Plant diversity of olive groves under different management practices: a case study on Lesbos Island (East Aegean area, Greece)

The Mediterranean Basin is evolving due to human – nature interactions. The management of agroecosystems strongly affects plant diversity. Olive groves cover 19% of the cultivated area in Greece of which 8% is organic, cultivated using environment-friendly farming practices, while the rest includes conventional (intensive) or abandoned olive groves. Lesbos, the third largest island of Greece, is characterized by high plant diversity. The current study aims to investigate plant species diversity of olive groves under different management practices. Sampling activities have been carried out in 65 plots. Field surveys to sample the vascular flora and vegetation were performed between April and May of 2020 and 2021. More than 210 plant taxa have been recorded in the studied olive groves. The results showed that organic olive groves are characterized by a rich and diverse flora, mainly dominated by therophytes and especially of annual leguminous species indicating moderate long-term human interference. Intensive olive groves have a poor and rather common vascular flora also dominated by therophytes. Abandoned olive groves present a rather poor but diverse flora, mainly dominated by chamaephytes, hemicryptophytes and phanerophytes and by a lower proportion by annual plants, depending also on the time lapse after abandonment.