Irons Rachel D, Harding Scurr April, Rose Alexandra P, Hagelin Julie C, Blake Tricia, Doak Daniel F
University of Colorado, Boulder, CO, USA, Alaska Department of Fish and Game, Threatened, Endangered and Diversity Program, Fairbanks, AK, USA.
Alaska Songbird Institute, Fairbanks, AK, USA.
Proc Biol Sci. 2017 Apr 26;284(1853). doi: 10.1098/rspb.2017.0412.
While the ecological effects of climate change have been widely observed, most efforts to document these impacts in terrestrial systems have concentrated on the impacts of temperature. We used tree swallow () nest observations from two widely separated sites in central Alaska to examine the aspects of climate affecting breeding phenology at the northern extent of this species' range. We found that two measures of breeding phenology, annual lay and hatch dates, are more strongly predicted by windiness and precipitation than by temperature. At our longest-monitored site, breeding phenology has advanced at nearly twice the rate seen in more southern populations, and these changes correspond to long-term declines in windiness. Overall, adverse spring climate conditions known to negatively impact foraging success of swallows (wet, windy weather) appear to influence breeding phenology more than variation in temperature. Separate analyses show that short windy periods significantly delay initiation of individual clutches within years. While past reviews have emphasized that increasing variability in climate conditions may create physiological and ecological challenges for natural populations, we find that long-term reductions in inclement weather corresponded to earlier reproduction in one of our study populations. To better predict climate change impacts, ecologists need to more carefully test effects of multiple climate variables, including some, like windiness, that may be of paramount importance to some species, but have rarely been considered as strong drivers of ecological responses to climate alteration.
虽然气候变化的生态影响已被广泛观察到，但在陆地系统中记录这些影响的大多数努力都集中在温度的影响上。我们利用来自阿拉斯加中部两个相距甚远地点的树燕（）巢穴观测数据，来研究在该物种分布范围的北部边缘影响繁殖物候的气候因素。我们发现，繁殖物候的两个指标，即每年的产卵日期和孵化日期，受风况和降水量的预测比受温度的预测更强。在我们监测时间最长的地点，繁殖物候提前的速度几乎是更南部种群的两倍，而且这些变化与风况的长期下降相对应。总体而言，已知对燕子觅食成功率有负面影响的不利春季气候条件（潮湿、多风的天气）似乎比温度变化对繁殖物候的影响更大。单独的分析表明，短时间的有风天气会显著延迟年内单个窝卵的开始孵化。虽然过去的综述强调气候条件变率增加可能给自然种群带来生理和生态挑战，但我们发现恶劣天气的长期减少与我们其中一个研究种群更早的繁殖相对应。为了更好地预测气候变化的影响，生态学家需要更仔细地测试多种气候变量的影响，包括一些对某些物种可能至关重要但很少被视为气候改变生态响应的强大驱动因素的变量，如风况。
