Habitat characterization and potential distribution of Tylototriton vietnamensis in northern Vietnam

Abstract

The habitat preferences of the endemic Vietnam Crocodile Newt, Tylototriton vietnamensis were investigated on two scales: (1) at Yen Tu Nature Reserve, Bac Giang Province, Vietnam, while compiling information about pond occupancy and developing a qualitative comparison among breeding sites and (2) by developing a Species Distribution Model based on climate and land cover data identifying further suitable habitats in northern Vietnam. A factor analysis followed by a multiple linear regression showed 94% support for our occupancy ranking model. Our results suggest that T. vietnamensis preferentially inhabits small pools with long hydroperiod and pH above 4.3. Suitable areas for the species have higher incidence in northern regions, where undisturbed vegetation and temperature-related variables seem to make greater contributions. Additionally, these potentially suitable areas are strongly fragmented and only a few are under IUCN protection, increasing their vulnerability towards further degradation.

Keywords:

• Vietnam Crocodile Newt
• ecology
• breeding ponds
• species distribution modelling
• Maxent

Acknowledgements

We thank the Institute of Ecology and Biological Resources (IEBR), the Vietnam National Museum of Nature (VNMN) and the Bac Giang and Lang Son Forest Protection Departments for their cooperation. We are indebted to Professor Le XC (IEBR), Professor Pham VL (VNMN) and Mr Duong XB (Bac Giang FPD) for their support. We further thank Vera Hecht and Detlef Karbe for companionship and support during the field work. SERA® kindly provided research equipment for the keeping, breeding and investigation of amphibians in the IEBR Amphibian Station and in related field studies in northern Vietnam. This research project was mainly funded by EAZA (European Association of Zoos and Aquaria) Amphibian Conservation Fund, the Nagao Natural Environment Foundation (Japan) and by the Cologne Zoo. To all of them we wish to express our sincerest gratitude.