Key S. African leopard population 'crashing', study warns

The leopard population in a region of South Africa once thick with the big cats is crashing, and could be wiped out within a few years, scientists warned on Wednesday.

The clash between humans and leopards, experts agree, is mostly due to humanity's expanding footprint, 
especially in Africa, whose population is set to expand by more than a billion before mid-century 
[Credit: AFP/Gianluigi Guercia]

Illegal killing of leopards in the Soutpansberg Mountains has reduced their numbers by two-thirds in the last decade, the researchers reported in the Royal Society Open Science journal.

"If things don't change, we predict leopards will essentially disappear from the area by about 2020," lead author Samual Williams, a conservation biologist at Durham University in England, told AFP.

"This is especially alarming given that, in 2008, this area had one of the highest leopard densities in Africa."

The number of leopards in the wild worldwide is not known, but is diminishing elsewhere as well. The "best estimate" for all of South Africa, said Williams, is about 4,500.

What is certain, however, is that the regions these predators roam has shrunk drastically over the last two centuries.

The historic range of Panthera pardus, which includes more than half-a-dozen sub-species, covered large swathes of Africa and Asia, and extended well into the Arabian Peninsula.

Leopards once roamed the forests of Sri Lanka and Java unchallenged.

Today, they occupy barely a quarter of this territory, with some sub-species teetering on the brink of extinction, trapped in one or two percent of their original habitat.

Leopards were classified last year as "vulnerable" to extinction on the International Union for the Conservation of Nature's Red List of endangered species, which tracks the survival status of animals and plants.

South Africa recently suspended trophy hunting of leopards, though experts agree this is not a major cause of the population decline.

Bleak findings

A 2008 census of leopards in the 6,800-square kilometre (2,600-square mile) Soutpansberg Mountains found a robust population of nearly 11 adult cats for each hundred square kilometres (39 square miles).

South Africa recently suspended trophy hunting of leopards, though experts agree this 
is not a major cause of the population decline [Credit: AFP/Alexander Joe]

To find out how the carnivores had fared since then, Williams and his team set up four dozen motion-triggered camera traps across the area, and left them in place from 2012 to 2016.

The cameras captured a total of 65 individual leopards during the four-year period: 16 adult males, 28 adult females and 21 younger cats.

They also fitted eight adults with GPS collars to track their movements -- or lack thereof.

Only two of the GPS-tagged leopards survived the monitoring period. Three were done in by snares, one was shot by a local resident whose cattle had been attacked, and two went missing, probably killed since they also disappeared from camera surveillance.

A statistical analysis of the results showed "a 66 percent decline over a period just over 7.5 years," the study concluded.

Ironically, the bleak findings helped conservationists and local officials raise money to hire a "community engagement officer."

Lake Fundudzi sits among the foothills of South Africa's Soutpansberg Mountains 
in the northern province of Limpopo [Credit: AFP/Alexander Joe]

"One of the things he does is help local people adopt non-lethal techniques" to prevent leopards from attacking cattle and other livestock, including the use of guard dogs, Williams added.

But the clash between humans and big carnivores, experts agree, is mostly due to humanity's expanding footprint, especially in Africa, whose population is set to expand by more than a billion before mid-century.

As a result, the habitats of most wild megafauna are diminishing, and getting chopped up into smaller and smaller parcels.

"It is extremely alarming that the trends that we are reporting exemplify trends in large carnivores globally," Williams said.

Studies in Africa of lions, black-backed jackals and bat-eared foxes have showed similar rates of decline.

Author: Marlowe Hood | Source: AFP [April 19, 2017]

byUnknown

in Africa, Endangered Species, Natural Heritage, South Africa, Wildlife

April 19, 2017

Key S. African leopard population 'crashing', study warns

The leopard population in a region of South Africa once thick with the big cats is crashing, and could be wiped out within a few years, scie...

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Retreating Yukon glacier caused a river to disappear

The massive Kaskawulsh Glacier in northern Canada has retreated about a mile up its valley over the past century.

A Sept. 2, 2016 aerial photo shows the meltwater stream along the toe of Kaskawulsh Glacier, seen on the left, that is 
diverting fresh water from one river to the other [Credit: Dan Shugar/University of Washington Tacoma]

Last spring, its retreat triggered a geologic event at relatively breakneck speed. The toe of ice that was sending meltwater toward the Slims River and then north to the Bering Sea retreated so far that the water changed course, joining the Kaskawulsh River and flowing south toward the Gulf of Alaska.

This capture of one river's flow by another, documented in a study led by the University of Washington Tacoma and published in Nature Geoscience, is the first known case of "river piracy" in modern times. "Geologists have seen river piracy, but nobody to our knowledge has documented it happening in our lifetimes," said lead author Dan Shugar, a geoscientist at the University of Washington Tacoma. "People had looked at the geological record -- thousands or millions of years ago -- not the 21st century, where it's happening under our noses."

River piracy, also known as stream capture, can happen due to tectonic motion of Earth's crust, landslides, erosion or, in this case, changes in a glacial dam. The new study documents one of the less-anticipated shifts that can occur in a changing climate.

Shugar and co-authors Jim Best at the University of Illinois and John Clague at Canada's Simon Fraser University had planned fieldwork last summer on the Slims River, a geologically active system that feeds Kluane Lake in the Yukon. When they arrived in August, the river was not flowing. River gauges show an abrupt drop over four days from May 26 to 29, 2016.

By late summer, "there was barely any flow whatsoever. It was essentially a long, skinny lake," Shugar said. "The water was somewhat treacherous to approach, because you're walking on these old river sediments that were really goopy and would suck you in. And day by day we could see the water level dropping."

Images captured by the European Space Agency’s Sentinel2 satellite in 2015 and 2016 show a dramatic drop in the Slims 
River’s flow. The receding toe of Kaskawulsh Glacier is seen at the bottom. Kluane Lake can be seen at the top of the 
2016 image. Water now flows east and then south via the Kaskawulsh River [Credit: European Space Agency]

The research team puzzled about what to do next. They got permission to use their mapping drone to create a detailed elevation model of the glacier tongue and headwater region. The resulting paper is a geological postmortem of the river's disappearance.

"For the last 300 years, Slims River flowed out to the Bering Sea, and the smaller Kaskawulsh River flowed to the Gulf of Alaska. What we found was the glacial lake that fed Slims River had actually changed its outlet," Shugar said. "A 30-meter (100-foot) canyon had been carved through the terminus of the glacier. Meltwater was flowing through that canyon from one lake into another glacial lake, almost like when you see champagne poured into glasses that are stacked in a pyramid."

That second lake drains via the Kaskawulsh River in a different direction than the first. The situation is fairly unique, Shugar said, since the glacier's toe was sitting on a geologic divide.

Clague began studying this glacier years ago for the Geological Survey of Canada. He observed that Kluane Lake, which is Yukon's largest lake, had changed its water level by about 40 feet (12 meters) a few centuries ago. He concluded that the Slims River that feeds it had appeared as the glacier advanced, and a decade ago predicted the river would disappear again as the glacier retreated.

"The event is a bit idiosyncratic, given the peculiar geographic situation in which it happened, but in a broader sense it highlights the huge changes that glaciers are undergoing around the world due to climate change," Clague said.

A close-up view of the ice-walled canyon at the terminus of the Kaskawulsh Glacier, with recently collapsed ice blocks. 
This canyon now carries almost all meltwater from the toe of the glacier down the Kaskawulsh Valley 
and toward the Gulf of Alaska [Credit: Jim Best/University of Illinois]

The geologic event has redrawn the local landscape. Slims River crosses the Alaska Highway, and its banks were a popular hiking route. Now that the riverbed is exposed, Dall sheep from Kluane National Park are making their way down to eat the fresh vegetation, venturing into territory where they can legally be hunted. With less water flowing in, Kluane Lake did not refill last spring, and by summer 2016 was about 3 feet (1 meter) lower than ever recorded for that time of year. Waterfront land, which includes the small communities of Burwash Landing and Destruction Bay, is now farther from shore. As the lake level continues to drop researchers expect this will become an isolated lake cut off from any outflow.

On the other hand, the Alsek River, a popular whitewater rafting river that is a UNESCO world heritage site, was running higher last summer due to the addition of the Slims River's water.

Shifts in sediment transport, lake chemistry, fish populations, wildlife behavior and other factors will continue to occur as the ecosystem adjusts to the new reality, Shugar said.

"So far, a lot of the scientific work surrounding glaciers and climate change has been focused on sea-level rise," Shugar said. "Our study shows there may be other underappreciated, unanticipated effects of glacial retreat."

The Kaskawulsh Glacier is retreating up the valley because of both readjustment after a cold period centuries ago, known as the Little Ice Age, and warming due to greenhouse gases. A technique published in 2016 by UW co-author Gerard Roe shows a 99.5 percent probability that this glacier's retreat is showing the effects of modern climate change.

"I always point out to climate-change skeptics that Earth's glaciers are becoming markedly smaller, and that can only happen in a warming climate," Clague said.

Source: University of Washington [April 17, 2017]

byUnknown

in Canada, Climate Change, Ecosystems, Natural Heritage, North America

April 17, 2017

Retreating Yukon glacier caused a river to disappear

The massive Kaskawulsh Glacier in northern Canada has retreated about a mile up its valley over the past century. A Sept. 2, 2016 aerial pho...

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Hunting accounts for massive declines in tropical animal populations

Hunting is a major threat to wildlife particularly in tropical regions, but a systematic large-scale estimate of hunting-induced declines of animal numbers was lacking so far. A study published in Science fills this gap. An international team of ecologists and environmental scientists found that bird and mammal populations were reduced within 7 and 40 km of hunters' access points, such as roads and settlements.

A decline of species abundance in hunted forest within 0-40 km from hunter access points 
[Credit: Radboud University/Joeri Borst]

Within these impact zones, mammal populations declined on average by 83% and bird populations by 58%. Additionally, the team found that commercial hunting had a higher impact than hunting for family food, and that hunting pressure was higher in areas with better accessibility to major towns where wild meat could be traded. The impact of hunting was found to be larger than the team expected. 'Thanks to this study, we estimate that only 17 percent of the original mammal abundance and 42 percent of the birds remain in hunted areas.'

The researchers synthesised 176 studies to quantify hunting-induced declines of mammal and bird populations across the tropics of Central and South America, Africa and Asia. The study was led by Ana Benítez-López, who works at the department of Environmental Science at Radboud University in Nijmegen, the Netherlands. She cooperated with researchers from the Netherlands Environmental Assessment Agency (PBL), the universities of Wageningen and Utrecht in the Netherlands and a colleague from the School of Life Sciences, University of Sussex.

Higher hunting pressure around villages and roads

'There are several drivers of animal decline in tropical landscapes: habitat destruction, overhunting, fragmentation etcetera. While deforestation and habitat loss can be monitored using remote sensing, hunting can only be tracked on the ground. We wanted to find a systematic and consistent way to estimate the impact of hunting across the tropics. As a starting point, we used the hypothesis that humans gather resources in a circle around their village and in the proximity of roads. As such, hunting pressure is higher in the proximity of villages and other access points. From there the densities of species increase up to a distance where no effect of hunting is observed. We called this species depletion distances which we quantified in our analysis. This allowed us to map hunting-induced declines across the tropics for the first time,' Benítez-López explains.

Not only the big cuddly species

The main novelty of the current study is that it combined the evidence across many local studies, thus for the first time providing an overarching picture of the magnitude of the impact across a large number of species. The study takes all animals into account -- not only the big cuddly species, but birds and rodents as well. Benítez-López explains the difference in impact between birds and mammals: 'Mammals are more sought after because they're bigger and provide more food. They are worth a longer trip. The bigger the mammal, the further a hunter would walk to catch it.' With increasing wild meat demand for rural and urban supply, hunters have harvested the larger species almost to extinction in the proximity of the villages and they must travel further distances to hunt. Besides, for commercially interesting species such as elephants and gorillas, hunting distances are much larger because the returns are higher.

Protected areas are no safe haven

Another interesting finding of this study is that mammal populations have also been reduced by hunting even within protected areas. 'Strategies to sustainably manage wild meat hunting in both protected and unprotected tropical ecosystems are urgently needed to avoid further defaunation,' she says. 'This includes monitoring hunting activities by increasing anti-poaching patrols and controlling overexploitation via law enforcement'.

Source: Radboud University Nijmegen [April 13, 2017]

byUnknown

in Endangered Species, Natural Heritage, Wildlife

April 13, 2017

Hunting accounts for massive declines in tropical animal populations

Hunting is a major threat to wildlife particularly in tropical regions, but a systematic large-scale estimate of hunting-induced declines of...

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X-ray scanning immortalizes endangered primates in the digital afterlife, in 3-D

If you're a medical student, obtaining a human cadaver for learning anatomy or practicing surgical techniques is relatively easy. Thousands of people donate their bodies to science each year. But if you study and care for endangered primates, it's a different story.

Skimmer, a pygmy slow loris, was 19 when she died at the Duke Lemur Center in 2013. She is one of more than 100 
rare or endangered primates whose bodies are being preserved with help from an X-ray imaging technique 
called micro-computed tomography [Credit: Duke University]

Almost all of the roughly 100 species of lemurs are facing extinction in the wild due to logging, mining, hunting and slash-and-burn agriculture. Which is why, when an animal at the Duke Lemur Center dies from illness, injury or old age, a licensed veterinarian performs a postmortem exam within 24 hours of death, organs are removed, and tissue samples are collected so that other researchers can make use of them.

Cadavers of each species are stored in freezers or preserved in formalin—not for ghoulish curiosity, but so that years from now their bodies could be still be used for research and education.

And though these animals are gone, their bodies are now being preserved for present and future generations with help from an X-ray imaging technique called micro-computed tomography (microCT).

Soon, anyone will be able to go online to MorphoSource.org and get 3-D views of the internal anatomy of dozens of lemurs and other rare and endangered prosimian primates, in micrometer detail, without disturbing the original specimens.

"Even when they've passed, these animals continue to contribute valuable scientific data," said former Duke graduate student Gabe Yapuncich, who has been leading the effort to scan the specimens with Duke assistant professor Doug Boyer.

Yapuncich got the idea for the project while earning his doctorate in evolutionary anthropology. He was scanning the skeletal remains of present-day primates to see if certain foot bone measurements could help to reconstruct how much their extinct relatives might have weighed.

Researchers can learn about many aspects of primate biology from fossils, but most fossil specimens consist of isolated teeth or fragments of bones. Complete or even partial skeletons are rare.

"It seemed like a waste just to scan the foot and send it back," Yapuncich said. "Once I had a specimen on loan, I tended to scan the whole thing."

Virtual Dissection: No Scalpel, No Forceps

Yapuncich demonstrated how the technology works at Duke's Shared Materials Instrumentation Facility. On the ground floor of the Fitzpatrick Building stands a giant lead-lined box, installed in 2013 with startup funds from Boyer, which looks like an airport security scanner.

Inside, a Styrofoam cooler filled with dry ice contains the frozen remains of Beauty, a female bamboo lemur that died in 1985.

The microCT scanner blasts a cone-shaped beam of X-rays at the cooler as it spins slowly on a rotating platform. The X-rays that pass through Beauty's body hit a detector on the back wall, which records a snapshot.

The scanner takes thousands of snapshots for each full rotation. The data are sent to a computer, which uses the images to reconstruct two-dimensional cross sections of Beauty's insides, and these are stacked like slices of bread into a 3-D model.

Former Duke graduate student Gabe Yapuncich and assistant professor of evolutionary anthropology Doug Boyer 
are making 3-D X-ray scans of dozens of lemurs and other rare and endangered primates 
[Credit: Photos by Megan Mendenhall; design by Jon Fuller]

Yapuncich peers at the result on a nearby computer screen. It's a 3-D close-up of Beauty's head built from 1,900 cross-sectional images.

With the click of a mouse, he digitally dissects away Beauty's fur, skin and soft tissue to reveal the skeleton underneath in stunning, three-dimensional detail. He can also look at any 2-D slice to see internal structures in cross section.

The Duke Lemur Center is committed to studying lemurs without harming them. Imaging cadavers makes it possible to perform "virtual" dissections that would never be allowed on living animals.

With standard microCT researchers can visualize hard tissues such as bones and teeth, but by using special iodine-based stains, they can also see soft tissues such as muscles, nerves and blood vessels in the deceased animals.

Yapuncich has scanned the remains of more than 100 animals so far. A fat-tailed dwarf lemur named Jonas is one of them. When he died in 2015 at age 29, suffering from cataracts and other signs of age, he was the oldest of his kind. The scan shows his tail curled around his body, the roughly two dozen tail bones neatly lined up one after the other. "If you go to a museum collection, the tail vertebrae are just a bunch of bones in a box," Yapuncich said.

The Duke Lemur Center has housed and bred more than 4,000 endangered primates in its 50-year history. During that time, more than 400 cadavers from three dozen species of lemurs, lorises, galagos and tarsiers have been preserved for study.

The center fields dozens of cadaver requests from researchers each year. But these rare and fragile specimens can only be examined so many times using traditional methods. Repeated shipping and handling may expose them to damage and freeze-thaw cycles that would inevitably speed their decay.

By creating high resolution 3-D scans and putting them online, researchers hope to reduce destructive sampling and insure the availability of specimens for future study.

"There aren't that many available," said Duke R&D engineer and microCT specialist Justin Gladman. "If one researcher dissects and destroys one, the next researcher can't do anything with it."

"By scanning them in the microCT and creating these beautiful 3-D models, we can digitize the specimens and share them online," Gladman said. "Instead of being locked in a museum drawer, they're freely available."

Good from Tragedy

In the digital afterlife, Merlin's bony appendages are no longer nimble but still intact.

He was one of four of the fewer than 60 endangered aye-ayes living in captivity worldwide that died suddenly over 36 hours at the Duke Lemur Center in October 2016. Staff and researchers were devastated.

The culprit, tests later revealed, was a natural toxin found in avocados, not previously known to be harmful to lemurs, which damaged their heart muscles.

In assistant professor Doug Boyer's lab on Science Drive, recent Duke graduate Darbi Griffith uses software to stitch together nearly 3,000 2-D images of Merlin into a 3-D rendering.

Merlin was very popular with lemur center staff, and often enjoyed using his incredibly slender and dexterous middle finger to gently tease mealworms from his keepers' closed fists.

The 3-D volume rendering shows his body cloaked in skin and muscle. With a click his flesh fades away, and Griffith can zoom in on Merlin's skull to examine the complex wear patterns on his teeth, or peer inside his cranial cavity to estimate the size and shape of his brain.

Griffith has uploaded these 3-D images to an online database Boyer created called MorphoSource. Because the digitization is ongoing the Lemur Center scans haven't been made publicly available yet, but when they are, visitors to MorphoSource will be able to compare Merlin to other individuals, or measure anatomical variation across species.

Anyone will be able to browse the specimens, measure them, download the raw data and even create their own 3-D lemur models, both of bodies and skeletons, on a 3-D printer.

"It's the largest collection of 3-D lemur scans. That's pretty cool," Griffith said.

Source: Duke University [April 12, 2017]

byUnknown

in Endangered Species, Natural Heritage, Wildlife

April 12, 2017

X-ray scanning immortalizes endangered primates in the digital afterlife, in 3-D

If you're a medical student, obtaining a human cadaver for learning anatomy or practicing surgical techniques is relatively easy. Thousa...

Read More

Antarctic penguin colony repeatedly decimated by volcanic eruptions

One of the largest colonies of gentoo penguins in Antarctica was decimated by volcanic eruptions several times during the last 7,000 years according to a new study. An international team of researchers, led by British Antarctic Survey (BAS), studied ancient penguin guano and found the colony came close to extinction several times due to ash fall from the nearby Deception Island volcano. Their results are published in Nature Communications.

Gentoo penguins climbing slopes to the nesting colony on Ardley Island 
[Credit: Stephen Roberts]

Ardley Island, near the Antarctic Peninsula, is currently home to a population of around 5,000 pairs of gentoo penguins. Using new chemical analyses of penguin guano extracted in sediment cores from a lake on the island, the researchers unraveled the history of the penguin colony.

Climate conditions around Ardley Island have been generally favourable for penguins over the last 7,000 years and the team had expected the local population to show minor fluctuations in response to changes in climate or sea ice. The surprising result was that the nearby Deception Island volcano had a far greater impact than originally anticipated.

Lead author Dr Steve Roberts from BAS says: "When we first examined the sediment cores we were struck by the intense smell of the guano in some layers and we could also clearly see the volcanic ash layers from nearby Deception Island. By measuring the sediment chemistry, we were able to estimate the population numbers throughout the period and see how penguins were affected by the eruptions.

Volcanic ash layers in lake sediment cores extracted from Kiteschee Lake on Fildes Peninsula. The ash layers shown are 
associated with comparatively small eruptions from Deception Island in the last c. 2000-3000 years. The largest 
eruptions preserved in our lake sediment records from Fildes Peninsula and Ardley Island occurred at c. 7,000 years 
ago and c. 5,500-4,500 years ago and deposited over a metre of airfall and reworked ash in some lake sediment cores 
[Credit: Stephen Roberts and Emma Pearson]

On at least three occasions during the past 7,000 years, the penguin population was similar in magnitude to today, but was almost completely wiped out locally after each of three large volcanic eruptions. It took, on average, between 400 and 800 years for it to re-establish itself sustainably."

Dr Claire Waluda, penguin ecologist from BAS says: "This study reveals the severe impact volcanic eruptions can have on penguins, and just how difficult it can be for a colony to fully recover. An eruption can bury penguin chicks in abrasive and toxic ash, and whilst the adults can swim away, the chicks may be too young to survive in the freezing waters. Suitable nesting sites can also be buried, and may remain uninhabitable for hundreds of years."

The techniques developed in this study will help scientists to reconstruct past changes in colony size and potentially predict how other penguin populations may be affected elsewhere. For example, the chinstrap penguins on Zavodovski Island, which were disturbed by eruptions from the Mt Curry volcano in 2016.

Waluda continues: "Changes in penguin populations on the Antarctic Peninsula have been linked to climate variability and sea-ice changes, but the potentially devastating long-term impact of volcanic activity has not previously been considered."

Source: British Antarctic Survey [April 11, 2017]

byUnknown

in Antarctic, Earth Science, Ecosystems, Natural Heritage, Wildlife

April 11, 2017

Antarctic penguin colony repeatedly decimated by volcanic eruptions

One of the largest colonies of gentoo penguins in Antarctica was decimated by volcanic eruptions several times during the last 7,000 years a...

Read More

Putting a price tag on biodiversity

Talk to just about any biologist long enough and the conversation will steer toward the benefits of biodiversity. Although the ecological benefits of biodiversity are well documented, those benefits have rarely been expressed in dollars and cents. A team of economists and ecologists, including University of Illinois professor of environmental economics Amy Ando, has developed one of the first models to assign a dollar value to the loss or gain of species in an ecosystem. This new work offers an economic argument for preserving biodiversity.

The Cedar Creek Biodiversity Experiment: Each plot has 1, 2, 4, 8 or 16 different species of perennial prairie plants. 
Planted in 1994, this long-term experiment has shown that greater biodiversity leads to greater ecosystem
 productivity and carbon storage [Credit: G. David Tilman]

"Biodiversity has value in its own right, as people marvel at the beauty and variety of the many faces of nature," says Ando. "But those intrinsic values can be hard to quantify. In this study, we pinned down the monetary value of one particular practical service that biodiversity provides to people: carbon storage." The research team was led by Bruce Hungate, director of the Center for Ecosystem Science and Society at Northern Arizona University. The findings are published in Science Advances.

To build the model, the researchers first had to identify some measurable service of biodiversity that society has priced. Although biodiversity provides many valuable services, concern about climate change has led economists to put a dollar value on the abatement of climate-warming carbon emissions (ranging between roughly $40 and $400 per metric ton). And now there's a $175 billion global carbon market that pays for activities that remove carbon from the atmosphere.

Biodiversity could enter the game through a 4-billion-year-old form of carbon storage that plants provide: photosynthesis. Plants absorb carbon dioxide for energy and growth, storing the carbon in their leaves, stems, and roots, and later transferring it to the soil through decay. The key is to link biodiversity and carbon storage in a quantitative way. So researchers asked: Will changing the number of plant species in an ecosystem affect the amount of carbon it stores over time?

The National Socio-Environmental Synthesis Center (SESYNC) convened the team of scientists, which analyzed data from two long-term experiments in Minnesota grasslands that measured how plant and soil carbon changed with the number of plant species in a plot. Modeling results over 50 years, they estimated the "marginal" increase in carbon storage, or how much additional carbon is stored for every species added to the mix.

Each additional species in a grassland plot increased the plot's overall carbon storage, on average. One reason for this gain may be that new species can fill new niches, yielding more overall growth.

With more species came diminishing returns in cumulative carbon storage. A change from five to six species stored almost 10 times more carbon than a change from 15 to 16 species, showing that the biggest benefit came from adding species to the least diverse plots.

At small scales, about 2.47 acres, going from one to two plant species over a 50-year time period would store an additional 9.1 metric tons of carbon, potentially saving $804 per 2.47 acres based on a mid-range estimate ($137 per metric ton) of the social cost of carbon. At larger scales, cost savings could hypothetically be significant. For example, adding just one species to the approximately 29.5 million acres of cultivated lands restored to grasslands by USDA's Conservation Reserve Program could save over $700 million. The biggest cost savings come from restoring the most degraded, species-poor lands.

These numbers underestimate the total value of increased biodiversity because biodiversity confers economic value in many ways beyond storing carbon. "Biodiversity means products like wood, food, and fuel, and services like recreation, water purification, and flood protection, all of which could be quantified using our approach," says Hungate. "Money is a language that speaks, and showing the economic value of biodiversity underscores the importance of conservation and the policies that support it."

Although the value of biodiversity is more complex than just one economic measure, this new research takes a bold step toward understanding the value of nature.

Author: Debra Levey Larson | Source: University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES) [April 06, 2017]

byUnknown

in Biodiversity, Ecosystems, Environment, Natural Heritage

April 06, 2017

Putting a price tag on biodiversity

Talk to just about any biologist long enough and the conversation will steer toward the benefits of biodiversity. Although the ecological be...

Read More

First world survey finds 9,600 tree species risk extinction

The first ever global database of trees on Wednesday revealed that 9,600 tree species are threatened with extinction and identified a total of 60,065 in existence.

Brazil is the country with the most diverse tree population, with 8,715 species, according to the Botanic Gardens 
Conservation International (BGCI) group [Credit: AFP]

Brazil is the country with the most diverse tree population, with 8,715 species, according to the Botanic Gardens Conservation International (BGCI) group.

It also has the largest number of tree species—4,333—that only exist there.

In total 58 percent of trees are so-called single country endemics, with 2,991 species only found in Madagascar and 2,584 only found in Australia.

After Brazil, Colombia is the second most diverse country, with 5,776 different tree species, followed by Indonesia, with 5,142.

The London-based BGCI, which represents an estimated 2,500 botanic gardens around the world, used data from more than 500 published sources to create the list.

Of the 60,065 tree species, only around 20,000 have been assessed for their conservation status—of which 9,600 are threatened with extinction.

"BGCI's main reason for publishing the list is to provide a tool for people trying to conserve rare and threatened tree species," the organisation said in a statement.

"Currently, around 10,000 tree species are known to be threatened with extinction, largely by deforestation and over-exploitation.

"This number includes over 300 species that are critically endangered with fewer than 50 individuals remaining in the wild."

Aside from the Arctic and the Antarctic where there are no trees, the Nearctic region—comprising most of North America—has the lowest diversity, with less than 1,400 tree species.

The database will be continually updated, as around 2,000 new plants are discovered and described each year.

Source: AFP [April 05, 2017]

byUnknown

in Brazil, Ecosystems, Endangered Species, Environment, Natural Heritage, Rainforests

April 05, 2017

First world survey finds 9,600 tree species risk extinction

The first ever global database of trees on Wednesday revealed that 9,600 tree species are threatened with extinction and identified a total ...

Read More

Future CO2 and climate warming potentially unprecedented in 420 million years

New research led by the University of Southampton suggests that, over the next 100 to 200 years, carbon dioxide concentrations in the Earth's atmosphere will head towards values not seen since the Triassic period, 200 million years ago. Furthermore, by the 23rd century, the climate could reach a warmth not seen in 420 million years.

A living Ginkgo leaf (left) and fossil (right). Density of stomata in such leaves is proxy of atmospheric CO2 in past 
[Credit: Dana Royer]

The study, published in Nature Communications, compiled over 1200 estimates of ancient atmospheric carbon dioxide (CO2) concentrations to produce a continuous record dating back nearly half a billion years. It concludes that if humanity burns all available fossil fuels in the future, the levels of CO2 contained in the atmosphere may have no geologically-preserved equivalent during this 420 million year period.

The researchers examined published data on fossilised plants, the isotopic composition of carbon in soils and the oceans, and the boron isotopic composition of fossil shells. Gavin Foster, lead author and Professor of Isotope Geochemistry at the University of Southampton, explains: "We cannot directly measure CO2 concentrations from millions of years ago. Instead we rely on indirect 'proxies' in the rock record. In this study, we compiled all the available published data from several different types of proxy to produce a continuous record of ancient CO2 levels."

This wealth of data shows that CO2 concentrations have naturally fluctuated on multi-million year timescales over this period, from around 200-400 parts per million (ppm) during cold 'icehouse' periods to up to 3000 ppm during intervening warm 'greenhouse' periods. Although evidence tells us our climate has fluctuated greatly in the past (with the Earth currently in a colder period), it also shows the current speed of climate change is highly unusual.

Carbon dioxide is a potent greenhouse gas and in the last 150 years humanity's fossil fuel use has increased its atmospheric concentration from 280 ppm in the pre-industrialisation era to nearly 405 ppm in 2016. However, it's not just CO2 that determines the climate of our planet, ultimately it is both the strength of the greenhouse effect and the amount of incoming sunlight that is important. Changes in either parameter are able to force climate change.

"Due to nuclear reactions in stars, like our sun, over time they become brighter," adds co-author Dan Lunt, Professor of Climate Science at the University of Bristol. "This means that, although carbon dioxide concentrations were high hundreds of millions of years ago, the net warming effect of CO2 and sunlight was less. Our new CO2 compilation appears on average to have gradually declined over time by about 3-4 ppm per million years. This may not sound like much, but it is actually just about enough to cancel out the warming effect caused by the sun brightening through time, so in the long-term it appears the net effect of both was pretty much constant on average."

This interplay between carbon dioxide and the sun's brightness has fascinating implications for the history of life on Earth. Co-author Professor Dana Royer, from Wesleyan University in the US, explains: "Up until now it's been a bit of a puzzle as to why, despite the sun's output having increased slowly over time, scant evidence exists for any similar long-term warming of the climate. Our finding of little change in the net climate forcing offers an explanation for why Earth's climate has remained relatively stable, and within the bounds suitable for life for all this time."

This long-term view also offers a valuable perspective on future climate change. It is well recognised that the climate today is changing at rates well above the geological norm. If humanity fails to tackle rising CO2 and burns all the readily available fossil fuel, by AD 2250 CO2 will be at around 2000 ppm - levels not seen since 200 million years ago.

Professor Foster adds: "However, because the Sun was dimmer back then, the net climate forcing 200 million years ago was lower than we would experience in such a high CO2 future. So not only will the resultant climate change be faster than anything the Earth has seen for millions of years, the climate that will exist is likely to have no natural counterpart, as far as we can tell, in at least the last 420 million years."

Source: University of Southampton [April 04, 2017]

byUnknown

in Ancient Environment, Climate Change, Environment, Fossils, Geology, Natural Heritage

April 04, 2017

Future CO2 and climate warming potentially unprecedented in 420 million years

New research led by the University of Southampton suggests that, over the next 100 to 200 years, carbon dioxide concentrations in the Earth...

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Scientists publish study on glacial carbon cycle

Two Montana State University researchers have played a major role in discovering how microbial communities in melting glaciers contribute to the Earth's carbon cycle, a finding that has global implications as the bulk of Earth's glaciers shrink in response to a warming climate.

The Cotton Glacier stream in the McMurdo Dry Valleys region of Antarctica, where MSU researchers 
Heidi Smith and Christine Foreman sampled glacier runoff in 2012, in shown in this aerial photo 
[Credit: Christine Foreman]

Heidi Smith, a postdoctoral researcher, and Christine Foreman, associate professor of chemical and biological engineering, both of the Center for Biofilm Engineering in MSU's College of Engineering, were co-authors of a paper published in the prestigious journal Nature Geoscience.

Titled "Microbial formation of labile organic carbon in Antarctic glacial environments," the article was co-authored by researchers at the University of Colorado at Boulder, the U.S. Geological Survey, Stockholm University in Sweden and the Max Planck Institute for Marine Microbiology in Germany.

The paper challenges the prevailing theory that microorganisms found in glacial meltwater primarily consume ancient organic carbon that was once deposited on glacial surfaces and incorporated into ice as glaciers formed.

"We felt that there was another side to the story," said Smith, the paper's lead author. Smith earned a Ph.D. in ecology and environmental sciences in MSU's Department of Land Resources and Environmental Sciences in 2016, with Foreman as her adviser.

"What we showed for the first time is that a large proportion of the organic carbon is instead coming from photosynthetic bacteria" that are also found in the ice and that become active as the ice melts, Smith said. Like plants, those bacteria absorb carbon dioxide and in turn provide a source of organic matter.

The research team made the discovery after sampling meltwater from a large stream flowing over the surface of a glacier in the McMurdo Dry Valleys region of Antarctica in 2012.

Afterward, Smith spent two months at the Max Planck Institute for Marine Microbiology in Bremen, Germany, with support from the National Science Foundation's flagship interdisciplinary training program, the Integrative Graduate Education and Research Traineeship. There, she worked with colleagues to track how different carbon isotopes moved through the meltwater's ecosystem, allowing the team to determine the carbon's origin and activity.

The researchers ultimately found that the glacial microbes utilized the carbon produced by the photosynthetic bacteria at a greater rate than the older, more complex carbon molecules deposited in the ice, because the bacterial carbon is more "labile," or easily broken down. The labile carbon "is kind of like a Snickers bar," meaning that it's a quick, energizing food source that's most available to the microbes, Smith said.

Moreover, the researchers found that the photosynthetic bacteria produced roughly four times more carbon than was taken up by the microbes, resulting in an excess of organic carbon being flushed downstream. "The ecological impact of this biologically produced organic carbon on downstream ecosystems will be amplified due to its highly labile nature," Foreman said.

Although individual glacial streams export relatively small amounts of organic carbon, the large mass of glaciers, which cover more than 10 percent of the Earth's surface, means that total glacial runoff is an important source of the material. Marine organic carbon underpins wide-ranging ecological processes such as the production of phytoplankton, the foundation of the oceans' food web.

As glaciers increasingly melt and release the organically produced, labile carbon, "we think that marine microbial communities will be most impacted," Smith said. "We hope this generates more discussion."

In a "News and Views" commentary accompanying the article in Nature Geoscience, Elizabeth Kujawinski, a tenured scientist at Woods Hole Oceanographic Institution, called the team's work "an elegant combination" of research methods.

Taken together with another study published in the same issue of Nature Geoscience, about microbial carbon cycling in Greenland, Smith's paper "deflates the notion that glacier surfaces are poor hosts for microbial metabolism," according to Kujawinski. The two studies "have established that microbial carbon cycling on glacier surfaces cannot be ignored," she added.

Source: Montana State University [April 04, 2017]

byUnknown

in Antarctic, Biology, Climate Change, Ecosystems, Environment, Natural Heritage

April 04, 2017

Scientists publish study on glacial carbon cycle

Two Montana State University researchers have played a major role in discovering how microbial communities in melting glaciers contribute to...

Read More