PROJECT DESCRIPTION
BACKGROUND
Situated in the Madeira archipelago, the islands of Ile Chao, Deserta Grande and Bugio cover a total of 1 423 ha. Of volcanic origin, they are characterised by three habitat types: shallow bays, reefs and marine caves. They also harbour a very rich and ecologically important endemic flora, as well as several important fauna species such as the monk seal, the Desertas tarantula and numerous marine birds.
The introduction of mammals including rabbits and goats to the islands at the time of their discovery has, however, led to the severe regression of its endemic (native) flora and to heavy erosion along all coastlines that has caused problems for nesting sites of several marine birds, namely the Pterodroma feae. This is exacerbated by the uneven physical geography of the islands, which makes them particularly vulnerable to erosion, and by the total absence of natural predators that would otherwise have controlled the populations of rabbits, goats, rats and cats. This situation is particularly acute on the Deserta Grande that is not only at risk ecologically, but also structurally.
OBJECTIVES
In order to consolidate the conservation measures already taken on the islands – e.g., the designation of protected areas and the implementation of management plans for certain species – it was essential to urgently address these problems before they had an irreversible impact on the species of flora and fauna. This project therefore aimed to restore the floral diversity and stem the erosion of Deserta Grande and enhance marine birds’ breeding areas by, in the first instance, removing introduced animals (i.e., rabbits, rodents, goats and cats) from the islands. This would be supported by an assessment of the ecological, biological and geological characteristics of the islands, especially of the floral communities that are out of reach of the herbivores and therefore still relatively intact.
RESULTS
The project was successful in the eradication of rabbits, cats and goats on Deserta Grande. For example, a total of 101 goats were killed. However, the eradication of rodents was not achieved, although the numbers were substantially lowered: Rodents are extremely resistant to poisons and their total elimination is virtually impossible.
The presence of predators (such as Buteo buteo and Tyto alba), in addition to the elimination of other food sources for the predators such as rabbits, should also help to control the future the rodent population, although this will need to be monitored.
The recovery of the vegetation cover was also achieved. This in turn, helps to reduce erosion and increases the potential nesting grounds and breeding areas for marine birds. A photographic survey of the vegetation cover was used as a basis for the evaluation of the flora restoration. It showed that recovery started soon after the completion of the first mammal elimination works.
Awareness was also raised about the recovery of terrestrial habitat of Deserta Grande. This was mainly targeted at schoolchildren namely through school conferences and visits to the Deserta Grande island and Madeira botanical garden.
Finally, this project was considered to be highly innovative: This was the first time such a project targeting the eradication of invasive non-native animals on an island at this scale had been attempted in Europe. The methodology was applied successfully in another LIFE project in Azores related to marine birds' conservation. Other institutions, such as the Asturias regional government, approached the project team for information on the problem in order to apply the methodology. The project was successful in the eradication of rabbits, cats and goats on Deserta Grande. For example, a total of 101 goats were killed. However, the eradication of rodents was not achieved, although the numbers were substantially lowered: Rodents are extremely resistant to poisons and their total elimination is virtually impossible.
The presence of predators (such as Buteo buteo and Tyto alba), in addition to the elimination of other food sources for the predators such as rabbits, should also help to control the future the rodent population, although this will need to be monitored.
The recovery of the vegetation cover was also achieved. This in turn, helps to reduce erosion and increases the potential nesting grounds and breeding areas for marine birds. A photographic survey of the vegetation cover was used as a basis for the evaluation of the flora restoration. It showed that recovery started soon after the completion of the first mammal elimination works.
Awareness was also raised about the recovery of terrestrial habitat of Deserta Grande. This was mainly targeted at schoolchildren namely through school conferences and visits to the Deserta Grande island and Madeira botanical garden.
Finally, this project was considered to be highly innovative: This was the first time such a project targeting the eradication of invasive non-native animals on an island at this scale had been attempted in Europe. The methodology was applied successfully in another LIFE project in Azores related to marine birds' conservation. Other institutions, such as the Asturias regional government, approached the project team for information on the problem in order to apply the methodology.