title: Comparing the two Greek archipelagos plant species diversity and endemism patterns highlight the importance of isolation and precipitation as biodiversity drivers.
abstract: BACKGROUND
  Greece has two island archipelagos, the Aegean and the Ionian, which host a rich array of plants and wildlife, particularly endemic and threatened plant species. Despite the long history of island biogeographic studies in the Aegean, similar studies in the Ionian remain limited, with the two island archipelagos rarely being compared.
  
  
  RESULTS
  The Aegean and Ionian archipelagos share many features, especially regarding total plant diversity, but exhibit different patterns of endemism. For instance, when considering similarly sized islands, those in the Ionian host as many as, if not more, species compared to the Aegean. In contrast, the Ionian Islands are poor in endemics (particularly narrow range endemics, such as single island or regional endemics) and threatened taxa, compared to the Aegean Islands. In the Ionian, endemics only persist on the largest islands, and form a very small proportion of the species pool, compared to the Aegean archipelago.
  
  
  CONCLUSIONS
  The lack of endemism might be attributed to the more recent separation of the Ionian Islands from the mainland and the shorter distance separating them from the mainland. In addition, the Ionian Islands receive higher levels of precipitation and are typically covered by denser and higher vegetation than the Aegean Islands. These conditions favour greater total species richness, but tend to lead to higher numbers of common species compared to threatened and endemic taxa. This study demonstrates that both isolation and precipitation serve as biodiversity drivers, influencing plant species diversity and endemism patterns, of the two Greek archipelagos.
authors.affiliation: Department of Environmental and Natural Resources Management, University of Ioannina, Agrinio, GR-30100 Greece ; Department of Environmental and Natural Resources Management, University of Patras, Agrinio, GR-30100 Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Iliadou
authors.affiliation: Department of Environmental and Natural Resources Management, University of Ioannina, Agrinio, GR-30100 Greece ; Department of Environmental and Natural Resources Management, University of Patras, Agrinio, GR-30100 Greece.
authors.forename: Athanasios S
authors.initials: AS
authors.lastname: Kallimanis
authors.affiliation: Department of Environmental and Natural Resources Management, University of Ioannina, Agrinio, GR-30100 Greece ; Department of Environmental and Natural Resources Management, University of Patras, Agrinio, GR-30100 Greece.
authors.forename: Panayotis
authors.initials: P
authors.lastname: Dimopoulos
authors.affiliation: Department of Environmental and Natural Resources Management, University of Ioannina, Agrinio, GR-30100 Greece ; Department of Environmental and Natural Resources Management, University of Patras, Agrinio, GR-30100 Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Panitsa
keywords: Aegean islands; Endemic species patterns; Ionian islands; Plant diversity; Plant geography; Single island endemics