Solanum elaeagnifolium threatens Croatian hot spots of biodiversity
Solanum elaeagnifolium (Solanaceae, EPPO List of invasive alien plants) is a very invasive plant which was studied in detail during a workshop co-organized by EPPO and FAO on 2006-05-29/31 in Sousse (TN). Conclusions and recommendations as well as pictures are available from the EPPO Website.
The presence of Solanum elaeagnifolium on the islet of Plavnik (Croatia) (EPPO RS 2006/018), has been confirmed by Goran Sušić from the Non-Governmental Organization ‘Caput Insulae Beli’. The island of Plavnik is 8.8 km² and is not inhabited, although there are some houses. There is no transport infrastructure, and it is only possible to reach the island by boat. The main activity on this island is extensive sheep breeding although commercial hunting began to be organized there recently (15 fallow deer Dama dama were released on the island a few years ago). Biodiversity is very high on Plavnik:
- breeding bird species: 12 pairs of griffon vultures (Gyps fulvus), golden eagle (Aquila chrysaetos), short-toed eagle (Circaetus gallicus), peregrine falcon (Falco peregrinus), kestrel (Falco tinnuncullus), eagle owl (Bubo bubo), rock partridge (Alectoris graeca), 20 pairs of shags (Phalacrocorax aristotelis desmarestii), pallid swift (Apus pallidus), alpine swift (Apus melba), nightjar (Caprimulgus europaeus), scops owl (Otus scops), little Owl (Athenae noctua), tawny owl (Strix aluco), blue rock thrush (Monticola solitarius), cuckoo (Cuculuc cannorus), hoopoe (Upupa epops), woodchat shrike (Lanius senator), golden oriole (Oriolus oriolus), jackdaw (Corvus monedula),
- amphibians: marsh frog (Rana ridibunda), common tree frog (Hyla arborea) and green toad (Bufo viridis),
- reptiles: Herman’s tortoise (Testudo hermanni), European pond terrapin (Emys orbicularis), green lizard (Lacerta viridis/bilineata), and several species of snakes…
- plants are unique because of pasturelands, old holly oak forests and cliffs with endemic plant community (Campanulo-Centaureetum dalmaticae).
This unique biodiversity is threatened by the very invasive Solanum elaeagnifolium. The pathway of introduction of S. elaeagnifolium on the island still remains to be discovered. One hypothesis is that the plant could have been introduced, and could therefore be spread, by sheep as there are at least 1000 sheep, with movement of lambs and wool between the continent and other islands. The plant could also be naturally spread by wind as there are strong north-east and south-west winds, sometimes attaining speeds of more than 150 km/h. After a study on the presence of S. elaeganifolium, eradication may be undertaken with the help of volunteers of the Non-Governmental Organization ‘Caput Insulae Beli’.
Sources
Caput Insulae Beli: www.caput-insulae.com
EPPO Website – Solanum elaeagnifolium Workshop conclusions and recommendations: http://archives.eppo.org/MEETINGS/2006_meetings/solanum_presentations/workshop_solanum_TN.htm
Personal communication with Goran Sušić, Non-Governmental Organization ‘Caput Insulae Beli’, Croatia, 2006.