Browsing by Author "Bayrakci, Y"

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    On the occurrence of the Pond Slider Turtle Trachemys scripta (Thunberg in Schoepff, 1792) from southwestern Türkiye
    Yakin, BY; Çiçek, K; Bayrakci, Y; Günay, UK; Afsar, M; Ayaz, D; Tok, CV
    Trachemys scripta is included among the 100 most invasive species worldwide. Since the first report on the presence of pond slider turtles from natural habitats in Turkiye, the distribution of this invasive species comprises almost thirty provinces. However, it spread to much wider sites than the regions determined until today. Besides, there is a lack of knowledge on which subspecies exist in the invaded habitats. Within this study, we presented the presence of two subspecies of the invasive alien slider turtle for the first time from the Resadiye, Datca, Mugla, Turkiye. We also suggest certain precautions should be taken against slider turtles to contribute to preventing their invasion of our biodiversity.
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    Unsustainable harvest of water frogs in southern Turkey for the European market
    Çiçek, K; Ayaz, D; Afsar, M; Bayrakci, Y; Peksen, ÇA; Cumhuriyet, O; Ismail, IB; Yenmis, M; Üstündag, E; Tok, CV; Bilgin, CC; Akçakaya, HR
    Frogs have been harvested from the wild for the last 40 years in Turkey. We analysed the population dynamics of Anatolian water frogs (Pelophylax spp.) in the Seyhan and Ceyhan Deltas during 2013-2015. We marked a total of 13,811 individuals during 3 years, estimated population sizes, simulated the dynamics of a harvested population over 50 years, and collated frog harvest and export statistics from the region and for Turkey as a whole. Our capture estimates indicated a population reduction of c. 20% per year, and our population modelling showed that, if overharvesting continues at current rates, the harvested populations will decline rapidly. Simulations with a model of harvested population dynamics resulted in a risk of extinction of > 90% within 50 years, with extinction likely in c. 2032. Our interviews with harvesters revealed their economic dependence on the frog harvest. However, our results also showed that reducing harvest rates would not only ensure the viability of these frog populations but would also provide a source of income that is sustainable in the long term. Our study provides insights into the position of Turkey in the 'extinction domino' line, in which harvest pressure shifts among countries as frog populations are depleted and harvest bans are effected. We recommend that harvesting of wild frogs should be banned during the mating season, hunting and exporting of frogs < 30 g should be banned, and harvesters should be trained on species knowledge and awareness of regulations.
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    It takes two to tango - Phylogeography, taxonomy and hybridization in grass snakes and dice snakes (Serpentes: Natricidae: Natrix natrix, N. tessellata)
    Asztalos, M; Ayaz, D; Bayrakci, Y; Afsar, M; Tok, CV; Kindler, C; Jablonski, D; Fritz, U
    Using two mitochondrial DNA fragments and 13 microsatellite loci, we examined the phylogeographic structure and taxonomy of two codistributed snake species (Natrix natrix, N. tessellata) in their eastern distribution area, with a focus on Turkey. We found evidence for frequent interspecific hybridization, previously thought to be extremely rare, and for backcrosses. This underscores that closely related sympatric species should be studied together because otherwise the signal of hybridization will be missed. Furthermore, the phylogeographic patterns of the two species show many parallels, suggestive of a shared biogeographic history. In general, the phylogeographies follow the paradigm of southern richness to northern purity, but the dice snake has some additional lineages in the south and east in regions where grass snakes do not occur. For both species, the Balkan Peninsula and the Caucasus region served as glacial refugia, with several mitochondrial lineages occurring in close proximity. Our results show that the mitochondrial divergences in both species match nuclear genomic differentiation. Yet, in the former glacial refugia of grass snakes there are fewer nuclear clusters than mitochondrial lineages, suggesting that Holocene range expansions transformed the glacial hotspots in melting pots where only the mitochondrial lineages persisted, bearing witness of former diversity. On the other hand, the deep mitochondrial divergences in N. tessellata across its entire range indicate that more than one species could be involved, even though lacking micro satellite data outside of Turkey prevent firm conclusions. On the contrary, our microsatellite and mitochondrial data corroborate that N. megalocephala is invalid and not differentiated from sympatric populations of N. natrix. For Cypriot grass snakes, our analyses yielded conflicting results. A critical assessment of the available evidence suggests that N. natrix is a genetically impoverished recent invader on Cyprus and taxonomically not distinct from a subspecies also occurring in western Anatolia and the southern Balkans. Based on combined mitochondrial and nuclear genomic evidence we propose that for grass snakes the following subspecies should be recognized in our study region: (1) Natrix natrix vulgaris Laurenti, 1768, southeastern Central Europe and northern Balkans; (2) Natrix natrix moreoticus (Bedriaga, 1882), southern Balkans, western Anatolia, and Cyprus; and (3) Natrix natrix scutata (Pallas, 1771), eastern Anatolia, Caucasus region, Iran, northeastern distribution range (from eastern Poland and Finland to Kazakhstan and the Lake Baikal region). Thus, Natrix natrix cypriaca (Hecht, 1930) becomes a junior synonym ofN. n. moreoticus and Natrix natrix persa (Pallas, 1814) becomes a junior synonym ofN. n. scutata. Due to insufficient material, we could not resolve the status of Natrix natrix syriaca (Hecht, 1930) from the Gulf of Iskenderun, southeastern Turkey.