Rabbits were introduced in many islands around the world, in order to ensure easy food for settlers in these remote locations devoid of mammals. However, rabbits have a great ability to adapt and reproduce at very high rates. In all the islands where they were introduced, rabbits became a serious threat to the conservation of the fragile insular ecosystems, in some cases at the level of disturbing ecological cycles. Being herbivores, rabbits feed on virtually all plants leading to the destruction of vegetation and, in some places large areas get completely bare devoid of any vegetation. This impact on vegetation may trigger a cascade effect and have serious consequences for the conservation of insular habitats and flora. Another problem associated with rabbits is the construction of tunnels and holes which alters soil dynamic and contributes to accelerated erosion.
It is thought that rabbits ware brought to Berlengas during the reign of D Afonso V, when the Berlenga Island served as a game reserve for the king. Nowadays, rabbits can be found in most of the Berlenga Island surface. The actual impact of rabbits on Berlengas’ vegetation is not truly known; however where rabbit densities are higher like in the island plateau, the vegetation is very sparse. Its impact on endemic plants, such as the Berlengas fleabane or the Berlengas rupturewort, can be quite negative.