| 英文摘要: | Understanding how climate change affects natural populations remains one of the greatest challenges for ecology and management of natural resources. Animals can remodel their physiology to compensate for the effects of temperature variation, and this physiological plasticity, or acclimation, can confer resilience to climate change1, 2. The current lack of a comprehensive analysis of the capacity for physiological plasticity across taxonomic groups and geographic regions, however, constrains predictions of the impacts of climate change. Here, we assembled the largest database to date to establish the current state of knowledge of physiological plasticity in ectothermic animals. We show that acclimation decreases the sensitivity to temperature and climate change of freshwater and marine animals, but less so in terrestrial animals. Animals from more stable environments have greater capacity for acclimation, and there is a significant trend showing that the capacity for thermal acclimation increases with decreasing latitude. Despite the capacity for acclimation, climate change over the past 20 years has already resulted in increased physiological rates of up to 20%, and we predict further future increases under climate change. The generality of these predictions is limited, however, because much of the world is drastically undersampled in the literature, and these undersampled regions are the areas of greatest need for future research efforts. In theory, environmental variability represents a selection pressure that results either in thermal adaptation or in the evolution of phenotypic plasticity1, 2. The efficacy of genetic adaptation depends on the relationship between generation time and rate of climate change. Under rapid human-induced climate change, short-lived animals may adapt successfully if the change in climate is relatively slow and the direction of change is constant to permit directional selection3, 4. In most cases, however, climate change is rapid and can occur across few generations or even within generations5. Furthermore, fluctuating climates do not provide a clear signal to drive directional selection, and selection in one generation may be maladaptive in subsequent generations4. Temperature fluctuations are predicted to increase under climate change, and plastic phenotypes should therefore be favoured4. Many individual ectotherms can remodel their physiology to reduce the extent to which physiological rates change in response to a chronic, recurring, or extemporaneous change in temperature (that is, thermal compensation via the process of thermal acclimation (in response to a single environmental variable) or acclimatization (in response to multiple environmental variables under field conditions)6). If thermal compensation were perfect, physiological rates would remain constant across environmental conditions, so that animals could maintain fitness across a broader temperature range compared to animals that show little or no plasticity7. We collated data from the literature (1968–2012) for ectothermic animals (n = 637 measurements of 202 species) that were chronically exposed (acclimated or acclimatized) to at least two temperatures and in which physiological rates (metabolic rates, heart rates, enzyme activities and locomotor performance) were measured acutely at these two acclimation temperatures (see Supplementary Methods and Data). These data allowed us, first, to determine by how much physiological rates changed in response to an acute change in temperature (Fig. 1). ‘Acute thermal sensitivity’ was defined as the change in a physiological rate function in response to a rapid change in environmental temperature in the absence of thermal acclimation—that is, within the acclimation set temperatures (see Fig. 1 for details). Second, we calculated by how much a physiological rate changes when an animal was allowed to acclimate to different thermal conditions—that is, across chronic acclimation conditions (Fig. 1; see ref. 8). This ‘post-acclimation thermal sensitivity’ thus provides the most physiologically realistic estimate of how sensitive ectothermic animals are to a temperature change that lasts longer than several days to weeks.
| http://www.nature.com/nclimate/journal/v5/n1/full/nclimate2457.html
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