In Mauritius, an island nation east of Madagascar, lives a plant species called Roussea simplex. This plant normally gets pollinated by the beautiful blue-tailed day-gecko (Phelsuma cepediana), a gecko that’s often kept as a pet.
However, due to human activity, the white-footed ant (Technomyrmex albipes) is now also present on this island. Since this happened, the plant has become critically endangered.
How did this happen?
Well, the ants like the nectar and fruit pulp of the plant, and also tend honeydew-producing mealybugs that live on the plant. This is nothing out of the ordinary, and the plant doesn’t get damaged directly by this. However, the ants also chase away the geckos. By preventing the gecko from coming near to the plant, they also prevent the plant from getting pollinated. Furthermore, normally the geckos take the fruit somewhere to eat, and thus disperse the seeds. Both pollination and seed-dispersal don’t happen anymore, leading the plant to extinction.
This shows that something seemingly small, like accidentally bringing an ant species to a place it normally doesn’t live, can severely impact an ecosystem, through means that might not be apparent at first glance (such as interrupting the interaction between different organisms like in this case).
Hansen, D.M. & Muller, C.B. (2009) Invasive ants disrupt gecko pollination and seed dispersal of the endangered plant Roussea simplex in Mauritus. Biotropica 41(2), 202-208