Department of Forest and Conservation Sciences, University of British Columbia Vancouver, Vancouver, British Columbia, Canada.
Glob Chang Biol. 2018 Mar;24(3):1212-1223. doi: 10.1111/gcb.13889. Epub 2017 Sep 21.
Studies of the phenological responses of animals to climate change typically emphasize the initiation of breeding although climatic effects on the cessation and length of the breeding period may be as or more influential of fitness. We quantified links between climate, the cessation and length of the breeding period, and individual survival and reproduction using a 34-year study of a resident song sparrow (Melospiza melodia) population subject to dramatic variation in climate. We show that the cessation and length of the breeding period varied strongly across years, and predicted female annual fecundity but not survival. Breeding period length was more influential of fecundity than initiation or cessation of breeding alone. Warmer annual temperature and drier winters and summers predicted an earlier cessation of breeding. Population density, the date breeding was initiated, a female's history of breeding success, and the number of breeding attempts initiated previously also predicted the cessation of breeding annually, indicating that climatic, population, and individual factors may interact to affect breeding phenology. Linking climate projections to our model results suggests that females will both initiate and cease breeding earlier in the future; this will have opposite effects on individual reproductive rate because breeding earlier is expected to increase fecundity, whereas ceasing breeding earlier should reduce it. Identifying factors affecting the cessation and length of the breeding period in multiparous species may be essential to predicting individual fitness and population demography. Given a rich history of studies on the initiation of breeding in free-living species, re-visiting those data to estimate climatic effects on the cessation and length of breeding should improve our ability to predict the impacts of climate change on multiparous species.
对动物物候对气候变化的反应的研究通常强调繁殖的开始，尽管气候对繁殖期的结束和长度的影响可能对适应度的影响更大或更大。我们使用对一个受剧烈气候变化影响的居留性麻雀（Melospiza melodia）种群进行了 34 年的研究，量化了气候、繁殖期的结束和长度与个体生存和繁殖之间的联系。我们表明，繁殖期的结束和长度在各年之间变化很大，并且预测了雌性的年繁殖力，但不能预测其存活率。繁殖期长度对繁殖力的影响大于繁殖的开始或结束。年平均温度升高、冬季和夏季干旱，预示着繁殖期结束更早。种群密度、繁殖开始的日期、雌性繁殖成功的历史以及以前开始的繁殖尝试次数也预测了每年的繁殖结束时间，这表明气候、种群和个体因素可能相互作用，影响繁殖物候。将气候预测与我们的模型结果联系起来表明，未来雌性将更早地开始和结束繁殖；这将对个体繁殖率产生相反的影响，因为提前繁殖预计会增加繁殖力，而提前结束繁殖则应该降低繁殖力。确定多胎物种繁殖期结束和长度的影响因素可能对预测个体适应度和种群动态至关重要。鉴于对自由生活物种繁殖开始的研究历史丰富，重新审视这些数据以估计气候对繁殖期结束和长度的影响，应该可以提高我们预测气候变化对多胎物种影响的能力。
