EPPO Global Database

EPPO Reporting Service no. 06 - 2025 Num. article: 2025/161

Alien plant species on the island of Menorca (Islas Baleares, Spain)


Island biodiversity can be particularly vulnerable to invasions by non-native species, largely due to the insular ecosystems which harbour endemic species. Menorca, the second largest island in the Balearic archipelago has been a designated Biosphere Reserve since 1993. A study was conducted on the alien plant species present on this island. The island was divided into 10 x 10 km grids and the habitat types in each grid was defined : cliffs (or rock walls), crops, dunes, forests (or shrublands), roadsides, rocky shores, streams and wetlands.  Alien species were mapped and their abundance was estimated using the DAFOR scale. In total, there were 858 occurrences of 117 alien plant taxa. Most alien flora were trees and shrubs (33 taxa), annuals (27 taxa), low growing perennials (33 taxa) and vines (15 taxa). The abundance of alien taxa differed between the eight habitats. The abundance in stream habitats was higher than in rocky shores, forests and dunes. Management of alien species on Menorca should focus in areas of high conservation value while at the same time avoiding spread from areas where potential invasive alien plants are planted. 


Table 1. Most abundant alien plant species on the island of Menorca

Species

Family 

Native range 

Habitats

Agave americana

Agavaceae

Nearctic

D, F, Cl, Rs, W

Amaranthus retroflexus

Amaranthaceae

Nearctic

Cr, St, Rs, W

Arundo donax*

Poaceae

Paleotropical

Cl, St, Rs, W

Cenchrus clandestinus

Poaceae

Paleotropical

All except Cl

Digitaria spp.

Poaceae

Neotropical

Cr, D, St, Rs, W

Erigeron bonariensis

Asteraceae

Neotropical

All habitats

Erigeron sumatrensis

Asteraceae

Mediterranean

All habitats

Jacobaea maritima

Asteraceae

Mediterranean

D, F, Cl, St, W

Lantana × strigocamara

Verbenaceae

Artificial hybrids

All except St

Opuntia ficus-indica

Cactaceae

Neotropical

F, Cl, St, Rs

Oxalis pes-caprae*

Oxalidaceae

South Africa

All except W

Phoenix canariensis

Arecaceae

Macaronesian

All habitats

Pittosporum tobira

Pittosporaceae

East Asia

All except Rs

Symphyotrichum squamatum

Asteraceae

South America

All habitats

* Species is listed on the EPPO List of Invasive Alien Plants

Habitats where the taxa are present in Menorca: crops (Cr), cliffs (Cl), dunes (D), forest (F), roadsides (Rs), streams (St), wetlands (W)


Sources

Capó M, Borrás J, Fraga-Arguimbau P, Rita J, Cursach J (2025) The alien flora on the island of Menorca, a biosphere reserve. Biodiversity and Conservation. https://doi.org/10.1007/s10531-025-03095-w