Invasion pattern of Solanum elaeagnifolium in Greece
Solanum elaeagnifolium (Solanaceae: EPPO A2 List) is a herbaceous perennial or a small shrub, native to the Americas and an alien invasive plant in parts of Asia, Africa and the EPPO region. Each plant can produce 40-60 fruits with each fruit containing 60-120 seeds which are spread both naturally (via wind and through water movement) and through human assisted spread (dispersal via agricultural machinery). Negative impacts include outcompeting native species, reducing crop yields in agricultural systems and impacts on ecosystem services (for example pollinators). In Greece, S. elaeagnifolium has spread over the last few decades due to intensive human activities such as constructions of new roads, building or agricultural activities. A drive-by survey was carried out during the period 2000 to 2020. In total, 150 road routes were surveyed connecting 54 Greek cities. Most routes started in the center of a specific city and finished in the center of a settlement or another city. The survey covered all administrative regions of Greece (except Mount Athos). Each of the routes were surveyed at least 3–5 times during 2000–2020 (resulting in a total sampling effort of approximately 100 000 km). The altitudinal range of the surveyed area was 0–2200 m. The data collected from the survey was overlayed with GIS (Geographic Information System) data. The results showed that the range of S. elaeagnifolium has increased by 1750 % during the last decades, and the species has reached higher elevations. S. elaeagnifolium is associated with higher maximum temperatures and precipitation in summer and low precipitation in winter, as well as with soil disturbance related to agricultural activities, settlements and road networks, which facilitate its spread mainly at low altitudes. Preventative measures should be implemented quickly to avoid further spread of the species in Greece.
Sources
Krigas N, Tsiafouli MA, Katsoulis G, Votsi NE, van Kleunen, M (2021) Investigating the invasion pattern of the alien plant Solanum elaeagnifolium Cav. (Silverleaf nightshade): environmental and human-induced drivers. Plants 10(4), 805. https://doi.org/10.3390/plants10040805