Beleid en debat

Herbicide-tolerant (HT) crops, developed to survive application of specific herbicides that previously would have destroyed the crop along with the targeted weeds, provide farmers with a broader variety of options for effective weed control. Based on USDA survey data, HT soybeans went from 17 percent of U.S. soybean acreage in 1997 to 68 percent in 2001 and 94 percent in 2014. Plantings of HT cotton expanded from about 10 percent of U.S. acreage in 1997 to 56 percent in 2001 and 91 percent in 2014. The adoption of HT corn, which had been slower in previous years, has accelerated, reaching 89 percent of U.S. corn acreage in 2014. Insect-resistant crops containing the gene from the soil bacterium Bt (Bacillus thuringiensis) have been available for corn and cotton since 1996. These bacteria produce a protein that is toxic to specific insects, protecting the plant over its entire life. Plantings of Bt corn grew from about 8 percent of U.S. corn acreage in 1997 to 26 percent in 1999, then fell to 19 percent in 2000 and 2001, before climbing to 29 percent in 2003 and 80 percent in 2014. The increases in acreage share in recent years may be largely due to the commercial introduction of new Bt corn varieties resistant to the corn rootworm and the corn earworm, in addition to the European corn borer, which was previously the only pest targeted by Bt corn. Plantings of Bt cotton also expanded rapidly, from 15 percent of U.S. cotton acreage in 1997 to 37 percent in 2001 and 84 percent in 2014.

Swallows, along with other birds that feed primarily on flying insects, are experiencing the greatest population decline of any group of birds in North America. The province was forced to add barn swallows to its list of protected species last year, after the birds experienced a drop of 60 to 98 per cent in numbers in recent years. One of the species, the purple martin, no longer breeds here. “It’s certainly alarming,” Blake Maybank, a naturalist and member of the Nova Scotia Bird Society, said in an interview Tuesday. “It’s happening across a whole suite of bird species, including all the birds that feed on flying insects, whether day or night.” Maybank said there has been a visible decline over the past 20 years of birds that migrate north and south. So what’s happening to the swallow population in Nova Scotia and across the Maritimes? That is what scientists are trying to find out.

Neonicotinoid insecticides exhibit very high toxicity to a wide range of invertebrates, particularly insects, and field-realistic exposure is likely to result in both lethal and a broad range of important sublethal impacts. The compounds are highly persistent in soils, tend to accumulate in soils and sediments, have a high runoff and leaching potential to surface and groundwater and have been detected frequently in the global environment. For imidacloprid, including its neurotoxic metabolites, lethal toxicity can increase up to 100,000 times compared to acute toxicity when the exposure is extended in time (Suchail et al. 2001). Recent studies have shown that chronic toxicity of neonicotinoids can more adequately be expressed by time to 50 % mortality instead of by the 10 day LD50 (Sánchez-Bayo 2009; Maus and Nauen 2010; Tennekes 2010; Tennekes 2011; Tennekes and Sánchez-Bayo 2012; Mason et al. 2013; Rondeau et al. 2014). There is a linear relation between the logarithm of the daily dose and the logarithm of the time to 50 % mortality (Tennekes 2010, 2011; Tennekes and Sánchez-Bayo 2012; Tennekes and Sánchez-Bayo 2013; Rondeau et al. 2014).

Two turtle doves may soon be the most precious gift you could give anyone for Christmas, as along with nearly 100 other types of British bird, they are in real danger of going extinct. Its numbers have declined by 96 per cent in just 40 years, and experts have warned there could be none left within a decade.The marsh warbler (Acrocephalus palustris) and red-backed shrike (Lanius collurio) also appear to be on their last wings, while birds like the wryneck (Jynx torquilla) - a tiny brown woodpecker - and the beautiful golden oriole (Oriolus oriolus) are believed to be close to or have already died out.

Martha the passenger pigeon, who died 100 years ago, is being remembered this month as a prescient symbol of what can happen when man meets nature. A comprehensive new report finds that many more American bird species could meet the same fate. "Right now, about a third of all bird species in the US are in decline," says Steve Holmer of the American Bird Conservancy, one of the 23 organisations that contributed to the State of the Birds report, the most comprehensive review of bird trends and data ever undertaken in the US. "The decline points to a very broad-scale problem where we're seeing habitat loss and a variety of threats," he says. "We're particularly concerned about the birds that live in deserts and grasslands in the West, such as the sage grouse (Centrocercus urophasianus). These lands are being heavily used and there's a great deal of oil and gas development, so it's created a huge conservation challenge." Birds living on the coasts are faring no better. Almost half of all shorebird species, such as ruddy turnstones (Arenaria interpres), red knots (Calidris canutus) and piping plovers (Charadrius melodus), are either endangered or at risk of becoming endangered.

The latest assessment by BirdLife Cyprus shows that the numbers of common breeding birds in our forests, scrublands and farmland have declined by 10% since 2006. But the really worrying news is that, taken as a group, common breeding birds in our farmland habitats have declined by a dramatic 43% over the same period (2006-2014). The analysis is based on a systematic monitoring scheme for common birds organized by BirdLife Cyprus on behalf of the Department of Agriculture, and covering over 100 randomly selected sites across all habitats (except wetlands) thanks to the efforts of a team of skilled volunteer recorders. The trend data (produced using the widely used TRIM programme analysis) shows ‘dips’ in bird numbers that seem linked to drought years, but the overall downward trend remains a concern. The steep decline in farmland areas and for more farmland-dependent species, as compared to the relatively small decline overall (i.e. when all habitats and all common breeding species are included in the analysis) is alarming and points clearly to the need for more wildlife-friendly farming practices in Cyprus. Notable among the farmland species showing declines are the Chukar, the Roller, the Cyprus Wheatear and the Spanish sparrow.