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Temperature-induced shifts in hibernation behavior in experimental amphibian populations.

Gao X, Jin C, Llusia D, Li Y - Sci Rep (2015)

Bottom Line: Using outdoor mesocosm experiments, we examined the effects of temperature (ambient vs. + ~2.2/2.4 °C of pre-/post-hibernation warming) and food availability (normal vs. 1/3 food) on the date of entrance into/emergence from hibernation in Pelophylax nigromaculatus.We found temperature was the major factor determining the hibernation period, which showed a significant shortening under experimental warming (6-8 days), with delays in autumn and advances in spring.We believe that this study provides some of the first experimental evidence for the effect of climate warming on the timing of amphibian hibernation.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China [2] University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049, China.

ABSTRACT
Phenological shifts are primary responses of species to recent climate change. Such changes might lead to temporal mismatches in food webs and exacerbate species vulnerability. Yet insights into this phenomenon through experimental approaches are still scarce, especially in amphibians, which are particularly sensitive to changing thermal environments. Here, under controlled warming conditions, we report a critical, but poorly studied, life-cycle stage (i.e., hibernation) in frogs inhabiting subtropical latitudes. Using outdoor mesocosm experiments, we examined the effects of temperature (ambient vs. + ~2.2/2.4 °C of pre-/post-hibernation warming) and food availability (normal vs. 1/3 food) on the date of entrance into/emergence from hibernation in Pelophylax nigromaculatus. We found temperature was the major factor determining the hibernation period, which showed a significant shortening under experimental warming (6-8 days), with delays in autumn and advances in spring. Moreover, the timing of hibernation was not affected by food availability, whereas sex and, particularly, age were key factors in the species' phenological responses. Specifically, male individuals emerged from hibernation earlier, while older individuals also entered and emerged from hibernation earlier. We believe that this study provides some of the first experimental evidence for the effect of climate warming on the timing of amphibian hibernation.

No MeSH data available.


Related in: MedlinePlus

The average air temperature of emergence from hibernation (°C) of P. nigromaculatus in outdoor mesocosms (mean ± SE) among experimental treatments: ambient temperature and normal (CG) or low food level (LF); and post-hibernation warming (i.e., in spring) and normal (SW) or low food level (SW-LF). The open bars indicate males, and the dark bars indicate females.
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f5: The average air temperature of emergence from hibernation (°C) of P. nigromaculatus in outdoor mesocosms (mean ± SE) among experimental treatments: ambient temperature and normal (CG) or low food level (LF); and post-hibernation warming (i.e., in spring) and normal (SW) or low food level (SW-LF). The open bars indicate males, and the dark bars indicate females.

Mentions: The date of emergence from hibernation of P. nigromaculatus also differed among the experimental treatments (Table 2). Post-hibernation warming, the sex and age of the subjects had a highly significant effect. Pairwise comparisons indicated that the experimental warming in spring (post-hibernation warming with normal food ‘SW’ or low food level ‘SW-LF’) advanced the date of emergence from hibernation relative to the exposure to ambient temperature (CG and LF; P < 0.001; Fig. 4). The air temperature of emergence from hibernation was not significantly different among treatments (one-way ANOVA, F = 0.177, df = 3, P = 0.912; Fig. 5). As shown by a Pearson correlation test, air temperature of each treatment was positively correlated with this phenological event (CG: r = 0.828, P < 0.001; LF: r = 0.819, P < 0.001; SW: r = 0.901, P < 0.001; SW-LF: r = 0.831, P < 0.001). Moreover, pairwise comparisons indicated that males exhibited an earlier date of emergence from hibernation than females (P < 0.001; Fig. 4). The age of the experimental subjects showed a negative correlation with the date of emergence from hibernation (β = −0.030, P < 0.001). Older individuals emerged from hibernation earlier than young ones (Fig. S2). No significant difference in the emerged from hibernation behavior was detected between individuals supplied with normal and low food levels (P < 0.965; Fig. 4). Furthermore, the post-hibernation body size, weight, and body condition are affected by food available and original body parameters, while the post-hibernation body size and weight were also influenced by age (details are shown in Supplementary information Fig. S3-5 and Table S1). The original body condition (as a covariate) has no effect on the timing of hibernation of the species, as shown by the additional two ANCOVAs (Table S2).


Temperature-induced shifts in hibernation behavior in experimental amphibian populations.

Gao X, Jin C, Llusia D, Li Y - Sci Rep (2015)

The average air temperature of emergence from hibernation (°C) of P. nigromaculatus in outdoor mesocosms (mean ± SE) among experimental treatments: ambient temperature and normal (CG) or low food level (LF); and post-hibernation warming (i.e., in spring) and normal (SW) or low food level (SW-LF). The open bars indicate males, and the dark bars indicate females.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477341&req=5

f5: The average air temperature of emergence from hibernation (°C) of P. nigromaculatus in outdoor mesocosms (mean ± SE) among experimental treatments: ambient temperature and normal (CG) or low food level (LF); and post-hibernation warming (i.e., in spring) and normal (SW) or low food level (SW-LF). The open bars indicate males, and the dark bars indicate females.
Mentions: The date of emergence from hibernation of P. nigromaculatus also differed among the experimental treatments (Table 2). Post-hibernation warming, the sex and age of the subjects had a highly significant effect. Pairwise comparisons indicated that the experimental warming in spring (post-hibernation warming with normal food ‘SW’ or low food level ‘SW-LF’) advanced the date of emergence from hibernation relative to the exposure to ambient temperature (CG and LF; P < 0.001; Fig. 4). The air temperature of emergence from hibernation was not significantly different among treatments (one-way ANOVA, F = 0.177, df = 3, P = 0.912; Fig. 5). As shown by a Pearson correlation test, air temperature of each treatment was positively correlated with this phenological event (CG: r = 0.828, P < 0.001; LF: r = 0.819, P < 0.001; SW: r = 0.901, P < 0.001; SW-LF: r = 0.831, P < 0.001). Moreover, pairwise comparisons indicated that males exhibited an earlier date of emergence from hibernation than females (P < 0.001; Fig. 4). The age of the experimental subjects showed a negative correlation with the date of emergence from hibernation (β = −0.030, P < 0.001). Older individuals emerged from hibernation earlier than young ones (Fig. S2). No significant difference in the emerged from hibernation behavior was detected between individuals supplied with normal and low food levels (P < 0.965; Fig. 4). Furthermore, the post-hibernation body size, weight, and body condition are affected by food available and original body parameters, while the post-hibernation body size and weight were also influenced by age (details are shown in Supplementary information Fig. S3-5 and Table S1). The original body condition (as a covariate) has no effect on the timing of hibernation of the species, as shown by the additional two ANCOVAs (Table S2).

Bottom Line: Using outdoor mesocosm experiments, we examined the effects of temperature (ambient vs. + ~2.2/2.4 °C of pre-/post-hibernation warming) and food availability (normal vs. 1/3 food) on the date of entrance into/emergence from hibernation in Pelophylax nigromaculatus.We found temperature was the major factor determining the hibernation period, which showed a significant shortening under experimental warming (6-8 days), with delays in autumn and advances in spring.We believe that this study provides some of the first experimental evidence for the effect of climate warming on the timing of amphibian hibernation.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China [2] University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049, China.

ABSTRACT
Phenological shifts are primary responses of species to recent climate change. Such changes might lead to temporal mismatches in food webs and exacerbate species vulnerability. Yet insights into this phenomenon through experimental approaches are still scarce, especially in amphibians, which are particularly sensitive to changing thermal environments. Here, under controlled warming conditions, we report a critical, but poorly studied, life-cycle stage (i.e., hibernation) in frogs inhabiting subtropical latitudes. Using outdoor mesocosm experiments, we examined the effects of temperature (ambient vs. + ~2.2/2.4 °C of pre-/post-hibernation warming) and food availability (normal vs. 1/3 food) on the date of entrance into/emergence from hibernation in Pelophylax nigromaculatus. We found temperature was the major factor determining the hibernation period, which showed a significant shortening under experimental warming (6-8 days), with delays in autumn and advances in spring. Moreover, the timing of hibernation was not affected by food availability, whereas sex and, particularly, age were key factors in the species' phenological responses. Specifically, male individuals emerged from hibernation earlier, while older individuals also entered and emerged from hibernation earlier. We believe that this study provides some of the first experimental evidence for the effect of climate warming on the timing of amphibian hibernation.

No MeSH data available.


Related in: MedlinePlus