Plant Biology Department, University of Georgia, Athens, Georgia, 30606, USA.
Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, 97403, USA.
Ecol Appl. 2021 Mar;31(2):e2242. doi: 10.1002/eap.2242. Epub 2021 Jan 18.
Spatial gradients in population growth, such as across latitudinal or elevational gradients, are often assumed to primarily be driven by variation in climate, and are frequently used to infer species' responses to climate change. Here, we use a novel demographic, mixed-model approach to dissect the contributions of climate variables vs. other latitudinal or local site effects on spatiotemporal variation in population performance in three perennial bunchgrasses. For all three species, we find that performance of local populations decreases with warmer and drier conditions, despite latitudinal trends of decreasing population growth toward the cooler and wetter northern portion of each species' range. Thus, latitudinal gradients in performance are not predictive of either local or species-wide responses to climate. This pattern could be common, as many environmental drivers, such as habitat quality or species' interactions, are likely to vary with latitude or elevation, and thus influence or oppose climate responses.
种群增长的空间梯度，如跨越纬度或海拔梯度的梯度，通常被认为主要是由气候的变化驱动的，并经常被用来推断物种对气候变化的反应。在这里，我们使用一种新颖的人口统计学、混合模型方法来剖析气候变量与其他纬度或当地地点效应对三种多年生丛生草种群表现的时空变化的贡献。对于所有三种物种，我们发现尽管种群生长的纬度趋势是向更凉爽和潮湿的北部地区减少，但当地种群的表现随着温暖和干燥条件的变化而下降。因此，性能的纬度梯度不能预测对气候的局部或种间响应。这种模式可能很常见，因为许多环境驱动因素，如栖息地质量或物种相互作用，可能随纬度或海拔而变化，从而影响或反对气候响应。
