This study assesses the impact of goat grazing on Fuerteventura’s remaining biodiversity refuges, whose ecosystems have been severely degraded by introduced herbivores. Focusing on the Jandía cliffs, which host the island’s highest concentration of endemic plant species, we assessed the effects of livestock on soil chemistry, seed banks, and the population structure of Asteriscus sericeus , a dominant, unpalatable Fuerteventura endemic. We compared plots managed with herbivore exclusion fences, areas fully accessible to goats, and natural, inaccessible cliff zones. The results revealed that the presence of goats significantly reduces soil organic matter, nitrogen, and saturation, thereby impoverishing the endemic seed bank. Only 1.68% of the plants that germinated in the fenced exclusion plots were endemic species, compared to 97.32% in the inaccessible cliff zones. The population structure of A. sericeus is also affected, with almost no regeneration in areas with goats due to flower consumption, despite branches and leaves not being browsed. The study concludes that current exclusion efforts are insufficient for restoring the original vegetation owing to depleted seed banks and degraded soils. Therefore, it is urgent to conserve the cliffs, and this must be accompanied by a comprehensive ecological restoration project for the summit areas, including the eradication of goats and the restoration of the seed bank, to prevent the extinction of Fuerteventura’s unique flora.
Cubas et al. (Fri,) studied this question.