Climatic factors act on populations at multiple timescales leading to the separation of long-term climate and shorter-term weather effects. We used passerine counts from 1995 to 2019 in subarctic Alaska (Denali National Park, USA) to assess the impacts of the prior breeding season’s weather on breeding season abundance and the impacts of climate measured through shifts in elevational distribution. Weather and climate appear to have had opposing effects on the abundance of some shrub-associated species as evidenced by a positive response to nesting phase temperature over a 1-year lag and a negative response to warming-induced shifts in shrub-dominated habitats over the long term. The latter response was indicated by declines in abundance which occurred in some part through portions of these populations shifting upslope of our fixed sampling frame. Overall, the abundance of species was related to one or more of the lagged effects of weather and the effects of weather alone drove nearly twofold variation in annual abundance in most species. The effect of nesting phase temperature was a strong positive predictor at both community and individual species levels, whereas arrival phase temperature had weak support at both levels. The effects of total precipitation during the nesting phase and snowmelt timing shared mixed support at community and species levels, but generally indicated higher abundance following seasons that were drier and had earlier snowmelt. Together, our findings of opposing effects of climatic variables at different timescales have implications for understanding the mechanisms of population and distributional change in passerines in the subarctic.

气候因素在多个时间尺度上作用于人口，导致长期气候影响和短期天气影响分离。我们使用了1995年至2019年北极亚拉斯加（美国Denali国家公园）的雀形目计数来评估先前繁殖季节的天气对繁殖季节丰度的影响以及通过海拔分布变化来衡量的气候影响。天气和气候似乎对某些灌木相关物种的丰度产生了相反的影响，这一点可以通过对一年期滞后对巢相温度的积极反应和对气候变化导致的以灌木为主的生境的变暖的负面反应来证明。长期。后一种响应通过丰度的下降来表明，丰度的下降在一定程度上是由于这些种群的一部分向固定采样框架的上坡移动。总体而言，物种的丰度与天气的滞后影响中的一项或多项有关，仅天气的影响就使大多数物种的年丰度发生了近两倍的变化。筑巢期温度的影响在群落和个体物种水平上都是很强的正向预测因子，而到达期温度在这两个水平上的支持都很弱。在筑巢期和融雪时期总降水量的影响在群落和物种水平上共享混合的支持，但通常表明在干燥和融雪较早的季节之后丰度更高。总之，我们在不同时间尺度上对气候变量的不利影响的发现对理解亚北极pass鱼中的种群和分布变化的机制具有重要意义。物种的丰度与天气的一种或多种滞后效应有关，仅天气的影响就使大多数物种的年度丰度发生了近两倍的变化。筑巢期温度的影响在群落和个体物种水平上都是很强的正向预测因子，而到达期温度在这两个水平上的支持都很弱。在筑巢期和融雪时期总降水量的影响在群落和物种水平上共享混合的支持，但通常表明在干燥和融雪较早的季节之后丰度更高。总之，我们在不同时间尺度上对气候变量的相反影响的发现对理解亚北极pass鱼中的种群和分布变化机制具有重要意义。物种的丰度与天气的一种或多种滞后效应有关，仅天气的影响就使大多数物种的年度丰度发生了近两倍的变化。筑巢期温度的影响在群落和个体物种水平上都是很强的正向预测因子，而到达期温度在这两个水平上的支持都很弱。在筑巢期和融雪时期总降水量的影响在群落和物种水平上共享混合的支持，但通常表明在干燥和融雪较早的季节之后丰度更高。总之，我们在不同时间尺度上对气候变量的不利影响的发现对理解亚北极pass鱼中的种群和分布变化的机制具有重要意义。