Unravelling the Interactions Between Endemic and Invasive Plant Species in the Galapagos Islands

Invasive species are a major threat to Earth's biodiversity, particularly in unique ecosystems such as the Galapagos Islands. Research on the ecology and genetics of these invasive species is essential to understand their interactions with native and endemic flora, and to alleviate the negative effects of these invasions. In one of our studies, it was found that that the most likely origin of the invasive tomatillo in Galapagos is the central region of mainland Ecuador. Hybridization between the invasive and two endemic tomato species was observed. This could imply an imminent fast extinction risk for the endemic tomatoes, as several of the populations reported decades ago couldn't be found anymore. Moreover, genetic hijacking by the invasive species could lead to an even more aggressive invasive tomatillo in the Galapagos Islands.We also study the Guava, which is one of the most aggressive invasive plants in the Galapagos Islands, displacing and outcompeting its endemic relative, the guayabillo, for resources and space. There is also the possibility of hybridization of guava with its endemic relative, which could lead to the fast extinction of the latter. However, this hybridization is probably not occurring, yet guava could still interfere with the successful reproduction of guayabillo, decreasing its populations. The most likely origin of the guava in Galapagos would be the Central Highlands of mainland Ecuador. A better understanding of the interactions between invasive and endemic plants can contribute to the conservation of the endemic species and a better management of invasive species.