Older Forests Have Irreplaceable Value for Conservation, Study Finds

There’s been a lot of wildlife losses over the past several decades and a tenth of the wilderness has disappeared since the 1990s. This research on forests and birds is a reminder that that there’s still much that needs to be done to get human activities on a better track.

Old, complex tropical forests support a wider diversity of birds than second-growth forests and have irreplaceable value for conservation, according to an Oregon State University-led exhaustive analysis of bird diversity in the mountains of southern Costa Rica.

During their surveys, researchers found similar numbers of bird species in secondary stands compared to stands comprised entirely or in part of old-growth forest. However, the bird community in secondary forest was clearly shifted towards non-forest species, and only old-growth forest stands tended to include rare birds and to benefit biodiversity across the entire landscape. Scientists reported their results this week in the Journal of Applied Ecology.

The findings are important because in some cases, conservation programs have focused on the potential benefits of secondary forests. Although secondary forests do have value for conservation, the study suggests that primary forests are necessary as sources of biodiversity and as a refuge for species that can colonize other sites that are being restored. Thus, these results suggest that a strategy focussing only on second-growth forests may not benefit conservation-relevant species. Indeed, such stands tend to support only a few common species that can survive in highly disturbed areas.

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Effective conservation efforts should include maintenance of large old-growth forest tracts, the scientists wrote, and insure that human activities in the forest do not drive away species that depend on such areas. The results also suggest that restoring forests is likely to be most effective for forest birds if such efforts are performed in the vicinity of primary forest. This is likely because primary forest will provide a source for forest birds that may colonize the restored forest. Relying on secondary forests alone may create “potentially misleading expectations,” researchers wrote, that landscapes significantly modified by people can still accomplish conservation goals.

Biodiversity Losses Increase Risks of Domino Effect of Further Extinctions

This phenomenon is referred to as an “extinction cascade.”

New research shows that the loss of biodiversity can increase the risk of “extinction cascades,” where an initial species loss leads to a domino effect of further extinctions.

The researchers, from the University of Exeter, showed there is a higher risk of extinction cascades when other species are not present to fill the “gap” created by the loss of a species.

Even if the loss of one species does not directly cause knock-on extinctions, the study shows that this leads to simpler ecological communities that are at greater risk of “run-away extinction cascades” with the potential loss of many species.

With extinction rates at their highest levels ever and numerous species under threat due to human activity, the findings are a further warning about the consequences of eroding biodiversity.

“Interactions between species are important for ecosystem (a community of interacting species) stability,” said Dr Dirk Sanders, of the Centre for Ecology and Conservation at the University of Exeter’s Penryn Campus in Cornwall. “And because species are interconnected through multiple interactions, an impact on one species can affect others as well.

“It has been predicted that more complex food webs will be less vulnerable to extinction cascades because there is a greater chance that other species can step in and buffer against the effects of species loss.

“In our experiment, we used communities of plants and insects to test this prediction.”

The researchers removed one species of wasp and found that it led to secondary extinctions of other, indirectly linked, species at the same level of the food web.

This effect was much stronger in simple communities than for the same species within a more complex food web.

Dr Sanders added: “Our results demonstrate that biodiversity loss can increase the vulnerability of ecosystems to secondary extinctions which, when they occur, can then lead to further simplification causing run-away extinction cascades.”

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The loss of a predator can initiate a cascade, such as in the case of wolves, where their extinction on one mountain can cause a large rise in the number of deer. This larger number of deer then eats more plant material than they would have before. This reduction in vegetation can cause extinctions in any species that also relies on the plants, but are potentially less competitive, such as rabbits or insects.

Add this research to one of the many reasons why rigorously addressing climate change — which can destabilize environments — is of paramount importance.

Steady Sea Level Rise Acceleration

A few hundred billion tons of glacial ice is melting every year due to the effects of climate change. This threatens to lead to a sea level rise that may create a future migration crisis far worse than any others in the recent era.

Global sea level rise is not cruising along at a steady 3 mm per year, it’s accelerating a little every year, like a driver merging onto a highway, according to a powerful new assessment led by CIRES Fellow Steve Nerem. He and his colleagues harnessed 25 years of satellite data to calculate that the rate is increasing by about 0.08 mm/year every year — which could mean an annual rate of sea level rise of 10 mm/year, or even more, by 2100.

“This acceleration, driven mainly by accelerated melting in Greenland and Antarctica, has the potential to double the total sea level rise by 2100 as compared to projections that assume a constant rate — to more than 60 cm instead of about 30.” said Nerem, who is also a professor of Aerospace Engineering Sciences at the University of Colorado Boulder. “And this is almost certainly a conservative estimate,” he added. “Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that’s not likely.”

If the oceans continue to change at this pace, sea level will rise 65cm (26 inches) by 2100 — enough to cause significant problems for coastal cities, according to the new assessment by Nerem and several colleagues from CU Boulder, the University of South Florida, NASA Goddard Space Flight Center, Old Dominion University, and the National Center for Atmospheric Research. The team, driven to understand and better predict Earth’s response to a warming world, published their work today in the journal Proceedings of the National Academy of Sciences.

Rising concentrations of greenhouse gases in Earth’s atmosphere increase the temperature of air and water, which causes sea level to rise in two ways. First, warmer water expands, and this “thermal expansion” of the oceans has contributed about half of the 7 cm of global mean sea level rise we’ve seen over the last 25 years, Nerem said. Second, melting land ice flows into the ocean, also increasing sea level across the globe.

The Ozone Layer Isn’t Recovering Enough Over Highly Populated Areas

This warning comes as recent evidence suggests that a thinning ozone layer may have driven Earth’s largest mass extinction 252 million years ago.

The ozone layer that protects people from the sun’s ultraviolet radiation is not recovering over most highly populated regions, scientists warned on Tuesday.

The greatest losses in ozone occurred over Antarctica but the hole there has been closing since the chemicals causing the problem were banned by the Montreal protocol. But the ozone layer wraps the entire Earth and new research has revealed it is thinning in the lower stratosphere over the non-polar areas.

Reduced protection from cancer-causing UV rays is especially concerning towards the equator, where sunlight is stronger and billions of people live. The reason for the falling ozone at lower latitudes is not known, though scientists suspect a chemical used in paint stripper and a change in atmospheric circulation caused by climate change.

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The cause of the decline is unknown but might be the result of global warming. Ozone is produced by chemical reactions in the atmosphere over the tropics and then distributed towards the poles world by large air circulation currents. But warming trends could be strengthening these currents, moving more ozone to the poles and leaving less at lower latitudes.

Another suspect is so-called “very short lived substances” (VSLS) – industrial chemicals that destroy ozone. It was thought they broke down too quickly to reach the stratosphere, but that may need to be re-examined.

Another Avenue for Converting Methane

The capture and conversion of greenhouse gases are important in the existential fight against climate change.

USC scientists have unlocked a new, more efficient pathway for converting methane — a potent gas contributing to climate change — directly into basic chemicals for manufacturing plastics, agrochemicals and pharmaceuticals.

In research published on Dec. 4 in the Journal of the American Chemical Society, chemists at USC Loker Hydrocarbon Research Institute say they have found a way to help to utilize this abundant and dangerous greenhouse gas, which is generally burnt or flared to produce energy.

Among common greenhouse gases, carbon dioxide is often cited as the largest culprit for trapping heat on earth, contributing to climate change. However, it is not the most potent.

That distinction belongs to methane. According to the Intergovernmental Panel on Climate Change, methane traps heat and warms the planet 86 times more than carbon dioxide over a 20-year horizon.

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Global methane emissions have surged since 2007 and output is particularly bad in the United States. According to a recent Harvard University study, the United States could be solely responsible for as much as 60 percent of the global growth in human-caused atmospheric methane emissions during this century.
Contributing to the global surge is the increased supply of livestock and rice fields in countries like India and China, the two leaders in total methane output, according to the World Bank.

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While being the most potent of our popular greenhouse gases, and even after the largest methane leak in U.S. history at the Aliso Canyon natural gas storage facility a few years ago, there are no signs that methane’s abundant production will slow down anytime soon.

Shale fracking and other resource extraction techniques are increasing natural gas reserves, and the Loker scientists believe methane may soon become the most popular of all raw materials for producing petrochemical products.

Immense Amount of Mercury Found in the Northern Permafrost, Posing Threats to Human Health

There’s a potent chance that this revelation will return in the coverage of a significant news story in the future. Mercury isn’t the only danger hidden in the permafrost, of course, as greenhouse gases such as methane are also found there too. And as methane traps about 86 times more heat than an equivalent amount of carbon dioxide does, that makes its potential of escalating climate change worrisome.

Mercury though is yet another confirmation that climate change is a truly serious problem that must be addressed. It wouldn’t be much of a surprise to find other worrying threats waiting to be melted in the permafrost either.

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Researchers have discovered permafrost in the northern hemisphere stores massive amounts of natural mercury, a finding with significant implications for human health and ecosystems worldwide.

In a new study, scientists measured mercury concentrations in permafrost cores from Alaska and estimated how much mercury has been trapped in permafrost north of the equator since the last Ice Age.

The study reveals northern permafrost soils are the largest reservoir of mercury on the planet, storing nearly twice as much mercury as all other soils, the ocean and the atmosphere combined.

The new study was published today in Geophysical Research Letters, a journal of the American Geophysical Union.

“This discovery is a game-changer,” said Paul Schuster, a hydrologist at the U.S. Geological Survey in Boulder, Colorado and lead author of the new study. “We’ve quantified a pool of mercury that had not been done previously, and the results have profound implications for better understanding the global mercury cycle.”

Warmer air temperatures due to climate change could thaw much of the existing permafrost layer in the northern hemisphere. This thawing permafrost could release a large amount of mercury that could potentially affect ecosystems around the world. Mercury accumulates in aquatic and terrestrial food chains, and has harmful neurological and reproductive effects on animals.

“There would be no environmental problem if everything remained frozen, but we know the Earth is getting warmer,” Schuster said. “Although measurement of the rate of permafrost thaw was not part of this study, the thawing permafrost provides a potential for mercury to be released — that’s just physics.”

The new findings have major implications for understanding how Earth stores mercury and for human and environmental health, according to James Shanley, a research hydrologist at the U.S. Geological Survey in Montpelier, Vermont, who was not involved with the new research.

“This study is very novel and makes a big discovery in an area that was previously somewhat ignored,” Shanley said. “It shows permafrost represents a huge source of mercury, and if it thaws due to climate change the mercury could be released and could significantly add to the global mercury burden.”

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The study found approximately 793 gigagrams, or more than 15 million gallons, of mercury is frozen in northern permafrost soil. That is roughly 10 times the amount of all human-caused mercury emissions over the last 30 years, based on emissions estimates from 2016.

The study also found all frozen and unfrozen soil in northern permafrost regions contains a combined 1,656 gigagrams of mercury, making it the largest known reservoir of mercury on the planet. This pool houses nearly twice as much mercury as soils outside of the northern permafrost region, the ocean and the atmosphere combined.

The effects of the released mercury

Scientists are still unsure how much of the stored mercury would affect ecosystems if the permafrost were to thaw. One major question revolves around how much of the mercury would leach out of the soil into surrounding waterways, according to Steve Sebestyen, a research hydrologist at the USDA Forest Service in Grand Rapids, Minnesota, who was not involved with the new research.

If the mercury is transported across waterways, it could be taken up by microorganisms and transformed into methylmercury, he said. This form of mercury is a dangerous toxin that causes neurological effects in animals ranging from motor impairment to birth defects.

“There’s a significant social and human health aspect to this study,” Sebestyen said. “The consequences of this mercury being released into the environment are potentially huge because mercury has health effects on organisms and can travel up the food chain, adversely affecting native and other communities.”

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The release of mercury could also have far-reaching global consequences, according to Shanley. Mercury released into the atmosphere can travel large distances and could affect communities and ecosystems thousands of miles away from the release site, he said.

Schuster believes his team’s research gives policymakers and scientists new numbers to work with and calibrate their models as they begin to study this new phenomenon in more detail. He intends to release another study modeling the release of mercury from permafrost due to climate change, and said this work changes scientists’ perspective of the global mercury cycle.

“24 percent of all the soil above the equator is permafrost, and it has this huge pool of locked-up mercury,” he said. “What happens if the permafrost thaws? How far will the mercury travel up the food chain? These are big-picture questions that we need to answer.”

Toxins from Air Pollution Damage Child Development and Disproportionately Affect Those in Poverty

Air pollution causes health damage that’s too often overlooked, and the research that’s coming out has been showing this more and more lately.

Schoolchildren across the US are plagued by air pollution that’s linked to multiple brain-related problems, with black, Hispanic and low-income students most likely to be exposed to a fug of harmful toxins at school, scientists and educators have warned.

The warnings come after widespread exposure to toxins was found in new research using EPA and census data to map out the air pollution exposure for nearly 90,000 public schools across the US.

“This could well be impacting an entire generation of our society,” said Dr Sara Grineski, an academic who has authored the first national study, published in the journal Environmental Research, on air pollution and schools.

Grineski and her University of Utah colleague Timothy Collins grouped schools according to their level of exposure to more than a dozen neurotoxins, including lead, mercury and cyanide compounds.

The research found that:

  • Only 728 schools achieved the safest possible score.
  • Five of the 10 worst polluted school counties have non-white populations of over 20%
  • The five worst polluted areas include New York, Chicago and Pittsburgh, as well as Jersey City and Camden in New Jersey. One teacher in Camden told the Guardian that heavy industry was “destroying our children”.

Cash-strapped authorities have routinely placed schools on the cheapest available land, which is often beside busy roads, factories or on previously contaminated sites. Teacher unions worry that the Trump administration’s enthusiasm for charter schools, championed by education secretary Betsy DeVos, will diminish federal intervention to reverse this.

The study found that pre-kindergarten children are attending higher risk schools than older students – a stark finding given the vulnerability of developing brains.

Pollution exposure is also drawn along racial lines. While black children make up 16% of all US public school students, more than a quarter of them attend the schools worst affected by air pollution. By contrast, white children comprise 52% of the public school system but only 28% of those attend the highest risk schools. This disparity remains even when the urban-rural divide is accounted for.

Schools with large numbers of students of colour are routinely located near major roads and other sources of pollution, with many also grappling with other hazards such as lead-laced drinking water and toxins buried beneath school buildings

Grineski said there were a range of consequences. “We’re only now realizing how toxins don’t just affect the lungs but influence things like emotional development, autism, ADHD and mental health,” she said. “Socially marginalized populations are getting the worst exposure. When you look at the pattern, it’s so pervasive that you have to call it an injustice and racism.”

The research is “important and is consistent with other localized information we’ve seen over the years,” according to Stephen Lester, science director of the Center for Health, Environment and Justice, who wasn’t involved in the study.

“Children are facing risks that will affect their ability to learn,” he said. “It’s a serious problem that needs a serious government response.”

As scientists have pieced together evidence showing the link between air toxins and neurological harm, American cities are still largely wedded to a legacy that has juxtaposed certain neighborhoods with heavy traffic and hulking industry.

Only a handful of states require that schools are not placed next to environmental hazards. In 2010, the EPA issued national guidelines on picking school locations but backed away from imposing mandatory buffer zones.

The guidelines were deemed voluntary “after a whole lot of pushback from various financial and political interests,” according to Lester, who was part of a group advising the EPA.

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Scientific endeavour is uncovering a jumble of neurological reactions to air pollution, from early onset Alzheimers to schizophrenia. Much of this work is in its infancy, but scientists say there is well established evidence that children are far more susceptible to pollutants than adults, with potentially severe consequences for their development.

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“Before, we might have labelled a kid with bad behaviour as just being a bad kid,” said Keith Benson, who taught history in the Camden school system before becoming the head of the local teacher’s union.

“Now we are thinking about it another way. There’s no telling how much potential has been lost because of environmental issues, how many hopes were stunted because these kids were not close to clear air and water.”