Dr Yvonne Buckley from The University of Queensland's School of Biological Sciences has collaborated with an international team of research ecologists to re-evaluate the relationship between species numbers and habitat productivity.
For decades, ecologists have tried to pin down general principles explaining why some habitats have so many more plant and animal species than others.
Much of this debate is focused on the idea that the number of species is determined by the productivity of the habitat.
The team's standardised global sampling of 48 sites on five continents, including five sites across Australia, has yielded an unprecedented data set.
Dr Buckley and her colleagues’ findings appear in the September 23, 2011 issue of the journal Science.
Lead author, Dr Peter Adler from Utah State University, said the study showed no clear relationship between productivity and the number of plant species in small study plots.
“We challenged a prevailing model developed in the early 1970s by British ecologist J. Philip Grime,” said Dr Adler.
“He proposed that the number of species rises then declines with increasing productivity.”
Though hotly debated, this “hump-shaped” model has remained a textbook standard for nearly four decades.
Five years ago, Dr Buckley and fellow ecological researchers formed the Nutrient Network or “NutNet”, a cooperative research initiative dedicated to investigating biodiversity and ecosystem processes in grasslands around the world.
“When I first heard about the Nutrient Network global project I thought we had a real chance to find out if this theory holds right around the world in different ecosystems”, said Dr Buckley.
“The idea of doing a globally replicated experiment is very powerful and we have already found out some very exciting ecological principle," she said.
“This is ecology’s version of the Large Hadron Collider – we have to work across multiple sites in multiple different ecosystems from sub-tropical grasslands to Arctic tundra to find answers to the really big questions in ecology."
Dr Adler said the data emphasises the need to consider many factors to explain patterns of diversity – not just productivity alone.
For the ecological community, Dr Adler said NutNet’s current findings should spur ecologists to focus on other important factors regulating biodiversity, such as evolutionary history, disturbance and resource supply.
“It’s time to remove outdated models from our textbooks and concentrate on more sophisticated approaches,” he said.
“That will improve our ability to predict the effect of environmental change on biodiversity.”
Media: Dr Yvonne Buckley y.buckley@uq.edu.au or 0403 330 228. Images available, please contact Tracey Franchi t.franchi@uq.edu.au
