Of the four populations of Azorina vidalii known on the island of Faial, three – Monte da Guia, Morro de Castelo Branco and Porto de Castelo Branco – were created by staff of the Faial Botanic Garden within the last 30 years. However, in 1999 the German botanist Hanno Schäfer, during his exhaustive study on the botany of the Azores, identified a peculiar and interesting population of Azorina vidalii in Caldeirão do Cabeço Verde that had never been identified until then. The Caldeirão is a secondary cone of the Cabeço Verde volcano, on the Capelo peninsula, Faial, located between 320 and 350 meters above sea level. Anyone who is familiar with Azorina vidalii expects to find it in coastal areas, so it may come as a surprise that it exists here at this altitude and about 2 km from the coastline. This small population of Azorina vidalii, with about 20 individuals, grows in the crevices of the rocky slope facing south inside the Caldeirão. The presence of this species here is strange, but this is not the only factor that suggests very particular ecological conditions in this place. There are other eminently coastal species here, including restricted ones, such as Tolpis succulenta. How they arrived here is still a mystery.
The recorded decline of the number of plants that compose this population led to taking effective measures to protect it. As such, the first population reinforcement efforts took place in 2010, with the propagation of plants produced from seeds that were collected here, but showed no success (see: https://shar.es/a3MDfd). Probably, rabbits predated the young plants and led to their disappearance. Now, with the LIFE VIDALIA Project underway, all the knowledge acquired in the Botanical Garden of Faial over decades of work with this species is applied to increase the number of Azorina vidalii plants in the islands of the Triangle, particularly in Caldeirão do Cabeço Verde. To this end, a set of actions were planned and are underway since 2018 with the collection of seeds for long-term conservation in the Azores Seed Bank and propagation in the Rare plant nursery of Faial Botanic Garden.
The intervention area defined within the scope of LIFE VIDALIA encompasses the area of occurrence of Azorina vidalii as well as a large area around it. The perspective is to intervene in the rocky wall, particularly in the crevices where Azorina vidalii grows, ridding them of invasive species and giving the endemic plants the opportunity to colonize, while also creating new areas to where the population can expand. A buffer area, as free as possible from invasive species, will also be created, thus helping to preserve the entire habitat.
This intervention, in addition to posing some technical challenges, encompasses completely different environmental conditions in comparison to those found in coastal areas. Of the invasive species to control and eradicate, Pittosporum undulatum, Hedychium gardenerianum and Cyrtomium falcatum stand out. As for the type of vegetation to be preserved, we highlight habitats such as the typical Macaronesian heaths, medium altitude Laurisilva and humid Laurisilva. This place is definitely an interesting mix of different types of vegetation.
The need for vertical and altitude works, the degree of infestation and the existing invasive species in this area are factors that give this operation a high degree of complexity.
Here, population reinforcement works are directed only at Azorina vidalii, since this ecosystem is considered able to recover naturally after the eradication of the invasive alien species that exert pressure over it.