Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA.
Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA.
Glob Chang Biol. 2017 Apr;23(4):1436-1447. doi: 10.1111/gcb.13550. Epub 2016 Nov 21.
Biological effects of climate change are expected to vary geographically, with a strong signature of latitude. For ectothermic animals, there is systematic latitudinal variation in the relationship between climate and thermal performance curves, which describe the relationship between temperature and an organism's fitness. Here, we ask whether these documented latitudinal patterns can be generalized to predict arthropod responses to warming across mid- and high temperate latitudes, for taxa whose thermal physiology has not been measured. To address this question, we used a novel natural experiment consisting of a series of urban warming gradients at different latitudes. Specifically, we sampled arthropods from a single common street tree species across temperature gradients in four US cities, located from 35.8 to 42.4° latitude. We captured 6746 arthropods in 34 families from 111 sites that varied in summer average temperature by 1.7-3.4 °C within each city. Arthropod responses to warming within each city were characterized as Poisson regression coefficients describing change in abundance per °C for each family. Family responses in the two midlatitude cities were heterogeneous, including significantly negative and positive effects, while those in high-latitude cities varied no more than expected by chance within each city. We expected high-latitude taxa to increase in abundance with warming, and they did so in one of the two high-latitude cities; in the other, Queens (New York City), most taxa declined with warming, perhaps due to habitat loss that was correlated with warming in this city. With the exception of Queens, patterns of family responses to warming were consistent with predictions based on known latitudinal patterns in arthropod physiology relative to regional climate. Heterogeneous responses in midlatitudes may be ecologically disruptive if interacting taxa respond oppositely to warming.
气候变化的生物效应预计在地域上有所不同，与纬度有很强的关联性。对于变温动物，气候与热性能曲线之间存在系统的纬度变化，热性能曲线描述了温度与生物体适应性之间的关系。在这里，我们询问这些记录的纬度模式是否可以推广到预测中高纬度地区节肢动物对变暖的反应，对于那些其热生理学尚未被测量的类群。为了解决这个问题，我们使用了一个新的自然实验，该实验由一系列不同纬度的城市变暖梯度组成。具体来说，我们在四个美国城市的单一常见街道树种上采样了节肢动物，这些城市的纬度从 35.8 到 42.4°不等。我们在每个城市内的 111 个地点捕获了来自 34 个科的 6746 只节肢动物，这些地点的夏季平均温度在每个城市内相差 1.7-3.4°C。我们用泊松回归系数来描述每个科在每个城市内每增加 1°C时数量的变化，来描述节肢动物对变暖的反应。两个中纬度城市中家族的反应是异构的，包括显著的正和负效应，而高纬度城市的反应在每个城市内变化不超过随机变化。我们预计高纬度类群的数量会随着变暖而增加，这种情况确实发生在两个高纬度城市中的一个城市；而在另一个城市皇后区（纽约市），大多数类群随着变暖而减少，这可能是由于与这个城市变暖相关的栖息地丧失所致。除了皇后区之外，家族对变暖的反应模式与基于节肢动物生理学与区域气候的已知纬度模式的预测一致。如果相互作用的类群对变暖的反应相反，那么中纬度的异质反应可能会对生态系统造成破坏。
