Date published: 2009/05/01
The BBC says:
Scientists have identified why excessive fertilisation of soils is resulting in a loss of plant diversity.
Extra nutrients allow fast growing plants to dominate a habitat, blocking smaller species' access to vital sunlight, researchers have found.
As a result, many species are disappearing from affected areas.
A team from the University of Zurich, writing in Science, warned that tighter controls were needed in order to prevent widespread biodiversity loss.
Estimates suggest that the global level of nitrogen and phosphorous available to plants has doubled in the past 50 years.
...
[Co-author] Professor Hector's team, led by PhD student Yann Hautier, fitted lights to the understory of grass in boxes containing fertilised soil."Additional understory light compensated for the increased shading caused by the greater above-ground biomass production," they explained.
The supplementary light "prevented the loss of species and maintained... levels of diversity".
The findings led the team to conclude that it was the lack of access to light that affects diversity, not an increase in the strength of competition.
...
"If it all depends on light levels, then if you put the light back then you should prevent a loss of biodiversity."
All very well. But it's one small experiment in a laboratory. It's not the real world. So the suggestion that "if you put the light back then you should prevent a loss of biodiversity" is just fanciful. Further, are these people really claiming that they can predict exactly the "correct" level of light so that the maximum amount of biodiversity is achieved? And they are also treating biodiversity as a benefit just in itself, pretty much by definition (which to be fair to them, is the attitude of most of the academic middle class).
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