Pollution Affects Plant Diversity

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Wednesday, 30 November 2005

Atmospheric pollution is affecting the western world's plant diversity by favouring those that can make use of the extra nitrogen, at the expense of those that can't.

In rural Hertfordshire an experiment that has been running since 1856 (over 150 years) has measured meadow plant diversity in controlled plots, some of which have artificial fertilisers applied. Those that don't, over time, have shown a consistently wider variety of flowers and other plants whereas those that do have tended to have a narrower range of mainly grasses which do well in the nitrogen-rich soil.

However, it seems that it is not just direct application that causes this effect - it is exacerbated by pollution, mainly from household heating and car emissions. This is clearly measurable in the Herts experiment: in summer when people in nearby Harpenden turn off their heating the nitrogen oxide readings halve but then climb steadily up to Christmas when they show a noticible brief dip as people leave their cars in the garage over the holiday.

Scientists are concerned that the long-term affect wil be that plant communities are severely restricted as certain plants dominate.

Source: New Scientist 26 Nov 2005