Tag Archives: ecology

Chronicling the Ecological Impact of C. Columbus

Chronicling the Ecological Impact of Columbus’ Journey | Magazine.

Columbus’ discovery of the New World unleashed centuries of geopolitical turmoil. But humans weren’t the only creatures whose fortunes were forever altered. Entire species of plants and animals either thrived or suffered as well. In the book 1493, author (and Wired contributor) Charles C. Mann traces the far-reaching biological consequences of Columbus’ journey across the ocean blue. “There is a Rube Goldberg aspect to this,” Mann says. “Things are connected in ways that you would never expect.” And just as with human societies, some organisms came out on top, while others were radically subjugated. Here are a few key flora and fauna and how they weathered the storm.

  1. PLANTAINS ENABLE FIRE ANTS. The African plantain is plagued by insects called scale. Back in Africa, however, predators help combat these scavengers. But when the fruit was brought to Hispaniola, it received no such aid. So the bugs proliferated—along with fire ants, which fed on the other insects’ sugary excrement. Both pests thrived until their unchecked appetites destroyed the local plantain crop.
  2. RUBBER CONQUERS ORCHIDS. For centuries, orchids thrived in the jungles of Southeast Asia. The damp terrain and omnipresent mist provided the perfect environment for the moisture-loving epiphytes. But when rubber trees from the Amazon rain forest were imported to southern China, their thirst for water dried out the soil. The once-plentiful morning fog began to disappear. Soon the orchids started to as well.
  3. EARTHWORMS STARVE TREES AND POWER UP MAIZE. Before being brought to the US, the common earthworm aided farmers in England by humbly tilling their soil. But once transplanted, the wrigglers’ tu nneling disrupted the nutrient-absorbing fungi on the roots of sugar maples, causing the trees’ decline. And by aerating the newly cleared land, the worm allowed crops like maize to grow year-round.
  4. POTATOES BATTLE NEW FOE. In its Andean motherland, the resilient potato grew in all shapes and sizes. But as the mighty tuber spread across the globe, its varieties dwindled to a monoculture—an easy target for opponents in adopted lands. None was quite so vicious as the Colorado potato beetle. Carried to North America in the manes of traveling horses, the bug became a permanent scourge to the plant in regions around the world.

New Dam evaluation protocols better but not perfect

Damned if they do : Nature : Nature Publishing Group.

An industry approach to greener hydropower is far from perfect, but it does offer a way forwards.

The mighty Iguaçu Falls in Brazil are an excellent illustration of the power of water, so what better place for the hydropower industry to promote what it says is a fresh approach to its sustainability?

There is ample room for scepticism about the effort — known as the Hydropower Sustainability Assessment Protocol (see page 430). It is an industry-led endeavour that requires next to nothing from the industry. It grades hydropower projects, but makes no judgement on what should happen to projects that rank poorly. And it is geared towards assessment of individual dams, independent of broader questions about energy-resource development. So far, so bad. Yet, if deployed properly, it could also be an invaluable tool to inject much-needed science and reason into a planning process that has operated with little of either for much too long.

Developers and governments have historically assessed dam projects mainly on the basis of cost and power. Engineers simply survey the landscape to identify the easiest places to block channels, set up turbines and run power lines. Sediments, endemic species and the consequences of severing communication between headwaters and estuaries are very much secondary issues. Even people get short shrift, leading indigenous groups to mount the kind of intense protests that last week saw the Peruvian government shelve plans for a massive dam in the Amazon.

“The hydropower assessment protocol asks all the right questions but fails to provide any answers.”

This standard approach has caused numerous environmental problems — such as siltation and blockages to migrating fish — in industrialized countries, which exploited their best hydropower resources long ago and are now trying to repair the damage. In some cases, the costs of improvement outweigh the benefits, and old dams are being decommissioned. But, in the developing world, hydropower projects continue to stack up. Countries in Southeast Asia and Latin America, in particular, are pursing hydropower with gusto, hoping to alleviate energy poverty and feed burgeoning economies. By one optimistic industry estimate, cumulative hydropower capacity could nearly double by 2030. Without a more coordinated approach, these countries are doomed to make the same mistakes.

The new hydropower protocol comes courtesy of the International Hydropower Association, which consulted with environmental and human-rights groups, as well as representatives from finance and government, in an effort to set out some basic principles of sustainable hydropower.

After three years of work, the result is a way to assess dam projects on a range of criteria — from planning, governance and public engagement to ecology and hydrology. It is voluntary, however, and there are no minimum standards. The protocol asks all the right questions but fails to provide any answers.

This has driven a wedge into the community of environmental and social activists that work in this arena. Critics argue that the protocol represents little more than a public-relations exercise that will allow bad developers to appear green while pursuing business as normal — often on projects that pre-date current environmental thinking. This may be true, but, unfortunately, in the political and corporate world such ‘greenwash’ is common. The new effort would at least create a common language with which to raise concerns, evaluate the best available science and negotiate improvements.

The biggest shortcoming lies in the assessment of individual dams that have already been proposed for specific locations. Much better would be an approach to analyse entire river basins in an effort to identify the most suitable locations, as well as areas where special precautions should be taken. Indeed, it might well be that some rivers should be left to flow freely to preserve ecological integrity.

The protocol does touch on these issues, raising questions about a dam’s role in the broader energy mix and about wider impacts from hydroelectric development. And it could yet offer a foundation to set minimum standards in these and other areas, so that companies would need to build and operate better dams, as well as integrate them into a more comprehensive energy strategy. For all of its faults, the protocol opens another bridge to a better future. Now it’s up to governments, banks and companies to make the journey across.

Royal Ontario Museum investigates sudden bee death

BBC News – Royal Ontario Museum investigates sudden bee death.

honey bees The bees were part of a popular biodiversity exhibit

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A Toronto museum is investigating the sudden death of thousands of bees in a glass-enclosed beehive exhibit.

Officials at the Royal Ontario Museum said 20,000 bees in a biodiversity exhibit had died within two days last week, though they had appeared healthy.

Scientists have ruled out staff error and starvation, but said poor ventilation, disease or a lack of worker bees could be to blame.

The museum plans to replace the colony in the spring.

“The queen stops laying eggs in early- to mid-October and starts laying again in late February,” University of Guelph researcher Janine McGowan told the Toronto Star newspaper.

“If she didn’t lay enough winter worker bee eggs to make sure the hive and honey is kept warm during the winter, that could have contributed to the die-off.”

A Devilish Grass Invades the West

A Devilish Grass Invades the West – ScienceNOW.

Armed with pointed tips so sharp that neither cows nor deer will eat it, medusahead (Taeniatherum caput-medusae) is an invasive grass species that seems to have stepped right out of the Little Shop of Horrors. With no enemies, it is spreading rapidly throughout the western United States, outcompeting native grasses and even other grass invaders. Unless steps are found to control its spread, medusahead is likely to turn millions of hectares of grazing land into worthless fields, say researchers in a study that determined why this grass is so successful.

“It is a devilish species because it is absolutely not of any worth,” says Seema Mangla, a plant ecologist at Oregon State University, Corvallis, who led the study. “Every animal avoids it.”

That’s because the medusahead’s long, twisting, snakelike seed stems (which give the grass its name) are stiff and pointed like needles. Any animal that leans in for a snack gets jabbed in the eyes and mouth. The grass is loaded with inedible silica, too, providing few nutrients to would-be grazers. As a result, the grass steadily accumulates, forming mounds of thatch, Mangla says. “It’s part of a huge change in vegetation structure,” as native grasses are overwhelmed by invaders. Other studies have shown that medusahead is spreading at a rate of 12% per year in 17 western states. Although it invaded the United States from the Mediterranean in 1880 and is now found only on more than 1 million hectares, Mangla and others worry that it is picking up steam and may be outcompeting not only native grasses, but even cheatgrass (Bromus tectorum), a more nutritious invader.

Measures to control medusahead’s spread—mowing or spraying with herbicides—aren’t effective, because they only treat the top of the plants, not the thatch beneath, which protects their seeds, Mangla says. “We need to understand its growth dynamics, what makes it such a successful invader, then we can figure out better ways to disrupt it.”

Invasive plants are thought to have especially high relative growth rates, enabling them to rapidly capture water and nutrients. To determine if the medusahead’s growth rate figures in its success, in 2008 and 2009 Mangla and her team randomly scattered the plant’s seeds on five 1-m2 test plots at the Eastern Oregon Agricultural Research Center in Burns. At regular intervals throughout the growing season, she and her team weighed harvested seedlings. She then compared the medusahead’s weight to that of two other grasses growing separately in similar plots: the native perennial bluebunch wheatgrass (Pseudoroegneria spicata), which the medusahead is rapidly replacing, and cheatgrass.

When she averaged the grasses’ weights across the two seasons, medusahead came up the winner. Only during 2008, which had below-average rainfall, did the native grass do slightly better. But after the more normal rainfall of 2009, the medusahead raced ahead, growing longer shoots for a longer period of time, the team reported in the 28 October Journal of Arid Environments.


Lush but prickly. Spiky and inedible medusahead is invading the western United States. Researchers plant a test plot with medusahead seeds (inset).

“It’s a good study, and shows why medusahead can be so competitive,” says Joseph Ditomaso, an invasive plant ecologist at the University of California, Davis. “Since animals won’t eat it, medusahead essentially creates its own thatch layer, which is a great tactic for preventing seeds from sprouting, as every gardener knows.” The only seeds that can make it past the medusahead’s thatch barrier are its own sharp, pointy, inedible ones. “It gives itself every advantage,” says Ditomaso, who says the best control right now is simply burning the thatch. Meanwhile, Mangla and her team expect that the medusahead will continue to spread, since climate conditions favoring native grasses are sporadic and rare.