Endangered plants persist under phosphorus limitation

Biodiversity under threat The assumption that nitrogen enrichment caused by human activities is threatening biodiversity in Europe and North America may be false. A survey of herbaceous terrestrial ecosystems covering a gradient of decreasing nitrogen deposition from Western Europe to Siberia suggests that phosphorus, not nitrogen, is often the key element. In the 274 sites examined, many more endangered plant species persist under phosphorus-limited than nitrogen-limited conditions, so extra phosphorus is the more likely to cause species loss. Conservation policies biased towards reducing nitrogen enrichment are unlikely to succeed; rather, attention should focus on reducing phosphorus availability. On the cover, Great Vasyugan in Western Siberia, a peatland harbouring many plant species under P-limited conditions, some of which are shown on the cover. Main image: Wladimir Bleuten; inserts: Franziska Tanneberger.