Effects of hypoxia on the thermal physiology of a high-elevation lizard: implications for upslope-shifting species |
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Authors: | Zhong-Wen Jiang Liang Ma Chun-Rong Mi Wei-Guo Du |
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Institution: | 1.Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People''s Republic of China;2.University of Chinese Academy of Sciences, Beijing 100049, People''s Republic of China;3.Princeton School of Public and International Affairs, Princeton University, Princeton, NJ 08544, USA;4.Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, People''s Republic of China |
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Abstract: | Montane reptiles are predicted to move to higher elevations in response to climate warming. However, whether upwards-shifting reptiles will be physiologically constrained by hypoxia at higher elevations remains unknown. We investigated the effects of hypoxic conditions on preferred body temperatures (Tpref) and thermal tolerance capacity of a montane lizard (Phrynocephalus vlangalii) from two populations on the Qinghai–Tibet Plateau. Lizards from 2600 m a.s.l. were exposed to O2 levels mimicking those at 2600 m (control) and 3600 m (hypoxia treatment). Lizards from 3600 m a.s.l. were exposed to O2 levels mimicking those at 3600 m (control) and 4600 m (hypoxia treatment). The Tpref did not differ between the control and hypoxia treatments in lizards from 2600 m. However, lizards from 3600 m selected lower body temperatures when exposed to the hypoxia treatment mimicking the O2 level at 4600 m. Additionally, the hypoxia treatment induced lower critical thermal minimum (CTmin) in lizards from both populations, but did not affect the critical thermal maximum (CTmax) in either population. Our results imply that upwards-shifting reptiles may be constrained by hypoxia if a decrease in Tpref reduces thermally dependent fitness traits, despite no observed effect on their heat tolerance. |
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Keywords: | elevation behavioural thermoregulation climate change oxygen reptile thermal tolerance |
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