A Multi-Metric Approach to Investigate the Effects of Weather Conditions on the Demographic of a Terrestrial Mammal, the European Badger (Meles meles)

Models capturing the full effects of weather conditions on animal populations are scarce. Here we decompose yearly temperature and rainfall into mean trends, yearly amplitude of change and residual variation, using daily records. We establish from multi-model inference procedures, based on 1125 life histories (from 1987 to 2008), that European badger (Meles meles) annual mortality and recruitment rates respond to changes in mean trends and to variability in proximate weather components. Variation in mean rainfall was by far the most influential predictor in our analysis. Juvenile survival and recruitment rates were highest at intermediate levels of mean rainfall, whereas low adult survival rates were associated with only the driest, and not the wettest, years. Both juvenile and adult survival rates also exhibited a range of tolerance for residual standard deviation around daily predicted temperature values, beyond which survival rates declined. Life-history parameters, annual routines and adaptive behavioural responses, which define the badgers’ climatic niche, thus appear to be predicated upon a bounded range of climatic conditions, which support optimal survival and recruitment dynamics. That variability in weather conditions is influential, in combination with mean climatic trends, on the vital rates of a generalist, wide ranging and K-selected medium-sized carnivore, has major implications for evolutionary ecology and conservation.

能够完整刻画天气条件对动物种群影响的模型尚属匮乏。本研究依托每日气象记录，将年度气温与降雨量拆解为平均趋势、年度变化振幅与残差变异三个组分。基于1987年至2008年间的1125条动物生活史数据，通过多模型推断流程，我们证实欧洲獾（Meles meles）的年死亡率与种群补充率会响应平均趋势变化及近期天气组分的变异性。本分析结果显示，平均降雨量的变异是影响力最为突出的预测变量。幼体存活率与种群补充率在中等水平的平均降雨量下达到峰值；而成体存活率偏低的情况仅出现在最为干旱的年份，与湿润年份并无关联。幼体与成体的存活率均对日预测气温值周边的残差标准差存在一定耐受区间，超出该区间后存活率会出现下降。由此可见，定义欧洲獾气候生态位的生活史参数、年度活动节律与适应性行为响应，似乎均受制于一个有限的气候条件范围——该范围可支撑最优的存活与种群补充动态。天气变异性与平均气候趋势共同作用，对广食性、活动范围广泛且属于K-选择类群的中型食肉动物的生命率产生影响，这一发现对进化生态学与物种保护研究均具有重要意义。