6. Carrying Capacity

2014-10-13. A Threat Is Seen in Pumas’ Isolation. By Douglas QuenQua, The New York Times.

2014-04-27. A variety of California kingsnake is wreaking havoc in Canary Islands. Excerpt: An albino variety of California kingsnake popular in the pet trade has infested the Canary Islands, decimating native bird, mammal and lizard species that have had no time to evolve evasive patterns in what was once a stable ecology northwest of Africa. ...Canary Island biologists fear that the snakes may be nibbling three native species of gecko, skink and giant lizard into extinction. ..."Most control programs for invasive reptiles are initiated long after the problem has gotten out of hand," Reed said. "Unfortunately, this sort of thing will probably become more common as international borders fall, incomes rise and more people get interested in owning exotic pets."...  http://www.latimes.com/science/la-me-kingsnake-20140428,0,2901782.story#ixzz30yhbHq5B.  By Louis Sahagun, Los Angeles Times.

2014-03-24. Carp(e) Diem: Kentucky Sends Invasive Fish To China. Excerpt: ...The invasive Asian carp has now been found in 12 states and in the Great Lakes watershed, gobbling up native fish, jumping aggressively into boats and reproducing like crazy. Researchers have tried various ways to slow the spread of the fish as it prowls other waterways. ...So now a processing plant in Kentucky is trying the latest method of Asian carp disposal: sending them to China. ...Angie Wu ships them to her native country — China — where they are a prized food. "There are a lot [of carp] in China but most of them are farmed ... not very clean as here," she says. Wu has shipped more than a half-million pounds of processed carp to China. ...Asian carp hasn't caught on in U.S. restaurants, but that hasn't stopped Kentucky from trying to teach people how to prepare it. ...The state has also hosted tastings to show people that when you fry Asian carp in cornmeal, it's not that different from catfish. ...one longtime fishermen and distributor, Ronnie Hopkins...says it is possible to make a living on Asian carp, but it's not easy. He says native fish sell for about 60 cents a pound — the abundant carp go for just 10 cents a pound ... and that's if he can find a local buyer. "I wish the state would get more involved and maybe use it as product in our schools. We're buying from other countries and other states right now when we've got an abundance of fish we could use," says Hopkins.... http://www.npr.org/blogs/thesalt/2014/03/24/293846571/carp-e-diem-kentucky-sends-invasive-fish-to-china. Whitney Jones, NPR.

2014-03-16. Officials give up on evicting pythons — big but nearly invisible in the wild — from Everglades.  Excerpt: ...Only in Florida can a search for one invasive monster lead to the discovery of another. ...recently, a group of volunteers called Swamp Apes was searching for pythons in Everglades National Park when it stumbled on something worse: a Nile crocodile, lurking in a canal near Miami suburbs. It was an all-points alarm, prompting an emergency response by experts from the national park, the Florida Fish and Wildlife Conservation Commission and the University of Florida. They joined the Swamp Apes and wrestled the reptile out of the canal. Nile crocs are highly aggressive man-eaters known to take down huge prey in Africa, and officials worried that the one in the canal might be breeding in the swamp since it was first spotted two years ago. Worrying is what Florida wildlife officials often do when it comes to invasive species. The state is being overrun by animals, insects and plants that should not be there, costing Floridians half a billion dollars each year in, among other things, damaged orange groves, maimed pets and dead fish in water where plants have depleted the oxygen. ...Native Florida alligators are already in a death match with giant Burmese pythons and other python species to sit atop the food chain. On top of that is a rogues’ gallery of bad-to-the-bone lizards, fish and frogs. They include the Argentine tegu, which eats sea turtle eggs; the Nile monitor lizard, which kills house pets; the Cuban tree frog, which dines on other frogs; and the greedy lionfish, which is eating scores of native fish. ...Up to 100,000 pythons are estimated to be living in the Everglades, and more than 1,500 thrill-seekers, amateurs and skilled hunters who flocked to the event from across the country caught only 68. http://www.washingtonpost.com/national/health-science/big-but-nearly-invisible-in-the-wild-officials-give-up-on-evicting-pythons-from-everglades/2014/03/16/58cab268-aa37-11e3-8599-ce7295b6851c_story.html. Darryl Fears, Washington Post.

2014-02-24. Science Takes On a Silent Invader. Excerpt: Since they arrived in the Great Lakes in the 1980s, two species of mussels the size of pistachios have spread to hundreds of lakes and rivers in 34 states and have done vast economic and ecological damage. ...the quagga and zebra mussels, have disrupted ecosystems by devouring phytoplankton, the foundation of the aquatic food web, and have clogged the water intakes and pipes of cities and towns, power plants, factories and even irrigated golf courses. ...Daniel P. Molloy, an emeritus biologist at the New York State Museum in Albany ...Leading a team at the museum’s Cambridge Field Research Laboratory in upstate New York, ... discovered a bacterium, Pseudomonas fluorescens strain CL145A, that kills the mussels but appears to have little or no effect on other organisms. ...New York State has awarded a license to Marrone Bio Innovations, a company in Davis, Calif., to develop a commercial formulation of the bacterium. The product, Zequanox, has been undergoing tests for several years, with promising results ...Zequanox killed more than 90 percent of the mussels in a test using tanks of water from Lake Carlos in Minnesota ...A control group of freshwater mussels, unionids from the Black River in Wisconsin, were unharmed. ...Natives of Eastern Europe ...zebra and quagga mussels began moving up the Volga River toward Western Europe 200 years ago. ...Both species are thought to have arrived in North America in the ballast of trans-Atlantic cargo ships....  http://www.nytimes.com/2014/02/25/science/science-takes-on-a-silent-invader.html. Robert H. Boyle, The New York Times.

2012 Jun 07. Warming nears point of no return, scientists say. By David Perlman, SF Gate. Excerpt:  The Earth is reaching a "tipping point" in climate change that will lead to increasingly rapid and irreversible destruction of the global environment unless its forces are controlled by concerted international action, an international group of scientists warns. Unchecked population growth, the disappearance of critical plant and animal species, the over-exploitation of energy resources, and the rapidly warming climate are all combining to bring mounting pressure on the Earth's environmental health…scientists from five nations, led by UC Berkeley biologist Anthony Barnosky, report their analysis Thursday in the journal Nature….

2011 July 14.  Ecosystems take hard hit from loss of top predators. By Sarah Yang and Robert Sanders, UC Berkeley News Center.  Excerpt: BERKELEY — A paper reviewing the impact of the loss of large predators and herbivores high in the food chain confirms that their decline has had cascading effects in marine, terrestrial and freshwater ecosystems throughout the world. The paper, published in the July 15 issue of the journal Science by an international team of 24 researchers, presented evidence highlighting the reverberating – and often unexpected – effects the loss of “apex consumers” have had not only on immediate prey species, but also on the dynamics of fire, disease, vegetation growth, and soil and water quality...

2011 May 31. Groundwater Depletion Is Detected From Space. By Felicity Barringer, The NY Times. Excerpt: Scientists have been using small variations in the Earth’s gravity to identify trouble spots around the globe where people are making unsustainable demands on groundwater, one of the planet’s main sources of fresh water…
...Jay S. Famiglietti, director of the University of California’s Center for Hydrologic Modeling here, said the center’s Gravity Recovery and Climate Experiment, known as Grace, relies on the interplay of two nine-year-old twin satellites that monitor each other while orbiting the Earth, thereby producing some of the most precise data ever on the planet’s gravitational variations. The results are redefining the field of hydrology, which itself has grown more critical as climate change and population growth draw down the world’s fresh water supplies….
…Yet even as the data signals looming shortages, policy makers have been relatively wary of embracing the findings….

2011 March 21. As Larger Animals Decline, Forests Feel Their Absence. By Sharon Levy, Environment 360 (Yale). Excerpt: …Today native Mauritian plants, under siege from a tide of invasive competitors and predators, hang on only in a few small conservation management areas. Even where invasive plants are laboriously weeded out by hand, large-fruited native tree populations are dwindling because of a lack of fruit-eating animals to disperse the trees’ seeds….
…As part of a restoration effort on Ile aux Aigrettes, an uninhabited islet off the Mauritius coast, the Mauritius Wildlife Federation and the Mauritius government in 2000 introduced giant Aldabra tortoises to test whether the tortoises could help revive native vegetation. The tortoises are now dispersing the seeds of several native plants and are knocking back an invasion of the exotic tree, Leuceana leucocephala, by devouring its seedlings….

2010 September 27. Old Trees May Soon Meet Their Match. By Jim Robbins, New York Times. Excerpt: For millenniums, the twisted, wind-scoured bristlecone pines that grow at the roof of western North America have survived everything nature could throw at them, from bitter cold to lightning to increased solar radiation. 
Living in extreme conditions about two miles above sea level, they have become the oldest trees on the planet. 
… Now, however, scientists say these ancient trees may soon meet their match in the form of a one-two punch, from white pine blister rust, an Asian fungus that came to the United States from Asia, via Europe, a century ago, and the native pine bark beetle, which is in the midst of a virulent outbreak bolstered by warming in the high-elevation West. 
…The pest and the disease working together are especially deadly. “Blister rust kills young trees rapidly,” Dr. Schoettle said. “The mountain pine beetle only kills the larger trees, but those are the trees that produce the seeds. So when you have a combination of blister rust and the beetle, that severely constrains recovery of the population.”
The long-term strategy that biologists are banking on to save the bristlecones from dying out completely is finding the few trees that are resistant to the fungus and growing their seeds into rust-resistant seedlings. 
…The bristlecones face even more fundamental changes. Warmer temperatures are significantly altering ecosystems… Some ecologists think that as warming continues, species that live at the top of mountains may no longer have a niche and simply disappear, something that has been called the “rapture hypothesis.” 
…“The key to the bristlecone is that they grow in a rigorous environment,” said Ronald Lanner, a retired forest biologist who studied bristlecones and has written a book about them, “and that environment is also rigorous to their pests.”

2010 May 7. Pythons in Florida Stalked by Hunters and Tourists Alike. By Damien Cave, NY Times. Excerpt: FLORIDA CITY, Fla. — Thousands of Burmese pythons, the offspring of former pets, have invaded the Everglades, eating birds, bunnies, even alligators. It has gotten so bad that Congress is considering an outright ban on buying or selling nine kinds of giant snakes.
But an odd thing has happened here in the swamp: the pythons have become celebrities. The snakes are fast becoming an element of Florida lore, attracting “oohs” and “ahhs” from tourists, along with groans from biologists and even python hunters like Bob Freer.
“It’s a little frustrating and very strange,” said Mr. Freer, who figures that his 40 captured pythons — most of which he has euthanized — make him the state’s top private hunter. “They’re asking about pythons that don’t even belong here, instead of alligators.”
Trouble is, the newfound fascination obscures what biologists and Mr. Freer describe as a serious problem. In their view, python proliferation — still significant despite a cold winter that might have killed half the population — is simply the sexiest example of widespread disrespect for pets and the wilderness....

2009 Fall. Hardrock Headache. By Alice Tallmadge, Forest Magazine. Excerpt: ...There’s no doubt that hardrock mining helped build the West. It lured the curious and the inventive, the brave and the greedy, the visionary and the hopeful across the plains and into the mountains of the arid West. The 1872 Mining Law made land and mining cheap and laid out a welcome mat for mining into the twenty-first century. Mining generated communities, agriculture, railroads and commerce and built an industry that provided a livelihood for thousands.
Now we know the earth exacts a huge price for the taking of its minerals. Thousands of acres of public lands across the West are affected by acid mine drainage from abandoned mines, an insidious mining residue that can appear years after a mine has been shuttered and can last for decades. In addition, tunnel openings, vertical shafts and mineral-laced pools pose safety hazards for humans and wildlife.
Today, thousands of abandoned hardrock mining sites are located in the western United States—19,000 inventoried sites on Bureau of Land Management land and about 40,000 on national forest land. Thousands more sites have not yet been inventoried. Because mining companies aren’t required to post bonds for cleanup, taxpayers are footing the bill for billions of dollars in reclamation costs that will, in some cases, be required for decades....
See also:
* The Mine Next Door by Scott Streater
* Mining for Reform by Joshua Zaffos
* Cleanup at the Blue Ledge by Alice Tallmadge
* Reclaim and Reuse by Scott Streater

2009 August 12. NASA RELEASE: 09-185. Satellites Unlock Secret to Northern India's Vanishing WaterExcerpt: WASHINGTON -- Using NASA satellite data, scientists have found that groundwater levels in northern India have been declining by as much as one foot per year over the past decade. Researchers concluded the loss is almost entirely due to human activity. 
More than 26 cubic miles of groundwater disappeared from aquifers in areas of Haryana, Punjab, Rajasthan and the nation's capitol territory of Delhi, between 2002 and 2008. This is enough water to fill Lake Mead, the largest manmade reservoir in the United States, three times. 
A team of hydrologists led by Matt Rodell of NASA's Goddard Space Flight Center in Greenbelt, Md., found that northern India's underground water supply is being pumped and consumed by human activities, such as irrigating cropland, and is draining aquifers faster than natural processes can replenish them....
The finding is based on data from NASA's Gravity Recovery and Climate Experiment (GRACE), a pair of satellites that sense changes in Earth's gravity field and associated mass distribution, including water masses stored above or below Earth's surface. As the twin satellites orbit 300 miles above Earth's surface, their positions change relative to each other in response to variations in the pull of gravity. 
Changes in underground water masses affect gravity enough to provide a signal that can be measured by the GRACE spacecraft. After accounting for other mass variations, such changes in gravity are translated into an equivalent change in water. 
..."We don't know the absolute volume of water in the northern Indian aquifers, but GRACE provides strong evidence that current rates of water extraction are not sustainable," said Rodell. "The region has become dependent on irrigation to maximize agricultural productivity. If measures are not taken to ensure sustainable groundwater usage, the consequences for the 114 million residents of the region may include a collapse of agricultural output and severe shortages of potable water."...

2009 August 8. Avian Silence: Without Birds to Disperse Seeds, Guam's Forest Is Changing. By Brendan Borrell, Scientific American. Excerpt: The forest on Guam is silent.
Sometime after World War II the brown tree snake arrived as a stowaway on this U.S. Pacific island territory 6,100 kilometers west of Hawaii. It has since extirpated 10 of the island's 12 native forest bird species. The remaining forest birds have been relegated to small populations on military bases, where the snakes are kept in check. In the first study of its kind, a rugby-playing researcher named Haldre Rogers is documenting how the forest itself is changing.
...Of the approximately 40 species of trees on Guam, about 60 to 70 percent once depended on birds to eat their fruits and disperse their seeds. The birds may have just nicked and dropped seeds somewhere along a flight path, or they could have swallowed the seeds, digested their tough coats, and pooped them out with a splatter of high-nitrogen urea.
Rogers went to neighboring islands that still have birds along with many of the same trees, collected seeds from the tree Premna obtusifolia, and brought them back to grow in a greenhouse on Guam. She found that seeds handled by birds are twice as likely to germinate as seeds that simply land on the forest floor. They also germinate about 10 days more quickly, giving them a better shot at evading seed-destroying rodents or fungi.
In another experiment, Rogers has found that seeds on Guam now always land directly in the shade of the mother tree and always have an intact seed coat. But seeds from neighboring islands that still have birds can sometimes end up 10 to 20 meters away from the mother tree, where they are more likely to find a sunny niche with fewer enemies. About 80 percent of these have had their seed coat removed, meaning they can germinate more quickly....
..."The brown tree snake is held up as textbook example of how a destructive invasive species can eradicate birds," she says. "This shows that the effects of introduced predators reverberate through the ecosystem."

2009 August 1. An Underwater Fight Is Waged for the Health of San Francisco Bay. By Malia Wollan, The NY Times. Excerpt: SAN FRANCISCO — Chela Zabin will not soon forget when she first glimpsed the golden brown tentacle of the latest alien to settle in the fertile waters of San Francisco Bay.
...The tentacle in question was that of an Asian kelp, Undaria pinnatifida, a flavorful and healthful ingredient in miso soup and an aggressive, costly intruder in waters from New Zealand to Monterey Bay.
The kelp, known as wakame (pronounced wa-KA-me), is on a list of “100 of the World’s Worst Invasive Alien Species,” compiled by the Invasive Species Specialist Group. Since her discovery in May, Dr. Zabin and colleagues have pulled up nearly 140 pounds of kelp attached to pilings and boats in the San Francisco Marina alone.
Every year the damage wrought by aquatic invaders in the United States and the cost of controlling them is estimated at $9 billion, according to a 2003 study by a Cornell University professor, David Pimentel, whose research is considered the most comprehensive. The bill for controlling two closely-related invasive mussels — the zebra and the quagga — in the Great Lakes alone is $30 million annually, says the United States Federal Aquatic Nuisance Species Task Force.
Many scientists say that San Francisco Bay has more than 250 nonnative species, like European green crab, Asian zooplankton and other creatures and plants that outcompete native species for food, space and sunlight....

2009 July 6. Some See Beetle Attacks on Western Forests as a Natural Event. By JIM ROBBINS, The NY Times. Excerpt: MISSOULA, Mont. — When Ken Salazar — then a senator from Colorado, now secretary of the interior — called the attack on millions of acres of pine forests by the bark beetle the Katrina of the West, he was expressing the common view of the explosive growth of the beetles as an unmitigated disaster.
But not everybody sees it that way. Some environmentalists and scientists support the beetles. While they acknowledge the severity of the problems the beetles are causing, they argue that the insects, which kill only mature trees larger than five inches in diameter, are a natural phenomenon, like forest fires, and play a vital ecological role.
“It’s not the end of the forests, and they are not destroyed,” said Diana L. Six, a professor of forest entomology and pathology at the University of Montana here, who has studied the beetle for 16 years, as she walked in a beetle-infected forest near here recently .
“Lodge pole pine evolved to go out with a stand-replacing event, such as fire or beetles, then regenerate really quickly,” she said. “When they hit 80 or 90 years of age all of a sudden the beetles become a player — the trees are big enough for the beetles to attack. They reset the clock on the stand.”
...Nothing can or should be done to halt the spread of the beetle, experts say. After they kill the mature trees, the soil becomes more fertile as nitrogen levels increase, sometimes tripling. The growth rate of surviving trees increases when the infestation ends. After dead trees fall over or burn, grass grows and provides elk habitat, and slightly more diverse forests rise up.
...Both Dr. DeNitto and Dr. Six allow that the current outbreak is not entirely natural. Human intervention in the form of fire suppression and large-scale clear cuts mean that many forests are simultaneously vulnerable.
...The major human-caused element of the current outbreak, though, is a warmer climate, which has opened new territory to the beetles. And this has caused some experts to view the beetle infestations as unnaturally severe....

2009 June 15. An Unsightly Algae Extends Its Grip to a Crucial New York Stream. By Anthony DePalma, The NY Times. Excerpt: SHANDAKEN, N.Y. — The Esopus Creek, a legendary Catskill Mountain fly fishing stream that is an integral part of New York City’s vast upstate drinking water system, is one of the latest bodies of water to be infected with Didymosphenia geminata, a fast-spreading single-cell algae that is better known to fishermen and biologists around the world as rock snot.
...Didymo has a natural tendency to grow upstream in fast-moving rivers and creeks, but it can spread by clinging to fishing equipment, especially the felt-bottom waders that fly fishermen use to keep from slipping on river bottoms.
Didymo is considered native to parts of North America, where it was found in higher elevations with cold, nutrient-poor waters. But in the last 20 years, the single-celled diatom seems to have morphed into a more aggressive invasive species, spreading from British Columbia across the continent to New York.
Unlike other algae, which float on the surface, Didymo clings to rocks on the bottom of rivers, streams and lakes. At times it grows furiously in blooms that can cover a river bottom from bank to bank, smothering the stone flies, worms and other organisms that trout and other sport fish live on....

2009 February 16. The Unintended Consequences of Changing Nature’s Balance. By Elizabeth Svoboda, The NY Times. Excerpt: With its craggy green cliffs and mist-laden skies, Macquarie Island — halfway between Australia and Antarctica — looks like a nature lover’s Mecca. But the island has recently become a sobering illustration of what can happen when efforts to eliminate an invasive species end up causing unforeseen collateral damage.
In 1985, Australian scientists kicked off an ambitious plan: to kill off non-native cats that had been prowling the island’s slopes since the early 19th century. The program began out of apparent necessity — the cats were preying on native burrowing birds. Twenty-four years later, a team of scientists from the Australian Antarctic Division and the University of Tasmania reports that the cat removal unexpectedly wreaked havoc on the island ecosystem.
With the cats gone, the island’s rabbits (also non-native) began to breed out of control, ravaging native plants and sending ripple effects throughout the ecosystem....
“Our findings show that it’s important for scientists to study the whole ecosystem before doing eradication programs,” said Arko Lucieer, a University of Tasmania remote-sensing expert... “There haven’t been a lot of programs that take the entire system into account. You need to go into scenario mode: ‘If we kill this animal, what other consequences are there going to be?’ ”...

  Archive of Past Articles for Chapter 6

Excellent video (15 minutes):
Mountain Lions in Nebraska (2011)

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