Preliminary data on the structure of freshwater turtle populations (Emys orbicularis and Mauremys leprosa) in a stream in the Natural Park of Los Arribes del Duero (Zamora, Spain)

Abstract

Although talking about the Iberian terrapins’ decline has become frequent, there are no intensive studies about their ecology and conservation in Castilla y León. Both the European pond terrapin (Emys orbicularis) and the Mediterranean pond turtle (Mauremys leprosa) are widely distributed in the region, especially in its south-western part (Zamora and Salamanca). We present the results of a one year-monitoring in one population of each species in the Natural Park of Los Arribes del Duero (Zamora). The study was carried out along a 3 km stretch of stream. The area is more appropriate for E. orbicularis, with 78 captured individuals, whereas only 16 M. leprosa were found. The Mediterranean pond turtle prefers greater water bodies, restricted in the area to three man-made ponds. The activity of E. orbicularis begins earlier in the year, with an aestivation period, while M. leprosa remains active in summer. The population size of the European pond terrapin was estimated in 110 individuals according to the Jolly-Seber method of mark-recapture. This population would be quite old, with only 13% of immature individuals. This population structure motivates the priority in establishing conservation measures directed to protect adult individuals. This is the first study of freshwater turtle populations in Castilla y León. The information presented here, as well as in further studies with similar methodology, will be necessary to protect these species in the region.