Herpetology Notes, volume 13: 25-28 (2020) (published online on 24 January 2020)

A Gecko : a herpetological survey on Lichadonissia, a small islet group in Greece

Panayiotis Pafilis1,2,*, Kostas Α. Triantis3, Ioannis Anastasiou1, Konstantinos Proios3, and Efstratios D. Valakos2,4

Ever since Wallace and Darwin, life has been to the sea believing that he betrayed him and the limbs fascinating to field biologists (Whittaker et al. 2017). of the unlucky servant formed the . Lichadonissia Island biogeography, a genuine offspring of nesiophilia, consists of multiple islands of various sizes (Fig. 2). i.e. the inordinate fondness and hungering for islands They are part of the NATURA 2000 network (site code (Wilson, 2009), focuses on insular populations and has GR2420013), as they host a small population of monk revealed impressive findings (MacArthur and Wilson, seals (Monachus monachus). Lichadonissia are volcanic 1967; Losos and Ricklefs, 2009). The study of the islands, consisting mainly of trachyandesite lava flows, Greek herpetofauna does not represent an exception to dated at 0.5 Ma (Pe-Piper and Piper, 2002), lying over a this general rule. Greek Islands, encompassing around magma chamber (Karastathis et al. 2011). Nowadays, all 8,000 islands of various sizes, were, and still are, the islands are uninhabited. However, in a 1928 census, 70 showcase of Greek herpetofauna, attracting the strong residents were reported from the largest island (Monolia, interest of herpetologists (Pafilis and Maragou, 2013; abandoned by the end of 70’s) and less than 10 from the Christopoulos et al. 2019; see Sfenthourakis et al. 2018 second largest island (Strogyli, abandoned in the early for a recent review of the Aegean biogeography overall). 90s) where a small monastery and a lighthouse still Despite the very important effort that has been put exist (Hellenic Statistical Authority). Kokkinonissi was hitherto studying small islands and islets in the Aegean never inhabited, but touristic activities (e.g. swimming, Sea (Lymberakis et al. 2018), there are still islands that snorkelling, bar) have recently begun to occur have never been assessed. This is the case of Lichades during summer (same on Monolia). Islands or Lichadonissia, a small islet group between On 3rd May 2019, we conducted a field trip to Euboea Island (closest distance: 0.72 km) and mainland Lichadonissia to assess the animal diversity of Greece (closest distance: 2.17 km) (Fig. 1). the archipelago and visited the four larger islands. The small archipelago was named after Heracles’ Climate conditions were ideal (clear sky, low winds servant Lichas (Λίχας), who brought Heracles a poisoned and air temperature around 27o C). We first landed tunic sent by the hero’s jealous wife Deianira. According on Kokkinonissi (38.8198 N, 22.8196 E, area: 0.082 to the myth, while Heracles was dying, he threw Lichas km2) and from there we were able to walk to Steno (38.8168 N, 22.8189 E, area: 0.005 km2) thanks to the low waters in the between them. Both islands are low (highest point: 1 m) and covered with . Vegetation comprises small halophyte plants (e.g.

1 Dept. of Zoology and Marine Biology, Faculty of Biology, Salicornia sp.), shrubby sea-blite (Suaeda vera) and National and Kapodistrian University of Athens, lentisks (Pistacea lentiscus). Overturning the very first Panepistimioupolis, 15784 Athens, Greece. rock, we encountered a Kotschy’s gecko Mediodactylus 2 Zoological Museum, National and Kapodistrian University of kotschyi (Steindachner, 1870) (Fig. 3A). Many insular Athens, Greece. populations of this species in Greece were recently 3 Dept. of Ecology and Taxonomy, Faculty of Biology, National described as separate species (Kotsakiozi et al., 2018). and Kapodistrian University of Athens, Panepistimioupolis, Nonetheless, Lichadonissia host the typical M. kotschyi. 15784 Athens, Greece. We soon found out that M. kotschyi were present 4 Dept. of Animal and Human Physiology, Faculty of Biology, National and Kapodistrian University of Athens, almost everywhere on both islets: on Kokkinonissi we Panepistimioupolis, 15784 Athens, Greece. counted 11 individuals in an hour and nine within the * Corresponding author. E-mail: [email protected] same period on Steno. Though this is not an accurate 26 Panayiotis Pafilis et al.

Figure 1. Map of Lichades Islands (or Lichadonissia) between Euboea and mainland Greece. The islands we visited are coloured with dark grey.

method to estimate population abundance (Buckley and In a recent study in Peloponnese, most specimens were Roughgarden, 2005), it certainly provides a measure found on trees (81%), especially on almond, olive and of the high population densities, when compared to eucalypts, in contrast to the Aegean Islands where other Aegean islands assessed with the same method only two geckos were encountered on trees out of 800 (Slavenko et al., 2015; Itescu et al., 2017). We did not individuals that were detected under rocks (Schwarz et find any other reptile on these two islands. al. 2016). It seems that this peculiar pattern (saxicolous Afterwards, we passed to Monolia (38.8235 N, life style on the islands and arboreal in the mainland) 22.8165 E, area: 0.599 km2, highest point: 13 m). The is reproduced on a small scale on Lichadonissia. It is island is characterized by an extended olive grove noteworthy that gecko numbers were lower on Monolia (Olea europaea) interrupted by clearings with many (three individuals within two hours) compared to the rock piles, probably deriving from the old buildings first two islets. The only other reptile on the island, and that used to stand on the island. Despite the many rocks actually on the whole archipelago, was the Balkan whip we flipped over, surprisingly we failed to detect even snake Hierophis gemonensis (Laurenti, 1768), of which a single gecko. After half an hour we discovered that we detected two specimens (Fig. 3C). However, we we were looking in the wrong place. Contrary to the should point out that due to the short period we spent on previous two islets, M. kotschyi on Monolia dwell on each island, we might have failed to detect other reptilian olive trees (Fig. 3B). This is a very interesting finding. species, particularly the more elusive, like snakes. Mediodactylus kotschyi is generally believed to be Finally, we visited Strogyli (38.8090 N, 22.8206 E, saxicolous, but in the mainland it tends to occur in high area: 0.071 km2, highest point: 17 m), an island with frequency on trees (Werner 1993; Schwarz et al. 2016). steep slopes and lush vegetation, atypical to small A Gecko archipelago: a herpetological survey on Lichadonissia, Greece 27

Aegean islets. Once more, the only reptile species we found was M. kotschyi, located exclusively under rocks but in lower numbers (two individuals in 90 min). It is hard to determine the ecological drivers that underlie the life style dipole between Monolia and the rest of the islets in the group. A possible explanation could be predation regime. Hierophis gemonensis is a snake that regularly consumes lizards (Valakos et al. 2008). On Monolia we also encountered rats and cats, both skilful saurophagous predators (Taylor and Thomas, 1993; Li et al., 2014). It could be that geckos on that islet seek shelter on trees to relieve predation pressure. Small like Lichadonissia lend themselves Figure 2. Lichadonissia panorama: photo taken from Monolia to investigate ecological particularities, such as density showing Kokkinonissi in the front, Steno just behind and compensation (Schoener et al., 2001), and the small Strogyli at the end. In the far distance the mountains of island effect (e.g. Triantis and Sfenthourakis, 2012). mainland Greece. The high densities of M. kotschyi on Kokkinonissi and

Figure 3. The two species encountered during the survey. A – an adult Mediodactylus kotschyi that was hidden under the rock on Kokkinonissi; B – Mediodactylus kotschyi individuals on Monolia that were detected on olive trees either on the bark or in tree hollows; C – Hierophis gemonensis on Monolia. 28 Panayiotis Pafilis et al.

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Accepted by Florina Stanescu