Invasive plants in the Ponziane islands - Ruschia tumidula and Malephora crocea

Flowers and leaves of Malephora crocea (photo R. Frondoni)

13 June 2022

Let's get to know other plants of the same family as Carpobrotus, the Aizoaceae, which are also alien to the Ponzian Islands and potentially invasive given their characteristics in terms of ecology and adaptability: Ruschia tumidula and Malephora crocea.

Both of these species are native of South Africa. They are small succulent shrubs (with woody base) with long finger-like leaves, triangular in cross-section. Ruschia tumidula has small bright pink flowers, whereas the flowers of Malephora crocea are larger and red-orange.

The two species are cultivated as ornamental in Ponza and Palmarola in the settlement behind the main beach of San Silverio.

In Ventotene, they have been observed in natural and seminatural habitats. The first observation dates to ten years ago, when they were found in Parata Grande. These populations are now well established and seem larger, even though limited. Malephora crocea is also present in Cala Rossano and on the rocks on the beach of  Cala Nave.

Currently, these species are not considered a threat to biodiversity, but as they are widely used in private or public gardens and their further spread could pose a threat. In fact, they are thermophilic and xerophilic plants, i.e., well adapted to high temperature and arid conditions, and in the future climate change could cause new wild stands of these species to form.