Ponderat aims at eradicating or controlling invasive alien species to preserve native habitat and species of the Ponziane Islands.

Alien species are animal or plants introduced by humans outside their natural range. Some alien species are called "invasive" as they cause damage to biodiversity, human activities and public health.

They are currently recognized as the leading cause of extinction for native plants and animals in the world.

Invasive alien species of the Ponziane Islands

Black rat

Among the species introduced on the Ponziane Islands, the black rat (Rattus rattus) is by far the one that has caused the greatest damage around the world. Among the vertebrates, the black rat is the most common invasive species in the Mediterranean, where it has been present for about two thousand years, having colonized almost all the large and medium-sized islands and most of those over 2-3 acres.

Multi-year monitoring activities have shown that on the Ponziane Islands, similarly to what is happening in the islands around the world, the black rat causes significant impacts on species and habitats, with particular regard to marine birds, such as in the case of shearwaters, whose chicks are predated by rats in their nest. Due to these impacts, rats are subject to control and eradication activities in many islands around the world, including those in the Mediterranean basin, where the species has been successfully eradicated on numerous islands, including Zannone, Giannutri and Montecristo.

In a recent scientific article, Palmarola is cited as the second Italian island where the eradication of rats would be effective for the conservation of marine birds such as Scopoli’s and Yelkouan shearwaters.

Hottentot fig

This name actually includes two different South African plant species (Carpobrotus spp.), very common in Mediterranean coastal ecosystems. Both species exhibit high invasive capacity thanks to the high production of seeds (over 5000 seeds per fruit), their resistance to aridity, the high rooting capacity of their stems and their tolerance to treading.

These are the two most widely spread and dangerous invasive plant species in the Mediterranean rocky and sandy coastal habitats, where they propagate in a short time at the expense of native spontaneous flora. In addition, the Hottentot fig represents a food source for the black rat, another target alien species of this project.

Wild goats of Palmarola

Goats are domesticated herbivores present with wild populations on several Mediterranean islands. Their presence on the islands produces significant impacts, with degradation of plant cover and consequent damage to soil stability.

Goats have been introduced for about twenty years on Palmarola, where they have become very numerous and widespread over the island, and where they are causing damage to native vegetation that is gradually becoming rare in many areas.

Mouflons of Zannone

The Mouflon is a direct descendant of domestic sheep, and on Mediterranean islands, where it has been brought by men, is to be considered an alien species.

Its introduction to Zannone dates back to a few decades ago for hunting purposes. Today there is a population of about 40-45 individuals. Being a herbivore, the mouflon expresses its grazing action at the expense of the native habitats of the island. In particular, its grazing action undermines the natural renewal of the holm oak forest, considered one of the most important of the Italian islands.

Animal species

Animal species

Eradication of invasive alien animals (like rats and goats).

Palmarola, Ventotene


Implementing a strong biosecurity effort to prevent rat reinvasion.

Ponza, Palmarola, S. Stefano, Ventotene, Zannone
Plant species

Plant species

Eradication of invasive alien plants (Carpobrotus sp.pl.).

Palmarola, Santo Stefano, Ventotene


Fencing of key land plot on Zannone to exclude wild alien ungulates (mouflons) to restore native habitats (holm oak forest).