Population estimate and body size of European pond turtles (Emys orbicularis) from Pazarağaç (Afyonkarahisar/Turkey)

Abstract

Data on population size, adult sex ratio, body size and mass are provided for a population of the turtle Emys orbicularis near Pazaragaç (Afyonkarahisar/Turkey). Using the mark-recapture method (triple catch), a population size of 664 turtles was estimated (95% confidence interval, range 332-996), corresponding to a density of 83 turtles per hectare (range 41.5-124.5). The adult sex-ratio was significantly skewed in favor of males (2.02 males : 1 female; P < 0.001). Almost all recorded specimens were adult (98.1%). Mean straight carapace length (SCL) and body mass (BM) of adult turtles were: SCL = 128.65 mm, BM = 345 g for males (n = 168) and SCL = 135.37 mm, BM = 463 g for females (n = 83).

Population size and density in two European pond turtle populations of central Italy

“…Likely, with this kind of approach, carrying capacity of selected habitats could be derived quite easily, even if in many cases a complete habitat analysis has not been carried out. The observed population size and the observed sexual dimorphism agrees well with the similar results from other studies (Zuffi and Odetti, 1998;Fritz, 2003; and indicates that body size range does not differ greatly among Mediterranean populations (Ayaz et al, 2007;Bayrakci and Ayaz, 2014). The low reproductive rate of Emys in Fiume Morto Vecchio (three out of 25 females were gravid) could be a local effect, due to factors not considered in this research (a closed environment, with inbreeding effect or a reduced food availability), and not previously observed at other sites of the San Rossore estate (see Zuffi, Odetti and Meozzi, 1999;.…”

“…Previous studies of capture-recapture frequency of E. orbicularis show high variability. For example, freshwater turtles have been captured and recaptured less frequently (Mazzotti, 1995;Auer and Taşkavak, 2004: 11.6-19.7%;Ayaz et al, 2007: 14.1%), than in our (28.6%) and other studies (e.g., Mosimann and Cadi, 2004: 177.7% Ayaz et al, 2008: 29%; Güçlü and Türkozan, 2010: 27.5%). This pattern is likely due to the different methods employed, ranging from few (Mazzotti, 1995;Bayrakci et al, 2016) to multiple sampling occasions (Mazzotti et al, 2007;Olivier et al, 2010;Bayrakci and Ayaz, 2014;present research), depending on the sampling area -from very small to much large areas (present research; Ayaz et al, 2008) -and, finally, to population abundance.…”

“…In Hungary (Balázs andGyörffy, 2006 cited in Bayrakci andAyaz, 2014) the estimated population density ranged from 128 to 242 individuals/ha at Feketevíz (Tisza river). In Turkish populations, densities varied widely from 22.5 to 242 individuals/ha (Auer and Taşkavak, 2004;Ayaz et al, 2007Ayaz et al, , 2008Ayaz and Çiçek, 2011;Bayrakci and Ayaz, 2014). Reported densities varied widely among several Mediterranean and non-Mediterranean regions.…”