Centre of New Technologies, University of Warsaw, 02-097, Warsaw, Poland.
Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
Sci Rep. 2021 Oct 4;11(1):19662. doi: 10.1038/s41598-021-99329-2.
While there are increasing examples of phenotypic and genotypic differences between urban and non-urban populations of plants and animals, few studies identified the mechanisms explaining those dissimilarities. The characterization of the urban landscape, which can only be achieved by measuring variability in relevant environmental factors within and between cities, is a keystone prerequisite to understand the effects of urbanization on wildlife. Here, we measured variation in bird exposure to metal pollution within 8 replicated urbanization gradients and within 2 flagship bird species in urban evolutionary ecology: the blue tit (Cyanistes caeruleus) and the great tit (Parus major). We report on a highly significant, positive linear relationship between the magnitude of urbanization-inferred as either tree cover, impervious surface cover, or an urbanization score computed from several environmental variables, and copper, zinc and lead concentrations in bird feathers. The reverse relationship was measured in the case of mercury, while cadmium and arsenic did not vary in response to the urbanization level. This result, replicated across multiple cities and two passerine species, strongly suggests that copper, zinc, lead and mercury pollution is likely to trigger the emergence of parallel responses at the phenotypic and/or genotypic level between urban environments worldwide.
虽然越来越多的例子表明，植物和动物的城市和非城市种群之间存在表型和基因型差异，但很少有研究确定解释这些差异的机制。只有通过测量城市内部和城市之间相关环境因素的变异性，才能对城市景观进行特征描述，这是理解城市化对野生动物影响的关键前提。在这里，我们在 8 个重复的城市化梯度内和城市进化生态学中的 2 个旗舰鸟类物种（蓝山雀（Cyanistes caeruleus）和大山雀（Parus major））中测量了鸟类暴露于金属污染的差异。我们报告了一个非常显著的线性关系，即城市化程度（以树木覆盖率、不透水表面覆盖率或从多个环境变量计算得出的城市化得分来表示）与鸟类羽毛中的铜、锌和铅浓度呈正相关。在汞的情况下测量到了相反的关系，而在镉和砷的情况下，其浓度并没有随着城市化水平的变化而变化。这一结果在多个城市和两种雀形目物种中得到了重复验证，强烈表明，铜、锌、铅和汞污染很可能在全球范围内的城市环境中引发表型和/或基因型层面的平行反应。
