In this study, the 11 species differed markedly in their competitive ability and in their ability to tolerate disturbance. When considered together, there was a strong tradeoff between the two traits, according to Jiang.
"Each species was most vulnerable to inter-species competition at its upper disturbance limit, which is when its population density was the most severely reduced," noted Jiang.
While this study provided unique experimental evidence that competition can consistently regulate species extinction and community richness over broad disturbance gradients, three characteristics of this experiment may influence the applicability of these results to other systems, according to Jiang.
First, since the protist species in these experiments competed for shared food resources and affected each other by reducing the availability of those resources, these findings may not apply to communities competing in other ways, such as those physically or chemically fighting with each other. Second, there was no outside immigration into the experimental microcosms, unlike natural communities in which other organisms can join the competition.
Finally, given the size of the microcosms, disturbance in the experiments could be considered "global", which contrasts with the more common situation in nature where disturbance is heterogeneous over an area.
In the future, more attention should be focused on examining other mechanisms that may potentially contribute to intermediate disturbance hypothesis patterns, says Jiang.
"Our results challenge conventiona
|Contact: Abby Vogel Robinson|
Georgia Institute of Technology Research News