A new study of shrublands in Southwest Australia has identified how plant species can successfully coexist while competing for space and limited resources.
A team of international researchers, including Dr François Teste, Dr Michael Renton and Dr Etienne Laliberté from The University of Western Australia, found that part of the answer for high plant diversity is due to the many organisms that live in soils.
The study is the first of its kind to show that soil organisms interact with the way plants absorb nutrients which plays an important role in maintaining plant diversity in rich ecosystems.
While some organisms are harmful to roots, causing diseases or even plant death, others are beneficial and enhance nutrient uptake and protect roots against harmful microorganisms.
Infertile shrublands in semi-arid regions support 20 per cent of the world’s plant species on just five per cent of the land surface, and those of Southwest Australia are some of the most species-rich of all.
By understanding the reason behind this high plant diversity, researchers can explore solutions for the conservation of species-rich ecosystems.
The study, published in the journal Science, looked at the interaction between a range of shrubland plant species and the organisms around their roots to understand how they influenced plants’ long-term coexistence.
Results reveal that soil organisms helped counteract growth differences between plant species. The researchers then used simulation modelling which showed this helped long-term coexistence of diverse plant species in ecosystems such as the Southwest Australian shrublands.
The researchers selected a large number of plant species and exposed them to soil organisms collected either from the plants own species or from other species.
While some plants grew better in their ‘own’ soils, many others actually performed best in the soils of other species.
Lead author Dr François Teste, said the results highlight the ‘unseen’ interactions that occur in soil.
“These interactions can enhance our understanding of the mechanisms that maintain local plant diversity, thus better informing ecosystem conservation efforts,” Dr Teste said.
“Ultimately, our study should enhance our ability to predict the way plants and ecosystems respond to global environmental change.”