Delayed phenology and reduced fitness associated with climate change in a wild hibernator
| Autor: | Loeske E. B. Kruuk, Jeffrey E. Lane, Anne Charmantier, F. Stephen Dobson, Jan O. Murie |
|---|---|
| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Nature. 489:554-557 |
| ISSN: | 1476-4687 0028-0836 |
| Popis: | Delay in the hibernation emergence date of female Columbian ground squirrels in Canada over 20 years is related to climatic conditions other than increasing temperature, and as years of later emergence are associated with decreased individual fitness, plastic responses to climate change may be associated with declines in population viability. The effects of climate change on the seasonal biological rhythms of bird and plant populations are well documented. How mammals are affected is less well known. Using a 20-year data set of hibernation-emergence dates for Columbian ground squirrels in Alberta, Canada, an international team of researchers reports a rare example of a delay resulting from climate change. The authors attribute this delay — which amounts to almost half a day per year — to an increasing prevalence of late-season snowstorms. Females experienced lower fitness during years of later emergence and, as a result, the growth rate of the population is lower than it was previously. Consensus projections from current climate models are for increased winter precipitation, so such events could become more common in future. These findings imply that behavioural responses to climate can be associated with declines in individual fitness, as well as being triggered directly by temperature increases. The most commonly reported ecological effects of climate change are shifts in phenologies, in particular of warmer spring temperatures leading to earlier timing of key events1,2. Among animals, however, these reports have been heavily biased towards avian phenologies, whereas we still know comparatively little about other seasonal adaptations, such as mammalian hibernation. Here we show a significant delay (0.47 days per year, over a 20-year period) in the hibernation emergence date of adult females in a wild population of Columbian ground squirrels in Alberta, Canada. This finding was related to the climatic conditions at our study location: owing to within-individual phenotypic plasticity, females emerged later during years of lower spring temperature and delayed snowmelt. Although there has not been a significant annual trend in spring temperature, the date of snowmelt has become progressively later owing to an increasing prevalence of late-season snowstorms. Importantly, years of later emergence were also associated with decreased individual fitness. There has consequently been a decline in mean fitness (that is, population growth rate) across the past two decades. Our results show that plastic responses to climate change may be driven by climatic trends other than increasing temperature, and may be associated with declines in individual fitness and, hence, population viability. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|