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Start Over Author "Cumhuriyet, Oğuzkan" Topic population dynamics
3 results on '"Cumhuriyet, Oğuzkan"'

1. Population dynamics of amphibian community in Lake Çıldır, Northeastern Anatolia.

Author

Cumhuriyet, Oğuzkan and Çiçek, Kerim

Subjects
*AMPHIBIAN populations, *POPULATION dynamics, *LIFE history theory, *WEATHER & climate change, *FROG populations
Abstract

Knowledge on life history traits and population dynamics of amphibians from northeastern Anatolia is limited. This results in a heavy reliance on published data regarding the European and Caucasian counterparts of the Anatolian populations in local conservation studies. The present study evaluated the phenology, age structure, population size, and population structure of the amphibian community in Lake Çıldır, northeastern Anatolia, Turkey. The site was surveyed between April 2017 and July 2019, detecting the presence of Bufo verrucosissimus, Bufotes viridis sitibundus, Pelophylax ridibundus, and Rana macrocnemis. The estimated population size ranged from 553 to 789 individuals for P. ridibundus and from 404 to 655 individuals for R. macrocnemis. The estimated mean capture probability was 0.09-0.10 for P. ridibundus and 0.08-0.11 for R. macrocnemis. The mean survival rates were estimated at 0.40-0.60 for P. ridibundus and 0.24-0.56 for R. macrocnemis. A male-biased sex ratio was observed for all species. The mean age was estimated at 5.28 years (2-9) for P. ridibundus, 4.32 years (2-6) for R. macrocnemis, and 5.55 years (3-9) for B. viridis sitibundus. Depending on weather conditions, the amphibian species emerged from brumation in the second half of April, and the breeding period took place between the end of April and June. The metamorphosis was attained in 55-125 days for P. ridibundus, 44-124 days for R. macrocnemis, and 56-128 days for B. viridis sitibundus, depending on weather conditions. The amphibian community of Lake Çıldır comprises healthy frog and toad populations, whose primary threats appear to be weather fluctuations and climate change. In contrast to their western Anatolian conspecifics, the studied amphibians suffered limited habitat loss and degradation, rendering them effective candidates as indicator species for climate change studies. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Monitoring amphibians of lake Çıldır (Ardahan)

Author

Cumhuriyet, Oğuzkan, Çiçek, Kerim, and Ege Üniversitesi, Fen Bilimleri Enstitüsü, Biyoloji, Ana Bilim Dalı

Subjects
Life Cycle, Ranidae, Northeast Anatolia, Population Dynamics, Popülasyon Dinamiği, Skeletochronology, Kuzeydoğu Anadolu, İskelet Kronolojisi, Yaşam Döngüsü, Bufonidae
Abstract

Bu çalışmada, Çıldır Gölü’nde yaşayan amfibi türlerinin ve dağılışlarının belirlenmesi, popülasyonların yapısı, yaşı ve markala tekrar yakala yöntemi ile popülasyon büyüklüklerinin hesaplanması amaçlanmıştır. Elde edilen verilere göre; göl ve yakın çevresinde Ova Kurbağası [Pelophylax ridibundus (Pallas, 1771)], Uludağ Kurbağası [Rana macrocnemis Boulenger, 1885], Değişken Desenli Gece Kurbağası [Bufotes sitibundus (Pallas, 1771)]ve Kafkas Siğilli Kurbağası [Bufo verrucosissimus (Pallas, 1814)] türlerinin varlığı tespit edilmiştir. Daimi 4 istasyonda Nisan 2017 – Temmuz 2018 tarihleri arasında ilkbahar ve yaz aylarında; B. verrucosissimus’a ait 4 birey (2 ♂♂, 2♀♀), B. sitibundus’a a ait 155 birey (5 genç, 86 ♂♂, 64 ♀♀), P. ridibundus’a ait 2715 birey (558 genç, 1158 ♂♂, 999 ♀♀) ve R. macrocnemis 2400 birey (496 genç, 1045 ♂♂, 859 ♀♀) markalanmıştır. Mevsime göre popülasyon büyüklüğü, P. ridibundus’ta 294 – 621 birey ve R. macrocnemis’te 277 – 514 birey arasında değişmektedir. Pollock’un Sağlam Dizaynı ile iki yıllık popülasyon büyüklüğü P. ridibundus’ta 553 – 789 birey ve R. macrocnemis’te 404 – 655 birey arasında değişmektedir. Ortalama yakalanma olasılığı P. ridibundus için 0,09 – 0,10 ve R. macrocnemis için 0,08 – 0,11 aralığında hesap edilmiştir. Ortalama hayatta kalma oranı P. ridibundus’ta 0,40 – 0,60 ve R. macrocnemis’te ise 0,24 – 0,56 aralığındadır. P. ridibundus, R. macrocnemis ve B. sitibundus popülasyonlarının tümünün erkek eğilimli olduğu tespit edilmiştir. Ortalama yaş; P. ridibundus’ta 5,28 yıl (2 – 9), R. macrocnemis’te 4,32 yıl (2 – 6) ve B. sitibundus’ta 5,55 yıl (3 – 9) olarak tespit edilmiştir. Tüm türlerin hibernasyondan çıkışlarının Nisan ayının 2. yarısında, üreme döneminin Nisan sonu-Haziran ayı aralığında ve metamorfozun P. ridibundus’ta 55 – 125 gün, R. macrocnemis’te 44 – 124 gün ve B. sitibundus’ta 56 – 128 gün arasında tamamlandığı gözlenmiştir. Türlere yönelik potansiyel tehdiler tartışılmıştır., In this study, it is aimed to determine the amphibian species living in Lake Çıldır and their distribution, to calculate the structure and sex ratio of the populations, to determine the age of the populations, to calculate the population sizes by catch and recapture method. According to the data obtained; Marsh Frog [Pelophylax ridibundus (Pallas, 1771)], Uludag Frog [Rana macrocnemis Boulenger, 1885], Variable Toad [Bufotes sitibundus (Pallas, 1771)] and Caucasian Toad [Bufo verrucosissimus (Pallas, 1814)] species have been identified. Between April 2017 – July 2018, in the spring and summer at 4 permanent stations; 4 specimens (2 ♂♂, 2 ♀♀) belonging to B. verrucosissimus, 155 specimens (5 young, 86 ♂♂, 64 ♀♀) belonging to B. sitibundus, 2715 specimens belonging to P. ridibundus (558 young, 1158 ♂♂, 999 ♀♀) and R. macrocnemis 2400 specimens (496 young, 1045 ♂♂, 859 ♀♀) were marked. According to the stations, population size varies between 294 – 621 specimens in P. ridibundus and 277 – 514 specimens in R. macrocnemis. According to Pollock's Robust Design formula, the population size of two years varies between 553 – 789 in P. ridibundus and 404 – 655 specimens in R. macrocnemis. The mean probability of detection was calculated between 0.09 - 0.10 for P. ridibundus and 0.08 - 0.11 for R. macrocnemis. Average survival rate is between 0.40 - 0.60 in P. ridibundus and 0.24 - 0.56 in R. macrocnemis. All of the P. ridibundus, R. macrocnemis and B. sitibundus populations were found to be male predisposed. Average age among species; It has been determined as 5.28 years (2 – 9) in P. ridibundus, 4.32 years (2 – 6) in R. macrocnemis, and 5.55 years (3 – 9) in B. sitibundus. It was observed that all species exit from hibernation in the second half of April, their breeding period was between the end of April – June, and the metamorphosis was completed between 55 – 125 days in P. ridibundus, 44 – 124 days in R. macrocnemis and 56 – 128 days in B. sitibundus. The potential threat on species were also discussed.

Published
2020

3. Unsustainable harvest of water frogs in southern Turkey for the European market.

Author

Çiçek, Kerim, Ayaz, Dinçer, Afsar, Murat, Bayrakcı, Yusuf, Pekşen, Çiğdem Akın, Cumhuriyet, Oğuzkan, İsmail, İlhan Bayram, Yenmiş, Melodi, Üstündağ, Erdal, Tok, Cemal Varol, Bilgin, C. Can, and Akçakaya, H. Reşit

Subjects
LEPTODACTYLIDAE, POPULATION viability analysis, FROG populations, ENDANGERED species, POPULATION dynamics, DEPENDENCY theory (International relations), BIRD declines
Abstract

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. [ABSTRACT FROM AUTHOR]

Published
2021
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