Fitness implications of seasonal climate variation in Columbian ground squirrels
Fitness implications of seasonal climate variation in Columbian ground squirrels
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DOI：
10.1002/ece3.2279
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发表时间：
2016-08-01
影响因子：
2.6
通讯作者：
Murie, Jan O.
中科院分区：
文献类型：
--
作者：
Dobson, F. Stephen;Lane, Jeffrey E.;Murie, Jan O.
气候变化对野生种群适合度的影响经常在春季生殖季节开始的背景下进行研究。这种关注与气候对繁殖成功的影响有关，但忽略了其他与健康相关的时期（例如，秋季准备越冬）。我们研究了21年来哥伦比亚地松鼠（Urocitellus columbianus）整个年度周期的气候变量（温度，降雨量，降雪量和积雪）的变化。我们调查了与适应度变量相关的季节性气候变量，在研究期间表现出方向变化的气候变量，最终观察到与气候变量方向变化相关的适应度下降（-0.03单位/年;总下降= 37%）。成年雌性地松鼠的年适合度与春季气温（r = 0.69）和初夏降雨量（r = 0.56）呈正相关，与春季降雪条件（r = -0.44 ~-0.66）呈负相关。在21年中，春季融雪已成为显着延迟（r = 0.48）和夏季降雨量显着减少（r = -0.53）。使用标准化偏回归模型，我们发现春季融雪和初夏降雨时间的方向变化（即，逐渐干燥的夏季）对年适合度有中等影响，后者具有统计学显著性（rho = -0.314和0.437，分别）。夏季是幼松鼠和成年松鼠冬眠前的育肥期。如果我们只关注一个时间点（即繁殖季节的开始），我们就会低估气候变化对我们种群的影响。相反，我们通过调查整个生命周期，全面了解了气候变化对个体健康的影响。
The influence of climate change on the fitness of wild populations is often studied in the context of the spring onset of the reproductive season. This focus is relevant for climate influences on reproductive success, but neglects other fitness- relevant periods (e.g., autumn preparation for overwintering). We examined variation in climate variables (temperature, rainfall, snowfall, and snowpack) across the full annual cycle of Columbian ground squirrels (Urocitellus columbianus) for 21 years. We investigated seasonal climate variables that were associated with fitness variables, climate variables that exhibited directional changes across the study period, and finally observed declines in fitness (-0.03 units/year; total decline = 37%) that were associated with directional changes in climate variables. Annual fitness of adult female ground squirrels was positively associated with spring temperature (r = 0.69) and early summer rainfall (r = 0.56) and negatively associated with spring snow conditions (r = -0.44 to -0.66). Across the 21 years, spring snowmelt has become significantly delayed (r = 0.48) and summer rainfall became significantly reduced (r = -0.53). Using a standardized partial regression model, we found that directional changes in the timing of spring snowmelt and early summer rainfall (i.e., progressively drier summers) had moderate influences on annual fitness, with the latter statistically significant (rho = -0.314 and 0.437, respectively). The summer period corresponds to prehibernation fattening of young and adult ground squirrels. Had we focused on a single point in time (viz. the onset of the breeding season), we would have underestimated the influences of climate change on our population. Rather, we obtained a comprehensive understanding of the influences of climate change on individual fitness by investigating the full lifecycle.