Responses to climate change can vary across functional groups and trophic levels, leading to a temporal decoupling of trophic interactions or “phenological mismatches.” Despite a growing number of single‐species studies that identified phenological mismatches as a nearly universal consequence of climate change, we have a limited understanding of the spatial variation in the intensity of this phenomenon and what influences this variation. In this study, we tested for geographic patterns in phenological mismatches between six species of shorebirds and their invertebrate prey at 10 sites spread across ~13° latitude and ~84° longitude in the Arctic over three years. At each site, we quantified the phenological mismatch between shorebirds and their invertebrate prey at (1) an individual‐nest level, as the difference in days between the seasonal peak in food and the peak demand by chicks, and (2) a population level, as the overlapped area under fitted curves for total daily biomass of invertebrates and dates of the peak demand by chicks. We tested whether the intensity of past climatic change observed at each site corresponded with the extent of phenological mismatch and used structural equation modeling to test for causal relationships among (1) environmental factors, including geographic location and current climatic conditions, (2) the timing of invertebrate emergence and the breeding phenology of shorebirds, and (3) the phenological mismatch between the two trophic levels. The extent of phenological mismatch varied more among different sites than among different species within each site. A greater extent of phenological mismatch at both the individual‐nest and population levels coincided with changes in the timing of snowmelt as well as the potential dissociation of long‐term snow phenology from changes in temperature. The timing of snowmelt also affected the shape of the food and demand curves, which determined the extent of phenological mismatch at the population level. Finally, we found larger mismatches at more easterly longitudes, which may be affecting the population dynamics of shorebirds, as two of our study species show regional population declines in only the eastern part of their range. This suggests that phenological mismatches may be resulting in demographic consequences for Arctic‐nesting birds.

中文翻译：

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北极水鸟和无脊椎动物之间变暖强度和物候不匹配的地理变化

对气候变化的响应可能会因功能组和营养水平而异，从而导致营养相互作用或“物候失配”在时间上脱钩。尽管越来越多的单物种研究认为物候不匹配是气候变化的近乎普遍的后果，但我们对这种现象的强度的空间变化以及影响这种变化的因素的理解仍然有限。在这项研究中，我们测试了在三年内分布在北纬〜13°和〜84°的10个地点的6种水鸟及其无脊椎动物猎物之间的物候失配的地理模式。在每个地点，我们以（1）个个体巢的水平对level鸟及其无脊椎动物猎物之间的物候失配进行了量化，（2）人口水平，无脊椎动物的日总生物量的拟合曲线下的重叠区域和雏鸡需求高峰的日期。我们测试了在每个站点观察到的过去气候变化的强度是否与物候失配的程度相对应，并使用结构方程模型测试了以下因素之间的因果关系：（1）环境因素，包括地理位置和当前气候条件，（2）时机无脊椎动物的出现和水鸟的繁殖物候学；（3）两个营养级之间的物候失配。物候失配的程度在不同位点之间的差异大于在每个位点内的不同物种之间的差异。在个体巢和种群水平上更大程度的物候失配与融雪时间的变化以及长期积雪物候与温度变化的潜在解离相吻合。融雪的时间也影响了食物和需求曲线的形状，从而决定了人口水平上物候不匹配的程度。最后，我们发现在更东经的地方存在较大的不匹配，这可能会影响水鸟的种群动态，因为我们的两个研究物种显示区域种群仅在其范围的东部下降。这表明物候不匹配可能会导致北极嵌套鸟类的人口统计学后果。