Contemporary geography dominates butterfly diversity gradients within the Aegean archipelago (Lepidoptera: Papilionoidea, Hesperioidea)

Abstract

Aim We compare the influence of contemporary geography and historical influences on butterfly diversity for islands in the Aegean archipelago. Location The Aegean archipelago (Greece) and two islands (Cyprus and Megisti) in the Levantine Sea. Methods Thirty‐one islands were examined. Data are taken from own surveys (Coutsis and Olivier) and from the literature. Stepwise multiple regression is used to determine relationships between species richness, frequency, rarity and endemicity against potential geographical predictors. Stepwise logit regression is used to determine geographical predictors of species incidence on islands. Inter‐island and inter‐species associations have been examined using multivariate ordination and clustering techniques. Results The Aegean butterfly fauna is characterized by decreasing diversity and rarity, and increasing homogeneity, from the periphery to the present geographical centre of the archipelago (Cyclades). Diversity and rarity are shown to relate closely to species richness, and species richness, in turn, is largely explained by contemporary geography, particularly the degree of isolation from the nearest mainland sources of Greece or Turkey, and island dimensions. Islands towards the centre of the archipelago are characterized by a group of mobile species (n ≥ 20 species) with extensive ranges across Europe; species that would have recolonized Santorini (Thira) following the VI6 eruption there c. 1630 bc. Endemic components, indicative of autochthonous evolutionary events, are few (5% of species are endemic) compared to known sedentary organisms (molluscs and isopods), but exceed those for more mobile animals (i.e. birds); their distribution is mainly confined to large isolated islands along the Aegean arc (i.e. Kriti) and in the Dodecanese group. Main conclusions Contemporary geography, i.e. processes currently operating in ecological time, dominates butterfly diversity gradients (species richness, frequency, rarity and incidence) in the archipelago. Two reasons are suggested to account for the lack of endemism and the pattern of decreasing diversity into the Cyclades. First, relict butterfly elements may have become extinct on all but a few larger islands, particularly from environmental changes since the Neolithic (fire and overgrazing). Second, colonization from the continental landmasses is ongoing with more mobile species transferring even to the most isolated islands.

Pseudamnicola Paulucci, 1878 (Caenogastropoda: Truncatelloidea) from the Aegean Islands: a long or short story?

“…In the same manner, vicariance cannot explain the whole pattern in the land snail Albinaria (Douris et al 1998(Douris et al , 2007 and other invertebrates and vertebrates in Fig. 9 Renal and pallial section of the female reproductive organs of Pseudamnicola chia from Khios Island, locality CH02: bc bursa copulatrix, cbc duct of bursa copulatrix, dgp gono-pericardial duct, ga albuminoid gland, gn nidamental gland, gp gonoporus, ov pallial oviduc, ovl loop of (renal) oviduct, rs receptaculum seminis, vc ventral canal the Aegean (Dennis et al 2000;Kasapidis et al 2005). Just as in the central European Bythinella (Falniowski 1987;Falniowski et al 1998Falniowski et al , 1999Szarowska 2000) and the Greek mainland Bythinella (Falniowski and Fig.…”

Do diversity patterns of the spring-inhabiting snail Bythinella (Gastropoda, Bythinellidae) on the Aegean Islands reflect geological history?

“…The current pattern of biodiversity in this area was shaped by substantial climatic changes as Messinian Salinity Crisis, Zanclean flood and repeated glaciations separated by warmer periods, causing fluctuations in the sea level that exceeded 200 m. The majority of studies on the Pleistocene phylogeography of European animals focus on the vertebrates and the terrestrial invertebrates (Dennis et al, 2000;Chatzimanolis et al, 2003;Benke et al, 2009, and the references therein), but to better understand the processes of diversification, species must be investigated that have different ecological restrictions. The freshwater snail species of cold springs are interesting examples of this kind, because these snails live in potentially isolated, unstable and ephemeral habitats.…”

“…Nevertheless, dispersal over sea or through occasional land bridges was also involved (see Douris et al, 1998;Dennis et al, 2000;Kasapidis et al, 2005).…”

SPATIAL VARIATIONS IN RARITY IN THE AEGEAN TENEBRIONID BEETLES (Coleoptera, Tenebrionidae)

“…Médail & Quézel 1999;Troumbis & Dimitrakopoulos 1998;Sfenthourakis & Legakis 2001;Fattorini 2006a). In addition, the Aegean Islands are of high biogeographical and conservation interest because of their location at the crossroad between the Balkan and the Anatolian faunas (Dennis et al 2000;Fattorini 2002;Fattorini & Fowles 2006). For these reasons, the Aegean tenebrionids represent a faunal group deserving special attention for the conservation of nature in the Mediterranean.…”