Richard Conniff's Blog, page 66

New River Monster Surfaces

The new Arapaima species

For more than 200 years, skeptics have been announcing the end of the great age of species discovery—and the end in particular for finding anything really big.  But giant species somehow just keep showing up.

Now scientists are reporting the discovery of a river monster in Brazil’s Amazonas State. It’s a new species, described from a single specimen measuring 33 inches from head to tail, in a genus that can grow to almost 10 feet and weigh up to 440 pounds.

Arapaima, also commonly known as pirarucu, are air-breathing fish that inhabit creeks and backwaters in and around the Amazon basin.  They live by crushing other fish between their large bony tongue and the roof of the mouth.  People prize them both for their tasty flesh and for their handsome scales, which tourists (including this writer) used to carry home incorporated in handsome necklaces and other folk art.  But these huge fish are now badly overharvested, in part because it’s so easy to harpoon them when they come to surface to breathe. Arapaima gigas is listed as endangered under the Convention on International Trade in Endangered Species, or CITES.

The only known specimen of the new species, Arapaima leptosoma, turned up not in the wild, but at a research facility in Manaus, the Instituto Nacional de Pesquisas da Amazônia. A collector originally caught it in 2001, at the confluence of the Solimões and Purus rivers 200 miles west of the city.  Until recently, though, everyone assumed it was simply another Arapaima gigas, because scientists said that was the only species in the genus. But then Donald Stewart arrived in Manaus for a closer look—and soon realized he was seeing something entirely new.

Stewart with other Arapaima species

Writing in the journal Copeia, Stewart named the species leptosoma from the Greek meaning “slender body.”  He says it is distinctively different not just in color pattern, but in such features as the shape of sensory cavities on the head and the presence of a sheath that covers part of the dorsal fin.  Leptosoma is the first new Arapaima in 144 years.  But Stewart, who teaches in the College of Environmental Science and Forestry at the State University of New York in Syracuse, has lately been turning all of Arapaima classification upside down.

Writing earlier this year in Copeia, he made the case that four species in the genus originally described in the early nineteenth century and later merged into a single species were in fact all valid.  Meanwhile, Arapaima gigas, might just be a great big taxonomic mistake–or extinct.  “Araipaima gigas is supposed to be everywhere,” Stewart said in an interview, “and it’s actually nowhere.”  He has collected at two sites in the Amazon and a third in Guyana, using a 500-foot-long net pulled by 10 men—without finding gigas anywhere. Even the fish displayed under that name in the U.S. National Aquarium does not fit the description, he said.

“Everybody for 160 years had been saying there’s only one kind of Arapaima. But we know now there are various species, including some not previously recognized.”  In an email, he added that the basic work of describing new species stopped with an influential but incorrect 1868 publication.  Since then the science has remained stuck “in a nineteenth century time warp.” His two recent papers, he promised, “are really the tip of the iceberg for 10 foot giants that await discovery and description.”

Getting the taxonomy right matters for the simple reason that you cannot protect species if you don’t know what they are.  “Failure to recognize that there are multiple species has consequences that are far reaching,” Stewart said. “For example, there is a growing aquaculture industry for Arapaima, so they are being moved about and stocked in ponds for rearing.”  That could mean moving fish of one Arapaima species into the habitat of another.  “Eventually pond-reared fishes escape and, once freed, the ecological effects are irreversible. A species that is endangered in its native habitat may become an invasive species in another habitat. The bottom line is that we shouldn’t be moving these large, predatory fishes around until the species and their natural distributions are better known.”

These big, strange-looking creatures have been working the waters of the Amazon for tens of millions of years.   So far, no one really knows what it is we are now in danger of throwing away.

How Naturalists Die

Oh, geez. A field biologist has charted all the ways naturalists have died on my Wall of the Dead.  Is this cautionary?  Or just macabre?

Anyway, here you go.  It automatically saved to my computer as death.jpg:

How naturalists die.

The Gross National Delusion

A professor at Yale read this aloud to me today and, if I am not mistaken, there was an emotional hitch in his voice, around the line about “the strength of our marriages.”

It’s Bobby Kennedy (I met him once) on the false values of GNP:

Too much and for too long, we seemed to have surrendered personal excellence and community values in the mere accumulation of material things.  Our Gross National Product, now, is over $800 billion dollars a year, but that Gross National Product – if we judge the United States of America by that – that Gross National Product counts air pollution and cigarette advertising, and ambulances to clear our highways of carnage.

It counts special locks for our doors and the jails for the people who break them.  It counts the destruction of the redwood and the loss of our natural wonder in chaotic sprawl.

It counts napalm and counts nuclear warheads and armored cars for the police to fight the riots in our cities.  It counts Whitman’s rifle and Speck’s knife, and the television programs which glorify violence in order to sell toys to our children.

Yet the gross national product does not allow for the health of our children, the quality of their education or the joy of their play.  It does not include the beauty of our poetry or the strength of our marriages, the intelligence of our public debate or the integrity of our public officials.

It measures neither our wit nor our courage, neither our wisdom nor our learning, neither our compassion nor our devotion to our country, it measures everything in short, except that which makes life worthwhile.

And it can tell us everything about America except why we are proud that we are Americans.

You can go to youtube and hear Kennedy say it himself.

But be forewarned, when I looked in the introductory ad was–unbelievably– for a fucking BMW

Nose-Picking For New Species

For all of you who have been covertly digging for hidden treasure up your nose, here’s proof that it really can happen.  I came across this little gem on the Verge:

Tony Goldberg, habitat

After returning from an African research expedition, pathobiology professor Tony Goldberg found an unexpected stowaway: a tick hiding up his right nostril. “When you first realize you have a tick up your nose, it takes a lot of willpower not to claw your face off,” Goldberg, a University of Wisconsin–Madison researcher, says in a statement.

But Goldberg managed to retrieve the tick from his nostril and send it off for analysis, leading him to not just discover a potentially new species of tick, but what could also be a new explanation for how diseases spread between chimps and humans.

Though DNA analysis could only confirm the tick’s genus — and not whether it was a new species — because it wasn’t fully developed, its presence made Goldberg curious about why it was hiding up there in the first place.

[Technical note:  That "wasn't fully developed" makes no sense.  What Goldberg's published account actually says is that the researchers couldn't find a match on GenBank for the mitochondrial DNA they sequenced.]

Goldberg and other researchers began studying high-resolution photographs of chimps, and they noticed that 20 percent of the chimps had ticks hiding up their nostrils. And that number could be even higher: the photos were far from perfect for studying tick infestations, as they’d originally been  taken to examine chimps’ teeth. The researchers speculate that additional ticks may simply have been out of sight in the photographs.

The findings were published on September 30th in The American Journal of Tropical Medicine and Hygiene, and focus on chimps and ticks in the Kibale National Park in Uganda. In their paper, Goldberg and others suggest that hiding up nostrils may be an adaptation that these ticks have picked up in order to remain undetected. Chimps frequently groom each other, and by hiding up a nostril, the ticks may be able to feed safely.

But many of these ticks need to feed on three different hosts before they can complete their life cycle, and because they’ve been found to carry diseases, the researchers suggest these undetected ticks may enable pathogens to spread.

“This could be an underappreciated, indirect, and somewhat weird way in which people and chimps share pathogens,” says Goldberg. The researchers note this could allow diseases to spread between animals as well.

The researchers haven’t been able to capture any additional ticks, and though they might like to, examining chimps directly isn’t an option they’re currently considering. “It’s not really practical or safe to pick ticks out of chimps’ noses,” Goldberg says in a statement. “The chimps of Kibale are very well habituated to humans, but they would still object vigorously.”

The researchers admit that ticks making their way into a human nostril is a rare occurrence, but nonetheless, they suggest there’s some risk of international travelers unknowingly helping the ticks set up a population in a foreign country.

Here’s another account from the University of Wisconsin.  The whole thing makes me wonder if I flushed my chance at discovery down the toilet that time I came back from the Panama rain forest with ticks between my toes.  And what about those land leeches on Madagascar?

For all the rest of you nose-pickers out there, well, happy hunting.

Counting Tanzania’s Vanishing Elephants

A wildlife survey might not sound like the stuff of international intrigue, but what’s happening this week in Tanzania fits that description. Scientists, military, government officials, and international observers have descended on the east African nation in an effort that’s being described as a critical step in turning back the tide of elephant poaching.

At 6 a.m. and 3 p.m. every day, three planes take off at the Selous Game Reserve and run precise transects, at 350 feet above the ground and 180 kilometers an hour, to count wildlife of all kinds.  The most closely watched figure will be how many elephants—and how many carcasses—are left on the ground in what has been one of the last great strongholds of the species.

“It’s the most important survey that needs to be done in Africa on elephants,” said Iain Douglas-Hamilton, founder of Save The Elephants. He was instrumental in organizing the first pan-African elephant survey, which led to 1989’s worldwide ban on ivory trading, and he lent his expertise to the current effort when it was in the planning stages. “Selous has the second-largest elephant population in Africa, after Botswana—and by far the most threatened. We have data coming in that suggests there’s a real crisis there.”.

What’s dramatic for conservationists is the mere presence of scientists from the international community, monitoring the daily results as closely as if this were a national election.  Representatives from the Frankfurt Zoological Society and other outside groups helped organize the survey together with the Tanzania Wildlife Research Institute (TAWIRI). Tanzania has never allowed that kind of transparency in its wildlife management until now.

“In the past, there was extraordinary reluctance to even admit that there was a poaching problem,” said Tim Davenport, director of the Tanzania program for the Wildlife Conservation Society, which is not involved in the survey. “Officials were cautious about having anyone do a true survey of elephants and carcasses,” largely because the government was hoping to win international permission to sell its stash of almost 100 tons of confiscated ivory. That effort failed, in the face of evidence that the legalized ivory trade from some nations in southern Africa has served to launder illegal ivory—much of it traced by DNA sequencing to Tanzania itself.

Now President Jakaya Kikwete appears to have changed course, under intense pressure from foreign governments and worldwide alarm at the imminent disappearance of elephants from the wild in East Africa. “It’s pretty amazing,” said one visitor, in a hasty email early in the week from the survey command center. “The situation is so dire.” For years Kikwete did nothing to stop his country from becoming the bloody source of much of the world’s illicit ivory trade. “And then he was just persuaded to send in the military. And, lo and behold, yesterday a military truck arrived in the Selous. (I’m actually there). Everyone thought they were going to have to hold his feet to the fire … “

Up to now Tanzania has taken a sort of bipolar approach to its wildlife. It has designated a remarkable 28 percent of its land  for wildlife conservation, and it currently has the second largest elephant population in Africa, estimated at 60-70,000 animals. More than 800,000 tourists visit annually, to see both the wildlife and some of the most storied landscapes in the world, including Mount Kilimanjaro, Ngorongoro Crater, the Serengeti, and the Selous Game Reserve. Tourism is the second largest contributor to the national economy, after agriculture.

And yet poachers now kill about 30 elephants a day there with near impunity. That’s more than 10,000 a year, according to TAWIRI, and at that rate, elephants could disappear from the wild in just seven years. The government response in the past has amounted to a wrist slap. Wildlife officials reported earlier this year that they had taken 670 poaching cases to court over one recent 15-month period, resulting in $109,377 in fines– $123 per case. Meanwhile, elephant ivory sells for about $1000 a pound on the global black market. In a frustrated outburst early this month, Khamis Kagasheki, the minister of natural resources and tourism, declared, “The only way to solve this problem is to execute the killers on the spot.”

Political corruption up to the ministerial level is widely believed to play a role in the poaching. For instance, Tanzania allows trophy hunting of elephants and charges a fee of more than $22,000 for a larger specimen. In theory, that should provide essential funds to protect the herd and to encourage cooperation from nearby communities. But the money often ends up elsewhere. A Tanzanian newspaper reported this week that politicians and wildlife officials sometimes issue trophy permits improperly, or look the other way as legal permits end up in the hands of poachers. China, the end market for much of the blood ivory, is also the leading international investor in Tanzania, with a significant presence of Chinese staff on the ground.

Reached by phone at the Selous, Felix Borner of the Frankfurt Zoological Society said that the survey team has gone to extraordinary lengths to make its elephant count accurate. Preparation included a week working with wildlife observers from TAWIRI and Tanzania National Parks before hand-picking the most accurate among them, followed by an additional three days of training.

Borner had just returned to base from a day’s survey work, having piloted a Cessna 182 over five 60-mile transects. The pilot sees no animals, he said, because he is too focused on keeping the plane at speed and altitude, on a precise GPS track, the standard protocol for surveys. An observer in the front seat and two in the rear do the actual counting, with GPS data and high-resolution photography to confirm every sighting. They speak their sightings into a recording device, because writing them down on paper would mean taking their eyes away from the ground.

Each transect, covers a precise strip width of 160 meters on each side of the plane. A couple of angled “streamers” on the wing struts define the transect boundaries for the observers. Because the angle of the plane on the ground is different from the angle flight, technicians actually put the front wheel of the plane in a ditch to get the streamers positioned correctly.

It’s a long way from past elephant surveys in Tanzania and it will take till the end of this week to complete the work in the Selous. The big question is what President Kikwete and the Tanzania Parliament will do with the results, once they come out around the end of the year. As the visitor to the survey put it, in an email: “Lots of talk about how to manage media once the numbers come out, since they’re expected to be so bad.”

The larger challenge will be how to manage the elephants and stop the poachers before the last of East Africa’s great elephants herds vanishes into memory and dust.

Jurassic Park’s Blood Meal Cometh. (Well, Almost.)

The blood meal turned to stone, c. 46 million years ago

Here’s my latest story for the folks at TakePart.

Somewhere in the afterworld, Jurassic Park author Michael Crichton must be twitching and grinning with the glee of the science fiction writer proved right, or at least not so woefully wrong:  Researchers have announced the discovery of specimen USNM 559050, a fossilized mosquito from northwestern Montana, containing what is indisputably a blood meal in its swollen belly.

The specimen, described in today’s Proceedings of the National Academy of Sciences, dates back 46 million years—not quite to the age of dinosaurs, but tantalizingly close.  Crichton built his novel Jurassic Park, published in 1990, on what then seemed to be a far-fetched premise:  Scientists had supposedly figured out both how to extract DNA from the blood in ancient mosquitoes preserved in amber, and also how to use that DNA to bring the dinosaurs on which those mosquitoes had fed back to life

That premise is still far-fetched, but now just a smidgeon less so.  USNM 559050 turned up not in amber, but in shale, like most mosquito fossils found to date.  (The fossils in amber are typically midges, which apparently liked to hang around in a certain type of primordial forest and thus sometimes got trapped forever in amber exuded by resin-producing trees.)

Dale Greenwalt and his prize specimen.

Preservation of the mosquito specimen “was an extremely improbable event,” according to biochemist Dale E. Greenwalt and his co-authors.  “The insect had to take a blood meal, be blown to the water’s surface, and sink to the bottom of a pond … to be quickly embedded in fine anaerobic sediment, all without disruption of its fragile distended blood-filled abdomen.”  In a phone interview, Greenwalt likened the blood-swollen abdomen to “a balloon ready to burst.” He put the probability that it would have been preserved at “almost one over infinity.”

The researchers were able to use modern mineral science technology to analyze the contents of the abdomen without destroying the specimen.  They found high levels of iron and porphyrins—both important components of hemoglobin, the oxygen-carrying molecule in red blood cells. It is the first time anyone has found actual blood in a fossilized mosquito, from the host animal it had been feeding on immediately prior to death.

Finding blood remnants is, however, not even close to Crichton’s fantasy of finding intact DNA. Jurassic Park was great entertainment, said Greenwalt, and it also caused scientists to undertake useful research to test the idea of recovering ancient DNA.  “But DNA is a very large, very fragile molecule,” he said, “and the consensus now is that it’s just not going to survive.”  Researchers have looked for DNA even in insects preserved for as little as 50 to 10,000 years in subfossilized resin, called copal, “and found nothing.”

The new find came about largely through the work of amateur paleontologists.  Greenwalt, a retired cell biologist in the biotech industry, now works as a volunteer at the Smithsonian Institution. A few years ago, he happened to be reading a huge tome about insect evolution when his attention riveted on a single paragraph about fossil insect specimens from the Coal Creek member of the Kishenehn Formation.

Leona Constenius collecting on the Flathead, around the time of the discovery

With permission from the U.S. Forest Service, Greenwalt began collecting there, on the Middle Fork of the Flathead River.  He eventually learned that the original insect fossils had been gathered in the early 1980s by a couple from Whitefish, Montana. Norm and Leona Constenius used to hike in the area while their son Kurt was doing his research for a doctorate in geology.  They eventually retrieved their collection from their basement and donated it to the Smithsonian.  There, Greenwalt found USNM 559050.

The new research proves conclusively that one of our least favorite animal behaviors—insect feeding on blood—has been around for tens of millions of years.  USNM 559050 is not the oldest fossil mosquito; other specimens date back into the Cretaceous, when dinosaurs lived.  Earlier specimens have also had a proboscis like modern mosquitoes, leading scientists to suspect that they were blood feeders.  Moreover, some of those fossils have revealed the presence of blood-borne disease organisms, including the malaria plasmodium.  But finding actual blood seals the case.

The study could help researchers patching together the early evolution of insect blood feeding—now practiced by about 14,000 living species, including flies, fleas, lice, bed bugs, and a few vampire moths.  It could also improve our understanding of important insect-borne diseases like malaria, yellow fever, and dengue fever.  “Mother Nature is always changing,” said Greenwalt, “and we’re never sure how.  Any information about the past might help us understand what could happen in the future.”

That leaves one big question: What species did USNM 559050 feed on in the moments before death? The specimen did not have enough detail for co-author Ralph E. Harbach, an entomologist at the Natural History Museum in London, to make a positive identification.  But the mosquito most closely resembles a modern genus, Culiseta, in which the mosquitoes feed exclusively on birds.

That is, the blood meal certainly didn’t come from dinosaurs. But it may well have come from the birds that we now know to be their closest living descendants.

Save Endangered Species: Die Young

New Zealand has a high percentage of endangered birds, like this yellow-eyed penguin. (Photo: © paradoxdes / Fotolia).

I apologize for the depressing headline, but that seems to be the message behind this press release from the University of California at Davis.

You would think the authors might have made some effort to disambiguate or disarticulate, or whatever it is careful researchers are supposed to do, these results, with the aim of separating longer lifespan from all the attendant socio-economic and medical changes that make it possible.

That is, we should be able to figure out how to enjoy a reasonably long healthy life without destroying the entire planet.

Not much help here about how to make that happen. So … just die, you miserable buggers.

And, oy, you in New Zealand, die sooner:

As human life expectancy increases, so does the percentage of invasive and endangered birds and mammals, according to a new study by the University of California, Davis.

The study, published in the September issue of Ecology and Society, examined a combination of 15 social and ecological variables — from tourism and per capita gross domestic product to water stress and political stability. Then researchers analyzed their correlations with invasive and endangered birds and mammals, which are two indicators of what conservationist Aldo Leopold termed “land sickness,” the study said.

Human life expectancy, which is rarely included among indexes that examine human impacts on the environment, surfaced as the key predictor of global invasions and extinctions.

“It’s not a random pattern,” said lead author Aaron Lotz, a postdoctoral scholar in the Department of Wildlife, Fish and Conservation Biology when the study was conducted. “Out of all this data, that one factor — human life expectancy — was the determining factor for endangered and invasive birds and mammals.”

The study analyzed data from 100 countries, which included roughly 87 percent of the world’s population, 43 percent of global GDP per capita, and covered 74 percent of Earth’s total land area. Additional factors considered were agricultural intensity, rainfall, pesticide regulation, energy efficiency, wilderness protection, latitude, export-import ratio, undernourishment, adult literacy, female participation in government, and total population.

The findings include:

New Zealand, the United States and the Philippines had among the highest percentages of endangered and invasive birds.
New Zealand had the highest percentage of all endangered and invasive species combined, largely due to its lack of native terrestrial mammals. The study said that in the past 700 to 800 years since the country was colonized, it has experienced massive invasion by nonindigenous species, resulting in catastrophic biodiversity loss.
African countries had the lowest percentage of invasive and endangered birds and mammals. These countries have had very little international trade, which limits opportunities for biological invasion.
As GDP per capita — a standard measure of affluence — increased in a country, so did the percentage of invasive birds and mammals.
As total biodiversity and total land area increased in a country, so did the percentage of endangered birds. (Biodiversity in this context is not a measure of health but refers to the number of species in an area.)

Lotz said the study’s results indicate the need for a better scientific understanding of the complex interactions among humans and their environment.

“Some studies have this view that there’s wildlife and then there’s us,” said Lotz. “But we’re part of the ecosystem. We need to start relating humans to the environment in our research and not leave them out of the equation. We need to realize we have a direct link to nature.”

Aaron Lotz, Craig R. Allen. Social-Ecological Predictors of Global Invasions and Extinctions. Ecology and Society, 2013; 18 (3) DOI: 10.5751/ES-05550-180315

The Secret to Jellyfish Success: Cruise Control

A jellyfish in the South China Sea. (Photo: David Lo/Getty)

Here’s my latest blog item for the TakePart web site. You can read it there. But I am posting the whole piece here so I can include a helpful video.

In the popular imagination, jellyfish are just blobs—listless drifting things, without eyes, ears, or even a brain for figuring out how to get from one place to another. Scientists have long argued against this misguided notion. They say the familiar medusa-style (or bell-shaped) jellyfish are highly effective at getting where they need to go, employing both jet propulsion and a rowing motion.  They travel efficiently enough, in fact, that jellyfish often outcompete the fish that appear to be their bigger, faster, smarter rivals.

So how do they do it? The secret to jellyfish locomotion, according to a new study in the Proceedings of the National Academy of Sciences, isn’t about how hard the jellyfish works.

It’s about how it relaxes.

Until now, scientists understood jellyfish movement this way:  When a jellyfish contracts, it shoots out water from within the bell.  At the same time, the outer edges of the jelly flap and push water away, much as each oar on a boat spins off a vortex in its wake.  The motion of contracting also causes a rubbery disk called the mesoglea in the middle of the jellyfish to bend down at its outer edges.  Then, when the jellyfish, relaxes, the mesoglea springs back out again, filling the bell with water for the next burst of speed.

Even to scientists, though, this explanation of how a jellyfish gets around has never been entirely satisfying.  Not to put too fine a point on it, a jellyfish is  mostly gelatinous goo.  Sea snot, even. Only about one percent of its mass is muscle, compared to more than 50 percent in the average fish. Moreover, jellyfish muscle is only one cell layer thick.

“It’s always been sort of counterintuitive,” says Brad Gemmell of the Marine Biological Laboratory at Woods Hole, MA. “Fish are highly advanced predators with great visual and chemosensory abilities.” They can spot an energy-rich food source at a distance and chase it down. A jellyfish, meanwhile, can eat only what it happens to bump into.

And yet a vast bloom of jellyfish can suddenly appear in a habitat and gobble up all the available food, including fish eggs and the fish themselves.  In one particularly ghastly case off the coast of Ireland, a jellyfish flotilla 10 square miles in area swarmed over an organic fish farm, killing 100,000 salmon worth more than $2 million.

Jellyfish blooms have become far more common in recent years, probably because of increasing ocean acidification. They’ve clogged intake lines and last week shut down a nuclear power plant in Sweden, and they’ve driven swimmers out of the water from Florida to Italy.  They’ve also slowed the recovery of commercial fisheries by outcompeting cod and other fish for prey.

Biologists who study how jellyfish get around have customarily focused on the way the jellyfish contracts its muscles.  There didn’t seem to be much happening during the relaxation part of the cycle.  But when Gemmell and his co-authors took a closer look at two common species, including moon jellies, they discovered that jellyfish are taking advantage of a hidden form of locomotion:  Because jellyfish have that familiar radial shape, each contraction creates a donut-shaped vortex inside the bell.  That vortex draws in water and pushes the jellyfish forward as it is basically coasting, with no muscle movement whatsoever.

Here’s a video that is, I’m afraid, really boring. But it will give you a better sense of how the donut vortex moves water and propels the jellyfish:

This energy-efficient power source accounts for about 30 percent of forward motion, according to the new study.  Combine it with the passive energy storage and recovery that comes from the springiness of the mesoglea, and muscle movement occurs just 20 percent of the time during the jellyfish swimming cycle.

That’s far more efficient than any fish.  The only limit has to do with size: Because jellyfish muscles are only one cell layer thick, they become less effective as a jellyfish gets bigger.  Even so, it takes a fish weighing more than 220 pounds to begin to match the energy efficiency of a jellyfish.

Gemmell says the new study, part of a larger U.S. Navy project on nontraditional forms of locomotion, could ultimately lead to high-efficiency, low speed vehicles–for instance, oceanic measuring devices meant to maintain their position in the water column unattended for months or years at a time.

For now, though, it’s enough to understand how one important animal group succeeds with almost no effort—and to know that strong and sophisticated do not always triumph over small, simple, and slow.

The Microbiome in the Forest

A rainforest in Panama, where nitrogen-fixing species abound ((Photo: Marcos Guerra, Smithsonian Tropical Research Institute)

Not long ago in Guangdong Province in southeastern China, botanists were working to save the last remnants of an obscure tree species, Euryodendron excelsum. Fewer than 200 hundred individuals in the species are known to survive, and they are scattered around the most densely populated corner of the most populous nation on Earth. Woodcutting and land clearing are constant threats.

Past studies had focused on the obvious biological and ecological aspects of these trees. But the species was still critically endangered. The new study, by researchers at Yunnan University, looked instead at a hidden world — the microbes living in and around the trees’ roots.

The basic conservation strategy was to grow seedlings in nurseries and transplant them out into new populations in protected areas — and the life-or-death factor turned out to be the mycorrhiza (literally “root fungi”) in the soil. Inoculating the seedlings with these fungi gave them an 80 percent survival rate, the study found. On their own, only 46 percent survived.

That result might not surprise most botanists, who have long recognized the critical role of microbes in mediating a plant’s uptake of nitrogen, phosphorous, water, and other essential nutrients. But until recently, this underground world was “a black box,” says ecologist Tom Horton of the State University of New York in Syracuse. The only way to study microbes was to grow them in culture or on seedlings. It took months, and it was sometimes hard to know what species you were looking at, much less how it functioned. The enormous diversity of microbes around a tree tended to get lumped into a few nebulous categories.

But that has changed dramatically over the past decade. Because of the increasing sophistication and affordability of genetic sequencing technology, researchers can now characterize the changing microbial community around a plant in precise detail in a matter of hours. As a result, the microbiome of trees is changing forest ecology much as the human microbiome now promises to transform the way we practice medicine.

Ecologists have come to recognize the vital importance of microbes to the survival of endangered species from Palm Beach, Florida, to Rajasthan, India. They are now also beginning to sort out the role of microbes in tropical forest restoration projects, climate change planning, bioremediation of toxic waste sites, pest or disease control, and commercial forestry.

Some of this new work involves using microbes to manipulate narrow environments in ways that can seem weirdly precise and powerful. In one recent study in Italy, for instance, researchers at the University of Verona took a bacterial strain they had found in an oil refinery’s discharge drain. Because these bacteria seemed to have developed the power to transform a variety of hydrocarbon pollutants into less noxious forms, and because another strain in the same species had recently turned up living in the soil around hybrid poplars, the researchers set out to test the oil refinery strain in poplars. In bioremediation projects, these fast-growing trees often get planted at mines, abandoned factories, and other hazardous waste sites because they can efficiently pull contaminants out of the soil. Untreated poplars in the study removed between 82 and 87 percent of the hydrocarbon contaminants. But tweaking the process with the oil refinery bacteria boosted that to 99 percent abatement.

Other research on trees and their microbes seems to touch on the fate of the Earth itself. A study published this month in Nature, for instance, looked at forest regrowth on abandoned agricultural land in Panama.  Just in the first 12 years, Princeton University researcher Sarah Batterman and her co-authors found, these young forests took up about 40 percent of the carbon they would ultimately store after 300 years. It worked out to 79 tons of carbon stored per acre, equivalent to the carbon emissions of an average American car driven 500,000 miles.

How does reforestation work this magic? Tropical forests benefit from an early surge of tree and vine species that fix nitrogen from the atmosphere — a process that is utterly dependent on the nitrogen-fixing bacteria that colonize their roots. For conservationists attempting to restore tropical forests, the take-home from the study is that it can be critical to ensure the diversity of nitrogen-fixing plants (and microbes) in the early re-growth.

That kind of surge happened naturally at the research sites in Panama, says co-author Dylan Craven, who worked on the study as a doctoral candidate at the Yale School of Forestry & Environmental Studies. But in nutrient-poor or drought-prone areas, he suggests, conservationists might need to take a more active approach. “It’s not like there’s a manual for how to do this,” he says.

In some restoration projects, workers already collect tree seedlings from nearby forests and thus import the nitrogen-fixing microbes in the soil along with the seedlings. Elsewhere, the most efficient strategy might be to plant scattered patches of nitrogen-fixing seedlings on a site, to stimulate re-growth around them and eventually fill in the gaps.

Given that half of tropical forests are secondary growth on abandoned farmlands, these microbial strategies can be a factor in the debate about using reforestation to offset climate emissions. (They matter less in temperate forests, where nitrogen-fixing species are scarce.)

Microbes may also determine whether different tree species will be able to adapt as the climate changes. At the University of British Columbia, forest ecologist Suzanne Simard looks at how Douglas firs will handle a projected shift in their range 500 kilometers north into the Yukon over the next 50 years. These trees depend on a community of about 2,000 species of fungi, as well as an unknown variety of bacteria, and together these microbes form a tightly connected network trading nutrients back and forth from one side of a forest stand to another.

“We really haven’t determined whether the mycorrhizal fungi will migrate along with their tree hosts,” says Simard. “And without an appropriate web of fungi to help the establishment of seedlings, forests may not migrate to new locations where climate becomes hospitable for them.” When commercial forestry companies first attempted to introduce Douglas fir trees to New Zealand in the mid-twentieth century, she notes, the trees sickened and died, until researchers figured out that they had to inoculate seedlings with the soil fungi from back home.

It’s possible that sort of strategy might also work in the Yukon. Moreover, inoculating seedlings with microbes has by now become standard practice for commercial forest companies, and they could perhaps make it happen. (Commercial nurseries often fumigate their seedlings to kill off fungal or bacterial pathogens. But fumigation also kills off the beneficial microbes, so a thriving business has grown up around reintroducing them to the soil.) The new ability to identify microbes and understand their function has even raised the tantalizing possibility of treating forests with microbes to boost disease resistance or tolerance to unfamiliar climate conditions.

“Everybody is always looking for the silver bullet, some way to inoculate seedlings and improve growth,” says Simard. “But in my research, the introduced microbes get wiped out by the native fungi right away. You go back in ten years, and they’re not there. It would be nice to think that we can add something to the forest that would make trees magically grow. But all the evidence suggests that we can’t.”

What the new microbial research can do is at least shift forest managers and biologists away from thinking simply about trees as board feet, or diameter at breast height, or even as habitat for birds, insects, mammals, and other creatures. Instead, the microbial underworld of a tree is turning out to be as diverse and complex as the canopy overhead, and it is the world on which all those other worlds depend.

Killing Dogs for Animal Welfare

A street dog–one of thousands– in Mumbai, India.

In the face of protests that the plan is “criminal” and “inhumane,” Romanians is about to begin a program to catching and euthanize its feral dogs.  The proposal arose from growing alarm over the 64,000 feral dogs said to be roaming the streets of Bucharest, and 7800 dog bite injuries in the city so far this year. It gained momentum last month after a stray dog mauled a four-year-old boy to death.

Legislation authorizing the culling of stray dogs—if no one adopts them within 14 days—has already cleared the Romanian parliament and been approved by the national court.  It now awaits the signature of President President Traian Basescu, who has declared that “humans are above dogs.”

Predictably, animal rights activists are outraged.  The World Society for the Protection of Animals has criticized the culling as “both inhumane and ineffective.” Vier Pfoten, a Romanian animal welfare group, calls it “mass killing,” arguing instead for continuing a program to catch stray dogs and sterilize them.

It’s easy enough to understand where the animal welfare activists are coming from: I love my dog, too.  The debate also matters because it isn’t just about Romania.  It’s happening everywhere from Detroit, which has 40,000 feral dogs, to Srinigar, India, which has one feral dog for every 13 people.  But instead of automatically opposing the euthanasia idea, it’s worth pausing to think more clearly about what animal welfare really means.  Feral dogs aren’t just bad for people, it turns out.  They’re also catastrophically bad for wildlife.

The evidence of the damage they cause …   to read the rest of this article, click here.

 [RC1]