Browsing by Author "Durmus, Atilla"

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Alterations in Histology and Antioxidant Defense System in the Testes of the Lake Van Fish (Alburnus Tarichi Guldenstadt, 1814)
(Springer, 2016) Kaptaner, Burak; Kankaya, Ertugrul; Dogan, Abdulahad; Durmus, Atilla
Recent reports have demonstrated gonadal abnormalities in the Lake Van fish (Alburnus tarichi) from Lake Van caused by increasing pollution. In the present study, the fish was collected from an area of Lake Van receiving mainly sewage treatment plant effluent at prespawning period (April) and from a river (Karasu) which is close to the polluted area of the lake and where the fish migrates at spawning period (May). Collected specimens were examined for testicular alterations, gonadosomatic index (GSI), condition factor (CF), and antioxidant defense system biomarkers based on comparison with a reference lake (Ercek) and a reference freshwater inlet (Memedik River). Histological examinations of the testes of fish from the polluted area and the connected river showed various alterations consisting of macrophage aggregates, vacuolation, pyknosis, germ cell degeneration, seminiferous tubule dilation, disorganization of tubules, reduced spermatozoa, and fibrosis. A lower GSI and CF were also observed. Moreover, alterations in the antioxidant system biomarkers were determined in the testis tissues of fish from the Lake Van and Karasu River, indicating oxidative stress. These results suggest that the abnormalities in the testes are causally related to the increased oxidative stress, and pollution in Lake Van may have adversely affected the reproductive health of the lake Van fish.
Application of Regression Models in Bird Population Data: an Example of Haçlı Lake
(2020) Çelik, Emrah; Durmus, Atilla
In this study, the effects of habitat, ordo, UTM frame, seasons and number of species on bird populations and distribution in Haçlı Lake were investigated. Bird population data were obtained using point counts and transect observation methods. Poisson regression is typically used in such data sets. The basic principle of Poisson regression assumes that the variance is equal to the mean. Failure to achieve this equality causes incorrect parameter estimates and standard errors. In practice, the variance is often higher than the mean (variance > mean). This is called over-dispersion, where the value of over- dispersion is greater than 1.0. The population status of the data set used in the study was over-dispersed. Negative binomial regression is the most common method used to eliminate the over-dispersion effect. In this case, the preferred method is the negative binomial regression method. The over-dispersion value in the Poisson regression was considerably greater than 1.0 (54.937) while the over-dispersion value was very close to 1.0 (1.588) in the negative binomial regression. The results indicated that the use of negative binomial regression method is more appropriate. Therefore, parameter estimations were interpreted according to negative binomial regression method. Herein, climatic factors including temperature and humidity exhibited significant impacts on population density and number of species.
A Bibliometric Analysis: What Do We Know About Metals(Loids) Accumulation in Wild Birds
(Springer Heidelberg, 2021) Celik, Emrah; Durmus, Atilla; Adizel, Ozdemir; Nergiz Uyar, Humeyra
Metals and metalloids pollution is an important worldwide problem due to the social and ecological effects and therefore has been the subject of many disciplines and the adverse impacts have been documented. In this study, content analysis and trends of studies focused on heavy metal accumulation in birds were presented. For this purpose, a bibliometric network analysis of the studies that use the concepts of "pollution," "heavy metal," and "birds" together in the abstract, keywords, and titles of the papers was carried out. The purpose of choosing this research method was summarizing the relation between birds and environmental pollution in an understandable manner to determine metals(loids) pollution, which become an important environmental problem. Bibliometric data consisting of approximately 971 papers were evaluated with VOSviewer program using the network analysis method to answer the research questions. The results revealed that birds act as bioindicators in the determination of environmental pollution and that the contaminant metals deposited in the various tissues of birds provide preliminary information about environmental pollution. The most of bird studies emphasized that the metal accumulation was mostly in the liver, kidneys, and feathers and the accumulation caused serious problems in most of the vital activities of the birds. The USA is in the leading country in birds-heavy metal studies followed by Spain, Canada, and China. In addition, the mercury (Hg) was the most extensively studied heavy metal in these studies.
Determination of Newcastle Disease Virus Among Wild Bird Populations in Lake Van Basin, Turkey
(Tubitak Scientific & Technological Research Council Turkey, 2013) Boynukara, Banur; Gulhan, Timur; Coven, Fethiye; Kiziroglu, Ilhami; Durmus, Atilla
In this study, 540 feces samples taken from a total of 22 bird species, including transit migrant, winter visitor, migratory, and resident bird species, in Lake Van basin were examined by real-time polymerase chain reaction (RT-PCR) with respect to the Newcastle disease virus (NDV). All of the feces samples were cultured in specific pathogen-free embryonated chicken eggs (ECEs) for NDV isolation. The NDV isolates were analyzed for virulent fusion (F) protein by RT reverse transcription PCR (RRT-PCR). Of the 540 examined feces samples, 28 (5.18%) were found to be positive by RT-PCR. The same samples were cultured in ECEs and, of those, 9 (1.66%) were positive for NDV isolations. Of the isolates, 7 were obtained from the migrant waterfowls Phoenicopterus ruber, Anas clypeata, Aythya ferina, and Aythya fuligula and 2 were from the resident species Columba livia. The RRT-PCR F protein was determined in 1 isolate belonging to Aythya ferina; this strain was typed as mesogenic/velogenic avian paramyxovirus type 1 and the other 8 isolates as lentogenic. In this study, we investigated, for the first time, the presence of NDV in wild, seemingly healthy bird feces from areas in Lake Van basin, in Turkey.
Determining the Seasonal Ornithological Potential of the Dönemeç (Engil) Delta and Generate the Digital Maps Using Geographical Information Systems (Gis)
(2017) Durmus, Atilla; Çelik, Emrah
Bu araştırma Van Gölü Havzası'ndaki önemli kuş alanlarından biri olan Dönemeç (Engil) Deltası'nda gerçekleştirildi. Nisan 2011 ve Nisan 2012 tarihlerini kapsayan bir yıllık arazi çalışmaları sonucunda 34 familyaya ait 91 tür ve 1 alttür tespit edildi. Bu türlerin 34.7% (32) Yerli, 53.2% (49) Göçmen, 4.34% (4) Kış ziyaretçisi, 6.52% (6) Transit Göçer, 1.08% (1) Rastlantısal tür olduğu belirlendi. Alandaki türler Uluslararası IUCN kriterlerine göre değerlendirildiğinde; 1 türün EN (Endangered), 1 türün VU (Vulnerable-Hassas), 1 türün NT (Near Threatened) ve 89 türün LC (Least Concern) statüsünde olduğu belirlendi. Alandaki türlerin, altı farklı habitatta populasyon dağılımı belirlenmiş, özellikle nesli tehlike altındaki türlerin yaşam alanları GIS tabanlı dağılım haritaları oluşturularak öne çıkarılmıştır
Diurnal Behaviour of Greater Flamingo (Phoenicopterus Roseus) at Lake Ercek, Turkey
(Parlar Scientific Publications (p S P), 2018) Nergiz, Humeyra; Durmus, Atilla
This study was conducted at Lake Ercek (Van Turkey) in 2015 breeding season using scan and focal sampling of individuals of the Greater Flamingo (Phoenicopterus roseus). Diurnal time -activity budgets of adults and juveniles were monitored separately in randomly selected focal flocks during 1200 observation sessions in 8 different behaviour patterns: feeding, resting, walking, flying, preening, aggression, showing alarm and courting. Feeding was the most important activity with rates of 46 of the time in both adult and juvenile individuals and showed a negative relationship with the degree of disturbance. Main diurnal activities of the Greater Flamingos during the study were walking and resting. Time use did not differ significantly between adults and juveniles (P>0.05). But, juveniles spent more time feeding and less time walking than adults (P<0.05).
Enteric Bacteria and Some Pathogenic Properties of Enterococcus Faecalis, Enterococcus Faecium and Escherichia Coli Strains Isolated From Wild Ducks and Gulls
(Parlar Scientific Publications (p S P), 2012) Gulhan, Timur; Boynukara, Banur; Durmus, Atilla; Kiziroglu, Ilhami; Sancak, Yakup Can
This study was performed to isolate enteric bacteria from the feces of wild duck and gull species in the Van Lake Basin, and to determine different virulence and pathogenic factors of the Enterococcus species and Escherichia coli. In this research, carried out for the first time on wild ducks in Turkey, a total of 357 feces samples were examined from the following animals: 126 Shoveler (Anas clypeata), 92 Common Pochard (Aythya ferina), 80 Black Headed Gull (Larus ridibundus), and 59 Yellow-Legged Gull (Larus michahellis). Forty-eight (13.5%) bacteria were isolated and identified in the feces samples in the following distribution: 23 (6.4%) Enterococcus faecium, nine(2.5%) Escherichia coli, 7 (2%) Enterococcus faecalis, 6 (1.7%) Citrobacter braakii, 1 (0.3%) Enterobacter cloacae, 1 (0.3%) Streptococcus pyogenes and 1 (0.3%) Corynebacterium diphtheria. When the virulence factors of Enterococcus isolates were evaluated: 18 of 23 (78.3%) E. faecium strains were positive for gelatinase; four (17.4%) for cytolysin; two (8.7%) for aggregation substance (AS); four of seven (57.1%) E. faecalis isolates were positive for gelatinase; four (57.1%) for cytolysin; and one (14.3%) for AS. Three of the E. faecium strains were found to be positive in both gelatinase and cytolysin, one in gelatinase and AS, one of the E. faecalis isolates was positive in gelatinase, AS and cytolysin, and one was positive in gelatinase and cytolysin. Nine E. coli strains were examined for pathogenic properties such as the O157:H7 serotype, verotoxin 1 (VT1), verotoxin 2 (VT2), stabile toxin (ST) and labile toxin (LT). Two E. coli strains (22.2%) were positive for the 0157 serotype. Positive strains belonged to the Anas clypeata and Aythya ferina duck species. All E. coli isolates were found to be negative for H7 serotype, VT1, VT2, ST and LT.
Feeding Ecology of Black-Crowned Night Heron (Nycticorax Nycticorax) in Van Lake Basin
(Foundation Environmental Protection & Research-fepr, 2011) Durmus, Atilla; Adizel, Ozdemir
In the present study, the feeding ecology of Black-crowned Night Heron (Nycticorax nycticorax) was investigated. The study was carried out in wetlands in the basin between 16th February 2006 and 4th October 2007. It was observed that The Night heron prefer the muddy and marshy places where freshwater joins to the lake for feeding. The morphometric measurement of chicks was done to determine the development related to the feeding. The measurement consisted of weight, tarsus, bill length, wing length, wing length, height and middle toe length. The Night heron feeds with animal foods. The vomiting samples of sixty (60) individuals and materials in nest were taken and seven (7) animal species belonging to five (5) classes were determined as feeding material of the Night heron (Chalcalburnus tarichi that a endemic fish species live in Van Lake, Rana sp., Bufo sp., Mus musculus, Microtus sp., Helix sp., Neuroptera's larvae). There is no plantal feeding material in feed range.
Gece Balıkçılı (Nycticorax Nycticorax)'nın Van Gölü Havzasındaki Beslenme Ekolojisi
(2011) Durmus, Atilla; Adızel, Özdemir
Bu çalışmada, Gece balıkçılı (Nycticorax nycticorax)'nın Van Gölü Havzasındaki beslenme ekolojisi araştırıldı. Araştırma; havzadaki sulak alanlarda 16 Şubat 2006-04 Ekim 2007 yılları arasında gerçekleştirildi. Gece balıkçılı beslenmek için tatlı suyun göle karıştığı sazlıkları ve bataklık alanları kullanmaktadır. Yavruların beslenmeye bağlı olarak gelişimlerini belirlemek amacı ile günlük morfometrik ölçümleri alındı. Bu ölçümler; ağırlık, tarsus, gaga, kanat, boy ve orta parmak ölçümleridir. Gece balıkçılı havzada hayvansal besinlerle beslenmektedir. Yuva içinden ve altmış farklı bireyden alınan kusmuk örneklerinden 5 sınıfa özgü 7 hayvan türü (Chalcalburnus tarichi-Van Gölü'nde yaşayan endemik balık türü, Rana sp., Bufo sp., Mus musculus, Microtus sp., Helix sp., Neuropter larvası) tespit edildi. Türün besin yelpazesinde bitkisel besinlere rastlanmamıştır.
A Study on Bird Species Under Threat and Avifauna of Ercek Lake (van-Turkey)
(Academic Journals, 2009) Adizel, Oezdemir; Durmus, Atilla
Ercek Lake is a lake characterized with volcanic lava set in ecosystem of Van Lake basin. Lake water contains soda and most important water source is Memedik stream. This study was carried out to determine avifauna of Ercek Lake between June 2000 and June 2004. One observation 0was carried monthly interval using Dobinson method. Total 177 species and 2 subspecies belong to 44 families were detected at the end of the study. The distribution of these species are following according to IUCN Red Data list Categories; 4 species of CR, 11 species of E, 32 species of V, 19 species of NT, 93 species of LC, 6 species of DD and 14 species of NE. 6 observed species were found to be in Globally Threatened category. Observed species were grouped as following; 71 Resident, 71 Migratory, 24 Winter Visitor, 10 Transit Migrant, 2 Transit Migrant-Migrant and 1 Migrant-Winter Visitor.
Van Gölü Havzasındaki Van Gölü Martısı’nın (Larus Armenicus Buturlin, 1934) Tüylerindeki Ağır Metal Konsantrasyonlarının Tespiti
(2024) Taşkın, Nurgül; Durmus, Atilla
Besin ağının üst basamağında yer alan kuşlar, çevresel kirleticilerden en fazla etkilenen canlı gruplarıdır. Bu çalışmada Van Gölü havzasını üreme ve beslenme amacıyla kullanan Van Gölü Martısındaki (Larus armenicus) bazı ağır metal birikimleri araştırıldı. Besin ağının en üst basamağında yer alan kuşların toksik maddeleri hangi oranlarda biriktirdiği ve nasıl etkilendiklerini tespit etmek amacı ile beslenme oranları da dikkate alınarak yetişkin ve yavru martılarının vücut tüylerinden ve beslendiği ortamlardaki sulardan örnekler alındı. Metal konsantrasyonları ICAP 6000 spektrofotometresi ile ölçüldü. Alınan örneklerde; Demir (Fe), Kadmiyum (Cd), Bakır (Cu), Kurşun (Pb) ve Arsenik (As) konsantrasyonlarına bakıldı. Analiz sonuçlarına göre; Cu (6.43 mg kg-1), Pb (4.02 mg kg-1) ve Cd (0.14 mg kg-1) konsantrasyonlarının en fazla yavrularda, Fe konsantrasyonun (94.32 mg kg-1) ise en fazla erginlerde olduğu görüldü. Dünya Sağlık Örgütü (WHO) ve TSE-266 standartlarına göre; Su içerisindeki As, Fe, Cd, Cu ve Pb konsantrasyonlarının içilebilir referans değerinden çok fazla olduğu tespit edildi. Yavru ve yetişkinlerdeki konsantrasyon farklılıklarının beslenme yoğunluğuna bağlı olarak değiştiği görülmektedir.