Zhao Yanyan, Liu Yu, Scordato Elizabeth S C, Lee Myung-Bok, Xing Xiaoying, Pan Xinyuan, Liu Yang, Safran Rebecca J, Pagani-Núñez Emilio
State Key Laboratory of Biocontrol School of Life Sciences/School of Ecology Sun Yat-sen University Guangzhou China.
College of Life Sciences Beijing Normal University Beijing China.
Ecol Evol. 2020 Dec 19;11(1):612-625. doi: 10.1002/ece3.7088. eCollection 2021 Jan.
Urbanization implies a dramatic impact on ecosystems, which may lead to drastic phenotypic differences between urban and nonurban individuals. For instance, urbanization is associated with increased metabolic costs, which may constrain body size, but urbanization also leads to habitat fragmentation, which may favor increases in body mass when for instance it correlates with dispersal capacity. However, this apparent contradiction has rarely been studied. This is particularly evident in China where the urbanization process is currently occurring at an unprecedented scale. Moreover, no study has addressed this issue across large geographical areas encompassing locations in different climates. In this regard, Barn Swallows () are a suitable model to study the impact of urbanization on wild animals because they are a widely distributed species tightly associated with humans. Here, we collected body mass and wing length data for 359 breeding individuals of Barn Swallow () from 128 sites showing different levels of urbanization around the whole China. Using a set of linear mixed-effects models, we assessed how urbanization and geography influenced body size measured using body mass, wing length, and their regression residuals. Interestingly, we found that the impact of urbanization was sex-dependent, negatively affecting males' body mass, its regression residuals, and females' wing length. We also found that northern and western individuals were larger, regarding both body mass and wing length, than southern and eastern individuals. Females were heavier than males, yet males had slightly longer wings than females. Overall, our results showed that body mass of males was particularly sensitive trait to urbanization, latitude, and longitude, while it only showed a weak response to latitude in females. Conversely, while wing length showed a similar geographical pattern, it was only affected by urbanization in the case of females. Further research is needed to determine whether these phenotypic differences are associated with negative effects of urbanization or potential selective advantages.
城市化对生态系统具有巨大影响，这可能导致城市个体与非城市个体之间出现显著的表型差异。例如，城市化与代谢成本增加相关，这可能限制体型大小，但城市化也会导致栖息地破碎化，例如当它与扩散能力相关时，可能有利于体重增加。然而，这种明显的矛盾很少被研究。这在中国尤为明显，目前城市化进程正以前所未有的规模进行。此外，尚无研究在涵盖不同气候地区的大地理区域内探讨这一问题。在这方面，家燕是研究城市化对野生动物影响的合适模型，因为它们是广泛分布且与人类紧密相关的物种。在这里，我们收集了来自中国各地128个不同城市化水平地点的359只家燕繁殖个体的体重和翅长数据。使用一组线性混合效应模型，我们评估了城市化和地理因素如何影响用体重、翅长及其回归残差衡量的体型大小。有趣的是，我们发现城市化的影响存在性别差异，对雄性个体的体重、其回归残差以及雌性个体的翅长有负面影响。我们还发现，就体重和翅长而言，北方和西方的个体比南方和东方的个体更大。雌性比雄性重，但雄性的翅膀比雌性略长。总体而言，我们的结果表明，雄性个体的体重对城市化、纬度和经度特别敏感，而雌性个体仅对纬度有微弱反应。相反，虽然翅长呈现出类似的地理模式，但仅在雌性个体中受城市化影响。需要进一步研究来确定这些表型差异是否与城市化的负面影响或潜在的选择优势相关。
