also suggests that conserving natural habitat in this way has no detectable threat to food safety. 

In this study, which was recently published in the journal Ecological Applications, the research team conducted surveys and experiments at 20 strawberry farms along California’s Central Coast.  This region is responsible for 43% of the nation’s strawberry production. 

The researchers found that strawberry farmers were better off with natural habitat, like forests, grasslands, wetlands, and shrubs, around their farms than without it.  According to the study’s models, adding natural habitat can reduce crop damage costs by 23%.  Removing natural habitat can increase costs by as much as 76%. 

Importantly, the strawberry farms with natural habitat surrounding them showed no signs of increased fecal contamination.  While bird feces were regularly encountered on the ground, only 2 of 10,000 strawberries examined show signs of direct fecal contamination.  Those contaminated berries would be discarded during the hand-harvesting process.   

These findings run contradictory to current best practice recommendations that support natural habitat removal around strawberry farms in order to decrease bird fecal contamination and crop damage.  These food safety requirements were a consequence of the deadly outbreak of E. coli in 2006, which was traced back to spinach grown in this region.   

It seems like our agricultural landscapes can both support and benefit from biodiversity. 

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Natural habitat around farms a win for strawberry growers, birds and consumers

Photo, posted June 16, 2011, courtesy of the USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Rising Threat Of Rising Seas | Earth Wise

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Global sea level rose by about 6 inches during the 20th century.  It is currently rising more than twice as fast and accelerating.  The rate of rise was 2.5 times faster from 2006 to 2016 than it was for nearly all of the 20th century.

Sea level rise occurs when glaciers and ice sheets lose mass.  Much of that meltwater comes from Greenland and Antarctica.  But levels also rise because, as water warms, it expands.  Added to that are the effects of human activities such as groundwater depletion and a geological phenomenon called isostatic adjustment that is going on in parts of the East Coast where the land is actually sinking.

In Atlantic Canada, sea level rise is outpacing the global average and has already led to boardwalks swamped by swelling tides, drowned forests, submerged wharfs, and threatened historic shoreline buildings.

Recent research suggests that globally, land now occupied by 300 million people could be affected by floods at least once a year by 2050 unless carbon emissions are significantly reduced, and coastal defenses strengthened.  (This new figure is more than three times higher than earlier estimates).

Researchers at Dalhousie University in Nova Scotia are studying nature-based strategies for mitigating the effects of the rising seas.  These include conserving or restoring coastal ecosystems like dunes, wetlands, and reefs which could provide protection at a lower cost than building seawalls and other man-made obstacles.  Wetlands, for example, can reduce the force of waves and act as obstacles to storm surges, while also trapping sediment and stemming erosion.  Wetlands also serve as important carbon stores, but it is estimated that roughly half of the world’s coastal wetlands have been lost over the past 100 years to human activity and extreme weather events.

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The Looming Threat of Rising Sea Levels – And What We Can Do About it

Photo, posted February 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Beavers And Biodiversity

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Beavers are large, semi-aquatic rodents known best for their ability to construct dams, canals, and lodges (their homes).  They are among the largest rodents in the world.  With powerful jaws and strong teeth, beavers fell trees to use as building materials, often changing their environment in ways few other animals can. But in a good way.  As it turns out, beavers are important for biodiversity. 

According to new research from the Faculty of Natural Sciences at the University of Stirling in Scotland, reintroducing beavers to their native habitats is an important step towards solving the freshwater biodiversity crisis. 

Researchers surveyed water plants and beetles in 20 wetlands in Sweden – 10 created by beavers and 10 that were not – in order to understand what impact beavers might have on the variety of plant and animal life around them. 

The research team’s findings build on previous work that has shown that beavers have an important impact on biodiversity.  This latest study discovered that the number of species found only in beaver-built ponds was 50% higher than in other non beaver-built wetlands in the same region. 

Beavers are known to be profound engineers of the environment. They use wood to build dams across rivers in order to form ponds behind them.  They do this to raise the water level in order to avoid predators, like bears and wolves. But it turns out many other plants and animals, like water plants and beetles, also benefit from their work.

According to the research team, reintroducing beavers to their native habitats should benefit the wider biodiversity and be seen as an important step towards solving the freshwater biodiversity crisis. 

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Beaver reintroduction key to solving freshwater biodiversity crisis

Photo, posted October 2, 2014, courtesy of USFWS Midwest Region via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Trees And Methane

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The Amazon is a source of many mysteries.  One that was as troubling as it was mysterious was the large amounts of methane emissions coming from the rainforest that were observed by satellites but that nobody could find on the ground.  In total, there were 20 million tons of methane whose origin was unknown.

An expedition by a British postdoctoral researcher who spent two months strapping gas-measuring equipment to thousands of trees has solved the mystery.  It turns out that trees, especially in the extensive flooded forests, were stimulating methane production in the waterlogged soils and pumping it into the atmosphere.

This research has uncovered a previously-ignored major source of the second most important greenhouse gas in the world.  Apparently, most of the world’s estimated 3 trillion trees emit methane at least some of the time.

This in no way implies that trees are bad for the climate and therefore should be cut down.  The reality is that the carbon storage capability of trees far outweighs their methane emissions.  But since corporations these days are planting trees to offset their carbon emissions, it is essential to know if their numbers add up.  Carbon accounting has to include the complex chemistry of trees and methane.

Wetland tree trunks can act as passive conduits for methane generated by micro-organisms in waterlogged soils.  The solid-looking trunks contain spaces and channels through which gases travel up and down.  But in wetland systems, trees also create the conditions, and provide the raw materials, for methane generation by micro-organisms.  Trees are essentially bioreactors.  Some trees even actively generate methane from photochemical reactions in their foliage.

Understanding the interactions of ecosystems and the atmosphere is a complicated business.

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Scientists Zero in on Trees as a Surprisingly Large Source of Methane

Photo, posted December 13, 2008, courtesy of Ivan Mlinaric via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Vulnerable Shorelines

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Global climate change is having noticeable effects on the environment. For example, glaciers are shrinking.  Plant and animal ranges are shifting and populations decreasing.  And droughts, floods, and wildfires are becoming more frequent and more intense.  According to the Intergovernmental Panel on Climate Change, the evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time. 

Our coastal shorelines, which are already stressed by human activity, pollution, storms, and invasive species, are one of many areas expected to be further threatened by climate change.  Sea level rise and more intense and frequent storms are expected to erode and inundate coastal ecosystems and eliminate wetlands.  Ocean acidification is also projected to disrupt marine environments. 

But according to scientists at the Massachusetts Institute of Technology, seagrasses could play a key role in protecting these vulnerable shorelines from this onslaught.  The MIT research team demonstrated how the ubiquitous marine plants dissipate wave energy and help protect against erosion, which could help mitigate damage from rising seas. 

Using mathematical modelling and experiments, the MIT researchers were able to quantify for the first time how large and dense a continuous meadow of seagrass must be in order to provide adequate damping of waves in a given setting.  They also found that seagrasses offer significant environmental benefits, including preventing beach erosion, protecting seawalls and coastal structures, improving water quality, and sequestering carbon. 

Submerged aquatic vegetation, including seagrasses, provides an ecosystem service exceeding $4 trillion annually.  Hopefully these findings can help provide useful guidance for seagrass restoration efforts.

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Seagrass’ strong potential for curbing erosion

The Effects of Climate Change

Photo, posted October 13, 2010, courtesy of the NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sand Mining And The Environment

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In discussions of the environment, we don’t hear much about sand mining.  But sand mining is the world’s largest mining endeavor, responsible for 85% of all mineral extraction.  Sand and gravel are mined on a huge scale around the world.  The UN estimates that the total exceeds 40 billion tons a year.  Most of this activity is unregulated and unmeasured, and much of it is corrupt and environmentally destructive.

Concrete is the predominant use for sand.  Every ton of cement requires six to seven tons of sand and gravel in order to make concrete.  But sand also makes up 90% of asphalt on roads and it is used for land reclamation in places like Singapore.  Sand is also widely used in industries such as glass manufacturing and fracking.

There are different sorts of sand.  Desert sand is mostly useless for making concrete because its grains are too rounded by erosion and don’t bind well in the concrete.   Marine sand is not great for concrete either because it has to be washed clean of corrosive salts.

As a result, salt miners mostly get sand from pits on land and dredged up from lakes and riverbeds.  Dredging massive quantities of sand from rivers and lakes drastically alters river flow, erodes riverbanks, dries up tributaries, lowers water tables, and trashes wetlands and fisheries.  In many countries, this even goes on in national parks where officials turn a blind eye to the activity.  India is the world’s second-largest sand mining country (after China) and widespread illegal extraction occurs throughout the country run by highly organized and even violent “sand mafias.”

Sand mining is a huge problem and, to date, is one that is pretty much off of most people’s radar.

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The Hidden Environmental Toll of Mining the World’s Sand

Photo, posted June 3, 2017, courtesy of Andrey Talalov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Natural Climate Solutions Are Not Enough

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A new policy perspective published in Science by researchers at seven prestigious institutions looked at the role of natural science solutions in stabilizing the Earth’s climate for people and ecosystems.   While they asserted that it is imperative to ramp up natural climate solutions, they also concluded that natural solutions alone will not be sufficient.

Natural science solutions include such things as enhancing carbon sinks from forests, agriculture and other lands.  Doing these things are very beneficial in their own right as they lead to improved forests, croplands, grazing lands, and wetlands.

However, these things will not be enough to meet the goals of the Paris Climate Agreement and must be combined with rapid efforts to decrease emissions from the energy and industrial sectors.  Among their various findings, the researchers warn that a ten-year delay in emissions reductions from these sectors could completely negate any potential benefits of natural climate solutions.

As has become increasingly clear, there is not an either-or situation with regard to the actions that need to be taken with respect to climate change.

Maximizing natural climate solutions and reducing emissions from the energy and industrial sectors will provide broad benefits beyond climate change mitigation.  Doing these things will improve forests and habitats, reduce the risk of wildfires, and decrease air and water pollution thereby improving human health and well-being.

Of course, to reduce cumulative emissions and put a cap on the warming of the planet, there will need to be policy mechanisms and incentives in place that support both natural climate solutions and increasing mitigation efforts across the energy and industrial sectors.

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Natural Climate Solutions Are Not Enough

Photo, posted February 11, 2012, courtesy of Joao Andre O. Dias via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Natural Climate Solutions

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The Paris Climate Agreement embodies a commitment to hold the increase in the global average temperature to less than 2 Celsius degrees above preindustrial levels.  Most strategies to achieve this goal involve reductions in greenhouse gas emissions from human activities such as burning fossil fuels as well as various land use activities.  But there are also so-called Natural Climate Solutions, which relate to the storage of carbon and reduction in carbon emissions across global forests, wetlands, grasslands, and agricultural lands.

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Pine Barrens Threatened

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Pine barrens occur throughout the northeastern U.S. from New Jersey to Maine.  They are plant communities that occur on dry, acidic, infertile soils dominated by grasses, forbs, low shrubs, and small to medium-sized pines.  The Pine Bush Preserve in Albany, New York is one of the larger inland pine barrens in the country.

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The Methane Riddle

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Most of the blame for climate change has been placed on the growing levels of carbon dioxide in the atmosphere, but methane also plays a major role.  Estimates are that about 1/5 of greenhouse effect warming is caused by methane in the atmosphere.  There is far less of it than carbon dioxide, but methane is tremendously more effective at trapping heat.

[Read more…] about The Methane Riddle

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