Nitrogen emissions could sink plant diversity in species hotspots
Rhett A. Butler, mongabay.com
April 11, 2006
Rising nitrogen emissions from human activities — such as fossil fuel burning and livestock farming — may soon threaten plant species in some of the world’s most biodiverse places according to researchers at the Universities of Sheffield and York.
Using computer modelling, a team led by Gareth Phoenix of the Department of Animal and Plant Sciences at the University of Sheffield, found that in the mid-1990s, the average amount of nitrogen deposited on the planet’s 34 biodiversity hotspots identified by Conservation International was more than 50 per cent higher than the global average. The researchers say that nitrogen deposition could more than double by 2050 should nitrogen emissions continue as anticipated.
Nitrogen gas is released into the atmosphere by fossil fuel combustion and returns to Earth in rainfall. Nitrogen deposition has been shown to damage plants by altering the nutrient content of the soil.
While nitrogen emissions from industrialized countries are stabilizing, emissions from developing countries climbing.
“Until recently, scientists have focused on the threat of atmospheric nitrogen deposition in Europe and North America — partially since these were the first areas of the world to receive high levels of this pollutant. However, our work shows that atmospheric nitrogen deposition is becoming a global threat, ” said Dr Gareth Phoenix in a statement.
Dr Kevin Hicks, at the Stockholm Environment Institute at the University of York, says that high levels of atmospheric nitrogen deposition in areas of with high plant diversity could significantly increase the threat to plant biodiversity over the next 50 years.
“Scientists know very little about the sensitivity of the hotspot ecosystems to nitrogen deposition, so accurate estimates of the amount of likely species loss are not possible,” said Hicks. “Understanding the impacts of [Nitrogen] deposition in hotspots is, therefore, a priority for future research.”
The paper, “Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts” is published in the March 2006 issue of Global Change Biology [12, 470—476]
This article is based on press materials from the University of Sheffield.