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Traditionally, grasslands were grazed by livestock and provided hay. Plants thrived in the sunlight, and wildlife took advantage of microhabitats created by half-nibbled grasses. In places where livestock has been removed, mowing can re-create some of those niches as well as help prevent shrubs and trees from changing the habitat.
Industrial agriculture has made meadows less welcoming to insects. Excess nitrogen from fertilizer and air pollution has reduced the diversity of meadow plants. And changes in mowing—entire fields are cut all at once—has also degraded habitat quality. More species of insects can thrive when there are patches of mown grass, which contain more herbaceous plants to feed on and niches for mating and nesting.
Since the 1990s, some farmers and land managers have begun to cut grasslands in phases, mowing just part of a field at a time. This approach of “phased mowing” helps some insects, but leaves much to be desired, says Laurian Parmentier, an entomologist at Ghent University. For example, grassland habitats would be more suitable for certain species if some parts are not cut every year. Also, the large rectangular shape of mowing patterns is awkward. That’s because if a large block is mown all at once, insects living there may be far away from the taller, uncut grass on the other side of the field.
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a failure for an arctic vessel
A ship designed for a different task, huge political donations and a bad ship when something is really needed.
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The icebreaker Aiviq is a gas guzzler with a troubled history. The ship was built to operate in the Arctic, but it has a type of propulsion system susceptible to failure in ice. Its waste and discharge systems weren’t designed to meet polar code, its helicopter pad is in the wrong place to launch rescue operations and its rear deck is easily swamped by big waves.
On its maiden voyage to Alaska in 2012, the 360-foot vessel lost control of the Shell Oil drill rig it was towing, and Coast Guard helicopter crews braved a storm to pluck 18 men off the wildly lurching deck of the rig before it crashed into a rocky beach. An eventual Coast Guard investigation faulted bad decision-making by people in charge but also flagged problems with the Aiviq’s design.
But for all this, the same Coast Guard bought the Aiviq for $125 million late last year.
The United States urgently needs new icebreakers in an era when climate change is bringing increased traffic to the Arctic, including military patrols near U.S. waters by Russia and China. That the first of the revamped U.S. fleet is a secondhand vessel a top Coast Guard admiral once said “may, at best, marginally meet our requirements” is a sign of how long the country has tried and failed to build new ones.
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05:22 in Current Affairs, General Commentary | Permalink | Comments (0)