The ecologists, who include OU research fellow Dr Carly Stevens, conducted parallel experiments at 48 different sites on five continents to test the long-held theory.
First proposed by ecologist Philip Grime, it suggests there is a clear relationship between the productivity of a habitat and the number of plant species in it.
This relationship is said to be "hump-shaped", because the number of species first rises then declines as land becomes more productive, with species' numbers peaking in land which is intermediate between low and high productivity.
However data from the NutNet (short for Nutrient Network) experiments shows no clear relationship at all between number of plant species and productivity.
"We are dismissing one of the fundamental rules of ecology," says Dr Stevens."Our work shows the relationship between species and productivity is much more complex than was thought."
She said the findings demonstrate the value of the network's innovative approach. "We all did the same experiments across the world, that is what is unique about NutNet. It is really exciting to be part of it."
Ironically, says Dr Stevens, a podcast of her interviewing the scientist who originally described the hump-shaped relationship model, is part of the study material for the OU's Ecosystems course S396. She says it will probably remain in the course.
"I don't think this will be changed because the relationship does apply in some situations. I think that when Phil Grime described this relationship originally, he didn't expect it to be applied in every situation."
The NutNet research is published today Friday 23 September in the journal Science (see below). OU students can access articles in Science for free via the OU Library.
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