Are Mediterranean forest ecosystems under the threat of invasive species Solanum elaeagnifolium?

Abstract

Abstract: Solanum elaeagnifolium Cav. is one of the most invasive plant species worldwide that colonizes crops and human disturbed lands, while it appears at the edge of forest ecosystems. Its control still remains an unsolved problem around the world. Understanding its distribution under predicted climate change, could contribute to an effective management and conservation of ecosystems in the future. This research was conducted in order to investigate the capacity of this species to invade Mediterranean forest ecosystems, and if the allelopathy effects of forest tree species could control its regeneration, thus contributing to a natural and biological management practice aimed to prevent the species from pervading into Mediterranean forest ecosystems. Results showed that S. elaeagnifolium can establish itself outside and along the forest edges, but not in a typical forest environment. The leaf extracts of Pinus brutia, Cupressus sempervirens, Quercus coccifera and Quercus pubescens significantly inhibited the germination of S. elaeagnifolium. Root regenerative ability of the cuttings was also significantly affected by the leaf extract treatments. P. brutia leaf extract had significantly the highest inhibitory activity on root regenerative ability of the species. Despite the promising findings of this study, absence of S. elaeagnifolium in Mediterranean forest ecosystems can be attributed to a combination of factors. In the context of climate change, especially in hot and dry Mediterranean areas, and the expected increase of forest disturbances (e.g., fires), the findings of the study could contribute towards the restriction of this invasive alien species by an appropriate management of forest ecosystems.