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Emys trinacris

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Ottonello Dario
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Two species of pond turtles belonging to the genus Emys are currently recognized in Italy: E. orbicularis in mainland Italy and Sardinia, and E. trinacris in Sicily (Di Cerbo, 2011; Zuffi et al., 2011). Emys trinacris has recently been described on the basis of its genetic distinctiveness (Fritz et al., 2005) and on the lack of gene flow between E. trinacris and E. orbicularis (Pedall et al., 2011). In Italy, pond turtle populations live in water bodies with a wide range of environmental features, including ponds, small lakes, swamps, canals and slow stream water courses. Most populations inhabit lowland areas, but the two species also occur up to 1540 and up to 1400 m of altitude, for E. orbicularis in Calabria and E. trinacris, respectively. The largest populations occur in protected areas of the Po River Delta, of Tuscany, Latium, Campania and Calabria (Mazzotti and Zuffi, 2006). There is, however, still large uncertainty about the numerical consistence of Emys populations in Italy (Zuffi et al., 2011).
Feeding ecology of a species is the result of its evolutionary history, biology, physiology and local constraints, such as prey availability, intra- and inter-specific interactions and environmental characteristics. In this study we investigated the still unknown diet of the Sicilian pond turtle, with special emphasis to the relationships with recently introduced alien species in the “Lake Preola and Gorghi Tondi” Nature Reserve (Sicily, Italy). A total of 83 faecal samples were collected in three different periods. Emys trinacris seems an opportunistic and generalist species. The main prey taxa were aquatic invertebrates, including the invasive Procambarus clarkii, while non-aquatic preys are found sporadically. Plant matter, mainly leaves and roots of aquatic forms, was also found in high frequency with a high occurrence of fruits and seeds in spring. We did not find a significant difference in diet composition within sex and age, while an evident divergence was found between periods and sites. In particular, we noticed a decrease in prey abundance and in food-niche breadth from pre-reproductive period to post-reproductive period. Moreover a very clear difference was found between a site with allochthonous fishes and a site fish-free, with a more abundant and wide diet spectrum in the last one, as a result of the increased availability of prey. We highlighted the importance to take any possible actions to avoid the spread of fishes in other basins and to study the indirect impact of Procambarus clarkii, as possible vector of harmful trace element.
Ottonello Dario
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The lack of data relating to basic life-history and population dynamics is one of the gaps to be filled in order to develop a proper strategy for the conservation of the Sicilian Pond Turtle (Emys trinacris). In this study, we present the results of the first year of a multi-annual monitoring program focusing on a specific wetland area, located within the “Lago Preola e Gorghi Tondi” Nature Reserve (Sicily, Italy). The sub- population size was estimated with capture-recapture method at 719 ± 47 turtles, with a mean density of 239.7 ± 15.7 ind./ha. The overall sex ratio of the captured individuals was males-biased (2.9 : 1) but also a significant differences between spring and summer was found. We discuss this finding in relation to differ- ential reproductive strategies of the sexes, with the support of data on movements and on body condition. The importance of a multi-year monitoring approach is underlined in order to get a better understanding of the factors that affect the population ecology.