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