Mediterranean cliffs with endemic limoniums
One of the habitats most affected by invasive alien plant species in the Mediterranean basin are the Mediterranean cliffs with endemic sea lavender (Limonium sp.). This habitat is formed by coastal cliffs and rocky shores influenced, to a lesser or greater extent, by the action of seawater.
The Mediterranean cliff habitat includes a supralittoral area with small ponds dug into the rocks that are filled with seawater where several species of plankton, lichens, small snails, and crustaceans are living. As we move away from the water, we find a land area where several flowering plants can grow. However, the plant cover is poor and dominated by scattered populations of small bushes with quite fleshy leaves and stems and often with salt-secreting glands. While sea fennel is a common plant species of this area, sea lavender and sea plantain grow in places where more saline soil is accumulated.
Thanks to the geological features and the rich vegetation of the coastal cliffs of Costa Brava and the Cap de Creus Natural Park, these places are home to numerous rare and unique species, some of which are endemic. Among these endemic plant species, there are two sea lavenders, Limonium geronense and Limonium tremolsii, and the seseli of Cap de Creus or “Farreny’ seseli” (Seseli farrenyi), which is a true botanical gem of the Cap de Creus Natural Park given its worldwide uniqueness, is considered one of the most endangered plant species in Catalonia.
Invasive plants threaten the conservation of all these three endemic plants. Therefore, by improving the current management of invasive plants in the coastal cliffs, the LIFE medCLIFFS project is intended to improve their conservation status.
At Cap de Creus there can be found three endemic species:
This plant is endemic to the Girona coastline, from Cap de Creus to Portbou, and is mainly threatened by urban development and the overcrowding of the rocky areas where it grows, usually frequented in summer by people who is looking for a place near the sea. It is listed as an endangered and therefore protected species.
This herb can grow up to 15 cm in height, it is perennial; it has simple, reddish leaves with an elongated shape similar to a spatula. Its flowering season lasts from July to September. It forms flowering spikes with two to four flowers that are purple to red in colour. Its fruits grow from August to October.
Although these sea lavenders are pollinated by insects, they can also produce seeds asexually, without the need for pollination. Once the seeds have formed, they fall down the cliff, where new sea lavenders will germinate and develop. When invasive plants occupy the cliffs, the potential growing area of sea lavender is covered and these seeds are not able to germinate, compromising the long-term conservation of the species.
It is a perennial herbaceous plant, which does not usually exceed 40 cm in height. Shaped as a small pillow and with small simple leaves, which have a margin folded towards the bottom, and a spike at the tip facing downwards. The leaves form a rosette at the end of each branch.
During the flowering season, from June to August, small reddish to purple flowers measuring 7 to 8 mm cluster together to form inflorescences. Unlike other plants in the genus Limonium, in Limonium tremolsii produces short and scattered flower clusters, and can be found on coastal rocky areas, forming small populations in the Cap de Creus Natural Park, the Montgrí Natural Park, the Medes Islands and the lower Ter River.
It is a perennial herb 6 to 30 cm tall, highly branched from the base. It usually blooms from July to September, although in some years the flowering season can last from February to November. It produces a set of small, white flowers grouped in an umbrella-shaped inflorescence called umbel. In strong episodes of Tramontane northern wind, the plant dries out and the fruits are dispersed more quickly. The Cap de Creus seseli is listed as an endangered species. There are only three known populations of this plant, very close to each other and located in the northern part of Cap de Creus, with a total of just over 800 individuals.