An exotic species can be a superior colonizer but inferior resource competitor relative to native species. Such species can spatially coexist for an extended time period in a habitat maintained via competition-colonization (CC) trade-offs. Whether fluctuations in resource supply within that habitat allow such exotic species to successfully invade and displace the native species or hold the coexistence is not previously explored, and it is the focus of present talk. In this presentation, we have modeled interspecific spatial competition explicitly linked with resource-competition within the framework of the classic CC-model, while time-dependent fluctuations in resource supply are considered as a sinusoidal function.

Results/Conclusions

The model predicts that if the amplitude of the fluctuations is greater than the average resource supply rate, there exist a range of values of fluctuation frequency that can allow the exotic species to successfully invade and displace the native species from the habitat maintained via CC-trade-offs. On the other hand, if the fluctuation amplitude is less than the average resource supply rate, such exotic species can coexist with the native species, independent of fluctuation frequencies. In addition, we found that at a constant resource supply rate, the exotic species can stably coexist with the native species at competitive equilibrium. We believe that these results will be useful to understand the impact of anthropogenic disturbances such as elevated rates of nitrogen deposition and resulting exotic invasion.