Effects of isolation, area and predators on invasion: A field experiment with artificial islands

The three most important ecological factors affecting the success of island invasions are the area of the island, isolation of the island and occurrence of predators on the island. Traditionally, invasion success has been studied on natural islands, which partly explains the rarity of controlled and replicated experiments. Here we report results from a field experiment investigating the influence of the above three factors in artificial islands. As an experimental system, we used predatory mites and a nematode community occurring naturally in boreal coniferous forests. We found that all three factors had an effect on invasion success, but surprisingly, that there were no interaction effects.