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Current Herpetology
Abstract
Abstract:
The red-eared slider turtle, Trachemys scripta elegans, is an invasive species, that may potentially induce negative impacts on native turtle communities and freshwater ecosystems. Effective control of invasive species requires knowledge of the process of invasion and the long-term dynamics of an introduced population. However, such studies are scarce. We investigated temporal changes in the species composition of a freshwater turtle assemblage including density and age structure of the red-eared slider turtle at the Kahokugata lagoon of Ishikawa Prefecture in central Japan over 15 years (2001–2003, 2013 and 2015). The number of red-eared sliders increased over time, whereas that of Reeves' pond turtle, Mauremys reevesii, remained flat for 15 years from 2001 to 2015. Data on morphological measurements in the red-eared slider population showed that the proportion of old individuals increased whereas juveniles decreased. Moreover, the body condition index decreased in all age classes. These results suggest that juvenile recruitment was limited in the recent years and thus breeding efficiency was lowered in the redeared slider population at this lagoon perhaps due to high population density.
We are grateful to the staff of Ishikawa Zoo for their help in our field research. We extend our cordial thanks to K. Nakamura and N. Kamata in the Ecological Laboratory of Kanazawa University for their advices. This study was partially supported by a Kahokugata Research Grant from the Kahokugata Lake Institute.
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