Georgopoulou E., Gkisakis V., Kabourakis E.

Cultivated land is rarely surveyed for land snails. In this study, we investigated, for the first time, the land snail fauna of olive orchards situated in western Messara valley in Crete (Greece). We surveyed bimonthly, from November 2019 till October 2020, 16 olive orchards located in two agroecological zones, i.e. hilly and plain, regarding the occurrence of land snails. The α-, β- and γ-diversities were recorded and richness differences between agroecological zones were investigated. We found 17 species belonging to 16 genera and seven families, while two more species belonging to the genera Mastus (H. Beck, 1837) and Albinaria (Vest, 1867) were further identified. The most common species found in all the olive orchards were Cornu aspersum (O.F. Müller, 1774), Cantareus apertus (Born, 1778) and Eobania vermiculata (O.F. Müller, 1774). Pseudoxerophila bathytera (Westerlund & Blanc, 1879) was only found in one olive orchard in the hilly zone. Caracollina lenticula (Michaud, 1831) was reported for the first time in the area. Three species endemic to the island of Crete were identified. On average, olive orchards in the hilly zone host more species that the plain ones. Species composition (i.e. β-diversity) is mainly shaped by species replacement among the olive orchards. The olive orchards under study host ca. 50% of the land snail species of the wider area. Reported richness differences appears to relate to altitudinal differences, although further investigation is required. Geographic proximity of the studied olive orchards hampers strong differences in species composition. This is a first attempt to understand the impact of human (agricultural/farming) activities on land snails in the Mediterranean region. We highlight the importance of cultivated areas, such as olive orchards, as sites of increased land snail diversity. Further research is required to evaluate land snails as potential indicators of the impact of agriculture on biodiversity.

Acknowledgments: This research is co-financed by Greece and the European Union (European Social Fund-ESF) through the Operation-al Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project “Impact of different management systems and spatial factors on the biodiversity of olive agroecosystems” (MIS 5048171).