Beleid en debat

The variety of animals and plants has fallen to dangerous levels across more than half of the world’s landmass, scientists have estimated. The unchecked loss of biodiversity is akin to playing ecological roulette and will set back efforts to bring people out of poverty in the long term, they warned. Analysing 1.8m records from 39,123 sites across Earth, the international study found that a measure of the intactness of biodiversity at sites has fallen below a safety limit across 58.1% of the world’s land.

Viele Tier- und Pflanzenarten sind vom Aussterben bedroht oder sind bereits verloren. Zu viele, meint eine neue britische Studie: Auf 58 Prozent der Erdoberfläche sei die Artenvielfalt gefährlich reduziert. Man geht davon aus, dass die Natur 10 Prozent weniger Tier- und Pflanzenarten gerade noch verkraften könne – das sei eine „sichere Grenze“, sagt der britische Biowissenschaftler Tim Newbold.

Studies on the risks of neonicotinoids have often focused on bees — pollinators vital to farm production that have been experiencing population declines — but “it’s really not just about bees,” said Christy Morrissey, a professor in the Department of Biology at the University of Saskatchewan.

Recent monitoring studies in several countries have revealed a world-wide contamination of creeks, rivers and lakes with neonicotinoid insecticides, with residue levels in the low μg/L (ppb) range. At least two main areas of concern can be identified: reduced capacity for decomposition of organic debris by aquatic organisms and starvation of insectivores and other vertebrate fauna that depend on invertebrates as a major or only food source.

In the early 2000s, Italian beekeepers began to report bee mortality events linked to maize sowing. Evidence pointed to three neonicotinoids (imidacloprid, clothianidin, thiamethoxam) and a phenylpyrazole (fipronil) used for seed dressing that were dispersed in the environment during sowing. Following these events and based on the precautionary principle, in September 2008, the Italian Ministry of Health suspended these four active ingredients as maize seed dressing.