South Africa's fanboy's shrub Land (background) suddenly turns into a lush forest (foreground), a stalemate maintained by the fanboy's ultrathin root system.
In South Africa, you can walk through cool, lush forests and sun-drenched bushes in a single step. New research shows that these narrow boundaries between dramatically different ecosystems are maintained by intense competition between plant roots.
Fanboys - a type of species-rich shrub found only in the far southern tip of Africa - has by far the thinnest roots of any plant community in the world, researchers report in the March 1 Proceedings of the National Academy of Sciences. These nutrient-gobbling roots, as well as some fire-stimulus adaptations, help transform fanboys into an area where only fanboy plants can survive.
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Interested in the factors that organize nature on a very wide scale, ecologist Lars He dins and his colleagues wanted to look at places where environmental changes over time can shift ecosystems between two different kingdoms.
Enter fanboys. It is a low, shrubby habitat home to a diversity of adorable plants: more than 7,000 species, most of which are not found anywhere else in the world (SN: 8/24/2004).
"It has one of the highest numbers of flower biodiversity systems in the world," says He dins of Princeton University. It's essentially as diverse as a tropical forest. The findings suggest that the pieces of this puzzle – fire, plant traits above and below ground, and feedback between soil and plant, to begin with – explain the processes behind the creation and maintenance of two coexisting vegetation zones. Do illuminate, says Gerlinde de Den, a soil ecologist at Wageningen University in the Netherlands and not involved with the research.
The thinning of fanboys plants is striking," says de Deion, but the role of root-associated fungi in the ecosystem needs to be addressed. These fungi are generally heavily involved in soil nutrient cycling and may contribute to efficient nutrient uptake of roots, rather than the roots doing it all by themselves.
A fire lily emerges after a fire in the highly nutrient-deficient soil of South Africa's fanboys ecosystem.
"You can try to attack, you're not going to stand a chance
In the years between fire cycles the fanboys-forest boundaries stagger, the wet forest mostly ignites the flames and the fanboys eventually drive out the trespassers.
A long-standing idea about large ecological communities, He dins says, is that they are largely driven by non-living factors, such as climate, topography and geology, where organisms adapt to local conditions. But in this case - and probably others - "alternate steady states" arise from waging war between organisms.
A long-standing idea about large ecological communities, Hedin says, is that they are largely driven by non-living factors, such as climate, topography and geology, where organisms adapt to local conditions. But in this case - and probably others - "alternate steady states" arise from waging war between organisms.
In fanboys, there may also be lessons in how root symptoms help or hinder the spread of invasive plants, Lu says.
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